UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, DC 20549

FORM 10-K

(Mark One)

xANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the fiscal year ended December 31, 2019

OR

o    TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the transition period from _ to _

Commission File Number: 001-38753

Moderna, Inc.

(Exact Name of Registrant as Specified in Its Charter)

Delaware	81-3467528
(State or Other Jurisdiction of Incorporation or Organization)	(IRS Employer Identification No.)
200 Technology Square Cambridge, Massachusetts	02139
(Address of Principal Executive Offices)	(Zip Code)

(617) 714-6500

(Registrant’s Telephone Number, Including Area Code)

Securities registered pursuant to Section 12(b) of the Act:

Title of each class	Trading Symbol(s)	Name of each exchange on which registered
Common stock, par value $0.0001 per share	MRNA	The Nasdaq Stock Market LLC

Securities registered pursuant to Section 12(g) of the Act: None

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Yes x No o

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act. Yes oNo x

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes xNo o

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§ 232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files). Yes x No o

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer”, “accelerated filer”, “smaller reporting company”, and “emerging growth company” in Rule 12b-2 of the Exchange Act.

Large accelerated filer x	Accelerated filer o	Non-accelerated filer o	Smaller reporting company o
			Emerging growth company o

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. o

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Act). Yes ☐ No x

As of June 30, 2019, the aggregate market value of voting and non-voting common equity held by non-affiliates of the registrant was approximately $3.38 billion based on the closing sale price on that date of $14.64. Shares of common stock held by each executive officer and director and by each other person who may be deemed to be an affiliate of the Registrant have been excluded from this computation. The determination of affiliate status for this purpose is not necessarily a conclusive determination for other purposes.

As of February 26, 2020, there were 368,642,548 shares of the registrant’s common stock, par value $0.0001 per share, outstanding.

DOCUMENTS INCORPORATED BY REFERENCE

Portions of the registrant’s Definitive Proxy Statement relating to its 2020 Annual Meeting of Stockholders to be filed hereafter are incorporated by reference into Part III of this Annual Report on Form 10-K where indicated.

Table of Contents

PART I.		Page
Item 1.	Business	5
Item 1A.	Risk Factors	160
Item 1B.	Unresolved Staff Comments	209
Item 2.	Properties	209
Item 3.	Legal Proceedings	209
Item 4.	Mine Safety Disclosures	209
PART II.
Item 5.	Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities	210
Item 6.	Selected Consolidated Financial Data	211
Item 7.	Management’s Discussion and Analysis of Financial Condition and Results of Operations	213
Item 7A.	Quantitative and Qualitative Disclosures about Market Risk	228
Item 8.	Financial Statements and Supplementary Data	229
Item 9.	Changes in and Disagreements with Accountants on Accounting and Financial Disclosure	287
Item 9A.	Controls and Procedures	287
Item 9B.	Other Information	289
PART III.
Item 10.	Directors, Executive Officers and Corporate Governance	290
Item 11.	Executive Compensation	290
Item 12.	Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters	290
Item 13.	Certain Relationships and Related Transactions, and Director Independence	290
Item 14.	Principal Accountant Fees and Services	290
PART IV.
Item 15.	Exhibits, Financial Statement Schedules	291
Item 16.	Form 10-K Summary	293
Signatures

SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

This Annual Report on Form 10-K, including the sections entitled “Business,” “Risk Factors,” and “Management’s Discussion and Analysis of Financial Condition and Results of Operations,” contains express or implied forward-looking statements within the

meaning of the federal securities laws, Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. We intend these forward-looking statements to be covered by the safe harbor provisions for forward-looking statements contained in the Private Securities Litigation Reform Act of 1995 and are including this statement for purposes of complying with those safe harbor provisions. All statements other than statements of historical facts contained in this Annual Report are forward-looking statements. These forward-looking statements are based on our management’s belief and assumptions and on information currently available to our management. Although we believe that the expectations reflected in these forward-looking statements are reasonable, these statements relate to future events or our future operational or financial performance, and involve known and unknown risks, uncertainties, and other factors that may cause our actual results, performance, or achievements to be materially different from any future results, performance, or achievements expressed or implied by these forward-looking statements. Forward-looking statements in this Annual Report on Form 10-K include, but are not limited to, statements about:

• the initiation, timing, progress, results, and cost of our research and development programs and our current and future preclinical studies and clinical trials, including statements regarding the timing of initiation and completion of studies or trials and related preparatory work, the period during which the results of the trials will become available, and our research and development programs;

• our anticipated next steps for our development candidates and investigational medicines;

• our ability to identify research priorities and apply a risk-mitigated strategy to efficiently discover and develop development candidates and investigational medicines, including by applying learnings from one program to our other programs and from one modality to our other modalities;

• our ability and the potential to successfully manufacture our drug substances, delivery vehicles, development candidates, and investigational medicines for preclinical use, for clinical trials and on a larger scale for commercial use, if approved;

• the ability and willingness of our third-party strategic collaborators to continue research and development activities relating to our development candidates and investigational medicines;

• our ability to obtain funding for our operations necessary to complete further development and commercialization of our investigational medicines;

• our ability to obtain and maintain regulatory approval of our investigational medicines;

• our ability to commercialize our products, if approved;

• the pricing and reimbursement of our investigational medicines, if approved;

• the implementation of our business model, and strategic plans for our business, investigational medicines, and technology;

• the scope of protection we are able to establish and maintain for intellectual property rights covering our investigational medicines and technology;

• estimates of our future expenses, revenues, capital requirements, and our needs for additional financing;

• the potential benefits of strategic collaboration agreements, our ability to enter into strategic collaborations or arrangements, and our ability to attract collaborators with development, regulatory, and commercialization expertise;

• future agreements with third parties in connection with the commercialization of our investigational medicines, if approved;

• the size and growth potential of the markets for our investigational medicines, and our ability to serve those markets;

• our financial performance;

• the rate and degree of market acceptance of our investigational medicines;

• regulatory developments in the United States and foreign countries;

• our ability to contract with third-party suppliers and manufacturers and their ability to perform adequately;

• our ability to produce our products or investigational medicines with advantages in turnaround times or manufacturing cost;

• the success of competing therapies that are or may become available;

• our ability to attract and retain key scientific or management personnel;

• the impact of laws and regulations;

• developments relating to our competitors and our industry; and

• other risks and uncertainties, including those listed under the caption “Risk Factors.” 

In some cases, forward-looking statements can be identified by terminology such as “may,” “should,” “expects,” “intends,” “plans,” “anticipates,” “believes,” “estimates,” “predicts,” “potential,” “continue,” or the negative of these terms or other comparable terminology. The risks set forth above are not exhaustive. Other sections of this report may include additional factors that could adversely affect our business and financial performance. Moreover, we operate in a very competitive and rapidly changing environment. New risk factors emerge from time to time and it is not possible for management to predict all risk factors, nor can we assess the impact of all risk factors on our business or the extent to which any factor, or combination of factors, may cause actual results to differ materially from those contained in any forward-looking statements. These statements are only predictions. You should not place undue reliance on forward-looking statements because they involve known and unknown risks, uncertainties, and other factors, which are, in some cases, beyond our control and which could materially affect results. Factors that may cause actual results to differ materially from current expectations include, among other things, those listed under the section entitled “Risk Factors” and elsewhere in this Annual Report on Form 10-K. If one or more of these risks or uncertainties occur, or if our underlying assumptions prove to be incorrect, actual events or results may vary significantly from those expressed or implied by the forward-looking statements. No forward-looking statement is a guarantee of future performance.

The forward-looking statements in this Annual Report on Form 10-K represent our views as of the date of this Annual Report on Form 10-K. We anticipate that subsequent events and developments will cause our views to change. However, while we may elect to update these forward-looking statements at some point in the future, we have no current intention of doing so except to the extent required by applicable law. You should therefore not rely on these forward-looking statements as representing our views as of any date subsequent to the date of this Annual Report on Form 10-K.

This Annual Report on Form 10-K includes statistical and other industry and market data that we obtained from industry publications and research, surveys, and studies conducted by third parties. Industry publications and third-party research, surveys, and studies generally indicate that their information has been obtained from sources believed to be reliable, although they do not guarantee the accuracy or completeness of such information. We have not independently verified the information contained in such sources.

NOTE REGARDING COMPANY REFERENCES

Unless the context otherwise requires, the terms “Moderna,” “the Company,” “we,” “us,” and “our” in this Annual Report on Form 10-K refer to Moderna, Inc. and its consolidated subsidiaries.

Table of Contents

PART I

Item 1. Business

THE mRNA OPPORTUNITY

mRNA, the software of life

Messenger RNA, or mRNA, transfers the information stored in our genes to the cellular machinery that makes all the proteins required for life. Our genes are stored as sequences of DNA which contain the instructions to make specific proteins. DNA serves as a hard drive, safely storing these instructions in the nucleus until they are needed by the cell.

When a cell needs to produce a protein, the instructions to make that protein are copied from the DNA to mRNA, which serves as the template for protein production. Each mRNA molecule contains the instructions to produce a specific protein with a distinct function in the body. mRNA transmits those instructions to cellular machinery, called ribosomes, that make copies of the required protein.

We see mRNA functioning as the “software of life.” Every cell uses mRNA to provide real time instructions to make the proteins necessary to drive all aspects of biology, including in human health and disease. This was codified as the central dogma of molecular biology over 50 years ago, and is exemplified in the schematic below.

mRNA is used to make every type of protein, including secreted, membrane, and intracellular proteins, in varying quantities over time, in different locations, and in various combinations. This is shown in the figure below.

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Given its essential role, we believe mRNA could be used to create a new class of medicines with significant potential to improve the lives of patients. Over the last 40 years, the biotechnology industry has created a new category of drugs based on recombinant protein technology. These drugs rely on secreted proteins, including antibodies and protein replacements, to treat a wide range of diseases. This category of drugs accounts for over $200 billion in annual worldwide sales. However, intracellular and membrane proteins represent as much as two-thirds of the proteins in humans, and are largely beyond the reach of recombinant protein technology. Based on the ability of mRNA to produce these proteins directly in cells, we believe that mRNA-based medicines have the potential to help patients in ways that could equal or exceed the impact of recombinant protein-based drugs.

The structure of mRNA

Messenger RNA is a linear polymer comprising four monomers called nucleotides: adenosine (A), guanosine (G), cytosine (C), and uridine (U). Within the region of the molecule that codes for a protein, or the coding region, the sequence of these four nucleotides forms a language made up of three-letter words called codons. The first codon, or start codon (AUG), signals where the ribosome should start protein synthesis. To know what protein to make, the ribosome then progresses along the mRNA one codon at a time, appending the appropriate amino acid to the growing protein. To end protein synthesis, three different codons (UAA, UAG, and UGA) serve as stop signals, telling the ribosome where to terminate protein synthesis. In total, there are 64 potential codons, but only 20 amino acids that are used to build proteins; therefore multiple codons can encode for the same amino acid.

The process of protein production is called translation because the ribosome is reading in one language (a sequence of codons) and outputting in another language (a sequence of amino acids). As shown in the figure below, the coding region is analogous to a sentence in English. Much like a start codon, a capitalized word can indicate the start of a sentence. Codons within the coding region resemble groups of letters representing words. The end of the sentence is signaled by a period in English, or a stop codon for mRNA.

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The intrinsic advantages of using mRNA as a medicine

We believe mRNA possesses inherent characteristics that could serve as the foundation for a new class of medicines. These characteristics include:

1. mRNA is used by every cell to produce all proteins: Cells in the human body use mRNA to make all types of proteins, including secreted, membrane, and intracellular proteins. mRNA is used by cells to vary the quantities of protein produced over time, in different locations, and in various combinations. Given the universal role of mRNA in protein production, we believe that mRNA medicines could have broad applicability across human disease.

2. Making proteins inside one’s own cells mimics human biology: Using a person’s own cells to produce protein therapeutics or vaccine antigens could create advantages over existing technologies such as recombinant proteins, which are manufactured using processes that are foreign to the human body. These advantages include the ability to:

• use multiple mRNAs to produce multiple proteins;

• reduce or eliminate immunogenicity;

• create multi-protein complexes;

• produce therapeutic or vaccine proteins locally;

• harness native protein folding and glycosylation; and

• make proteins that are unstable outside the body.

3. mRNA has a simple and flexible chemical structure: Each mRNA molecule comprises four chemically similar nucleotides to encode proteins made from up to 20 chemically different amino acids. To make the full diversity of possible proteins, only simple sequence changes are required in mRNA. A vast number of potential mRNA medicines can be developed, therefore, with only minor changes to the underlying chemical structure of the molecule or manufacturing processes, a significant advantage over small molecule or protein therapeutics.

4. mRNA has the potential for classic pharmacologic features: The intrinsic properties of mRNA translate into attractive pharmacologic features, including:

• each mRNA encodes for a specific protein and no other protein;

• each mRNA molecule can produce many copies of a protein in the cell before being degraded;

• increasing mRNA levels in a cell generally leads to increasing protein levels; and

• the effects of mRNA in a cell can be transient and limits risk of irreversible changes to the cell’s DNA.

As a result, mRNA could have many of the attractive pharmacologic features of most modern medicines, including reproducible activity, predictable potency, and well-behaved dose dependency; and the ability to adjust dosing based on an individual patient’s needs, including stopping or lowering the dose, to seek to ensure safety and tolerability.

mRNA as a new class of medicines

Based on these and other features, we have developed four core beliefs about the value drivers of mRNA as a new class of medicines:

1. mRNA has the potential to create an unprecedented abundance and diversity of medicines. mRNA medicines could be used to provide patients or healthy individuals with any therapeutic protein or vaccine, including those targeting intracellular and membrane proteins. This breadth of applicability has the potential to create an extraordinary number of new mRNA-based medicines that are currently beyond the reach of recombinant protein technology.

2. Advances in the development of our mRNA medicines can reduce risks across our portfolio. mRNA medicines share fundamental features that can be used to learn quickly across a portfolio. We believe that once safety and proof of protein production has been established in one program, the technology and biology risks of related programs that use similar mRNA technologies, delivery technologies, and manufacturing processes will decrease significantly.

3. mRNA technology can accelerate discovery and development. The software-like features of mRNA enable rapid in silico design and the use of automated high-throughput synthesis processes that permit discovery to proceed in parallel rather than sequentially. We believe these mRNA features can also accelerate drug development by allowing the use of shared manufacturing processes and infrastructure.

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4. The ability to leverage shared processes and infrastructure can drive significant capital efficiency over time. We believe the manufacturing requirements of different mRNA medicines are dramatically more similar than traditional recombinant protein-based drugs across a similarly diverse pipeline. When manufacturing at commercial scale, we believe mRNA medicines will benefit from shared capital expenditures, resulting in lower program-specific capital needs and an advantageous variable cost profile.

Recombinant protein-based drugs significantly advanced patient care and transformed the biopharmaceutical industry. We believe that the development of mRNA as a new class of medicines could represent another breakthrough for patients and our industry.

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OUR STRATEGIC PRINCIPLES AND APPROACH TO MANAGING RISK

Our strategy is designed to deliver on the full scope of the mRNA opportunity over the long-term. Reaching patients with mRNA medicines requires us to make complex choices, including: how much capital we devote to technology creation, drug discovery, drug development, and infrastructure; which programs we advance and how; whether we advance programs alone or with strategic collaborators; and which capabilities we build internally versus outsource.

To navigate these choices, we established five strategic principles that guide our approach to creating long-term value for patients and investors. No single strategic principle dominates our choices. Embedded in every decision we make is also our assessment of the most important risks inherent in our business. We believe these risks fall into four categories: technology, biology, execution, and financing.

To increase our chances of success, we often find it necessary to balance our near-to-mid-term risks against the strategic principles that guide our approach to long-term value creation.

Our strategic principles

1. We seek to discover and develop a large pipeline in parallel. Our goal is to address or prevent as many human diseases as our technology, talent, capital, and other resources permit. We do so as rapidly as we can, understanding both the urgency for patients and the need to be disciplined in our approach. We have a diverse pipeline of 24 development candidates, 12 of which are currently in clinical trials, and many of which have the potential to be first-in-class or best-in-class medicines.

2. We undertake sustained, long-term investment in technology creation. We aim to improve the performance of mRNA medicines in our current modalities, and to unlock new modalities, through investments within basic and applied science. We are committed to remaining at the forefront of mRNA science, which we believe will take many more years to fully mature.

3. We focus on the pace and scale of our learning. We believe that time is a critical resource. We seek to accelerate our progress by solving numerous technical problems in parallel rather than in sequence. Our scientists pursue experiments based on how much we can learn from the results, not just the probability of a positive outcome. We believe negative information is valuable and we can learn from our setbacks. We make significant investments in digital assets and research infrastructure to accelerate the pace and scale of our learning.

4. We integrate across the most critical parts of our value chain. mRNA is a complex multicomponent system and we believe it demands integration. We believe that we must be directly engaged in research, drug discovery, drug development, process and analytical development, and manufacturing to accelerate our learning, reduce our risk, and protect our critical know-how. Where appropriate, we seek out strategic collaborators that can augment our capabilities or expand our capacity in specific therapeutic areas, while being careful to resist the fragmentation of our core technology.

5. We forward invest in core enabling capabilities and infrastructure. To execute across a broad pipeline, we need to invest at risk before we have all the answers. Our forward investments focus on areas where lead times are long and where early investments can reduce execution risk and accelerate future progress. We proactively decided to invest in a dedicated manufacturing facility, Moderna Technology Center (“MTC”), in Norwood, MA, to support the anticipated growth of our pipeline.

Our approach to managing risk

In conjunction with the strategic principles that guide our approach to long-term value creation, we actively manage the risks inherent in our business. At present, these categories of risk include: technology, biology, execution, and financing. We summarize our approach to managing these risks below:

1. Technology risk encompasses the challenges of developing the product features of mRNA medicines, including delivery, controlling interactions with the immune system, optimizing therapeutic index, and manufacturing. We believe the best way to mitigate technology risk is to sustain long-term investments in our platform. In addition, we diversify our technology risk by compartmentalizing our pipeline into groups of programs with shared product features, which we call modalities. Lastly, we stage program development within a modality, leveraging the first program, whether successful or not, to generate insights that accelerate and reduce the risk of subsequent programs within the modality.

2. Biology risk entails the risk unique to each program based on its mechanism of action and of clinical development in the target patient population. We believe the best way to manage biology risk is to diversify it by pursuing multiple programs in parallel. In addition, within a modality we seek to initially pursue programs with well-understood biology. Lastly, we may seek strategic collaborators to share risk and upside in disease areas with high inherent biology risk, such as cancer and heart disease.

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3. Execution risk refers to the challenge of executing against the scale of our mission. We solve for this risk by seeking to hire the right people, the best talent in the industry. We seek to foster a culture of execution with a focus on quick review cycles and high velocity decision-making. We make forward investments in infrastructure, including manufacturing. Lastly, we have created a digital backbone to track all aspects of our programs and anticipate challenges before they arise.

4. Financing risk refers to our ability to access the capital required to fund the current breadth of our endeavor, as well as new opportunities. We manage this risk by attempting to maintain a strong balance sheet with several years of cash runway. As of December 31, 2019, we had cash, cash equivalents, and investments of $1.3 billion. During 2019, cash used in operations and for purchases of property and equipment was $459.0 million and $31.6 million in 2019, respectively. Lastly, we may continue to pursue strategic alliances, which provide resources and another source of funding.

There is no single strategic principle nor single category of risk that dominates our decision-making, and universal rules do not exist across our portfolio. Our trade-offs generally involve balancing near-term risks and long-term value creation. Because development cycles are long, our choices are complex. We expect the weighting and types of risk we face will evolve as our business matures. We believe that disciplined capital allocation across near- and long-term choices must be a core competency if we are to maximize the opportunity for patient impact and shareholder value creation.

Our progress

We are encouraged by our results to date. Across the six modalities that we have established, we have 23 programs in development, and manufactured dozens of drug substance lots for use in IND-enabling Good Laboratory Practice, or GLP, toxicology studies. “IND-enabling” refers to studies required for Investigational New Drug Application, or IND, or equivalent non-U.S. regulatory filings, such as a Clinical Trial Application, or CTA. We and our strategic collaborators have completed IND-enabling GLP toxicology programs to support our open INDs and/or CTAs for our development candidates, manufactured dozens of current good manufacturing practice, or cGMP, batches of clinical trial materials, and have 12 programs in clinical trials and another one with an open IND. Over 1,500 subjects have been enrolled in our clinical trials. To fund these activities, we have raised over $3.2 billion as of December 31, 2019, including $2.4 billion from equity issuances and $0.8 billion in upfront payments, milestone payments, and option exercise fees from strategic collaborators.

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OUR PLATFORM

Overview of our platform

Our “platform” refers to our accumulated knowledge and capabilities in basic and applied sciences across mRNA, the delivery of mRNA to target tissues, and the manufacturing processes for making potential mRNA medicines. We invest in basic science to discover foundational mechanistic insights, and we invest in applied sciences to invent technology that harnesses those insights. We use our platform to identify and develop new mRNA medicines. When we identify a combination of platform technologies or programs across mRNA technologies, delivery technologies, and manufacturing processes that can enable shared product features across multiple potential mRNA medicines, we group those programs as a modality. The primary goal of our platform is to identify new modalities and to expand the utility of our existing modalities. We are committed to advancing the technological frontier of mRNA medicines over the long term.

We define success in our platform as achieving the following pharmacologic properties:

• predictable dose response;

• reproducible pharmacology, including upon repeat dosing;

• therapeutic potency, through achieving the intended pharmacologic activity in the target tissue;

• safety and tolerability; and

• scalability for development.

Achieving any of these pharmacologic properties requires many, often interdependent, technological solutions. We organize our efforts into three core scientific areas: mRNA, delivery, and manufacturing process as shown in the figure below:

We pursue mRNA science both to minimize undesirable activation of the immune system by mRNA and to maximize the mRNA potency of mRNA once inside target cells. We pursue delivery science to protect mRNA from extracellular enzymes that would degrade it, to avoid counterproductive interactions of our delivery vehicles with the immune system, deliver mRNA to desired tissues, and facilitate mRNA transport across cell membranes to the translational machinery within cells. Finally, we have learned that the methods for producing mRNA and lipid nanoparticle, or LNP, delivery systems can have profound positive and negative effects on pharmacology. We pursue process science to optimize these features for our future medicines and to develop technical capabilities to scale our potential mRNA medicines for clinical development.

We have incurred over $500.0 million of expense to advance our platform technology and our intellectual property. This investment has underpinned the creation of all six of our existing modalities and helped us to establish fundamental intellectual property. We intend to sustain our investment in our platform in the future because we believe we can establish new modalities and continue to make meaningful improvements in the performance of our current modalities.

The success of our current platform and the current pipeline of over 20 programs that it underpins depends on hundreds of small advances in our three core scientific areas. Examples of many critical advances that we have made are described below. These advances demonstrate our significant progress to date, and exemplify our approach to tackling hundreds of smaller scientific problems and organizing them into technological solutions.

Our platform: mRNA science

An overview of mRNA biology

Messenger RNA is a linear polymer comprised of four monomers called nucleotides: adenosine (A), guanosine (G), cytosine (C), and uridine (U). Within the region of the mRNA molecule that serves as instructions for protein synthesis, the coding region, the exact sequence of these four nucleotides forms a language made up of three-letter words called codons. One codon, the start codon (AUG), serves to signal where the ribosome should start protein synthesis. To know what protein to make, the ribosome then progresses along the mRNA one codon at a time, appending the appropriate amino acid to the growing protein chain. Because the ribosome is reading in one language (a sequence of codons) and outputting in another language (a sequence of amino acids), this process is called translation. Finally, three different codons (UAA, UAG, and UGA) can serve as stop signals, telling the ribosome where to terminate protein synthesis. The production of proteins from mRNA sequences is called translation and is used to make all human proteins. The production of mRNA from DNA is called transcription.

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As shown in the figure below, the coding region in an mRNA molecule is analogous to a sentence in English. The start codon indicates the start of the protein, much like a capitalized word can indicate the start of a sentence. Codons within the coding region resemble groups of letters representing words. The end of the sentence is signaled by a period in English, or a stop codon for mRNA.

In every cell, hundreds of thousands of mRNAs make hundreds of millions of proteins every day. A typical protein contains 200-600 amino acids; therefore a typical mRNA coding region ranges from 600-1,800 nucleotides.

In addition to the coding region, mRNAs contain four other key features: (1) the 5’ untranslated region or 5’-UTR; (2) the 3’ untranslated region or 3’-UTR; (3) the 5’ cap; and (4) a 3’ polyadenosine, or poly-A, tail. The sequence of nucleotides in the 5’-UTR influences how efficiently the ribosome initiates protein synthesis, whereas the sequence of nucleotides in the 3’-UTR contains information about which cell types should translate that mRNA and how long the mRNA should last. The 5’ cap and 3’ poly-A tail enhance ribosome engagement and protect the mRNA from attack by intracellular enzymes that digest mRNA from its ends.

As a result of this biology, mRNA has several key features. First, mRNA is exquisitely specific. There is a one-to-one correspondence between an mRNA molecule and the protein dictated by the coding sequence. Second, the biological effects of mRNA are amplified. Because each mRNA copy can be translated thousands of times, we believe that in some cases, a small number of mRNA copies per cell may be sufficient to induce a pharmacologic effect. Finally, mRNA is impermanent. mRNAs produce proteins for a defined and biologically-regulated period of time without risk of changing genes or cell DNA. If dosing of mRNA stops, protein production will stop and the biological effects generally can be reversed.

Decades of academic investigation have uncovered the basic mechanisms of mRNA translation. Parallel efforts have uncovered how the innate immune system determines self-mRNA versus foreign RNA from RNA-based viruses. We are grateful for the deep scientific foundation established by these pioneers. Yet as we seek to develop mRNA into medicines we often find ourselves at the frontiers of current understanding. Therefore, we invest in both applied and basic research, seeking to advance both the state of our technology and the state of the scientific community’s understanding of mRNA. Examples of advances in mRNA science that combine nucleotide chemistry, sequence engineering, and targeting elements are described below.

mRNA chemistry: Modified nucleotides to mitigate immune system activation

The innate immune system has evolved to protect cells from foreign RNA, such as viral RNA, by inducing inflammation and suppressing mRNA translation once detected. Many cells surveil their environment through sensors called toll-like-receptors, or TLRs. These include types that are activated by the presence of double-stranded RNA (TLR3) or uridine containing RNA fragments (TLR7, TLR8). Additionally, all cells have cytosolic double-stranded RNA, sensors, including retinoic acid inducible gene-I, or RIG-I that are sensitive to foreign RNA inside the cell.

The immune and cellular response to mRNA is complex, context specific, and often linked to the sensing of uridine. To minimize undesired immune responses to our potential mRNA medicines, our platform employs chemically-modified uridine nucleotides to minimize recognition by both immune cell sensors such as TLR3/7/8, and broadly-distributed cytosolic receptors such as RIG-I. mRNA produced using our synthesis technologies and containing unmodified uridine results in significant upregulation of secreted cytokines such as IP-10, as shown in the figure below. Administration of monocyte-derived macrophages, or MDMs, with unmodified mRNA formulated in LNPs results in an increased ratio of IP-10 transcripts relative to a housekeeping gene. By substituting unmodified uridine with a modified uridine, we can substantially reduce immune cell activation in this assay. The control contains

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only transfection agent and no mRNA. In multiple preclinical experiments we have demonstrated reduced immune cell activation, including of B cells, lower immunoglobulin secretion, and lower cytokine expression when administering mRNA made with modified uridine versus unmodified uridine. To date, when deploying these technologies we have yet to observe dose-limiting toxicity attributable to the mRNA encoding proteins from our drug substance even at the exaggerated doses in IND-enabling GLP toxicology programs. Importantly, in preclinical testing, our chemically-modified uridine has not significantly affected the ribosome’s ability to read and translate the mRNA sequence.

Nucleotide chemistry of mRNA reduces immune activation in vitro (in MDMs)

mRNA sequence engineering: Maximizing protein expression

mRNA exists transiently in the cytoplasm, during which time it can be translated into thousands of proteins before eventually being degraded. Our platform applies bioinformatic, biochemical, and biological screening capabilities, most of which have been invented internally that aim to optimize the amount of protein produced per mRNA. We have identified proprietary sequences for the 5’-UTR that have been observed to increase the likelihood that a ribosome bound to the 5’-end of the mRNA transcript will find the desired start codon and reliably initiate translation of the coding region.

We additionally design the nucleotide sequence of the coding region to maximize its successful translation into protein. As previously described, there are often multiple codons that encode for a specific amino acid. The amount of protein produced by an mRNA sequence is known to be partly determined by the codons it uses, with certain codons being more or less common in endogenous mRNAs. We have found that the amount of protein produced is also determined by the secondary structure of mRNA, or the propensity of mRNA to fold on itself, with more structured mRNAs producing more protein. We designed a set of sequences which independently varied codon usage and structure of the mRNA. As shown in the figure below, protein expression in the Alpha mouse liver 12, cell line is highest for sequences containing more commonly occurring codons and also more structured mRNA. Both codon usage and structure have an independent and additive effect on protein expression, shown as mean expression (solid line), as measured by fluorescence of the expressed protein, with 95% confidence interval in gray. The total expression area under the curve, or AUC, and standard error of the mean for AUC are shown for each quadrant, in relative fluorescence units per hour. By optimizing translation initiation and efficiency, we have further increased the average number of full-length desired proteins expressed per molecule mRNA. This permits us to reduce the mRNA doses required to achieve the same therapeutic benefit.

Sequences with more structure and more common codons in mRNA maximize protein expression in vitro

Targeting elements: Enabling tissue-targeted translation

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All nucleated cells in the body are capable of translating mRNA, resulting in pharmacologic activity in any cell in which mRNA is delivered and translated. To minimize or prevent potential off-target effects, our platform employs technologies that regulate mRNA translation in select cell types. Cells often contain short RNA sequences, called microRNAs or miRNAs, that bind to mRNA to regulate protein translation at the mRNA level. Different cell types have different concentrations of specific microRNAs, in effect giving cells a microRNA signature. microRNA binding directly to mRNA effectively silences or reduces mRNA translation and promotes mRNA degradation. We design microRNA binding sites into the 3’-UTR of our potential mRNA medicines so that if our mRNA is delivered to cells with such microRNAs, it will be minimally translated and rapidly degraded.

As an example, we have demonstrated by intratumoral administration in an animal model that an mRNA encoding a cytotoxic protein and containing a microRNA binding site can be used to selectively kill cancer cells, while protecting systemic tissues such as liver cells. In a mouse model of cancer (Hep3b subcutaneous xenograft mouse), liver enzyme levels and immunohistochemistry, or IHC, of cleaved caspase-3, indicate production of an apoptosis-inducing protein encoded by mRNA in tumor cells but not healthy liver cells when the mRNA has multiple miR-122 target sites. This is denoted as 3x122ts in the figure below; miR-122 is more prevalent in non-cancerous liver cells, but absent in the cancerous liver cells. We published this work in Nucleic Acid Therapeutics in 2018.

Tissue-targeted translation of mRNA encoding a pro-apoptotic protein

and microRNA binding sites in mouse study

Our platform: Delivery science

We focus on the delivery of our mRNA molecules to specific tissues. Our mRNA can, in specific instances, such as our VEGF therapeutic, be delivered by direct injection to a tissue in a simple saline formulation without lipid nanoparticles, or LNPs, to locally produce small amounts of pharmacologically active protein. However, the blood and interstitial fluids in humans contain significant RNA degrading enzymes that rapidly degrade any extracellular mRNA and prevent broader distribution without LNPs. Additionally, cell membranes tend to act as a significant barrier to entry of large, negatively-charged molecules such as mRNA. We have therefore invested heavily in delivery science and have developed LNP technologies, as well as alternative nanoparticle approaches to enable delivery of larger quantities of mRNA to target tissues.

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LNPs are generally composed of four components: an amino lipid, a phospholipid, cholesterol, and a pegylated-lipid, or PEG-lipid. Each component, as well as the overall composition, or mix of components, contributes to the properties of each LNP system. LNPs containing mRNA injected into the body rapidly bind proteins that can drive uptake of LNPs into cells. Once internalized in endosomes within cells, the LNPs are designed to escape the endosome and release their mRNA cargo into the cell cytoplasm, where the mRNA can be translated to make a protein and have the desired therapeutic effect. Any mRNA and LNP components that do not escape the endosome are typically delivered to lysosomes where they are degraded by the natural process of cellular digestion.

Examples of tools we developed by using our platform include proprietary LNP formulations that address the steps of mRNA delivery, including cell uptake, endosomal escape, and subsequent lipid metabolism, and for avoidance of counterproductive interactions with the immune system. Examples of delivery tools we have developed are described below.

Chemistry: Novel lipid chemistry to potentially improve safety and tolerability

We initially used LNP formulations that were based on known lipid systems, which we refer to as “legacy LNPs.” A recognized limitation of these legacy LNPs is the potential for inflammatory reactions upon single and repeat administration that can impact tolerability and therapeutic index. Our later-developed, proprietary LNP systems are therefore designed to be highly tolerated and minimize any LNP vehicle-related toxicities with repeat administration in vivo. The changes we made have included engineering amino lipids to avoid the immune system and to be rapidly biodegradable relative to prior lipids as shown in the figure below. Administered intravenously in non-human primates, at 0.2 mg/kg, our proprietary LNPs demonstrate rapid clearance of the lipid from panel A (plasma) and B (various organs 12 hours post administration).

Rapid clearance of lipid components of LNPs from plasma in non-human primate study

(y-axis in log-scale)

Panel (A)

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Rapid clearance of LNP lipid from tissue 12 hours post administration in non-human primate study

Panel (B)

Even in the case of vaccines, where one might hypothesize that LNP-induced immune stimulation could potentially increase the effectiveness of the vaccine, we have demonstrated in preclinical studies that we can maintain the desired immune response to the vaccine while reducing undesired local immune reaction, or reactogenicity, to the LNP as shown in the figure below. Representative histology sections in the muscle stained with hematoxalin and eosin two days after a single intramuscular administration in rats demonstrated less inflammation and muscle cell necrosis with our proprietary LNPs vs. legacy LNPs containing 0.1 mg of our mRNA. As exemplified in the box with the legacy LNP in panel A, necrosis and degeneration of muscle cells and inflammation were observed (dotted box). With our proprietary LNPs, inflammation (dotted box) and muscle cell necrosis were less extensive. Serum cytokine levels shown in panel B, are lower with our proprietary LNPs vs. legacy LNPs.

Vaccines with our proprietary LNPs demonstrate less inflammation and muscle cell necrosis compared to legacy LNPs in rat study

Panel (A)

Lower serum cytokines with our proprietary LNP in rat study

Panel (B)

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Composition: Proprietary LNPs enhance delivery efficiency

Our platform includes extensive in-house expertise in medicinal chemistry, which we have applied to design large libraries of novel lipids. Using these libraries in combination with our discovery biology capabilities, we have conducted high throughput screens for desired LNP properties and believe that we have made fundamental discoveries in preclinical studies about the relationships between structural motifs of lipids and LNP performance for protein expression. By screening for components and compositions that enhance the amount of mRNA delivered per cell and protein expression, we have demonstrated with intravenous administration up to a six-fold improvement in protein production over the prior state of the art for LNPs as shown in the figure below (n=3 rats, 95% CI shown).

Enhanced protein production with our proprietary LNP in rat study

Surface properties: Novel LNP design to avoid immune recognition

We have designed our proprietary LNP systems for sustained pharmacology upon repeat dosing by eliminating or altering features that activate the immune system. These are based on insights into the surface properties of LNPs. Upon repeated dosing, surface features on traditional LNPs such as amino lipids, phospholipids, and PEG-lipids, can be recognized by the immune system, leading to rapid clearance from the bloodstream, a decrease in potency upon repeat dosing, and an increase in inflammation.

Based on our insights into these mechanisms, we have engineered our LNP systems to reduce or eliminate undesirable surface features. In preclinical studies in non-human primates for our systemic therapeutic development candidates that use our novel LNP systems, we have been able to repeat dose with negligible or undetectable loss in potency, liver damage, and immune system activation.

Our platform: Manufacturing process science

We invest significantly in manufacturing process science to impart more potent features to our mRNA and LNPs, and to invent the technological capabilities necessary to manufacture our potential mRNA medicines at scales ranging from micrograms to kilograms, as well as achieve pharmaceutical properties such as solubility and shelf life. We view developing these goals of manufacturing and pharmaceutical properties as stage appropriate for each program. In some cases, this includes inventing novel analytical technologies that make it possible to connect analytical characterization of mRNA and LNPs to biological performance.

mRNA manufacturing process: Improving pharmacology

Our platform creates mRNA using a cell-free approach called in vitro transcription in which an RNA polymerase enzyme binds to and transcribes a DNA template, adding the nucleotides encoded by the DNA to the growing RNA strand. Following transcription, we employ proprietary purification techniques to ensure that our mRNA is free from undesired synthesis components and impurities that could activate the immune system in an indiscriminate manner. Applying our understanding of the basic science underlying each step in the manufacturing process, we have designed proprietary manufacturing processes to impart desirable pharmacologic features, for example increasing potency in a vaccine. Using a model antigen injected intramuscularly in mice at a 3 µg mRNA dose, the figure below shows the significant improvement in CD8 T cell response we have achieved through mRNA manufacturing process science and engineering as evidenced by Process B.

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Manufacturing process changes to tune immune response in mouse study

LNP manufacturing process: Improving pharmacology

Our platform technology includes synthetic processes to produce LNPs. Traditionally LNPs are assembled by dissolving the four molecular components, amino lipid, phospholipid, cholesterol, and PEG-lipid, in ethanol and then mixing this with mRNA in an aqueous buffer. The resulting mixture is then purified to isolate LNPs from impurities. Such impurities include molecular components that have not been incorporated into particles, un-encapsulated mRNA that could activate the immune system, and particles outside of the desired size range.

Going beyond optimization of traditional manufacturing processes, we have invested in understanding and measuring the various biochemical and physical interactions during LNP assembly and purification. We have additionally developed state-of-the-art analytical techniques necessary to characterize our LNPs and biological systems to analyze their in vitro and in vivo performance. With these insights, we have identified manufacturing process parameters that drive LNP performance, for example, the potency in a secreted therapeutic setting. These insights have allowed us to make significant improvements in the potency of our LNPs, as exemplified in the figure below. For example, expression of a secreted protein in our Relaxin program (AZD7970) demonstrates an approximate eight-fold increase in AUC and approximate six-fold increase in maximum concentration for manufacturing process Y versus manufacturing process X in rats dosed intravenously with 0.5 mg/kg mRNA.

Manufacturing process changes to enhance relaxin protein production by mRNA in rat study

Our platform progress to date

Since our inception, we have solved numerous interdependent problems related to the pharmacologic features of our potential mRNA medicines. These features are detailed and exemplified below. Please also see the section of this Annual Report on Form 10-K titled “Business—Program Descriptions” for recent clinical results for our investigational medicines, including CMV vaccine (mRNA-1647), hMPV/PIV3 vaccine (mRNA-1653), antibody against Chikungunya virus (mRNA-1944), and PCV (mRNA-4157) utilizing Moderna proprietary technology.

Dose-dependent protein expression at clinically relevant levels

We have demonstrated in preclinical studies the ability to generate consistent dose-dependent levels of protein, which is particularly important for therapeutics. A recent example is from our IND-enabling non-human primate study for our antibody against Chikungunya virus program (mRNA-1944). We demonstrated linear dose-dependence, meaning three- and ten-fold increases in the dose of mRNA led to three- and ten-fold increases in antibody as shown in the figure below. At the top dose, antibody levels reached

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16.2 ± 4.6 µg/mL (SD) following first dose (0 hours), and effectively doubled to 28.8 ± 10.0 µg/mL upon second dose (168 hours). This dose regimen also maintained antibody trough levels above 2 µg/mL for 100 days in non-human primates, a level consistent with clinically efficacious levels of many approved antibodies. All doses (0.3, 1, and 3 mg/kg) tested in non-human primates showed no dose-limiting toxicities related to mRNA-1944, and all other observations were generally reversible.

Expression of antibody against Chikungunya virus with repeat dosing of mRNA-1944 in non-human primate study

Reproducible pharmacology, including upon repeated dosing

By combining advances in mRNA, delivery, and manufacturing process science, we have demonstrated in preclinical studies sustained and reproducible pharmacology. The figure below shows a recent example in a mouse model that recapitulates metabolic defects in propionic acidemia, or PA. In this rare disease, a defect in one or both of two different subunits (PCCA and PCCB) of the mitochondrial enzyme propionyl-CoA carboxylase results in accumulation of toxic metabolites such as 2-methylcitrate, or 2MC. In mice hypomorphic for the PCCA subunit, monthly intravenous, or IV, administration of mRNAs encoding PCCA and PCCB formulated in our proprietary LNP (mRNA-3927) resulted in a significant and sustained lowering of 2MC throughout the duration of the 6-month study compared to control (luciferase) mRNA (1 mg/kg, n=6/group).

Plasma 2-methylcitrate levels with repeat dosing of PCCA+PCCB mRNA in PA mouse study

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Decreased immune activation upon repeat dosing in non-human primates

We have observed decreased immune activation with repeat dosing in non-human primates, as shown in the figure below. Panel A indicates serum concentration of human erythropoietin, or hEPO, with repeat dosing of mRNA encoding hEPO in our proprietary LNPs with weekly IV administration at 0.2 mg/kg in non-human primates. Panels B and C demonstrate comparable serum concentrations of MCP-1 (promoting immune cell recruitment to sites of inflammation) and C5b9 (indicative of innate immune activation via the complement system) with our proprietary LNP at 0.2 mg/kg weekly IV infusion in non-human primates vs. legacy LNP.

Repeat dosing with mRNA encoding for hEPO in our proprietary LNP in non-human primate study

Panel (A)

Decreased immune activation with mRNA encoding for hEPO in proprietary LNP in non-human primate study

Panel (B)	Panel (C)

In addition to this example we have completed multiple IND-enabling toxicology studies under GLP for our two systemic therapeutics modalities. For many such programs the no adverse event level was the top dose tested, generally 2 mg/kg or higher. We believe that by combining proprietary mRNA technologies, delivery technologies, and manufacturing process technologies we have significantly advanced the potential therapeutic index of our potential mRNA-based therapeutics.

Pharmacologic activity in the target tissue and cell

While some of our modalities, such as systemic secreted therapeutics, can leverage many different cell types to make therapeutic proteins, others such as systemic intracellular therapeutics, may require delivery of our mRNA into specific tissues, for instance hepatocytes in certain liver metabolic diseases. Combining our proprietary mRNA, delivery, and manufacturing process technologies we have observed on-target pharmacologic activity in hepatocytes in non-human primates. The on-target potency of this approach

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contrasts with traditional delivery technologies. In the figure below, our proprietary LNP and process result in mRNA delivery to and protein expression in liver hepatocytes in non-human primates as demonstrated with a reporter mRNA detected by in situ hybridization and a reporter protein detected by immunohistochemistry at 12 hours after IV infusion at 0.5 mg/kg.

mRNA delivery to and protein expression in hepatocytes with our proprietary LNPs in non-human primate study

Our platform’s future: Improving and expanding our modalities

We are committed to sustaining investment in our platform, both in basic science to elucidate new mechanistic insights, and in applied science to discover new technologies that harness these insights. Our platform investments have enabled six modalities to date, most of which have already led to multiple development candidates and investigational medicines in our pipeline. We believe that sustaining our investment in platform research and development will enable further improvements in the current modalities and will lead to the creation of new modalities, both of which will benefit our clinical pipeline in the years ahead.

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CREATING MODALITIES WITH SHARED PRODUCT FEATURES

Our approach to developing modalities

Within our platform, we develop technologies that enable the development of mRNA medicines for diverse applications. When we identify technologies that we believe could enable a new group of potential mRNA medicines with shared product features, we call that group a “modality.” While the programs within a modality may target diverse diseases, they share similar mRNA technologies, delivery technologies, and manufacturing processes to achieve shared product features. The programs within a modality will also generally share similar pharmacology profiles, including the desired dose response, the expected dosing regimen, the target tissue for protein expression, safety and tolerability goals, as well as pharmaceutical properties. Programs within a modality often have correlated technology risk, but because they pursue diverse diseases they often have uncorrelated biology risk. We have created six modalities to date:

• prophylactic vaccines;

• cancer vaccines;

• intratumoral immuno-oncology;

• localized regenerative therapeutics;

• systemic secreted and cell surface therapeutics; and

• systemic intracellular therapeutics.

When entering into a new modality, our approach is consistent with our strategic principles and perspectives on risk management discussed previously. The tenets of our approach are summarized below.

• We identify a first program (or programs) through which we seek to discover and develop solutions for any modality-specific technological challenges. We then leverage the learnings from this first program to the benefit of all subsequent programs in the modality.

• We seek to diversify biology risks within the modality by advancing multiple programs in parallel, against multiple diseases, following the first program.

• When we believe a strategic collaborator could significantly de-risk our early efforts in a new modality, we seek a strategic collaborator to share the risks and benefits on a specific set of early programs.

• After experience with the first program (or programs) in a modality, we seek to rapidly expand our pipeline within that modality to take full advantage of the opportunity.

Illustrating our approach: From our first modality to today

We started with prophylactic vaccines as our first modality because we believed this modality faced lower technical hurdles, relative to other areas. Our early formulations of mRNA tended to stimulate the immune system, which would present a challenge to therapeutics but was a desired feature for vaccines. In addition, many potential prophylactic vaccine antigens are well-characterized, allowing us to reduce biology risk. Lastly, the dosing regimens for vaccines require as few as one or two administrations, and generally involve relatively low doses.

For our first programs in this modality we chose our H10N8 and H7N9 pandemic influenza vaccines, each requiring expression of a single membrane protein. We chose to pursue two programs in two separate, but parallel, clinical trials to establish the flexibility of our platform.

When both programs met our goals for safety, tolerability, and pharmacology, we accelerated and expanded our vaccine pipeline to include multiple commercially meaningful and increasingly complex vaccines. These included a combination vaccine, designed to protect against two unrelated respiratory viruses, human metapneumovirus, or hMPV, and human parainfluenza 3, or PIV3, and a vaccine that combines six different mRNAs, our cytomegalovirus, or CMV, vaccine, to express a complex pentameric antigen. We also sought strategic alliances with Defense Advanced Research Projects, or DARPA, Biomedical Advanced Research Development Authority, or BARDA, and Merck & Co., or Merck, to allow us to rapidly expand our pipeline and complement our capabilities with their expertise.

Over time, we have taken on more challenging applications and technological hurdles with each successive modality, but we have also tried to build upon our prior experiences to manage risk. For example, in our cancer vaccines modality, we are now applying our technology to elicit T cell responses to potentially recognize and eradicate cancer as a logical extension of our prophylactic vaccines

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modality. Having demonstrated local expression of protein in our vaccines, we expanded into local therapeutic applications. For example, in our intra-tumoral immuno-oncology modality, we are seeking to use local expression to drive anti-cancer T cell responses by transforming tumor microenvironments. We can also use local expression to drive regenerative processes as in our Vascular Endothelial Growth Factor A, or VEGF-A program. Most recently, we have expanded into two new modalities that use systemic delivery of mRNA to encode secreted and cell surface or intracellular proteins. We have moved multiple programs in these areas into development for the treatment of diseases as varied as rare genetic disorders, preventing viral infections, or treating heart failure.

Expanding within our designated core modalities

In 2019, we believe that positive Phase 1 data from our infectious disease vaccine portfolio, including our CMV vaccine, and chikungunya antibody program reduced the risk of our prophylactic vaccines and systemic secreted and cell surface therapeutics modalities, which we have now designated core modalities. In these core modalities, our strategy is to invest in additional development candidates using our accumulated innovations in technology, our process insights and our preclinical and clinical experience. As such, we have brought five new development candidates forward in early 2020: interleukin-2 (“IL-2”), programmed death-ligand 1 (“PD-L1”), a pediatric Respiratory Syncytial Virus (“RSV”) vaccine, an Epstein-Barr Virus (“EBV”) vaccine and a SARS-CoV-2 vaccine, as part of our mission to use our technology to advance global public health. Our exploratory modalities continue to be a critical part of advancing our strategy to maximize the application of our potential mRNA medicines.

How modalities continue to build our pipeline

We believe our portfolio of modalities—each with distinct technological and biological risk profiles—allows us to maximize long-term value for patients and investors. We see our six current modalities as six distinct multi-product pipelines that represent different risk profiles and benefit from common infrastructure and a shared platform technology. We believe the high technology correlation within a modality allows us to rapidly accelerate the expansion of the pipeline in that modality based on learnings from the initial programs. We believe the lower technology correlation between modalities allows us to compartmentalize the technology risks.

We believe our ongoing investments in our platform will lead to the identification of additional new modalities in the future, and will expand the diversity of our pipeline.

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EXECUTING ON OUR BROAD PIPELINE

In order to capitalize on the breadth of the mRNA opportunity, we built a set of capabilities across the drug development value chain to enable us to efficiently execute on many pipeline programs in parallel.

mRNAs encode proteins across diverse biology using the same chemical building blocks arranged into different sequences. This lends itself to common rules when designing a new mRNA medicine and common processes for manufacturing. We have invested in scalable infrastructure, built on a digital backbone and enabled by automation to advance a large pipeline of mRNA programs in parallel.

Our capabilities and infrastructure are grouped into three basic units, or engines, that are applied at different stages of the drug development value chain, as shown in the following figure:

Our current pipeline programs utilize our Research Engine and Early Development Engine. We are starting to build the Late Stage Development and Commercial Engine to handle the further advancement of our programs. Each of these engines integrates critical internal capabilities with outsourced, flexible capacity.

Our Research Engine enables us to advance new product ideas into development candidates via our drug discovery efforts, and includes infrastructure to enable rapid supply of thousands of preclinical mRNAs for research involving in vitro and in vivo experiments in order to accelerate programs from idea to development candidate designation.

Our Early Development Engine enables progression of preclinical development candidates to investigational medicines upon IND filing or its equivalent, through early clinical trials that seek to demonstrate human proof of concept, or hPOC. This includes internal and outsourced infrastructure for IND-enabling GLP toxicology studies, the scale up and cGMP manufacture of the investigational medicine, initial regulatory submissions, and the execution of clinical trials.

Our Late Stage Development and Commercial Engine is being built to enable progress of our investigational medicines from hPOC through late-stage development to approval and eventual commercialization. Catalyzed by our progress with our CMV vaccine program toward a phase 3 clinical trial, we are establishing internal infrastructure for cGMP manufacturing of late stage development supply of products, regulatory submissions, and capabilities to execute later stage clinical trials. Commercial supply investments will be planned in the future.

All of these engines are supported and enabled by our integrated digital investments, our focus on highly talented and motivated team members, and our deep capital base.

Our digital infrastructure facilitates efficient integration and control of virtually every aspect of what we do. We design and implement digital operations to control or support complex workflows, accelerate learnings across our enterprise real-time, and provide deeper insights through analytical tools, artificial intelligence, and custom automation.

Our talented employees drive our mission across this value chain for patients and investors. Our culture also plays an invaluable role in our execution at all levels in our organization. An example of our commitment to the development of our employees is our investment in Moderna University, our extensive program of internal and external course offerings curated to meet the learning and development needs of our people.

Our capital from our investors and strategic collaborators enables the scale required to execute on our pipeline. We sought, and continue to seek, diverse funding sources. Of approximately $3.2 billion in cash we have received through December 31, 2019, $0.8 billion has been in the form of upfront payments, milestone payments, and option exercise payments from strategic collaborators, such

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as AstraZeneca and Merck, and $2.4 billion has been from equity issuances in both private and public markets to a diverse set of global investors. As of December 31, 2019, we had cash, cash equivalents, and investments of $1.3 billion.

Examples of our proprietary infrastructure

Our Drug Design Studio enables rapid design of multiple mRNAs

As our scientists create new mRNA concepts, they can design mRNAs for research and testing, within days, using our proprietary systems. We utilize the software-like property of mRNA in our proprietary, web-based Drug Design Studio. Our scientists request mRNAs for a specific protein, and the protein target is automatically converted to an initial optimized mRNA sequence. Using our Sequence Designer module, they can tailor entire mRNAs from the 5’-UTR to the coding region to the 3’-UTR based on our ever-improving proprietary learnings. The mRNA sequence is then further optimized using our proprietary bioinformatics algorithms. Our digital ordering then ensures rapid and accurate transmission of sequences to our modular synthesis robotics.

Our high throughput systems facilitate rapid synthesis of research grade mRNA

Once our scientists design mRNAs, we make them at a small scale to test them in cells or in animal models to see if our ideas will work. We integrated the Drug Design Studio mRNA sequence into a modular synthesis system comprised of custom high-throughput automation for making up to 1,000 orders of unique mRNA sequences and formulations per month with a turnaround time of a few weeks at 1-1000 mg per lot, the amounts required for testing in cells or animal models. This has accelerated our learnings by allowing us to test many different mRNAs in parallel.

Our Moderna Technology Center (“MTC”) manufacturing site in Norwood, MA provides modular and automated capacity that can scale with our pipeline

Manufacturing is strategically important to us, and we believe we need to control a significant portion of our manufacturing supply chain. We initially used an outsourced global supply chain to make our multi-component mRNA products. However, we believe that managing quality, supply, and timing in such a supply chain for cGMP material could increase our overall business risk. Accordingly, we elected in 2016 to build our own manufacturing facility. We opened our newly constructed 200,000 square foot Moderna Technology Center, or MTC, manufacturing facility in Norwood MA, in July 2018, and brought multiple cGMP suites online, thereby providing integration of our supply chain from raw materials to filled vials at a single site. We can make mRNA, lipids, key raw materials and LNPs at this site to control quality and supply, while also potentially creating new manufacturing intellectual property. In February 2019, based on our anticipated future growth, we entered into a lease agreement for additional office and laboratory space nearby as part of our MTC facility in Norwood, totaling an additional approximately 200,000 square feet. We can readily flex the capacity at our MTC facility via its modular systems to produce up to 100 cGMP lots per year. This capacity will support our current pipeline, will enable significant future pipeline expansion, and, under certain scenarios, could serve some commercial supply needs.

OVERVIEW OF OUR MODALITIES

At Moderna, we define a modality as a group of potential mRNA medicines that share similar mRNA technologies, delivery technologies, and manufacturing processes to achieve shared product features. Typically, programs within a modality will also share similar pharmacology profiles, including the desired dose response, the expected dosing regimen, the target tissue for protein expression, safety and tolerability goals, and their pharmaceutical properties. We have created six modalities to date:

• Prophylactic vaccines;

• Cancer vaccines;

• Intratumoral immuno-oncology;

• Localized regenerative therapeutics;

• Systemic secreted and cell surface therapeutics; and

• Systemic intracellular therapeutics.

We believe our portfolio of modalities, each with distinct technological and biological risk profiles, allows us to maximize long-term value for patients and investors. We see our six current modalities as six distinct multi-product pipelines that represent different risk profiles and benefit from common infrastructure and a shared technology platform. We believe the risk correlation within a modality allows us to rapidly accelerate the expansion of the pipeline in that modality based on learnings from the initial programs. We believe the lower risk correlation between modalities allows us to mitigate the risks of expanding into new areas. The cell map illustration of our pipeline in the section of this Annual Report on Form 10-K titled “Business—Our Pipeline” depicts the diversity of the biology of our pipeline across our six modalities.

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I. PROPHYLACTIC VACCINES OVERVIEW - CORE MODALITY

We designed our prophylactic vaccines modality to prevent or control infectious diseases. This modality currently includes nine development candidates, all of which are vaccines against viruses. The goal of any vaccine is to safely pre-expose the immune system to a small quantity of a protein from a pathogen, called an antigen, so that the immune system is prepared to fight the pathogen if exposed in the future, and prevent infection or disease.

Within this modality, our portfolio includes programs for both commercial and global health uses. We have strategic alliances with Merck on select commercial vaccines, and BARDA, DARPA, the National Institutes of Health, or NIH, as well as the Coalition for Epidemic Preparedness Innovations, or CEPI, on global health vaccine programs. We have accumulated several innovations in technology, have gained process insights, and built a significant set of preclinical and clinical experiences in our prophylactic vaccines modality. Based on these, we believe this modality is core to our portfolio and we have expanded this portfolio with three new development candidates in 2020.

Our pipeline is shown in two formats, with a cell map illustrating the diversity of biology addressed by our mRNA pipeline programs, and a traditional format that shows the current stages of development of our pipeline programs, in the section of this Annual Report on Form 10-K titled “Business—Our Pipeline.”

Prophylactic vaccines: Opportunity

Vaccines to prevent infectious diseases are one of the great innovations of modern medicine. In the United States alone, the Centers for Disease Control and Prevention estimates that childhood vaccinations given in the past two decades will in total prevent 322 million Americans from falling ill, 21 million hospitalizations, 732,000 deaths, $295 billion of direct costs, and $1.3 trillion in social costs. The commercial opportunity for vaccines is significant, with more than $35 billion in annual worldwide sales of vaccines, and with 16 different vaccine franchises each generating more than $500 million in annual worldwide sales in 2017. More innovative vaccines have been able to achieve pricing per regimen generally ranging from 5 to 20 times that of seasonal flu vaccines.

Prophylactic vaccines: Product features

We believe mRNA-based vaccines offer several advantages, including:

• Ability to mimic many aspects of natural viral infections. mRNA enters cells and is used to produce viral antigen proteins from within the cell that include natural, post-translational modifications. This mimics the process by which natural viral infections occur, where information from viral genomes is used to produce viral proteins from within a cell. This can potentially enhance the immune response, including improved B and T cell responses.

• Multiplexing of mRNA for more compelling product profiles. Multiple mRNAs encoding for multiple viral proteins can be included in a single vaccine, either permitting production of complex multimeric antigens that are much more difficult to achieve with traditional technologies, or producing antigens from multiple viruses at once. As an example, our CMV vaccine (mRNA-1647) contains six mRNAs, five of which encode five different proteins that combine to form a pentameric protein complex that is a potentially critical antigen for immune protection against CMV.

• Rapid discovery and advancement of mRNA programs into the clinic. Many viral antigens are known. However, with traditional vaccines, the target pathogens or antigens have to be produced in dedicated cell-cultures and/or fermentation-based manufacturing production processes in order to initiate testing of potential vaccine constructs. Our ability to design our antigens in silico allows us to rapidly produce and test antigens in preclinical models, which can dramatically accelerate our vaccine selection. As an example, the first clinical batch for SARS-CoV-2 vaccine (mRNA-1273) was designed and manufactured in 42 days and the batch was released on February 24, 2020 to the NIH who will conduct the Phase 1 clinical trial.

• Capital efficiency and speed from shared manufacturing processes and infrastructure. Traditional vaccines require product-dedicated production processes, facilities, and operators. Our mRNA vaccines are produced in a manufacturing process that is sufficiently consistent across our pipeline to allow us to use a single facility to produce all of our mRNA vaccines.

Prophylactic vaccines: Status and next steps

Our prophylactic vaccines modality currently includes eight programs, five of which have entered into clinical trials. In addition, to the eight programs being developed, the H10N8 vaccine (mRNA-1440) and Chikungunya vaccine (mRNA-1388) are two public health programs that are not being further developed without government or other funding. Of these programs, we have demonstrated desired pharmacology, in the form of immunogenicity, in the Phase 1 clinical trials for the following: H10N8 vaccine (mRNA-1440), H7N9 vaccine (mRNA-1851), RSV vaccine (mRNA-1777), Chikungunya vaccine (mRNA-1388), hMPV/PIV3 vaccine (mRNA-1653), and CMV vaccine (mRNA-1647). For the Zika vaccine (mRNA-1325), although the Phase 1 safety and tolerability

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data generated would permit additional dose escalation of mRNA-1325, our current development efforts are focused on our next-generation vaccine, mRNA-1893, which has been shown to be 20 times more potent in non-human primate Zika challenge studies. We will not further develop mRNA-1325. We have an ongoing Phase 1 trial for the next generation Zika vaccine (mRNA-1893) and Merck is conducting a Phase 1 trial for an additional RSV vaccine (mRNA-1172).

Prophylactic Vaccines Clinical Data Summary
Safety information	Immunogenicity information
>1,000 subjects dosed in Phase 1 trials at levels up to 300µg.	Interim Phase 1 data for our CMV vaccine (mRNA-1647) showed a dose-related increase in neutralizing antibody titers in participants who are naive to CMV infection (CMV-seronegative) at seven months (one month after the third vaccination) in the 30, 90 and 180 µg dose levels; Interim Phase 1 data for our hMPV/PIV3 vaccine (mRNA-1653) showed boosted serum neutralization titers against hMPV and PIV3 at all dose levels tested; Interim Phase 1 data for our RSV vaccine (mRNA-1777) showed humoral immune response as measured by neutralizing antibody titers post a single dose; 100% seroresponse was observed for subjects at the 100 µg dose level for our Chikungunya vaccine (mRNA-1388); 96% of subjects at 25 µg achieved hemagglutination inhibition, or HAI, titer > 1:40 for our H7 influenza vaccine (mRNA-1851); and 100% of subjects at 100 µg achieved HAI titer > 1:40 for our H10 influenza vaccine (mRNA-1440).

For our commercial vaccine programs, we expect the next series of milestones will involve the reporting of Phase 2 safety and immunogenicity data from our CMV vaccine (mRNA-1647) and Phase 1b safety and immunogenicity data for our hMPV/PIV3 vaccine (mRNA-1653). For the programs being conducted by our strategic collaborator Merck, the next milestones will be the safety and immunogenicity data from the Phase 1 trial for the second RSV vaccine (mRNA-1172) which has been shown to be more potent than the first (mRNA-1777) in preclinical studies. For our global health programs, the next series of milestones will involve the reporting of Phase 1 safety and immunogenicity data for our next generation Zika vaccine (mRNA-1893) and Phase 1 safety and potential immunogenicity data for our SARS-CoV-2 vaccine (mRNA-1273). We do not intend to advance our H10N8 vaccine (mRNA-1440), our H7N9 vaccine (mRNA-1851), or our Chikungunya vaccine (mRNA-1388) through further clinical development without government or other third-party funding.

Each of these programs is more fully described in the section of this Annual Report on Form 10-K titled “Business—Program Descriptions.”

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II. CANCER VACCINES OVERVIEW - EXPLORATORY MODALITY

We designed our cancer vaccines modality to treat or cure cancer by enhancing immune responses to tumor neoantigens, defined below. This modality has two programs currently for neoantigen vaccines, a personalized cancer vaccine, or PCV, program and a vaccine against neoantigens related to a common oncogene called KRAS, both conducted in collaboration with Merck. The goal of a cancer vaccine is to safely expose the patient’s immune system to tumor related antigens, known as neoantigens, to enable the immune system to elicit a more effective antitumor response. This exploratory modality is focused on the use of mRNA to express neoantigens found in a particular tumor in order to elicit an immune response via T cells that recognize those neoantigens, and therefore the tumor. These neoantigens can either be unique to a patient, as in the case of our personalized cancer vaccine program, or can be related to a driver oncogene found across subsets of patients, as in the case of our KRAS vaccine program.

Our pipeline is shown in two formats, with a cell map illustrating the diversity of biology addressed by our mRNA pipeline programs, and a traditional format that shows the current stages of development of our pipeline programs, in the section of this Annual Report on Form 10-K titled “Business—Our Pipeline.”

Cancer vaccines: Opportunity

More than 1.6 million new cancer cases and approximately 600,000 deaths due to cancer were predicted in the United States for 2017. Despite the recent success of checkpoint inhibitors, the majority of patients with the most common types of epithelial cancer still do not benefit from checkpoint inhibitors, as many patients still have incomplete or no response to currently available therapies. In addition, treatment resistance is thought to arise from a number of mechanisms, principally the local immunosuppressive effects of cancer cells, which prevent either access to or recognition by T cells.

Recent breakthroughs in cancer immunotherapy, such as checkpoint inhibitors and chimeric antigen receptor T cell therapies, have demonstrated that powerful antitumor responses can be achieved by activating antigen specific T cells. We believe one approach to improve the efficacy of checkpoint inhibitors is to develop vaccines that increase both the number and antitumor activity of a patient’s T cells that recognize tumor neoantigens.

Cancer vaccines: Product features

We believe that mRNA technology is an attractive approach for cancer vaccines for many reasons, including:

• mRNA vaccines can deliver multiple neoantigens concatenated in a single mRNA molecule. We currently encode up to 34 neoantigens in one of our personalized cancer vaccines (mRNA-4157), and four KRAS mutations in our KRAS vaccine (mRNA-5671). Given that a T cell response against a single antigen has the potential to eradicate cancer cells, we believe that delivering multiple neoantigens could increase the probability of a successful treatment outcome for a patient.

• mRNA encoding for neoantigens is translated and processed by patients’ endogenous cellular mechanisms for presentation to the immune system. Neoantigen peptides are then potentially processed in multiple ways to give rise to different, smaller peptides for presentation by the immune system. We believe this endogenous antigen production and presentation has the potential to drive a more effective immune response.

• mRNA vaccines can be efficiently personalized. The shared features of mRNA, combined with our investments in automated manufacturing technology, enable us to manufacture individual cGMP batches of personalized cancer vaccines rapidly, in parallel. For example, we have demonstrated the ability to manufacture and release a “custom-designed” vaccine for an individual patient within 60 days of sequencing the patient’s tumor for the personalized cancer vaccine program (mRNA-4157).

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Cancer vaccines: Status and next steps

We are currently developing two programs within our cancer vaccines modality. Our personalized cancer vaccine program mRNA-4157 is being developed in collaboration with Merck and is in a multiple-arm Phase 1 trial. A second personalized cancer vaccine, NCI-4650 was being developed in collaboration with the National Cancer Institute, or NCI, and was in an investigator-initiated single-arm Phase 1 trial which has been completed. The two vaccines mRNA-4157 and NCI-4650 differ in the neoantigen selection protocols used, but are otherwise substantially the same. Our second program within this modality, mRNA-5671, is a KRAS vaccine. Our strategic collaborator Merck has a Phase 1 trial ongoing for mRNA-5671.

PCV (mRNA-4157) Clinical Data Summary
	Safety information	Activity information
	As of February 12, 2020, 15 patients with resected solid tumors (melanoma, colon and lung cancers) received mRNA-4157 as adjuvant monotherapy after resection of their primary tumor. An additional 56 patients with metastatic, unresected solid tumors (melanoma, bladder, lung, colon, prostate, head and neck and endometrial cancers) received at least one dose of mRNA-4157 in combination with pembrolizumab. There have been no dose-limiting toxicities or significant related toxicities observed in these patients to date.	As of June 2019, we have detected antigen specific T cell responses in both the monotherapy arm and in combination with pembrolizumab in the Phase 1 trial for mRNA-4157. We have also observed potential clinical activity in some patients receiving mRNA-4157 in combination with pembrolizumab in the Phase 1 trial.

We expect the next steps for the PCV program (mRNA-4157) to involve the continued reporting of immunogenicity data from the Phase 1 clinical trial in cancer patients and the continuation of the randomized Phase 2 trial to assess whether post-operative adjuvant therapy with mRNA-4157, in combination with pembrolizumab, improves relapse-free survival compared to pembrolizumab alone. The next steps for the KRAS vaccine (mRNA-5671) include continuation of the Phase 1 trial by our strategic collaborator Merck.

Each of these programs is more fully described in the section of this Annual Report on Form 10-K titled “Business—Program Descriptions.”

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III. INTRATUMORAL IMMUNO-ONCOLOGY OVERVIEW - EXPLORATORY MODALITY

We designed our intratumoral immuno-oncology modality to treat or cure cancer by transforming the tumor microenvironment to drive anti-cancer T cell responses against tumors. Our mRNA technology within this modality allows for the combination of multiple therapeutics that can be directly injected into a tumor with the goal of activating the tumor microenvironment to kill cancer cells in the injected tumor as well as in distal tumors, known as the abscopal effect. Intratumoral administration allows for localized effect of these therapeutics that could be toxic if administered systemically. This exploratory modality has three development candidates.

Our pipeline is shown in two formats, with a cell map illustrating the diversity of biology addressed by our mRNA pipeline programs, and a traditional format that shows the current stages of development of our pipeline programs, in the section of this Annual Report on Form 10-K titled “Business—Our Pipeline.”

Intratumoral immuno-oncology: Opportunity

More than 1.6 million new cancer cases and approximately 600,000 deaths due to cancer were predicted in the United States for 2017. There have been several advances in the treatment of cancer through immune-mediated therapies in recent years. However, the outlook for many patients with advanced cancer remains poor, especially in tumors that have little immune system engagement and are sometimes termed immunologically “cold.” We aim to activate the tumor microenvironment with our mRNA therapeutics, in conjunction with a checkpoint inhibitor, to activate the immune system against these otherwise immunologically cold tumors.

Intratumoral immuno-oncology: Product features

We believe our approach to immuno-oncology using our mRNA medicines could complement checkpoint inhibitors and has several advantages over recombinant protein-based drugs, including:

• mRNA focuses and limits exposure of immune stimulatory proteins. One of the intrinsic properties of mRNA is its transient nature. This allows for short exposure of the proteins encoded by the mRNA in the target tissue thereby potentially enhancing tolerability.

• mRNA can produce membrane associated immune stimulatory proteins. In contrast to recombinant proteins, mRNA administered to a tumor site can lead to the production of either secreted or membrane proteins, depending on the mRNA sequence.

• Multiplexing of mRNA allows access to multiple immune stimulatory pathways. The ability to combine multiple mRNAs to express multiple proteins allows for activation of several immune pathways simultaneously. For example, OX40L/IL-23/IL-36γ (Triplet) (mRNA-2752) encodes for two secreted cytokines (IL-23 and IL-36γ) and one membrane protein (OX40L).

• mRNA sequences can be engineered to reduce off-target effects. Our mRNA can be designed to minimize translation in off-target tissues. For immune-stimulatory proteins this can potentially prevent toxicities.

• Local administration of mRNA can create a concentration gradient for encoded proteins. mRNA administered intratumorally allows for the local production of encoded immune-stimulatory proteins, such as cytokines. The mRNA and encoded protein are expected to form a concentration gradient that decreases as a function of the distance from the tumor, thereby potentially lowering undesirable systemic effects and increasing immune-stimulatory effects close to the tumor.

Intratumoral immuno-oncology: Status and next steps

We have three programs in this modality. The first program in this modality, OX40L (mRNA-2416), was designed to overcome technological challenges in advancing this modality, including engineering the mRNA sequence to minimize off-target effects, utilizing our proprietary LNPs to enhance safety and tolerability, and to demonstrate expression of a membrane protein in patients. OX40L (mRNA-2416) is currently being evaluated in an ongoing Phase 1/2 trial in the United States, and protein expression has been demonstrated in a number of patients. Our second program, OX40L/IL-23/IL-36γ (Triplet) (mRNA-2752), has dosed patients in a Phase 1 study for the treatment of advanced or metastatic solid tumor malignancies or lymphoma. Our third program, IL-12 (MEDI1191), is being developed in collaboration with AstraZeneca.

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Intratumoral Immuno-oncology Clinical Data Summary
	Safety information	Activity information
	For mRNA-2416, no safety findings observed that met study pause criteria; rapid onset of multiple grade 2 and one grade 3 transient reversible injection-related reactions were observed, all of which were resolved with standard interventions; three suspected unexpected serious adverse reactions, or SUSARs, were reported as of November 15, 2018.	As of February 13, 2020, 26 patients have been dosed with mRNA-2752 with 16 patients on monotherapy and 10 patients in combination with durvalumab. As of February 12, 2020, 41 patients were dosed with OX40L mRNA-2416 (39 patients in monotherapy and 2 patients in combination with durvalumab). As of Oct. 22, 2018, 26 patients were evaluated for response with OX40L mRNA-2416 monotherapy, and the best overall response was stable disease (n=6). Two patients with ovarian cancer have demonstrated clinical observations of tumor shrinkage in injected and/or uninjected lesions.

The monotherapy arm of the Phase 1 trial for mRNA-2416 has been completed and we are not planning an expansion cohort of mRNA-2416 as a monotherapy. We have initiated a dose-finding cohort at 4 mg mRNA-2416 given in combination with durvalumab (IMFINZI®) followed by a Phase 2 expansion cohort in ovarian cancer. We plan to collect Phase 1 clinical trial data including potential clinical responses for OX40L/IL-23/IL-36γ (Triplet) (mRNA-2752). AstraZeneca has initiated an open-label, multicenter Phase 1 clinical trial of intratumoral injections of IL-12 (MEDI1191) alone or in combination with a checkpoint inhibitor.

Each of these programs is more fully described in the section of this Annual Report on Form 10-K titled “Business—Program Descriptions.”

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IV. LOCALIZED REGENERATIVE THERAPEUTICS OVERVIEW - EXPLORATORY MODALITY

We designed our localized regenerative therapeutics modality to develop mRNA medicines to address injured or diseased tissues. Our mRNA technology in this modality allows for the local production of proteins that provide a therapeutic benefit in the targeted tissue. The development of our program in this modality, AZD8601, for the local production of VEGF-A, is being led by our strategic collaborator AstraZeneca. This program completed a Phase 1a/b clinical trial in which we observed both a dose-dependent protein production and a pharmacologic effect, as measured by changes in local blood flow in patients. We believe this data provides clinical proof of mechanism for our mRNA technology outside of the vaccine setting.

Our pipeline is shown in two formats, with a cell map illustrating the diversity of biology addressed by our mRNA pipeline programs, and a traditional format that shows the current stages of development of our pipeline programs, in the section of this Annual Report on Form 10-K titled “Business—Our Pipeline.”

Localized regenerative therapeutics: Opportunity

There are multiple applications for tissue regeneration. With AstraZeneca, we have focused on ischemic heart failure for the first program. Coronary artery disease, the primary cause of ischemic heart failure, affects the arteries providing blood supply to the cardiac muscle. In 2015, coronary artery disease resulted in 366,000 deaths in the United States, and 8.9 million deaths globally.

Localized regenerative therapeutics: Product features

We believe our approach to localized regenerative therapeutics using mRNA has several advantages over alternative approaches, including:

• mRNA can be administered locally to produce the desired protein for an extended duration. Local exposure to the therapeutic protein encoded by our mRNA is sustained by the ongoing translation of the mRNA into protein, often from hours to days. This pharmacokinetic profile closely mimics the optimal tissue exposure profile for regenerative applications and cannot be achieved by injections of recombinant proteins that rapidly diffuse out of the tissue after injection.

• Local administration of mRNA allows for focused activity. mRNA administered to a specific tissue or organ should allow for local production of the encoded protein, which could lead to lower levels of encoded protein in distant or systemic locations. This could help to prevent potential toxicity from production of the encoded protein outside of the targeted tissue.

• mRNA allows for dose-dependent and repeated production of the encoded protein. mRNA therapies should also allow for dose titration and repeat dosing. This provides several advantages over gene therapy. Gene therapy typically results in a permanent change to cellular DNA that may result in uncontrolled or constant production of the desired protein in local tissue or in distant sites, which could cause local or systemic side effects. Further, some gene therapy delivery vehicles are associated with immune responses that limit the ability to repeat dose, preventing dose titration.

Localized regenerative therapeutics: status and next steps

Our localized VEGF-A program, AZD8601, which is being developed by AstraZeneca, has completed a Phase 1a/b trial to describe its safety, tolerability, protein production, and activity in diabetic patients. The study has met its primary objectives of describing safety and tolerability and secondary objectives of demonstrating protein production and changes in blood flow post AZD8601 administration. In this trial, AZD8601 was administered by intradermal injection in the forearm skin of patients for single ascending doses. These data are consistent with studies previously conducted in preclinical models. We believe these data provide clinical proof of mechanism for our mRNA technology outside of the vaccine setting.

Localized Regenerative Therapeutics Clinical Data Summary
Safety information	Activity information
Demonstrated sufficient tolerability in the Phase 1a/b trial at all dose levels (33 patients received AZD8601 for the Phase 1 trial) to warrant advancement to a Phase 2a study.	Increase in VEGF-A and bioactivity of VEGF-A protein was observed by increase in blood flow at injection sites up to seven days following a single dose of AZD8601.

AstraZeneca has initiated a Phase 2a trial for AZD8601 in ischemic heart disease. The Phase 2a study is designed to provide initial safety and tolerability data in approximately 24 coronary artery bypass patients.

This program is more fully described in the section of this Annual Report on Form 10-K titled “Business—Program Descriptions.”

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V. SYSTEMIC SECRETED AND CELL SURFACE THERAPEUTICS OVERVIEW - CORE MODALITY

We designed our systemic secreted therapeutics modality to increase levels of desired secreted proteins in circulation or in contact with the extracellular environment, in order to achieve a therapeutic effect in one or more tissues or cell types. The goal of this modality is to provide secreted proteins, such as antibodies or enzyme replacement therapies across a wide range of diseases, such as heart failure, infectious diseases, and rare genetic diseases. This modality has benefitted from our strategic alliances with AstraZeneca, DARPA, and the Bill & Melinda Gates Foundation. We have accumulated several innovations in technology, have gained process insights, and have built a set of preclinical and clinical experiences in our systemic secreted and cell surface therapeutics modality. Based on these, we believe this modality is core to our portfolio and we have expanded this portfolio with two new development candidates in a new autoimmune therapeutic area in 2020. Our systemic secreted and cell surface therapeutics modality has five development candidates.

Our pipeline is shown in two formats, with a cell map illustrating the diversity of biology addressed by our mRNA pipeline programs, and a traditional format that shows the current stages of development of our pipeline programs, in the section of this Annual Report on Form 10-K titled “Business—Our Pipeline.”

Systemic secreted and cell surface therapeutics: Opportunity

The ability to systemically deliver mRNA for a therapeutic effect would allow us to address a number of diseases of high unmet medical need. Systemically delivered, secreted and cell surface therapeutics address conditions often treated with recombinant proteins that are typically administered to the blood stream. These current therapies include, for example:

• Enzyme replacement therapies, or ERTs, for rare diseases;

• Antibodies for membrane and extracellular soluble targets; and

• Circulating modulation factors for common and rare diseases such as growth factors and insulin.

Systemic secreted and cell surface therapeutics: Product features

Systemically delivered, secreted and cell surface therapeutics, we believe, would allow us to target areas of biology that cannot be addressed using recombinant proteins. Our potential advantages in these areas include:

• mRNA can produce hard-to-make or complex secreted proteins. Some proteins, due to their folding requirements or complexity, are challenging to make using recombinant technologies, but can potentially be produced by human cells using administered mRNA.

• mRNA can produce membrane associated proteins. In contrast to recombinant proteins, mRNA can lead to the production of membrane associated proteins on the cell surface, allowing the expression of native forms of signaling receptors or other cell surface complexes.

• Native post-translational modifications are possible through intracellular protein production using mRNA. mRNA administered to a human cell uses natural secretory pathways inside the cell to make and process the encoded protein. The resulting post-translational modifications, such as glycosylation, are human. With recombinant proteins, these post-translational modifications are native to the non-human cells used for manufacture. These non-human post-translational modifications in recombinant proteins may lead to sub-optimal therapeutic outcomes, side effects, and increased immunogenicity.

• mRNA can sustain production of proteins, which can increase exposure to proteins with short half-lives. mRNA can lead to protein production by cells that can last from hours to days depending on design. This feature could increase the levels of short half-life proteins for therapeutic benefit.

• mRNA allows for desirable pharmacology in rare genetic diseases currently addressed by enzyme replacement therapies. Our mRNA technology potentially permits several differentiated pharmacologic features for treating rare genetic diseases currently addressed by enzyme replacement therapies, including the ability to repeat dose as needed, lower immunogenicity of the replacement protein, the ability to adjust dose levels in real-time based on individual patient needs, and the ability to stop dosing. Gene therapies may also prove to be useful for treating rare genetic diseases; however, mRNA is not limited by pre-existing immunity that may exist for certain gene therapies using viral vectors, and does not localize to the nucleus or require persistent changes to cellular DNA to have the desired effect.

•

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Systemic secreted and cell surface therapeutics: Status and next steps

We have five systemic secreted and cell surface therapeutics development candidates in our pipeline. Our secreted programs include our antibody against Chikungunya virus (mRNA-1944), Relaxin (AZD7970) for the treatment of heart failure, Fabry disease (mRNA-3630), and IL-2 (mRNA-6231) for autoimmune disorders. Our antibody against Chikungunya virus (mRNA-1944) is currently being evaluated in an ongoing Phase 1 dose escalation study in healthy adults that is randomized and placebo-controlled. The remaining three programs for Relaxin (AZD7970), Fabry disease (mRNA-3630), and IL-2 (mRNA-6231) are currently in preclinical development. We have a cell surface therapeutic program in this modality. PDL-1 (mRNA-6981) for autoimmune hepatitis is currently in preclinical development.

Systemic Secreted and Cell Surface Therapeutics Clinical Data Summary
Safety information	Activity information
As of September 2019, in a Phase 1 study of mRNA-1944 in healthy volunteers, no significant adverse events were observed at the low and middle doses; infusion-related adverse events were observed at the high dose, which resolved spontaneously without treatment.	As of February 12, 2020, dose level cohorts 0.1, 0.3, 0.6 mg/kg of mRNA-1944 administered without dexamethasone in the premedication regimen and dose level cohort 0.6 mg/kg with dexamethasone in the premedication regimen have been completed. As of September 2019, at the first dose levels tested (0.1, 0.3 and 0.6 mg/kg) of mRNA-1944, all participants had measured antibody levels exceeding the levels of antibody expected to be protective against chikungunya infection (> 1 µg/mL) following a single dose, with the middle and high doses projected to maintain antibody levels above protective levels for at least 16 weeks. The average serum antibody level was quantified at various time points to demonstrate a half-life of 62 days.

We expect the next steps for the antibody against Chikungunya virus (mRNA-1944) program will be additional Phase 1 clinical trial safety and serum antibody level data. We plan to file INDs and take our programs for Relaxin (AZD7970), Fabry disease (mRNA-3630), IL-2 (mRNA-6231), and PDL-1 (mRNA-6981) into the clinic for Phase 1 testing.

Each of these programs is more fully described in the section of this Annual Report on Form 10-K titled “Business—Program Descriptions.”

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VI. SYSTEMIC INTRACELLULAR THERAPEUTICS OVERVIEW - EXPLORATORY MODALITY

We designed our systemic intracellular therapeutics modality to increase levels of intracellular proteins, using cells in the human body to produce proteins located in the cytosol or specific organelles of the cell to achieve a therapeutic effect in one or more tissues or cell types. The goal of this modality is to provide intracellular proteins, such as intracellular enzymes and organelle-specific proteins, as safe, tolerable, and efficacious therapies. Our initial focus within this exploratory modality is on rare genetic diseases. This modality currently has four programs.

Our pipeline is shown in two formats, with a cell map illustrating the diversity of biology addressed by our mRNA pipeline programs, and a traditional format that shows the current stages of development of our pipeline programs, in the section of this Annual Report on Form 10-K titled “Business—Our Pipeline.”

Systemic intracellular therapeutics: Opportunity

Systemically delivered, intracellular therapeutics focus on areas currently not addressable with recombinant proteins, which are typically administered systemically and cannot reach the inside of the cell. Objectives for potential new therapies in this area include, for example, increasing the levels of:

• intracellular pathway proteins;

• soluble organelle-specific proteins; and

• organelle-specific membrane proteins.

Systemic intracellular therapeutics: Product features

Systemically delivered, intracellular therapeutics, we believe, would allow us to target areas of biology that cannot be addressed using recombinant proteins. Our potential advantages in these areas include:

• Using mRNA to encode for intracellular and organelle-specific proteins. Our modality permits the expression of intracellular proteins, including those that must be directly translated and moved into organelles such as mitochondria. The ability of mRNA to produce protein inside of the cell enables production of these protein types that we believe are beyond the reach of recombinant proteins.

• mRNA can produce hard-to-make or complex proteins. For example, some proteins, due to their folding requirements or complexity, are challenging to make using recombinant technologies, but can potentially be produced by human cells using administered mRNA.

• Native post-translational modifications are possible through intracellular protein production using mRNA. mRNA administered to a human cell uses natural secretory pathways inside the cell to make and process the encoded protein. The resulting post-translational modifications, such as glycosylation, are human as opposed to recombinant proteins where these post-translational modifications are native to the non-human cells used for manufacture. These non-human post-translational modifications in recombinant proteins may lead to sub-optimal therapeutic outcomes, side effects and increased immunogenicity.

• mRNA can sustain production of proteins, which can increase exposure to proteins with short half-lives. mRNA can lead to protein production by cells that can last from hours to days depending on design. This feature could increase the levels of short half-life proteins for therapeutic benefit.

• mRNA allows for desirable pharmacology in complex metabolic diseases. Our mRNA technology potentially permits several differentiated pharmacologic features for treating complex metabolic diseases, including the ability to repeat dose as needed, a rapid onset of action, the ability to adjust dose levels real-time based on individual patient needs, and the ability to stop dosing. Gene therapies may also prove to be useful for treating rare genetic diseases; however, mRNA is not limited by pre-existing immunity that may exist for certain gene therapies using viral vectors, and does not localize to the nucleus or require persistent changes to cellular DNA to have the desired effect.

Systemic intracellular therapeutics: Status and next steps

We have four systemic intracellular therapeutics development candidates in our pipeline. Our intracellular programs address methylmalonic acidemia, or MMA (mRNA-3704), propionic acidemia, or PA (mRNA-3927), phenylketonuria, or PKU (mRNA-3283), and glycogen storage disorder type 1a, or GSD1a (mRNA-3745).

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Systemic Intracellular Therapeutics Data Summary
	Safety information	Activity information
Preclinical	Successfully completed GLP toxicology program for MMA (mRNA-3704) and PA (mRNA-3283), that were included in the open IND to support advancement into the clinic; IND-enabling GLP toxicology program for PKU (mRNA-3283) is ongoing.	Activity measured in animal models for MMA (mRNA-3704), PA (mRNA-3927), PKU (mRNA-3283), and GSD1a (mRNA-3745); data published for MMA (mRNA-3704).
Clinical	—	—

We have received Rare Pediatric Disease Designation and Orphan Drug Designation from the FDA and Orphan Drug Designation from the European Commission for the MMA program. The FDA has also designated the investigation of mRNA-3704 for the treatment of isolated MMA due to MUT deficiency as a Fast Track development program. We have initiated a Phase 1/2 trial for MMA (mRNA-3704). As of February 12, 2020, we have enrolled the first patient in this trial. This patient has entered an observational period prior to treatment, which evaluates the patient’s baseline disease prior to starting the treatment period. We expect the next steps for mRNA-3704 will be Phase 1/2 clinical trial safety, proof of concept, and biomarker data. We have received Rare Pediatric Disease Designation and Orphan Drug Designation from the FDA and Orphan Drug Designation from the European Commission for the PA program. The FDA has also granted Fast Track designation to mRNA-3927. With an open IND currently, we expect the next steps for mRNA-3927 to be initiation of the Phase 1 clinical trial to describe safety, proof of concept, and biomarker data in PA patients. We have an ongoing global natural history study for MMA and PA. Up to 60 PA and 60 MMA patients in the United States and Europe will be followed prospectively for 1-3 years. Enrollment in this study has been completed. Retrospective data are being collected as available. PKU (mRNA-3283) and GSD1a (mRNA-3745) are currently in preclinical development. We plan to file INDs and take these programs into the clinic for Phase 1 testing.

Each of these programs is more fully described in the section of this Annual Report on Form 10-K titled “Business—Program Descriptions.”

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OUR PIPELINE

This section describes the pipeline that has emerged thus far from the combination of our strategy, our platform, our infrastructure, and the resources we have amassed. Complete descriptions of our programs are found in the section of this Annual Report on Form 10-K titled “Business—Program Descriptions.”

Since we nominated our first program in late 2014, we and our strategic collaborators have advanced in parallel a diverse development pipeline which currently consists of 24 development candidates across our 23 programs, of which 17 have entered clinical studies and another one has an open investigational new drug application (“IND”). Over 1,500 subjects have been enrolled in our clinical trials since December 2015. Our diverse pipeline comprises programs across six modalities and a broad range of therapeutic areas. A modality is a group of potential mRNA medicines with shared product features, and the associated combination of mRNA technologies, delivery technologies, and manufacturing processes. Aspects of our pipeline have been supported through strategic alliances, including with AstraZeneca, Merck, and Vertex Pharmaceuticals, or Vertex, and government-sponsored organizations and private foundations focused on global health initiatives, including BARDA, DARPA, NIH, CEPI and the Bill & Melinda Gates Foundation.

Our selection process for advancing new development candidates reflects both program-specific considerations as well as portfolio-wide considerations. Program-specific criteria include, among other relevant factors, the severity of the unmet medical need, the biology risk of our chosen target or disease, the feasibility of clinical development, the costs of development, and the commercial opportunity. Portfolio-wide considerations include the ability to demonstrate technical success for our platform components within a modality, thereby increasing the probability of success and learnings for subsequent programs in the modality and in some cases in other modalities.

The breadth of biology addressable using mRNA technology is reflected in our current development pipeline of 23 programs. These span 28 different proteins or protein complexes: 11 different antigens (including virus-like particles) for infectious disease vaccines; two different cancer vaccines, one personalized cancer vaccine addressing neoantigens and one for a shared cancer antigen; four different immuno-modulator targets (including membrane and systemically secreted proteins) for immuno-oncology programs; one secreted, local regenerative factor for a heart failure program; five secreted or cell surface proteins of diverse biology (an antibody, an engineered protein hormone, a lysosomal enzyme, a secreted cytokine and a cell surface receptor); and four intracellular enzymes for rare disease programs. The diversity of proteins made from mRNA within our development pipeline is shown in the figure below.

The following chart shows our current pipeline of 24 development candidates across our 23 programs, grouped into modalities-first the 2 core modalities where we believe we have reduced the technology risk, followed by the 4 exploratory modalities in which we are continuing to investigate the clinical use of mRNA medicines.

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Portfolio-wide evidence in support of our platform and approach

We have generated significant learnings across our portfolio that we believe provide compelling support for our approach and pipeline across a broad array of human diseases.

We have generated safety and tolerability data, and demonstrated immunogenicity in the clinic for multiple programs in our core modality of prophylactic vaccines

We have nine development candidates in various stages of preclinical or clinical development (two of which are being developed by our strategic collaborator Merck) in the prophylactic vaccines modality, which is one of our core modalities. In addition, we have two development candidates for H10N8 vaccine and Chikungunya vaccine which are not being progressed any further, pending government or other agency funding. Of these development candidates, the CMV vaccine mRNA-1647 is the most advanced with an ongoing Phase 2 trial. Among our prophylactic vaccines, we have generated clinical safety and tolerability data in more than 1,000 subjects. In addition, we have observed the ability in clinical trials to elicit neutralizing antibodies to viral antigens from six prophylactic vaccine programs to date; our two influenza vaccines, the RSV vaccine being developed in collaboration with Merck, the Chikungunya vaccine being developed in collaboration with DARPA, our hMPV/PIV3 vaccine, and our CMV vaccine, both the preclinical models and immune responses in humans showed increased antibody levels to pathogenic viral antigens.

We have demonstrated the ability to manufacture clinical supplies for our core modality of prophylactic vaccines in less than 30 days

The mRNA-1273 program is to develop a vaccine against SARS-CoV-2. Clinical supply for this mRNA vaccine was designed and manufactured in 25 days.

We have generated safety, tolerability, and pharmacology data in the clinic for the lead program in our core modality of systemic secreted and cell surface therapeutics

We have demonstrated the ability of cells preclinically to make and secrete antibodies and soluble modulating factors that exert their pharmacologic activity by binding to targets and in some cases, having a signaling effect. We have five development candidates this this core modality. We have generated safety and tolerability data for the antibody against Chikungunya virus program (mRNA-1944) in a Phase 1 clinical trial. There have been no serious AEs in the study. All AEs were transient and resolved spontaneously without treatment. We have clinically demonstrated dose-related increases in antibody levels produced, which were at protective levels at all doses, and we have demonstrated that these antibodies were functional by way of neutralizing activity against Chikungunya virus. For our Relaxin program, we have demonstrated an ability to make relaxin as a secreted and engineered protein, which can impact heart failure in preclinical models.

We continue to describe safety and tolerability in clinical trials from hundreds of subjects for programs in our exploratory modalities

The translation of preclinical safety and tolerability into the clinic is a key step for each of our programs and in totality supports the creation of a new class of medicines. We continue to generate safety and tolerability data across ten investigational medicines in four different exploratory modalities.

We have demonstrated pharmacologic effect in the clinic for certain of our exploratory modalities through immunological responses

For PCV (mRNA-4157), which is the most advanced program in clinical development within the cancer vaccines modality, we have observed antigen specific T cell responses in some patients. In the ongoing clinical trial for OX40L (mRNA-2416) in the intratumoral immuno-oncology modality, we have observed early indications of the ability to impact the tumor microenvironment from tumor regression in injected lesions and an adjacent uninjected lesion.

We have demonstrated the ability of our intratumoral immuno-oncology programs to transform immunologically cold tumor microenvironments in preclinical studies for our OX40L Triplet (OX40L/IL-23/IL-36γ), and IL-12 programs. These responses include long-term T cell responses that eliminate tumors in animal models and makes them able to combat a second tumor challenge, indicating immunological memory. We also have preclinical evidence of immunological responses for programs in our cancer vaccines modality, including personalized cancer vaccines and KRAS vaccine.

We have demonstrated pharmacologic effect for certain of our exploratory modalities through enzyme-driven changes in metabolic phenotypes

We have tested our ability to impact metabolic phenotypes via the expression of over 24 different types of proteins. We have also progressed four development candidates, methylmalonic acidemia, or MMA, propionic acidemia, or PA, phenylketonuria, or PKU, and Fabry disease, through early preclinical development efforts. We have demonstrated the ability of our mRNA development candidates to drive metabolic change in animal models for MMA, PA, PKU, and Fabry disease.

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We have produced a diverse set of proteins across both core and exploratory modalities

Our scientists, in conjunction with scientists from Merck and AstraZeneca and other strategic collaborators, have tested over 12,000 unique mRNA sequences in in vitro and in vivo preclinical studies. This includes over 500 invivo preclinical studies that were designed to show evidence of pharmacologic effect or the production of the desired protein. These studies included the following types of proteins:

• Extracellular soluble ligands (e.g., VEGF, IL-12, Relaxin, IL-2 and erythropoietin);

• Antibodies (e.g., immunoglobulins, which are composed of two light chain and two heavy chain proteins);

• Extracellular protein complexes (e.g., Chikungunya virus-like particles);

• Membrane proteins, in some cases as multimers (e.g., F protein, glycoprotein B, CMV pentamer, OX40L and PL-L1);

• Intracellular soluble protein complexes (e.g., methylmalonic-CoA mutase homodimer and propionyl-CoA carboxylase heterododecamer);

• Intracellular membrane proteins with activating mutations (e.g., STING); and

• Neoantigens presented to the immune system as short peptides.

Fifteen first-in-human trials since December 2015 and clinical material supply

We invest in capabilities and infrastructure that enable us to execute at scale. We first dosed a subject in a clinical trial in December 2015. We or our strategic collaborators have achieved first-in-human for fifteen different mRNA investigational medicines. Eleven of those programs were run and sponsored by us.

Each first-in-human, or FIH, trial involved successful completion of one or more IND-enabling GLP toxicology studies, successful technical development, scale-up and cGMP manufacture of adequate quantities of mRNA drug product, IND or CTA regulatory filings and interactions with health authorities, and successful clinical operations start-up activities. We or our strategic collaborators have run clinical trials in the United States, Europe, and Australia.

Conclusion

We believe that this body of preclinical and clinical data are indicative of our significant progress, and provides a strong foundation for our ongoing mission to create a new class of medicines for patients.

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PROGRAM DESCRIPTIONS

Using our platform, we have found solutions to many scientific and technical challenges in order to develop the desirable features of our potential mRNA medicines for different applications. A “modality” refers to a group of potential mRNA medicines with shared product features, and the associated combination of enabling mRNA technologies, delivery technologies, and manufacturing processes.

Each of our modalities is designed to overcome the challenges of delivering the right amount of mRNA to the right tissue at the right times across a variety of applications. In advancing our platform technologies and identifying new product features for novel mRNA medicines, we may designate additional modalities.

We started with prophylactic vaccines as our first modality as we believed there would be lower technical hurdles for vaccines compared to therapeutics. Early formulations of mRNA tended to stimulate the immune system, which is a desired feature for a vaccine, but not therapeutics. In addition, antigens for many viruses tend to be well-characterized and of lower biology risk. Also, dosing regimens for vaccines can require as few as one or two administrations.

I. PROGRAM DESCRIPTIONS IN OUR PROPHYLACTIC VACCINES MODALITY

We designed our prophylactic vaccines modality to prevent or control infectious diseases. Since we nominated our first program in late 2014, this modality has grown to currently include nine active programs, all of which are vaccines against viruses. The goal of any vaccine is to safely pre-expose the immune system to a small quantity of a protein from a pathogen, called an antigen, so that the immune system is prepared to fight the pathogen if exposed in the future, and prevent infection or disease.

Within this modality, our portfolio includes programs for both commercial and global health uses. We have strategic alliances with Merck on select commercial vaccines, and with the Biomedical Advanced Research and Development Authority, or BARDA, the Defense Advanced Research Projects Agency, or DARPA, the National Institutes of Health, or NIH, as well as the Coalition for Epidemic Preparedness Innovations, or CEPI, on global health vaccine programs.

Our global public health portfolio is focused on epidemic and pandemic diseases in which funding has been sought from government and non-profit organizations. Given current funding and priorities, the influenza H10N8 vaccine (mRNA-1440) and chikungunya vaccine (mRNA-1388) are being deprioritized at this time and removed from the active pipeline, contingent upon future funding. Discussions on funding the influenza H7N9 vaccine (mRNA-1851) through approval are ongoing.

Our prophylactic vaccine pipeline is shown below:

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Opportunity

Vaccines to prevent infectious diseases are one of the great innovations of modern medicine. In the United States alone, the Centers for Disease Control and Prevention estimates that childhood vaccinations given in the past two decades will in total prevent 322 million Americans from falling ill, 21 million hospitalizations, 732,000 deaths, $295 billion of direct costs, and $1.3 trillion in social costs. The commercial opportunity for vaccines is significant, with more than $35 billion in annual worldwide sales, including 16 different vaccine products each generating more than $500 million in annual worldwide sales in 2017.

Our approach

Our vaccine research approach starts by identifying the antigens most likely to induce a protective immune response against a specific infectious disease. We test one or more antigens in vivo in multiple animal species. The immune response can be measured in multiple ways including:

• Generation of binding antibodies, where the antibodies generated by the vaccine bind to the pathogen antigens being targeted;

• Generation of neutralizing antibodies, where the antibodies generated by the vaccine are able to prevent the pathogen from infecting cells;

• Ability of the vaccine to protect vaccinated animals against a pathogen, as measured by reductions in detectable pathogen or by the survival of the challenged animal if the pathogen is lethal; and

• Generation of an antigen specific T cell response.

Clinical correlates of protection are levels of immune response that when achieved in response to vaccination are associated with protection against infection or disease. Influenza, for instance, has an established correlate of protection based on the serum hemagglutination inhibition, or HAI, assay. HAI titers of 40 or above are associated with 50% to 70% protection against influenza. However, such correlates are generally only available for approved vaccines. As a result, new vaccines generally, but not always, have to demonstrate efficacy against clinical disease before being approved. Our first two programs in this modality are H10N8 and H7N9 vaccines for an established antigen with HAI clinical correlates.

Typically, subjects require only a limited number of administrations of a vaccine to confer long-lasting protection. Many of our mRNA vaccines are developed to be administered in two doses, one to prime the immune response and the second to boost it. In cases where populations have been exposed to the virus previously, such as with many respiratory viruses, a subject might be administered a single dose of an mRNA vaccine.

We believe that our potential mRNA vaccines will have a more standardized manufacturing process compared to traditional vaccines that would provide considerable advantages. Current approaches include attenuation and replication of live viruses and cell-culture methods to produce recombinant antigens. These approaches require considerable customization compared to the standardized process of producing mRNA vaccines.

We believe the inherent characteristics of mRNA, coupled with our strategy to execute at scale, will allow us to bring potential mRNA vaccines to the clinic in a relatively short period of time. We have chosen to be methodical for our early programs to understand the technology risks within the modality. If needed, as in the case of a pandemic, we could potentially exploit the scalability of mRNA medicines and our infrastructure to rapidly advance a potential mRNA vaccine to the clinic.

We believe that the positive safety and immunogenicity data obtained from six separate Phase 1 clinical trials with our prophylactic vaccines, including the most recent results with our CMV vaccine candidate (mRNA-1647), have provided support for a reduced risk profile with respect to key aspects of our approach and technology in infectious disease vaccines. We believe the clinical data demonstrate that our proprietary vaccine technology is generally well-tolerated and can elicit durable immune responses to viral antigens. We have discussed the platform nature of our vaccine technology with FDA, including our body of non-clinical and Chemistry, Manufacturing and Controls ("CMC") experience and they have provided specific guidance on how to leverage our body of non-clinical data generated using the vaccine platform, potentially expediting preclinical development of our novel vaccines. We have designated prophylactic vaccines as a core modality. We also believe we have demonstrated the ability to leverage common technological and digital platforms and a flexible manufacturing infrastructure to advance a large portfolio quickly and in parallel. Therefore, consistent with our portfolio strategy, we are expanding our portfolio of vaccines against important infectious diseases. In early 2020, we introduced three new development candidates, in this modality, mRNA-1345 for the prevention of pediatric respiratory disease caused by RSV, mRNA-1189 for the prevention of EBV infection and associated diseases and mRNA-1273 for the prevention of disease caused by SARS-CoV-2. Each of these programs is described in detail below, along with the other programs in this core modality.

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PROPHYLACTIC VACCINES MODALITY: COMMERCIAL PROGRAMS

RSV vaccine (mRNA-1777 and mRNA-1172): Summary

mRNA-1777 RSV vaccine program completed dosing in a Phase 1 clinical trial; our strategic collaborator Merck has initiated Phase 1 clinical trial with mRNA-1172 which has been shown to have enhanced potency in preclinical studies.

Respiratory syncytial virus, or RSV, is one of the most common causes of respiratory disease in infants and the elderly. More than 86,000 children and about 177,000 older adults are hospitalized due to RSV associated respiratory infections each year in the United States. To date, no effective vaccine to prevent RSV has been approved, and the only approved prophylaxis treatment is limited to the monoclonal antibody palivizumab, marketed as Synagis in the United States for pediatric patients at high risk for RSV infection. In collaboration with Merck, we designed mRNA-1777 to encode a membrane-anchored version of stabilized prefusion F protein, the main target of potently neutralizing and protective antibodies. This vaccine is administered as a single dose with no boost. We conducted the Phase 1 trial for mRNA-1777 in Australia. mRNA-1172 or V172 has been shown to have enhanced potency in preclinical studies compared to mRNA-1777. Therefore further development on mRNA-1777 has been paused and Merck has initiated a Phase 1 trial in the United States for mRNA-1172.

RSV vaccine (mRNA-1777 and mRNA-1172): Disease overview

RSV impacts young children and older adults, and no approved vaccine exists today

RSV causes upper and lower respiratory tract illness worldwide and is transmitted primarily via aerosolized droplets from an infected person, or via contamination of environmental surfaces with infectious secretions. Following introduction of RSV into the nose or upper respiratory tract, the virus replicates primarily in the ciliated cells of the respiratory epithelium. Upper respiratory symptoms typically begin within several days of exposure. In healthy adults, the infection may remain confined to the upper respiratory tract. However, in those with compromised immune systems, such as premature infants, the elderly, or individuals with underlying respiratory disease, lower respiratory tract infections commonly occur and may manifest as wheezing, bronchiolitis, pneumonia, hospitalization or even death. Infections with RSV follow a seasonal pattern, occurring primarily in the Northern hemisphere between the months of November and April, and in the Southern hemisphere primarily between March and October.

More than 86,000 children are hospitalized due to RSV infection each year in the United States. About 177,000 older adults are hospitalized each year in the United States due to RSV-associated respiratory infections, with approximately 14,000 deaths as a result. RSV infection is common in adults over the age of 60 years, occurring in an average of 5.5% of older adults every season and resulting in physician’s visits for 17% of infected older adults. The cost of RSV disease to society can be considerable.

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RSV vaccine (mRNA-1777 and mRNA-1172): Our product concept

Prevent RSV infections with an improved RSV antigen using a single vaccine dose

Our RSV investigational medicine, mRNA-1777, includes an mRNA encoding an engineered form of the RSV fusion (F) glycoprotein stabilized in the prefusion conformation in an LNP. The F protein is present as a homotrimer on the surface of RSV. The prefusion conformation of the F protein interacts with a host cell membrane, and the conformational change from prefusion to postfusion drives virus fusion with a host cell. The majority of RSV-specific neutralizing antibodies in convalescent people are directed to epitopes present only on the prefusion conformation of the F protein. The prefusion state of the F protein elicits a superior neutralizing antibody response compared to the postfusion state in animal studies conducted by others. A schematic of the prefusion F protein on the surface of a host cell, with sites recognized by neutralizing antibodies, is depicted in the figure below; the inset on the left of the figure shows the intended design of the mRNA formulated in LNP, and the inset on the right shows the intended prefusion F protein on the surface of the cell. We believe that neutralizing antibodies elicited by mRNA-1777 may lead to an efficacious RSV vaccine.

mRNA-1172 includes an mRNA encoding for an engineered form of the RSV F glycoprotein in a Merck proprietary LNP.

RSV vaccine (mRNA-1777 and mRNA-1172): Preclinical information

mRNA vaccines encoding different versions of the prefusion F protein have been evaluated in mice, cotton rats, and African green monkeys, or AGM. These studies demonstrate that mRNA vaccines encoding the prefusion F protein induce robust neutralizing antibody titers in preclinical species tested, do not lead to vaccine-enhanced respiratory disease (evaluated in cotton rats), and are protective against RSV challenge (evaluated in cotton rats and AGM). The data for a study in AGM are shown in the figure below. In this study, one group of AGM (4 per group) was vaccinated intramuscularly with vaccine, a second group was infected with 5.5 log ₁₀ plaque forming units, or pfu, of RSV strain A2 intranasally as a positive control, and a third group received no vaccine as a negative control, each on weeks 0, 4, and 8. Serum neutralizing antibody titers, or SN titers, were measured on the indicated weeks and are shown in panel A. All animals were challenged intranasally and intratracheally on study week 10. On multiple time points after the challenge, virus present in bronchoalveolar lavage, or BAL, fluid was quantified by plaque assay as shown in panel B. In this study, we observed an increase in serum neutralizing titers with each vaccine dose. The animals that received mRNA-1777 showed complete protection (no virus detected) in lungs, similar to the control group immunized with RSV A2. These results are shown in the figures below.

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Serum neutralizing titers for mRNA-1777 in non-human primate study

Panel (A)

Lung viremia detected post challenge in non-human primate study with mRNA-1777

Panel (B)

Recent studies in cotton rats and AGM demonstrate immunogenicity of mRNA-1172. The data for a study in AGM are shown below. In this study, two groups of AGM (4 per group) were vaccinated intramuscularly with the same dose level of vaccine, a fifth group was infected with 5.5 log10 plaque forming units, or pfu, of RSV strain A2 intranasally as a positive control, and a sixth group received no vaccine as a naïve control, each on weeks 0,4, and 8. Serum neutralizing antibody titers were measured on the indicated weeks and are shown in panel C. In this study, mRNA-1172 was shown to be significantly more potent than mRNA-1777.

Serum Neutralizing titers for mRNA-1172 and mRNA-1777 in non-human primate study

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RSV vaccine (mRNA-1777 & mRNA-1172): Clinical data

The Phase 1 trial for mRNA-1777 in Australia generated safety and tolerability data and demonstrated immunogenicity and has been completed; further development of mRNA-1777 has been paused pending data from the ongoing Phase 1 trial for mRNA-1172 sponsored by Merck

The Phase 1 trial for RSV vaccine has met its objectives of assessing the safety and tolerability profile of mRNA-1777 versus placebo including capturing solicited and unsolicited local and systemic adverse events. The Phase 1 trial for RSV vaccine has also demonstrated immunogenicity and we have observed a humoral immune response as measured by neutralizing antibody titers against RSV A for dose levels one, two, and three of mRNA-1777.

The mRNA-1777 Phase 1 study is a randomized, partially double-blind, placebo-controlled, dose-escalation first-in-human study to describe the safety, tolerability, and immunogenicity in healthy adult subjects in Australia. We are the sponsor for this trial. The study evaluated three dose levels in healthy younger adults, and 4 dose levels in healthy older adults. All subjects were given a single intramuscular injection. The key objectives of the study included:

• assess the safety and tolerability of mRNA-1777 versus placebo; and

• determine the immunogenicity of mRNA-1777 by measuring serum neutralizing antibody titers against RSV.

The key endpoints for the study included safety and tolerability of mRNA-1777.

The study was conducted in two parts. Part A evaluated healthy younger subjects (ages > 18 and < 49 years) and Part B evaluated healthy older subjects (ages > 60 and < 79 years). There were four dose levels, where the highest dose, or dose four, was twelve times the lowest dose, or dose one, and dose three, the second highest dose, was eight times the lowest dose. In Part A, dose levels one, two, and three were evaluated. The safety data from the sentinel safety group for each dose level was reviewed before permitting enrollment of the expansion group within that dose level cohort. The safety data of each expansion group was reviewed before permitting dose escalation/enrollment of the sentinel safety group at the next dose level. In Part B, all four dose levels were evaluated. The first sentinel dose cohort was triggered after review of the first sentinel dose level cohort in Part A. The safety data from the sentinel safety group for each dose level cohort was reviewed before permitting enrollment of the expansion group within that dose level cohort. The safety data of each expansion group was reviewed before permitting dose escalation/enrollment of the sentinel safety group at the next dose level. Part B includes the highest dose level, dose four, which was enrolled after review of the available safety and immunogenicity data of the preceding Part B dose level cohorts. Expansion groups in Part A and B were both randomized 3:1 mRNA-1777: placebo.

This 200-subject study has been completed. As of April 9, 2018, we have the majority of data through three months (90 days) post-vaccination for younger subjects in dose levels one and two, and for older subjects in doses one, two, and three. Based on the interim data as of April 2018, dose levels one, two, and three of mRNA-1777 were observed to elicit a humoral immune response as measured by neutralizing antibody titers against RSV A, neutralizing antibody titers against RSV B (dose level three only, dose levels one and two have yet to be assayed), absolute serum antibody titers to RSV prefusion F protein and RSV postfusion F protein, and competing antibody titers to RSV prefusion F protein in a dose-dependent manner up to dose level two in both younger and older subjects. The immune response measured by neutralizing antibody titers against RSV A in older adults that received dose level three of mRNA-1777 was not higher than that of the subjects that received dose level two. We have observed an increase in neutralizing antibody titers relative to placebo in younger adult subjects in panel A and older adult subjects in panel B who received our RSV vaccine, as shown in the figure below. In the figure, geometric mean titer and 95% confidence interval are depicted by time for neutralizing antibody titers against RSV A for older and younger subjects. At day ninety, between 10 and 19 healthy younger subjects and between 11 and 27 healthy older subjects were tested at each dose level.

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Neutralizing antibody titers in healthy younger subjects

[Ages>18 and< 49 years] in Phase 1 trial for mRNA-1777 per protocol set

Panel (A)

Neutralizing antibody titers in healthy older subjects

[Ages>60 and< 79 years] in Phase 1 trial for mRNA-1777 per protocol set

Panel (B)

In addition, based on interim data as of April 2018, we observed an increase in T cell response relative to baseline at day 15 and day 60 in both healthy younger and healthy older adult subjects vaccinated with doses two and three of mRNA-1777.

Based on interim safety data as of April 9, 2018, mRNA-1777 was well tolerated with no dose limiting toxicities at dose levels one, two, and three in both the younger and older adults. As of September 2018, the highest dose level, which was evaluated in older subjects only, dose level four, was not as well tolerated as the lower dose levels. However, across all treatment arms, there were no treatment-related serious adverse events, or SAEs, treatment emergent adverse events, or TEAEs, leading to withdrawals, adverse events, or AEs of special interest, or new onset of chronic illnesses or autoimmune disorders in either of the age cohorts. There were no patterns in clinically significant laboratory abnormalities.

As of September 19, 2018, we have observed 15 SAEs in nine subjects, all of which were deemed unrelated to study product. These SAEs occurred approximately one to ten months from receipt of study product and included aortic aneurysm repair, paralytic ileus, spinal decompression, death from pre-existing cardiomyopathy, hernia, transient ischemic attack, peripheral vascular disorder, vasovagal syncope, diagnosis of non-small cell lung cancer, anterior cruciate ligament tear, left knee tendon tear, right knee tendon tear, left patella dislocation, right patella dislocation, and bilateral patella tendon repair.

Based on the interim safety, tolerability, and immunogenicity data in collaboration with Merck, we have opted to pause further development of mRNA-1777. Merck is conducting a Phase 1 trial with mRNA-1172 in the United States.

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CMV vaccine (mRNA-1647): Summary

Our CMV program targets congenital CMV infections to reduce or prevent birth defects

Congenital cytomegalovirus, or CMV, infection is the leading cause of birth defects in the United States. Despite several attempts, to date, there is no vaccine approved to prevent congenital transmission of CMV. We believe that in addition to the glycoprotein B, or gB, protein antigen, a successful CMV vaccine would need to include the Pentamer, a 5-protein membrane-bound antigen complex required for epithelial, endothelial, and myeloid cell infection by the virus. A CMV vaccine containing the Pentamer as a recombinant protein or a replication defective virus is complex to make and scale. We used our platform to generate an mRNA vaccine designed to make the Pentamer in its natural membrane-bound conformation. This investigational medicine is designed to prevent or control CMV infection and includes five mRNAs encoding for the Pentamer, as well as one mRNA encoding for CMV gB that has previously demonstrated partial clinical efficacy. The Phase 1 trial for mRNA-1647 has generated safety and tolerability data, and demonstrated immunogenicity. As of September 2019, interim data from the Phase 1 trial indicated that the vaccine was generally well-tolerated. There were no vaccine-related serious adverse events. The most common solicited local adverse reaction, or AR, was injection site pain. The most common solicited systemic ARs were headache, fatigue, myalgia and chills. A dose-related increase in neutralizing antibody titers was observed in CMV-seronegative participants at seven months (one month after the third vaccination) in the 30, 90 and 180 µg dose levels. Based on the interim data from the Phase 1 trial, we have initiated a Phase 2 trial for mRNA-1647 in the United States.

CMV (mRNA-1647): Disease overview

CMV is a major cause of birth defects with no approved vaccine

Human CMV is a common human pathogen and member of the herpes virus family. Seropositivity, demonstrating prior exposure to virus, increases with age and is approximately 40-60% in women of child-bearing potential in the United States. However, general awareness of CMV is not high. Less than 10-20% of adults are aware of CMV and most healthy adults after initial (primary) CMV infection do not have symptoms. However, approximately 0.6-0.7% of newborns are congenitally infected by CMV annually in industrialized countries. Congenital CMV results from infected mothers transmitting the virus to their unborn child and it is the leading cause of birth defects, with approximately 25,000 newborns per year in the United States infected. Birth defects occur in approximately 20% of infected babies and include permanent neurodevelopmental disabilities, which can include hearing loss (often permanent), vision impairment, varying degrees of learning disability, decreased muscle strength and coordination, and even death. Some studies report approximately one-third of infants with severe congenital disease will die within the first year of life, and the survivors, their caregivers, and health systems bear significant long-term burdens.

There is currently no available vaccine for CMV, and many previous attempts at developing a vaccine to reduce or prevent congenital transmission have been missing a key antigen, the Pentamer. We believe the Pentamer is critical for the infection of epithelial, endothelial, and myeloid cells by the virus. We believe the Pentamer was not included in certain prior recombinant protein vaccine attempts due to the complexity of producing it as a multi-unit antigen complex. Prior vaccine studies demonstrated insufficient efficacy against CMV infection and limited durability of immune response. A vaccine that leads to durable immunity in women of child-bearing age would address a critical unmet need in the prevention of congenital CMV infection.

CMV vaccine (mRNA-1647): Our product concept

We are developing a single vaccine with complex antigens to prevent or control infection

Our ability to generate a multi-antigen vaccine enables us to combine a traditional target antigen (gB) with the Pentamer in order to specifically focus the immune system on these important antigens. We believe this gives us greater potential to produce neutralizing antibodies that can block CMV transmission from the mother to the fetus. Our approach to block transmission could either be:

• direct, by vaccinating adolescents or adults of child-bearing potential (female and male); or

• indirect, by vaccinating toddlers who could spread CMV to each other, their mothers, and their childcare workers.

Unlike a protein-based or live-attenuated vaccine, our mRNA instructs cells to specifically make predetermined antigens with a structure that mimics the one presented to the immune system by the virus, thus focusing the immune system on these important antigens.

mRNA-1647 comprises six mRNAs that encode for these known hard-to-make CMV antigens in a proprietary LNP:

• In CMV seropositive individuals, the majority of neutralizing antibodies target the Pentamer. The CMV Pentamer is made by five CMV glycoproteins that form a membrane-bound complex. The Pentamer is required for CMV entry into epithelial, endothelial, and myeloid cells. The mRNA-expressed Pentamer is displayed on the surface of the cell and stimulates the production of neutralizing antibodies that prevent the virus from entering the cells.

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• gB is a trimeric CMV membrane glycoprotein that abundantly resides on the surface of the viral particles. Fusion between virus and host cells, and hence infection, requires gB. Antibodies to gB can prevent CMV infection. gB has been utilized in some earlier attempts at a CMV vaccine as the sole antigen which had resulted in partial efficacy but not at levels sufficient for approval.

An illustration of our proposed approach for CMV is shown in the figure below.

CMV vaccine (mRNA-1647): Preclinical information

We have published preclinical data for our CMV vaccine

We have demonstrated that the Pentamer and gB mRNAs can elicit potent and durable antibody titers against the antigens in mice and non-human primates, and have published these results in Vaccine in 2018. In one study, mice were immunized with the Pentamer and gB mRNAs encapsulated in our proprietary LNP. Serum samples were taken from the mice at specific timepoints post vaccination. Post-vaccination neutralizing titers were measured by admixing serial dilutions of each sample with CMV virus, incubating the mixture in a human primary epithelial cell culture, and counting the number of infected cells. We used CytoGam, an approved product for prevention of CMV in transplant patients, as a control in our experiment. CytoGam is cytomegalovirus immune globulin from pooled plasma of CMV seropositive donors. The table below shows the neutralization antibody titers in epithelial cells for escalating vaccine doses in mice, demonstrating our ability to generate neutralizing antibodies. We also observed that at the highest dose, our mRNA vaccine generated a response more than 75-fold higher than CytoGam at estimated clinical levels. In addition, we have also observed that the Pentamer and gB mRNAs can elicit strong T cell responses.

Neutralizing titers in human primary epithelial cells for escalating CMV mRNA vaccine doses in mouse study

Dose for vaccine including the Pentamer and gB in our proprietary LNP	At 41 days
	Neutralization titers in epithelial cell
1.2 µg	58,336
3.5 µg	682,989
10.5 µg	457,913
CytoGam comparator (used at maximum concentration of 2 mg/ml observed in human serum)	5,905

CMV vaccine (mRNA-1647): Clinical data

We have demonstrated safety and tolerability and generated immunogenicity data in our Phase 1 trial; based on the interim Phase 1 data, we have initiated a Phase 2 trial with mRNA-1647

We announced positive data from the second interim analysis of the Phase 1 clinical trial of mRNA-1647, which has completed enrollment and is evaluating the safety and immunogenicity of mRNA-1647 in 181 healthy adult volunteers. The clinical trial population includes those who are naïve to CMV infection (“CMV-seronegative”) and those who had previously been infected by

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CMV (“CMV-seropositive”). Participants were randomized to receive either placebo, or 30, 90, 180 or 300 µg of mRNA-1647 on a dosing schedule of 0, 2 and 6 months. This second planned interim analysis assessed safety and immunogenicity of the first three dose levels (30, 90, and 180 µg) at seven months (one month after the third vaccination), and the highest dose level (300 µg) at three months (one month after the second vaccination). Neutralizing antibody titers (levels of circulating antibodies that block infection) were assessed in two assays utilizing epithelial cells and fibroblasts, which measure immune response to the pentamer and gB vaccine antigens, respectively. gB antigen-specific T cell responses after the second and third vaccinations were measured in a subset of CMV-seronegative participants in the 30, 90 and 180 µg dose levels utilizing an ELISpot assay. Pentamer-specific T cell assays remain in development. Vaccine-induced neutralizing antibody responses in the CMV-seronegative group were compared to the baseline neutralizing antibody titers in the CMV-seropositive group, noting that prior maternal CMV infection is associated with an approximately 30-fold lower risk of congenital CMV infection compared to the risk in the setting of maternal primary CMV infection.

In CMV-seronegative participants at seven months (one month after the third vaccination) in the 30, 90 and 180 µg dose levels:

A dose-related increase in neutralizing antibody titers was observed in both epithelial cell and fibroblast assays.

After the third vaccination, neutralizing antibody titers against epithelial cell infection were greater than 10 times higher in the 90 and 180 µg dose levels than CMV-seropositive baseline titers at the 90 and 180 µg dose levels.

After the third vaccination, neutralizing antibody titers against fibroblast infection were 1.3 to 1.4 times higher than CMV-seropositive baseline titers at the 90 and 180 µg dose levels.

In CMV-seropositive participants at seven months (one month after the third vaccination) in the 30, 90 and 180 µg dose levels:

A dose-related increase in neutralizing antibody titers was observed in both epithelial cell and fibroblast assays.

The third vaccination boosted neutralizing antibody titers against epithelial cell infection to levels of 22-fold to 40-fold over baseline titers in all dose levels.

The third vaccination boosted neutralizing antibody titers against fibroblast infection to levels of approximately 4-fold to 6-fold over baseline titers in all dose levels.

Participants receiving 300 µg of mRNA-1647 followed through three months (one month after the second vaccination) continued to show consistent dose-dependent increases in neutralizing antibodies against epithelial cell infection and against fibroblast infection in both CMV-seronegative and CMV-seropositive groups. Safety and tolerability in participants receiving 300 µg of mRNA-1647 was comparable to that observed at the 180 µg dose level. In a subset of CMV-seronegative participants in the 30, 90 and 180 µg dose levels, gB antigen-specific T cell activation was observed at all dose levels after the second and third vaccinations.

A safety analysis indicated that the vaccine was generally well-tolerated. There were no vaccine-related serious adverse events. The most common solicited local adverse reaction, or AR, was injection site pain. The most common solicited systemic ARs were headache, fatigue, myalgia and chills. Fever was reported in 0-55% of CMV-seronegative treatment groups and in 8-67% of CMV-seropositive treatment groups. In general, solicited systemic ARs occurred less frequently after the third vaccination compared to the second, and were more common in the CMV-seropositive cohorts compared to the CMV-seronegative cohorts. Grade 3 solicited ARs were more common in CMV-seropositive participants, and were fatigue (0-27% of a given dose cohort), chills (0-27% of a given dose cohort) and fever (0-33% of a given dose cohort). As reported in the previous interim analysis, there was a single Grade 4 AR of an isolated lab finding of elevated partial thromboplastin time, which was elevated at baseline (Grade 1) and self-resolved on the next lab test with no associated clinical findings. Safety and tolerability data at the 300 µg dose level were generally similar to that observed at the 180 µg dose level.

Although the small sample size limits the conclusions that can be drawn from the data, the findings from this interim analysis build on an earlier interim analysis of safety and immunogenicity data through one month after the second vaccination in the 30, 90 and 180 µg dose levels. A 12-month interim analysis of safety and immunogenicity, which will report safety and immunogenicity results through six months after the third vaccination, is pending.

Phase 2 Start and Phase 3 Planning

mRNA-1647 is the first mRNA vaccine for an infectious disease to enter a Phase 2 study. The randomized, observer-blind, placebo-controlled, dose-confirmation Phase 2 study will investigate the safety and immunogenicity of mRNA-1647 in approximately 252 healthy CMV-seronegative and CMV-seropositive adult volunteers in the U.S. Participants are randomized to receive either placebo, or 50, 100, or 150 µg mRNA-1647 on a dosing schedule of 0, 2 and 6 months. This Phase 2 study is testing the intended Phase 3 formulation, which contains the same lipid nanoparticle (“LNP”) used in the Phase 1 study. The first interim analysis will evaluate safety and immunogenicity at three months (one month after the second vaccination) and is intended to inform Phase 3 dose selection.

We are actively preparing for a global randomized, observer-blind, placebo-controlled Phase 3 pivotal study to evaluate the efficacy of mRNA-1647 against primary CMV infection in women of childbearing age. We have solicited and received Type C meeting feedback

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from the U.S. Food and Drug Administration (“FDA”) on the preliminary design of the pivotal trial. We believe this can be achieved with a trial with no more than 8,000 participants and feasibility assessments of study sites has already begun across North America and Europe. The pivotal trial design will be finalized after discussion with the FDA and other global health authorities. Manufacturing and planning are already underway for the pivotal Phase 3 study, which we expect to start in 2021. Additional lot-to-lot consistency and adolescent bridging clinical trials are being planned.

hMPV/PIV3 vaccine (mRNA-1653): Summary

We are developing a vaccine to address two viruses that are leading causes of respiratory infection

Human metapneumovirus, or hMPV, and human parainfluenza virus 3, or PIV3, are important causes of respiratory tract infections in children. Despite the substantial impact hMPV and PIV3 have on human health, attention and research on these viruses have lagged relative to RSV. To date, no vaccine to prevent hMPV or PIV3 infections has been approved. Our platform allows us to combine mRNAs encoding antigens for the two pathogens in one combination vaccine, enabling a single vaccine that could protect against both respiratory infections. In our approach, we utilize mRNA sequences encoding for the membrane fusion (F) glycoproteins, or F proteins, for each of the viruses. We have generated safety, tolerability, and immunogenicity data from the Phase 1 trial for mRNA-1653 in the United States which has been completed. Based on this data, we have a Phase 1b trial for mRNA-1653 ongoing in the United States in healthy adults and children aged 12-36 months.

hMPV/PIV3 vaccine (mRNA-1653): Disease overview

hMPV and PIV3 have a substantial impact on human health yet have lagged in research and attention relative to RSV

There is no approved vaccine for hMPV although this RNA virus has been determined to be one of the more frequent causes of upper and lower respiratory tract infections. hMPV has been detected in 4% to 15% of patients with acute respiratory infections. hMPV causes disease primarily in young children but can also infect adults, the elderly, and immunocompromised individuals. Clinical signs of infection range from a mild upper respiratory tract infection to life-threatening severe bronchiolitis and pneumonia. hMPV was discovered in 2001 and identified as a leading cause of respiratory infection.

There is no approved vaccine for PIV3 although this RNA virus is recognized as an important cause of respiratory tract infections in children. Infections from parainfluenza virus, or PIV, account for up to 7% of acute respiratory infections among children younger than 5 years. Of the four PIV types identified, PIV3 most frequently results in infections and leads to the more serious lower respiratory tract infections compared to the other three PIV types. Though PIV3 related infections were identified in the past, awareness of their burden to patients and hospitals has risen over the past several years.

The majority of hMPV or PIV3-associated hospitalizations in children occur under the age of 2 years. Despite the substantial impact hMPV and PIV3 have on human health, attention and research on these viruses have lagged relative to RSV. Awareness of hospitalizations due to hMPV or PIV3 infections have risen, and we believe that a single vaccine intended for active immunization of infants and toddler against both hMPV and PIV3 would be valuable. Previous attempts at developing a vaccine have focused on only hMPV or PIV alone with no known attempts at a combination vaccine.

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hMPV/PIV3 vaccine (mRNA-1653): Our product concept

Our approach is to develop a combination vaccine for all infants and toddlers

mRNA-1653 is a single investigational vaccine consisting of two distinct mRNA sequences that encode the membrane F proteins of hMPV and PIV3, co-formulated in our proprietary LNP as shown in the figure below.

hMPV/PIV3 vaccine (mRNA-1653): Preclinical information

Our mRNA vaccine is immunogenic in multiple species

We have evaluated multiple combinations for hMPV/PIV3 mRNA vaccines encoding full-length F proteins for hMPV and PIV3 viruses in mice, Sprague Dawley rats, cotton rats, and African green monkeys, or AGM, each following intramuscular, or IM, injection. These studies demonstrate that mRNA encoding for F proteins from these viruses induce robust neutralizing antibody titers in all species tested. For example, neutralizing antibody titers for mRNA encoding for F proteins of hMPV and PIV3 encapsulated in LNP in mice are shown in the figure below. C57Bl/6 mice were immunized with 0.33, 2, or 12 µg of formulated material intramuscularly on study days 1 and 29. Neutralizing antibody titers were measured in serum collected on day 43. Results are represented as geometric mean titers, or GMT, of seven mice per group. In the figure below, neutralizing antibody titers in mice after immunization with mRNA for hMPV and PIV3 in our proprietary LNP by hMPV (left panel) and PIV3 (right panel) are depicted along with the lower limit of quantification, or LLOQ, of the assay.

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Neutralizing antibodies are thought to be important for protection against hMPV and PIV3. The titer of neutralizing antibodies induced by natural infection from hMPV or PIV3 can be used to benchmark the titers induced by our hMPV/PIV3 vaccine in preclinical models and in our clinical trial. We determined the geometric mean neutralizing antibody titer for 15 seropositive adult donors to be 3,807 (range 499 to 20,751) for hMPV, and 263 (range 47 to > 1024) for PIV3. Our hMPV/PIV3 mRNA vaccine induces a similar neutralizing antibody titer in mice after 2 vaccinations of the dose levels evaluated as shown in the figure above, and we believe it has the potential to confer protection in humans.

We have demonstrated that our hMPV and PIV3 mRNA combination vaccine does not lead to vaccine-enhanced respiratory disease (evaluated in cotton rats) and is protective against hMPV or PIV3 viral challenge (evaluated in cotton rats and AGM).

hMPV/PIV3 vaccine (mRNA-1653): Clinical data

We have generated safety, tolerability, and immunogenicity data from a Phase 1 trial in the United States which has been completed; based on the data, we have a Phase 1b trial in healthy adults and children aged 12-36 months ongoing in the United States

The mRNA-1653 Phase 1 study is a blinded, randomized, observer-blind, placebo-controlled, dose ranging first-in-human study to evaluate the safety and tolerability, reactogenicity, and immunogenicity of mRNA-1653 in healthy adult subjects in the United States. The study evaluates four dose levels of mRNA-1653 (25, 75, 150, and 300 µg) administered intramuscularly at day one and month one, with the one-month immunization randomized to be mRNA-1653 or placebo in the dose selection phase of the study.

The key objectives of the study include evaluating:

• safety and reactogenicity of mRNA-1653 through 28 days after the last vaccination;

• humoral immunogenicity of mRNA-1653 through 28 days after the last vaccination;

• optimal dose and vaccination schedule of mRNA-1653 for further clinical development; and

• safety of mRNA-1653 through 12 months after the second vaccination.

The key endpoints for the study include safety and tolerability of mRNA-1653.

The schematic of the trial is shown in the figure below. In the dose-escalation phase, there was sequential enrollment into one of the four dose levels of mRNA-1653 or placebo. Advancement to the next dose level was permitted after an internal safety review. In the dose-escalation phase, five subjects were randomly assigned in a 4:1 ratio to receive mRNA-1653 or placebo. The safety monitoring committee, or SMC, reviewed safety data after dose-escalation enrollment was completed to permit enrollment into the dose-selection phase at the three highest dose levels with acceptable safety profiles. In addition, the SMC periodically reviewed safety data during the dose-selection phase.

124 subjects were enrolled in the study and subjects received both doses. Based on an unblinded evaluation of safety data from the dose-escalation phase by the SMC, the three highest dose levels (75, 150, and 300 µg) were evaluated in the dose-selection phase. The study has been completed.

Interim data from the Phase 1 trial showed that a single vaccination with mRNA-1653 boosted serum neutralization titers against hMPV and PIV3, and that the magnitude of the boost was similar at all dose levels tested. Consistent with prior exposure to hMPV and PIV3, all study participants had neutralizing antibodies against both viruses at baseline. One month after a single mRNA-1653 vaccination, the hMPV neutralization titers were approximately six-fold greater than baseline and PIV3 neutralization titers were

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approximately three-fold greater than baseline (based on geometric mean ratios). A second mRNA-1653 vaccination one month after the first vaccination did not further boost antibody titers. In addition, the interim data showed that hMPV and PIV3 serum neutralizing antibody titers remained above baseline through seven months. mRNA-1653 was found to be generally well tolerated. No SAEs, adverse events of special interest, or adverse events leading to withdrawal were reported. Injection site pain was the most commonly reported AE and the most common grade 3 AE.

We are conducting a Phase 1b trial to evaluate mRNA-1653 in healthy adults and children aged 12-36 months. The Phase 1b trial is a randomized, observer-blinded, placebo-controlled, dose-ranging trial to evaluate the safety and immunogenicity of two dose levels of mRNA-1653 in healthy adults (18-49 years of age) and three dose levels in children (12-36 months of age) with serologic evidence of prior hMPV and PIV3 exposure. As of February 12, 2020, 24 adults were randomized in the ratio 1:1:1 to receive two doses of 30 μg of mRNA-1653, 150 μg of mRNA-1653, or placebo two months apart.

Pediatric RSV vaccine (mRNA-1345): Summary

We are developing a pediatric RSV vaccine which we intend to ultimately combine with mRNA-1653, our hMPV/PIV3 vaccine, to address a wide array of viral respiratory illness in young children.

RSV is one of the most common causes of respiratory disease in infants and children under the age of five. Together with human metapneumovirus (“hMPV”) and human parainfluenza virus 3 (“PIV3”), the three viruses represent the majority of the causes of respiratory tract infections in children. To date, no vaccine to prevent any of these three infections has been approved. Our platform allows us to combine mRNAs encoding multiple antigens in one vaccine, utilizing mRNA sequences encoding for the membrane fusion (F) glycoproteins (“F proteins”) for each of the viruses. We believe we can develop a single vaccine that could protect against all three respiratory infections in young children. We intend to develop mRNA-1345 independently in early clinical development, and subsequently to evaluate its use in combination with mRNA-1653.

To date, no effective vaccine to prevent RSV has been approved, and the only approved prophylactic treatment is the monoclonal antibody (“mAb”) palivizumab, marketed as SYNAGIS in the United States for pediatric patients at high risk for RSV infection. The pediatric RSV vaccine mRNA-1345 is being developed for active immunization of young children to protect them from RSV-associated respiratory disease. Like our RSV development candidates in collaboration with Merck, mRNA-1777 and mRNA-1172 or Merck V172, the pediatric RSV vaccine mRNA-1345 encodes a membrane-anchored version of the stabilized prefusion F protein, the main target of potently neutralizing and protective antibodies. mRNA-1345 was engineered for increased expression and immunogenicity relative to mRNA-1777, and the mRNA and protein sequence of mRNA-1345 are distinctive from both mRNA-1777 and mRNA-1172 or Merck V172. The pediatric RSV vaccine mRNA-1345 is formulated in our proprietary LNP and is being developed solely by us. Under the terms of our collaboration with Merck, we retain the right to commercialize certain mRNA vaccines for the prevention of RSV infection in populations of up to 12 years of age when in combination with our hMPV and PIV3 vaccine (mRNA-1653).

Pediatric RSV vaccine (mRNA-1345): Disease overview

RSV is the leading cause of unaddressed severe lower respiratory tract disease and hospitalization in infants and young children worldwide.

RSV is a common cause of respiratory tract illness, with most children infected at least once by two years of age. The virus is transmitted primarily via contamination of environmental surfaces with infectious secretions, and symptoms typically begin within several days of exposure. The illness may manifest as wheezing, bronchiolitis, pneumonia, hospitalization or even death. In the United States, it is estimated that over two million children younger than five years of age receive medical attention and more than 86,000 are hospitalized due to RSV infection annually. Globally, it is estimated that RSV is responsible for over approximately 33 million episodes of acute lower-respiratory tract infection, 3.2 million hospitalizations and as many as 118,000 deaths per year in children younger than five years of age. Infections with RSV follow a seasonal pattern, occurring primarily in the Northern Hemisphere between the months of November and April, and primarily in the Southern Hemisphere between the months of March and October.

Pediatric RSV vaccine (mRNA-1345): Our product concept

Prevent RSV disease in young children with an improved RSV antigen and our proprietary LNP formulation in the context of a combination vaccine that prevents other viral respiratory illnesses.

The pediatric RSV vaccine mRNA-1345 encodes an engineered form of the RSV F proteins stabilized in the prefusion conformation and is formulated in our proprietary LNP. The F protein is present as a homotrimer on the surface of RSV. The prefusion conformation of the F protein interacts with a host cell membrane, and the conformational change from prefusion to postfusion drives virus fusion with a host cell. The majority of RSV-specific neutralizing antibodies in convalescent people are directed to epitopes present only on the prefusion conformation of the F protein. The prefusion state of the F protein elicits a superior neutralizing antibody response compared to the postfusion state in animal studies conducted by others. A schematic of the prefusion F protein on the surface of a host

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cell, with sites recognized by neutralizing antibodies, is depicted in the figure below; the inset on the left of the figure shows the intended design of the mRNA formulated in our proprietary LNP, the same LNP formulation as mRNA-1653, and the inset on the right shows the intended prefusion F protein on the surface of the cell. We believe that neutralizing antibodies elicited by mRNA-1345 may lead to an efficacious RSV vaccine in young children.

Pediatric RSV vaccine (mRNA-1345): Preclinical information

We evaluated expression and conformation of the F protein by treating cultured cells with mRNA from mRNA-1345 and measuring F protein on the cell surface using a prefusion conformation-indicating mAb called AM14. The figure below shows that prefusion F protein is detected on cells treated with mRNA-1345, and at a greater level than cells treated with mRNA-1777.

RSV-F expression by cultured cells treated with mRNA from mRNA-1345 or mRNA-1777

We have demonstrated that the pediatric RSV vaccine mRNA-1345 induces robust RSV neutralizing antibody titers in mice. For example, the left panel below shows the results of a study in which mice were immunized with different dose levels of mRNA-1345 intramuscularly on study days 1 and 21 and RSV neutralizing antibody titers were measured in serum collected on day 33. When compared to the results of a similar mouse study conducted with mRNA from mRNA-1777 formulated in the same proprietary LNP as mRNA-1345, the pediatric RSV vaccine mRNA-1345 was shown to be significantly more immunogenic. We believe we can leverage

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our body of non-clinical, clinical and CMC experience from our vaccine portfolio to expedite preclinical development of our pediatric RSV mRNA-1345 vaccine.

Serum neutralizing titers in mice for mRNA-1345 and for mRNA-1777 mRNA formulated in our same proprietary LNP

Clinical trials of a formalin-inactivated RSV vaccine conducted in the 1960s resulted in higher rates of severe RSV disease in vaccinated infants than in control infants, a finding referred to as vaccine enhanced respiratory disease (“ERD”). It is thought that nucleic acid-based vaccines, including mRNA, present a lower risk of ERD because of their biologic similarities with live virus. Given that the pediatric RSV vaccine mRNA-1345 is designed to enable intracellular production of prefusion F protein by a person’s own cells, we believe that it likely recapitulates the antigenic presentation and immune cell stimulation as seen with natural infection. Further, the mRNA-1777 RSV vaccine did not predispose for ERD in a cotton rat RSV model. To provide further confirmation that the pediatric RSV vaccine mRNA-1345 does not present a risk for ERD, additional preclinical studies will be conducted prior to clinical development of mRNA-1345 in RSV seronegative children or infants.

Pediatric RSV vaccine (mRNA-1345): Clinical plan

We plan to conduct a Phase 1 dose-ranging safety and immunogenicity trial for mRNA-1345 in healthy adults and proceed to RSV-seropositive children after a review of the adult data. Following the assessment of the results of this Phase 1 study and potential future dose-ranging studies in younger RSV-seronegative children, we plan to evaluate the timeline for the combination of mRNA-1345 with mRNA-1653, our hMPV/PIV3 vaccine, for further development as a combination RSV/hMPV/PIV3 vaccine.

Epstein-Barr Virus vaccine (mRNA-1189): Summary

Our EBV vaccine seeks to prevent the development of infectious mononucleosis and EBV infection.

EBV, a member of the herpesvirus family that includes CMV, infects approximately 90% of people by adulthood, with primary infection typically occurring during childhood and late adolescence (approximately 50% and 89% seropositivity, respectively) in the U.S. EBV is the major cause of infectious mononucleosis (“IM”) in the U.S., accounting for over 90% of the approximately 1-2 million cases of IM in the U.S. each year. IM can debilitate patients for weeks to months and, in some cases, can lead to hospitalization and splenic rupture. EBV infection is associated with the development and progression of certain lymphoproliferative disorders, cancers, and autoimmune diseases. In particular, EBV infection and IM are associated with increased risk of developing multiple sclerosis (“MS”), an autoimmune disease of the central nervous system. There is no approved vaccine or effective treatment for EBV. Similar to CMV, EBV has lytic and latent stages in its lifecycle and contains on its surface (envelope) multiple glycoproteins and glycoprotein complexes (gp350, gH/gL, gH/gL/gp42 and gB) that mediate virus entry and infection in different cell types. EBV gp350 mediates attachment to B cells through binding to the complement receptor 2 (“CR2”), followed by binding of the viral gH/gL/gp42 complex to human leukocyte antigen (“HLA”) class II. Infection of epithelial cells instead requires binding of gH/gL to a

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different set of receptors. For both B cell and epithelial cell entry, binding of an EBV gH/gL complex to a cell-specific receptor leads to activation of gB, which in turn facilitates virus-cell-membrane fusion and infection. gH/gL and gB comprise the core viral-fusion machinery conserved across all herpesviruses.

Similar to our CMV vaccine (mRNA-1647) product concept, we used our platform to generate an mRNA vaccine containing five mRNAs encoding for gp350, gB, gH, gL, and gp42, which are expressed in their native membrane-bound conformation for recognition by the immune system. We have observed preclinical immunogenicity in the form of high and durable levels of antigen-specific antibodies against both B cell and epithelial cell infection in mice and in non-human primates (“NHPs”). We intend to conduct a Phase 1 trial to test the safety and immunogenicity of the vaccine to understand its potential to prevent primary infection, and prevent IM following EBV infection, in seronegative adults.

Epstein-Barr Virus: Disease overview

EBV is the major cause (approximately 90%) of IM and has been associated with the development of a range of malignancies and autoimmune disorders.

EBV is a common herpesvirus that is spread through bodily fluids, most commonly saliva, and is contracted primarily by young children and adolescents. Adolescents and young adults seroconvert at high rates, particularly in college-aged populations (approximately 10-25% per year) resulting a seroprevalence of approximately 90% by the age of 20. After primary infection, the virus establishes latency and persists in that state for life in most infected individuals. The virus can reactivate intermittently over time even in immunocompetent hosts. The virus usually infects resting B cells in the oropharynx or epithelial cells, which line the mucosal surfaces of the body and in turn infect B cells. B cells disseminate systemically and act as a reservoir for latent virus. Primary infection can cause IM in 35% to 75% of instances, depending on age, and is characterized by symptoms requiring physician visits, including sore throat, lymph node swelling, fever, body aches and fatigue, often resulting in months of missed work and school for patients and caregivers.

There is currently no approved vaccine against EBV, but the potential of gp350 alone to reduce the rate of IM has already been clinically demonstrated. An experimental vaccine, developed by others, consisting of adjuvanted recombinant gp350 protein led to a reduction in the incidence of IM in 78% of the participants in a Phase 2 study of 181 healthy volunteers between the ages of 16-25. However, there was no significant difference between groups in protection against asymptomatic EBV infection. We believe that the addition of gH/gL and gB has the potential to provide protection against epithelial cell infection. We believe the immune response against gp350, gH/gL or gB has the potential to provide B cell protection, which may be further enhanced by the inclusion of gp42. By preventing infection in epithelial cells and B cells, this mRNA vaccine has the potential not only to significantly reduce the rate of IM, but also to prevent EBV infection.

EBV infection is associated with increased risk of developing certain cancers and multiple sclerosis. In Western industrialized countries, EBV is implicated in the development of post-transplant lymphoproliferative disorder conditions as well as multiple cancers, including Hodgkin’s lymphoma. Additionally, in those seropositive for EBV, development of infectious mononucleosis is associated with a greater than 2-fold increased relative lifetime risk of developing multiple sclerosis. In East Asia, EBV is associated with 80-99% of nasopharyngeal carcinomas that arise. In Africa, EBV is implicated in the development of approximately 95% of cases of endemic Burkitt’s lymphoma. Together, approximately 1.5% of worldwide cancer deaths are attributable to EBV-associated malignancies.

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EBV vaccine (mRNA-1189): Our product concept

We are developing a vaccine with multiple antigens designed to prevent development of infectious mononucleosis and EBV infections.

Similar to our CMV vaccine (mRNA-1647) product concept, we believe that an effective EBV vaccine must generate an immune response to antigens that are required for viral entry in most of the susceptible cell types. We have thus designed our EBV vaccine, mRNA-1189, to elicit an immune response to EBV envelope glycoproteins gp350 as well as gB, gp42, and the gH/gL complex, which are required for infection of both epithelial and B cells. mRNA-1189 contains five mRNAs encoding the viral proteins gp350, gB, gp42, gH, and gL encapsulated in our proprietary LNPs. Proteins translated from our mRNA will be displayed on the cell surface in their native conformation, stimulating the production of neutralizing antibodies. By training the immune system to recognize and neutralize the machinery used to infect B and epithelial cells, we believe that our vaccine has the potential to prevent EBV primary infection and therefore the development of IM. Further, in the long-run, should our EBV vaccine be approved, we may pursue post-marketing and population studies to potentially evaluate its impact on other EBV-associated diseases. Our EBV vaccine utilizes the same proprietary platform technology as our CMV vaccine (mRNA-1647), which was generally well-tolerated and demonstrated durable neutralizing antibody titers higher than those measured in CMV-seropositive patients following up to three doses of mRNA-1647 in our Phase 1 trial.

EBV vaccine (mRNA-1189): Preclinical information

We have demonstrated the ability to induce antibodies against EBV antigens required for viral entry into B cells and epithelial cells.

Naïve Balb/c mice were given two doses of a vaccine against EBV antigens in combination approximately four weeks apart. Antibody titers against viral proteins involved in epithelial cell entry (gH/gL and gB) or B cell entry (gp350, gH/gL and gB) were measured in peripheral blood at day 57. Results shown here represent five animals per group and demonstrate high levels of antigen-specific immunoglobulin G (“IgG”) as compared to negative controls.

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Day 57 post-vaccination

EBV vaccine (mRNA-1189): Clinical plan

We are planning a Phase 1 clinical trial to test the safety and immunogenicity of mRNA-1189 in seronegative adults.

We intend to conduct a Phase 1 trial to test the safety and immunogenicity of the vaccine to understand its potential to prevent primary infection, and prevent IM following EBV infection, in seronegative adults.

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PROPHYLACTIC VACCINES: GLOBAL HEALTH PROGRAMS

Our global health portfolio for prophylactic vaccines seeks to leverage our mRNA technology to address epidemic and pandemic diseases. We are currently working with strategic collaborators such as BARDA, DARPA, and NIH to fund and support our programs within this area. The first programs in this portfolio, H10N8 vaccine and H7N9 vaccine, helped identify and overcome the technical challenges with mRNA vaccines and could eventually address pandemics for these viruses. We have also gone from mRNA sequence to a first-in-human trial for Zika vaccine in twelve months. As we continue to build infrastructure and capabilities in the Research Engine and Early Development Engine, we believe we can help address future pandemics rapidly. Given current funding and priorities, the influenza H10N8 vaccine (mRNA-1440) and chikungunya vaccine (mRNA-1388) are being deprioritized at this time, contingent upon future funding. Discussions on funding the Company’s influenza H7N9 vaccine program through approval are ongoing.

Through investment in our platform and manufacturing technology, we have established the capability to design and manufacture small batches of cGMP vaccines within 60 days. This has been clinically demonstrated by our Personalized Cancer Vaccine (“PCV”) program (mRNA-4157), for which we have demonstrated the ability to manufacture and release a “custom-designed” vaccine for an individual patient within 60 days of sequencing the patient’s tumor. We believe that this capability can be applied to rapidly produce clinical supply of mRNA vaccine candidates for early clinical studies. In collaboration with the Vaccine Research Center (“VRC”) and Division of Microbiology and Infectious Diseases (“DMID”) of the National Institute of Allergy and Infectious Diseases (“NIAID”), part of the National Institutes of Health (“NIH”), as well as the Coalition for Epidemic Preparedness Innovations (“CEPI”), we are pursuing the rapid manufacture of a vaccine to address the current SARS-CoV-2 outbreak. We have leveraged our learnings across our vaccines to design and manufacture clinical supplies for our SARS-CoV-2 vaccine in 25 days. SARS-CoV-2 was first identified in Wuhan, China on January 7, 2020.

SARS-CoV-2 vaccine (mRNA-1273): Summary

In collaboration with the NIH and CEPI we are rapidly developing a vaccine to address the SARS-CoV-2 outbreak.

In collaboration with the NIH and CEPI, we are applying our platform for rapid vaccine design and manufacture to produce a vaccine against SARS-CoV-2 virus in response to the currently emerging outbreak of SARS-CoV-2. SARS-CoV-2 is a novel coronavirus that has infected thousands of people since identification on January 7, 2020, spreading to multiple continents. In collaboration with the VRC, we are developing an mRNA-based vaccine designed to express the coronavirus Spike (S) protein based on the genomic sequence of SARS-CoV-2. On January 13, 2020, the NIH and our infectious disease research team finalized the sequence for the SARS-CoV-2 vaccine and we mobilized toward clinical manufacture. As of February 24, 2020, the first clinical batch has been shipped to and received by the NIH for use in their planned Phase 1 clinical trial in the U.S.

SARS-CoV-2: Disease overview

SARS-CoV-2 is a novel coronavirus with demonstrated animal-to-human and human-to-human transmission that has spread rapidly from China to multiple continents.

Coronaviruses are a family of viruses that can lead to respiratory illness, including Middle East Respiratory Syndrome (“MERS”) and Severe Acute Respiratory Syndrome (“SARS”). Coronaviruses are transmitted between animals and people and can evolve into strains not previously identified in humans. On January 7, 2020, SARS-CoV-2 was identified as the cause of pneumonia cases in Wuhan, China, and additional cases have been found in a growing number of countries.

Estimates from the World Health Organization as of February 19, 2020 indicate that there are approximately 75,000 confirmed cases in at least 25 countries and over 2,000 deaths worldwide. The suspected number of infections is likely to be substantially higher. It is important to note that there is not yet a good understanding of the rate of asymptomatic infection. Currently, there are no approved vaccines specific to SARS-CoV-2.

SARS-CoV-2 vaccine (mRNA-1273): Our product concept

We are developing a vaccine against the Spike protein complex to prevent SARS-CoV-2 infection.

In collaboration with the VRC, we have selected the viral Spike protein as the antigen for our SARS-CoV-2 vaccine (mRNA-1273). Our vaccine includes mRNA encoding the Spike protein, which we believe will form a homotrimeric complex on the cell surface as it does when expressed on the surface of coronavirus particles. The Spike protein complex is necessary for membrane fusion and host cell infection and has been the target of experimental vaccines against the coronaviruses responsible for MERS and SARS. We are leveraging our manufacturing platform to respond rapidly to the ongoing public health crisis.

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SARS-CoV-2 vaccine (mRNA-1273): Representative preclinical information regarding a related coronavirus, MERS

We have demonstrated the ability to induce neutralizing antibodies that confer protection against viral challenge with a related coronavirus, MERS.

We have begun evaluating our SARS-CoV-2 vaccine construct in animal models, with further testing of the clinical batch expected shortly. In an existing collaboration with the VRC to develop a vaccine against MERS, we designed an mRNA-based vaccine targeting the prefusion-stabilized Spike protein.

In preclinical studies to assess the immunogenicity of the potential vaccine against MERS, rabbits were dosed with either one or two doses of vaccine (one dose plus a booster at day 21) and then challenged with MERS virus at day 42. At day 46, MERS viral load was measured in the throat and nose, and via bronchoalveolar lavage (“BAL”). We observed induction of neutralizing antibodies which were sufficient to affect an approximately 3-log reduction in viral titers in the nose, and approximately 4-log reduction in viral titers detected from BAL. Viral titers in the throat were reduced to the lower limit of detection.

MERS neutralizing antibody titer MERS viral load Day 46 (4 days post-challenge)

H10N8 vaccine (mRNA-1440) and H7N9 vaccine (mRNA-1851): Summary

Our H10N8 and H7N9 investigational vaccines demonstrate the potential of our platform to respond to an influenza pandemic

Influenza is one of the most variable and deadly infectious diseases, ranging from 12,000-56,000 deaths per year in the United States alone. The antigens in circulating seasonal influenza strains change slightly, which is called antigenic drift, from one year to the next, necessitating a change in the vaccine to match the new strains. Potential pandemic influenza strains can arise very quickly from substantial changes in antigens, which is called antigenic shift, and because pre-existing immunity is nonexistent in some populations, they can be pathogenic. Addressing a potential pandemic requires the ability to produce an effective vaccine rapidly. We believe that our platform enables the rapid development of safe and effective vaccines. As a proof of concept, we developed vaccines for H10N8 and H7N9 avian influenza strains, where there is a quantitative correlate for protection in humans (hemagglutinin inhibition, or HAI, titer of > 1:40). We have observed tolerability and immunogenicity in Phase 1 clinical trials for both mRNA vaccines for H10N8 and H7N9 and have published preclinical and interim clinical data for H10N8 in Molecular Therapy in 2017 and Phase 1 results for H10N8 and H7N9 in Vaccine in 2019. We do not intend to progress these programs through clinical development on our own. We may advance these programs with government or other grant funding.

H10N8 vaccine (mRNA-1440) and H7N9 vaccine (mRNA-1851): Disease overview

Traditional vaccines cannot respond easily to a new influenza pandemic

Influenza A is an RNA virus, with a genome packed into eight individual gene segments that code for at least eleven functional proteins needed for infection, replication, and evasion of host antiviral responses. The two major glycoproteins expressed on the surface of the virion are hemagglutinin, or HA, and neuraminidase, or NA, both of which are crucial for infection. HA mediates viral entry into host cells by binding to sialic acid containing receptors on the host cell surface and causing fusion of viral and host endosomal membranes. NA mediates enzymatic cleavage of the viral receptor at late stages of infection, allowing for the release of progeny virions.

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Influenza A viruses infect a variety of species, including birds, pigs, sea mammals, and humans. Wild aquatic birds serve as the reservoir of influenza A viruses infecting avian and mammalian species. Although many of these viruses are non-pathogenic in birds and most do not infect humans, in recent decades, some avian influenza viruses such as H10N8 and H7N9 have crossed the species barrier to cause human disease.

There have been five epidemics of human infection due to H7N9, totaling over 1,500 cases, with mortality rates of 34-47%. To date, there have been three reported cases of H10N8, of which two have been fatal. For both H10N8 and H7N9, severe or fatal infections are characterized by rapid progression to respiratory failure within days of initial symptoms.

There are efforts ongoing to develop a H7N9 vaccine and a universal influenza vaccine that covers H10N8. However, we believe the use of traditional methods to produce these vaccines can lead to several shortcomings in the vaccine. These include:

• production of vaccines in eggs requires selection of vaccine-virus strains that can be grown in eggs and this strain may not always match the pandemic strain; and

• growth of the virus in eggs has also been shown to induce structurally relevant mutations that can negatively impact vaccine potency.

H10N8 vaccine (mRNA-1440) and H7N9 vaccine (mRNA-1851): Our product concept

Our platform can bring mRNA encoding for influenza HA antigen to clinical testing rapidly

Our H10N8 and H7N9 influenza vaccine programs are each based on the mRNA sequence for the cell viral HA membrane protein in a legacy LNP. mRNA-1440 encodes for the HA protein of the H10N8 strain and mRNA-1851 encodes for the HA protein of the H7N9 strain.

We believe that mRNA technology offers several advantages to traditional approaches of producing these vaccines, including:

• short time period between strain selection and when the vaccine can be made available; this is enabled by intrinsic features of mRNA and the infrastructure we have built, allowing for shorter research and development and time to manufacture;

• potential improved vaccine efficacy by avoidance of egg-based manufacture; this prevents the antigenic mismatch due to egg-adapted strains;

• potential for improved efficacy by way of improved antigen presentation; an mRNA vaccine, upon administration to a cell, produces the antigen in its natural conformation; and

• combination of multiple antigens into a single vaccine, allowing one to target multiple strains if needed; one of the intrinsic features of mRNA is the ability to utilize multiple mRNA sequences so that the cell produces multiple antigens at the same time.

H10N8 vaccine (mRNA-1440) and H7N9 vaccine (mRNA-1851): Preclinical information

We have observed immunogenicity of our mRNA H10N8 vaccine in multiple species

The level of a vaccine’s protection against influenza infection is traditionally measured using the HAI assay. The European Medicines Agency, or EMA, and U.S. Food and Drug Administration, or FDA, have endorsed HAI titers of > 1:40 to indicate an antibody level considered to be 50% protective against infection. This benchmark was based on data from inactivated vaccines and varies with age group and setting.

Proof-of-concept for the use of mRNA vaccines encoding the HA protein from H10N8 has been demonstrated in murine studies. After a single dose of H10N8 vaccine, mice exhibited antibody production sufficient to achieve HAI titers of > 1:40, which is regarded as a quantitative correlate for protection from influenza. Supporting immunogenicity data in ferrets and cynomolgus monkeys for the H10N8 vaccine have also been published by us in Molecular Therapy in 2017.

We have also observed immunogenicity of our mRNA H7N9 vaccine in multiple species

Proof-of-concept for the use of mRNA vaccines encoding the HA protein from H7N9 influenza A virus has been demonstrated in murine studies. After vaccination with mRNA vaccines, mice exhibited antibody production sufficient to achieve HA inhibition titers of > 1:40. Additionally, a single dose of H7N9 vaccine protected 100% of mice from a lethal challenge with H7N9 virus even 84 days after completion of immunization. In a ferret study where H7N9 vaccine was administered intradermally, a reduction in

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lung viral titers was observed when ferrets were challenged 7 days post immunization. Supporting immunogenicity data in cynomolgus monkeys have also been reported by us in Molecular Therapy in 2017.

H10N8 vaccine (mRNA-1440) and H7N9 vaccine (mRNA-1851): Clinical data

The Phase 1 clinical trial for H10N8 in Germany has been completed and we have generated safety and tolerability data and demonstrated immunogenicity

The results of the Phase 1 trial for H10N8 vaccine were reported by us in Vaccine in 2019. The trial met its objectives of describing the safety and tolerability profile of mRNA-1440 vs. placebo including capturing solicited and unsolicited local and systemic adverse events. The Phase 1 trial for H10N8 vaccine has also demonstrated immunogenicity and we have observed 100% of the subjects demonstrating hemagglutinin inhibition, or HAI, titer > 1:40 at day 43 (21 days post-second vaccination) for the 100 µg dose where HAI > 1:40 is regarded as a quantitative correlate for protection from influenza. We believe the data provides support to advance the program in clinical development if we choose to with additional government or other funding. In this randomized, double-blind, placebo-controlled, dose-ranging study, we evaluated safety and immunogenicity of IM dose levels of 25, 50, 75, 100, and 400 µg on a two-dose vaccination schedule on Day 1 and Day 21. We also evaluated intradermal, or ID, dose levels of 25 and 50 µg on a two-dose vaccination schedule on Day 1 and Day 21. The study objectives were safety, tolerability, and immunogenicity by HAI, and microneutralization, or MN, assays. 201 subjects were enrolled in this study, of which 145 received IM vaccination and 56 received ID vaccination. Of the 145 subjects in the IM vaccination group, there were 30, 30, 24, 23, and 3 subjects in the 25, 50, 75, 100, and 400 µg dose level groups, respectively. Thirty-five subjects received the placebo. The Phase 1 trial was conducted with the name of the intervention listed as VAL-506440, in accordance with our legacy naming convention. We have since changed our naming convention and have adopted mRNA-1440 in place of VAL-506440.

Doses up to 100 µg administered IM demonstrated immunogenicity in the Phase 1 trial. The 75 µg cohort was started later and we chose not to proceed with its completion because the safety, tolerability, and immunogenicity data generated supported further development of the 100 µg dose. Intradermal vaccination was associated with high rates of solicited adverse events, or AEs (mainly injection site reactions), and we elected to discontinue enrollment of the ID cohorts.

Geometric mean titers, or GMTs, in the participants who received a two-dose IM series of the H10N8 vaccine at doses of 25, 50, and 100 µg at day 43 are shown in panel A of the figure below. Also, for those doses, 34.5%, 55.2%, and 100% of the participants, respectively, reached HAI titers > 1:40 at day 43 as shown in panel B of the figure below.

HAI GMT for H10N8 vaccine (mRNA-1440) in Phase 1 clinical trial

Panel (A)

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Percent of subjects with HAI >1:40 at day 43 with H10N8 vaccine (mRNA-1440) in Phase 1 clinical trial

Panel (B)

The 100 µg dose showed 100% seroconversion. For this dose, we observed persistence in HAI titer six months after the second dose, with a HAI geometric mean titer of 13.9 and 95.6% of participants remaining seropositive (HAI titer > 1:10) as shown in the figure below.

HAI antibody persistence at 100 µg dose for H10N8 vaccine (mRNA-1440) in Phase 1 clinical trial

Overall, up to the 100 µg IM dose, mRNA-1440 was well tolerated. A detailed list of the solicited adverse events, or solicited AEs, is provided in the table below. In the 400 µg IM dose group, two out of the three participants developed severe solicited adverse reactions (erythema, headache) within 24 hours of the first vaccination. These events met pre-specified study pause rules, and after safety committee review, further vaccinations at this dose level were stopped. These events resolved spontaneously without the need for medical intervention or medications.

Three severe unsolicited AEs (separately back pain, tonsillitis, and ruptured ovarian cyst) and 2 serious AEs, or SAEs, (separately cholecystitis and ruptured ovarian cyst) were reported and deemed unrelated to mRNA-1440. 124 unsolicited AEs were reported in the IM groups. The most common unsolicited AEs were upper respiratory tract infection, back pain, pharyngitis, and oropharyngeal pain. No adverse event of special interest, or AESIs, or cases of new onset of chronic illness were reported.

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Solicited adverse events for H10N8 vaccine at all dose levels within 7 days after each IM vaccination on days 1 and 22^* 

	25 µg	50 µg	100 µg	Placebo
Dose 1	n=30	n=30	n=23	n=35
Injection site pain	23, 76.7 (0)	25, 83.3 (0)	19, 82.6 (0)	2, 5.7 (0)
Erythema	1, 3.3 (0)	0	3, 13.0 (0)	0
Injection site swelling	2, 6.7 (0)	5, 16.7 (0)	3, 13.0 (0)	0
Headache	5, 16.7 (0)	12, 40.0 (0)	7, 30.4 (0)	5, 14.3 (0)
Fatigue	8, 26.7 (0)	13, 43.3 (0)	8, 34.8 (0)	7, 20.0 (0)
Myalgia	16, 53.3 (0)	17, 56.7 (0)	12, 52.2 (0)	1, 2.9 (0)
Arthralgia	0	2, 6.7 (0)	2, 8.7 (0)	1, 2.9 (0)
Nausea	0	1, 3.3 (0)	1, 4.3 (0)	0
Fever	1, 3.3 (0)	1, 3.3 (0)	2, 8.7 (0)	0
Dose 2	n=28	n=29	n=23	n=27
Injection site pain	22, 78.6 (0)	27 93.1 (0)	20, 87.0 (0)	3, 11.1 (0)
Erythema	0	0	4, 17.4 (8.7)	0
Injection site swelling	2, 7.1 (0)	4, 13.8 (0)	3, 13.0 (4.3)	0
Headache	4, 14.3 (0)	14, 48.3 (0)	16, 69.6 (0)	6, 22.2 (3.7)
Fatigue	8, 28.6 (0)	13, 44.8 (0)	11, 47.8 (0)	4, 14.8 (0)
Myalgia	14, 50.0 (0)	17, 58.6 (0)	11, 47.8 (0)	1, 3.7 (0)
Arthralgia	0	2, 6.9 (0)	7, 30.4 (0)	1, 3.7 (0)
Nausea	1, 3.6 (0)	1, 3.4 (0)	3, 13.0 (0)	0
Fever	1, 3.6 (0)	2, 6.9 (0)	4, 17.4 (0)	1, 3.7 (0)

^*  Data represent n, % with solicited AEs (% with severe solicited AEs) in the safety population; 75 µg dose group not shown (2 participants had severe solicited AEs of fatigue and injection site swelling following first vaccination, and no participants received dose 2); 400 µg dose group not shown.

The Phase 1 clinical trial for H7N9 vaccine in the United States has ended and we have generated safety and tolerability data and demonstrated immunogenicity

The results of the Phase 1 trial for H7N9 vaccine were reported by us in Vaccine in 2019. The trial has met its objectives of assessing the safety and tolerability profile of mRNA-1851 vs. placebo including capturing solicited and unsolicited local and systemic adverse events. The Phase 1 trial for H7N9 vaccine has also demonstrated immunogenicity and we have observed 96% of the subjects demonstrating HAI titer > 1:40 at day 43 (21 days post-second vaccination) for the 25 µg dose where HAI > 1:40 is regarded as a quantitative measure for protection from influenza. We believe the data provides support to advance the program in clinical development if we choose to with additional government or other funding. This randomized, double-blind, placebo-controlled, dose-ranging study evaluated intramuscular, or IM, dose levels of 10, 25, and 50 µg using two vaccination schedules (Day 1, Day 22 and Day 1, Month 6). The objectives were safety, tolerability, and immunogenicity by HAI and MN assays. 156 subjects were enrolled in this study. 30 subjects per dose cohort received two doses of 10 µg, 25 µg, and 50 µg at days 1 and 22. 10 subjects per dose cohort received one dose of 10, 25, and 50 µg at day one and a total of 9 of those subjects received a second dose at 6 months (data not shown). Thirty-six subjects received placebo. A total of 10 subjects withdrew from the study. The Phase 1 trial was conducted with the name of the intervention listed as VAL-339851, in accordance with our legacy naming convention. We have since changed our naming convention and have adopted mRNA-1851 in place of VAL-339851.

Doses up to 50 µg administered IM to patients who received vaccinations on Day 1 and Day 22 in this Phase 1 clinical trial demonstrated immunogenicity.

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Geometric mean titers in the participants who received a two-dose IM vaccination series on Day 1 and Day 22 at doses of 10, 25, and 50 µg are shown in panel A of the figure below. Also, for those doses, 36.0%, 96.3%, and 89.7% of the participants respectively reached HAI titers > 1:40 at day 43 as shown in panel B of the figure below.

HAI GMT for H7N9 vaccine (mRNA-1851) in Phase 1 clinical trial

Panel (A)

Percent of subjects with HAI>1:40 at day 43 with H7N9 vaccine (mRNA-1851) in Phase 1 clinical trial

Panel (B)

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The 25 µg dose achieved 96% seroconversion. For this dose, we observed persistence in HAI titers six months after the second dose. HAI GMT decreased but remained above HAI titer level of 10 as shown in the figure below. In addition, 52% of participants remained seropositive (HAI titer > 1:10) at six months.

HAI antibody persistence at 25 µg dose for H7N9 vaccine (mRNA-1851) in Phase 1 clinical trial

Overall, up to the 50 µg IM dose of mRNA-1851 was well tolerated. A detailed list of the solicited AEs is provided in the table below. The majority of possibly- and probably-related unsolicited AEs were >  grade 2 laboratory abnormalities and occurred at similar rates in vaccine and placebo groups. Four severe unsolicited AEs were deemed possibly related to vaccination: two cases of increased alanine aminotransferase (one 50 µg, one placebo), one case of increased aspartate aminotransferase (50 µg), and one case of thrombocytopenia (placebo). All cases were asymptomatic and resolved without intervention. Five SAEs (separately unintentional firearm-related death, testicular cancer, pancreatitis, facial cellulitis, and exacerbated hypertension) were reported and deemed unrelated to mRNA-1851. 124 unsolicited AEs were reported in the IM groups. The most common unsolicited AEs were upper respiratory tract infection, back pain, pharyngitis, and oropharyngeal pain. No AESIs or cases of new onset of chronic illness were reported.

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Solicited adverse events for H7N9 at all dose levels within 7 days after each IM vaccination on days 1 and 22^* 

	10 µg	25 µg	50 µg	Placebo
Dose 1	n=30	n=30	n=30	n=36
Injection site pain	22, 73.3 (0)	17, 56.7 (0)	24, 80.0 (6.7)	5, 13.9 (0)
Erythema	0	0	0	0
Injection site swelling	5, 16.7 (0)	5, 16.7 (0)	9, 30.0 (0)	2, 5.6 (0)
Headache	5, 16.7 (0)	5, 16.7 (0)	7, 23.3 (6.7)	6, 16.7 (0)
Fatigue	1, 3.3 (0)	4, 13.3 (0)	3, 10.0 (0)	2, 5.6 (0)
Myalgia	3, 10.0 (0)	6, 20.0 (0)	8, 26.7 (0)	6, 16.7 (0)
Arthralgia	2, 6.7 (0)	3, 10.0 (0)	3, 10.0 (0)	4, 11.1 (0)
Nausea	1, 3.3 (0)	1, 3.3 (0)	1, 3.3 (0)	1, 2.8 (0)
Fever	0	1, 3.3 (0)	0	0
Dose 2	n=30	n=30	n=30	n=36
Injection site pain	14, 46.7 (0)	13, 43.3 (0)	22, 73.3 (10.0)	2, 5.6 (0)
Erythema	0	0	0	0
Injection site swelling	3, 10.0 (0)	6, 20.0 (0)	6, 20.0 (0)	1, 2.8 (0)
Headache	3, 10.0 (0)	2, 6.7 (3.3)	8, 26.7 (6.7)	1, 2.8 (0)
Fatigue	1, 3.3 (0)	3, 10.0 (0)	4, 13.3 (0)	0
Myalgia	3, 10.0 (0)	4, 13.3 (0)	8, 26.7 (3.3)	0
Arthralgia	2, 6.7 (0)	1, 3.3 (0)	6, 20.0 (3.3)	0
Nausea	0	0	1, 3.3 (0)	0
Fever	0	0	6, 20.0 (6.7)	0

*Data represent n, % with solicited AEs (% with severe solicited AEs)

Zika vaccine (mRNA-1893): Summary

In collaboration with BARDA, we have advanced a second generation Zika vaccine candidate to Phase 1

Zika is an infectious disease caused by the Zika virus, in which infection during pregnancy has been linked to severe brain damage in infants with congenital infection and Guillain-Barré Syndrome in adults. To date, no vaccine to prevent Zika infection has been approved. In September 2016, we were awarded a contract with BARDA to be reimbursed up to approximately $125.0 million for the development of a Zika mRNA vaccine. In order to rapidly respond to a potential epidemic, we developed a Zika vaccine, mRNA-1325, which went from mRNA sequence design to first-in-human clinical testing in twelve months. In addition, we also developed a second Zika vaccine, mRNA-1893. mRNA-1893, at 1/20 of the dose, demonstrated better protection in non-human primates, as compared to mRNA-1325. mRNA-1893 is in a Phase 1 trial in the United States. As of February 12, 2020, we have enrolled 90 subjects in the Phase 1 trial.

Zika vaccine (mRNA-1893): Disease overview

We faced a Zika epidemic in 2015 for which there were no vaccines or treatments

The Zika virus is a single stranded RNA virus of the flaviviridae family. It was first isolated in a rhesus macaque in the Zika Forest, Uganda in 1947 and the first human case was documented in 1952. Seroepidemiology data suggest that it is endemic to regions of Africa and Asia where the Aedes mosquito vectors are found. Zika virus is predominantly spread by mosquitos from the Aedes genus, but it can also be transmitted congenitally, sexually, and through blood donation.

In 2007, a Zika infection outbreak progressed across the Pacific islands. It arrived in Brazil in 2015 and the epidemic spread across the Americas. This led to the World Health Organization, or WHO, declaring it a public health emergency of international concern in 2016. During the period, there were tens of thousands of cases of microcephaly and congenital Zika syndrome reported in infants and of resulting neurological sequelae such as Guillain-Barré syndrome reported in adults.

Zika infection is usually asymptomatic or mild in adults, leading to fever, rash, and conjunctivitis. However, infection of women during pregnancy can result in devastating microcephaly in newborns. Microcephaly is a birth defect characterized by an abnormally small head and brain, associated with lifelong neurodevelopmental delay, seizures, intellectual disability, balance

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problems, and dwarfism / short stature, resulting in significant disability and requiring lifelong support. To date, over one million cases of Zika have been officially reported in Latin America. Since most of the cases are asymptomatic, we believe the actual number of cases may be far higher. International travel means that Zika infection has the potential to take on global significance. While the number of cases has declined in the past couple of years, there is currently no treatment or vaccine available for the Zika virus to prevent and respond to potential future epidemics.

Currently, there is no approved vaccine for Zika. Designing and synthesizing conformationally correct protein antigen vaccines, attenuated or vectored live viral vaccines, or inactivated vaccines is time consuming and challenging. These traditional vaccine approaches have therefore found it difficult to respond fast enough to the emerging Zika epidemic.

Zika vaccine (mRNA-1893): Our product concept

We advanced a complex antigen to the clinic in twelve months and followed up with a next generation vaccine

We believe our platform allows for rapid development of mRNA vaccines with complex, immunogenic antigens faster than traditional vaccines. In order to rapidly deploy an mRNA vaccine for Zika, we leveraged available sequences and legacy LNPs to develop mRNA-1325. mRNA-1325 contains a sequence encoding for structural proteins in the Zika virus. The intended design is for translation of a polyprotein and processing inside the cell to make a secreted virus-like particle, or VLP. This process mimics the response of the cell after natural infection as shown in the figure below.

Continued efforts at identifying different mRNA sequences with improved immunogenicity led to mRNA-1893, a sequence distinct from mRNA-1325 that increases production of Zika VLPs and generates enhanced immunogenicity and protection in preclinical animal models compared to mRNA-1325. mRNA-1893 is also formulated in our proprietary LNP.

Zika vaccine (mRNA-1893): Preclinical information

We have observed and published our immunogenicity data for our Zika vaccine

The mRNA sequences for mRNA-1325 and mRNA-1893 have been tested in mice and non-human primates, or NHPs. We have published a subset of these data in the journal Cell in 2017. The mRNA sequence for mRNA-1893 produces equivalent immunogenicity and better protection compared to the sequence used in mRNA-1325 at 1/20 of the dose in NHPs, as shown in the figure below. In this study, mRNA vaccine or placebo was administered intramuscularly in a two-dose vaccination schedule (28 days apart), with five animals included in each group. NHPs were challenged with Zika virus 28 days post-boost, and viral titers were measured post challenge via quantitative PCR. Measurements were quantified in terms of focus forming units.

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Sequence for mRNA-1893 provided comparable protection to that of mRNA-1325 in non-human primate challenge study

Zika vaccine (mRNA-1893): Clinical data

We are conducting a Phase 1 trial for mRNA-1893 in the United States and we will not further develop mRNA-1325

We are currently enrolling in a Phase 1 randomized, observer-blind, placebo-controlled, dose-ranging study to evaluate the safety, tolerability, and immunogenicity of mRNA-1893 in healthy adults (18 to 49 years of age, inclusive) in endemic and non-endemic Zika regions. mRNA-1893 is administered intramuscularly in a two-dose vaccination schedule (28 days apart) at four dose levels (10 µg, 30 µg, 100 µg, and 250 µg). Key objectives of the study include:

• To assess the safety, tolerability, and reactogenicity of a 2‑dose vaccination schedule of mRNA-1893 Zika vaccine, given 28 days apart, across a range of dose levels in flavivirus-seronegative and flavivirus-seropositive participants compared with placebo;

• To assess the immunogenicity of a range of doses of mRNA-1893 Zika vaccine.

Subjects were randomly assigned in a blinded fashion in an approximate 4:1 ratio to receive mRNA-1893 or placebo at one of four dose levels (10 µg, 30 µg, 100 µg, and 250 µg), with each subject receiving two vaccinations separated by 28 days. Twenty-five of the enrolled participants at each dose level will be flavivirus seronegative and five will be flavivirus seropositive.

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As of February 12, 2020 we have enrolled 90 subjects with 30 subjects each in the 10 µg, 30 µg, and 100 µg dose cohorts.

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II. PROGRAM DESCRIPTIONS IN OUR CANCER VACCINES MODALITY

We designed our cancer vaccines modality to treat or cure cancer by enhancing immune responses to tumor neoantigens, defined below. This modality has two programs currently for neoantigen vaccines, a personalized cancer vaccine, or PCV, program, and a vaccine against neoantigens related to a common oncogene called KRAS, both conducted in collaboration with Merck. The goal of a cancer vaccine is to safely expose the patient’s immune system to tumor related antigens, known as neoantigens, to enable the immune system to elicit a more effective antitumor response. Our cancer vaccines modality is focused on the use of mRNA to express neoantigens found in a particular tumor in order to elicit an immune response via T cells that recognize those neoantigens, and therefore the tumor. These neoantigens can either be unique to a patient, as in the case of our personalized cancer vaccine program, or can be related to a driver oncogene found across subsets of patients, as in the case of our KRAS vaccine program.

Our pipeline is shown in two formats, with a cell map illustrating the diversity of biology addressed by our mRNA pipeline programs, and a traditional format that shows the current stages of development of our pipeline programs, in the section of this Annual Report on Form 10-K titled “Business—Our Pipeline.”

Opportunity

More than 1.6 million new cancer cases and approximately 600,000 deaths due to cancer were predicted in the United States for 2017. Despite the recent success of checkpoint inhibitors, the majority of patients with the most common types of epithelial cancer still do not benefit from checkpoint inhibitors, as many patients still have incomplete or no response to currently available therapies. In addition, treatment resistance is thought to arise from a number of mechanisms, principally the local immunosuppressive effects of cancer cells, which prevent either access to or recognition by T cells.

Recent breakthroughs in cancer immunotherapy, such as checkpoint inhibitors and chimeric antigen receptor T cell therapies, have demonstrated that powerful antitumor responses can be achieved by activating antigen specific T cells. We believe one approach to improve the efficacy of checkpoint inhibitors is to develop vaccines that increase both the number and antitumor activity of a patient’s T cells that recognize tumor neoantigens.

Our approach

We are developing mRNA-based cancer vaccines to utilize the anti-tumor killing capacity of T cells to drive anti-tumor efficacy. Evidence of tumor killing by T cells in treating certain cancers has increased in the last decade with advances in immunotherapies. The immune system’s anti-tumor response relies on T cells recognizing tumor cells as non-self and eradicating these “foreign” cells. Human Leukocyte Antigen, or HLA, complexes are a diverse set of genes, or alleles, that present fragments of proteins from inside (HLA I) or outside (HLA II) cells to the immune system. A person’s HLA type defines what HLA alleles they express and can restrict what antigen may be presented to their immune system. Antigens presented in HLA molecules are recognized by T cell receptors, or TCRs, present on the cell surface of CD4 and CD8 T cells. These two main classes of T cells have distinct mechanisms to potentially attack tumor cells; CD4 cells play an important role in activating other immune cells after recognition of antigens in HLA II molecules, whereas CD8 cells can have direct cytotoxic cell killing capabilities upon recognition of antigens in HLA I molecules. Both cell types have been demonstrated to have important roles in driving an effective anti-tumor immune response.

Over the past three decades there have been many attempts to develop cancer vaccines, few of which have been successful. Key reasons include (1) past attempts were directed against shared “self” non-mutated antigens; (2) nearly all previous attempts utilize peptide fragments to try to mimic peptides displayed by HLA I molecules, this method may not have been able to mimic the natural processing and presentation of antigens by the immune system and therefore may not be recognized; and (3) earlier work was done in the era prior to the benefit of checkpoint inhibitors.

We believe one approach to improve the efficacy of checkpoint inhibitors is to develop vaccines that increase both the number and antitumor activity of a patient’s T cells that recognize tumor neoantigens. Our cancer vaccines modality is focused on the use of mRNA to express neoantigens found in a particular cancer in order to elicit an immune response via T cells that recognize those neoantigens, and therefore the tumor. These neoantigens can either be unique, as in the case of our personalized cancer vaccine program, or can be related to a driver oncogene found across subsets of patients, as in the case of our KRAS vaccine program.

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PCV (mRNA-4157 and NCI-4650): Summary

We are collaborating with Merck to use the strength of our platform to develop cancer vaccines with multiple neoantigens unique to each patient, also known as personalized cancer vaccines, or PCVs

Recent breakthroughs in cancer immunotherapy have demonstrated that powerful antitumor responses can be achieved by activating antigen specific T cells in a variety of cancer settings. Despite these advances, many patients still have incomplete or no response to anti-cancer therapies. One approach is to administer a cancer vaccine that encodes for peptides containing mutations found in their cancer, i.e., to create a personalized cancer vaccine composed of neoantigens unique to a patient’s tumor. Previous attempts have demonstrated the ability of mRNA and peptide-based platforms to drive immune responses toward patient-specific neoantigens. Preclinical studies have shown that the combination of cancer vaccines with checkpoint inhibitors provides improved benefit over single-agent therapies. Our platform is positioned for bringing personalized cancer vaccines to patients with our proprietary in silico design of each patient’s neoantigen-based mRNA vaccine, to be coupled with our automated cell-free manufacturing processes and infrastructure based in our MTC facility in Norwood, MA, as well as our digital infrastructure. We believe these attributes coupled with our proprietary LNPs help differentiate our approach from ongoing efforts at developing mRNA-based cancer vaccines. mRNA-4157 is administered either as monotherapy, or in combination with pembrolizumab, marketed in the United States as KEYTRUDA. This is in collaboration with Merck as governed by a joint steering committee. NCI-4650 is a personalized cancer vaccine being tested by the National Cancer Institute, or NCI, as a monotherapy for patients with advanced, metastatic cancers. NCI-4650 differs from mRNA-4157 in its neoantigen selection process. mRNA-4157 has a Phase 1 trial ongoing in the United States and Phase 2 trial ongoing in the United States and Australia. The NCI-4650 Phase 1 trial in the United States was completed in November 2019. As of February 12, 2020, 15 patients with resected solid tumors (melanoma, colon and lung cancers) received mRNA-4157 as adjuvant monotherapy after resection of their primary tumor. An additional 56 patients with metastatic, unresected solid tumors (melanoma, bladder, lung, colon, prostate, head and neck and endometrial cancers) received at least one dose of mRNA-4157 in combination with pembrolizumab. As of June 2019, we have detected antigen specific T cell responses in both the monotherapy arm and in combination with pembrolizumab. We have also observed clinical activity in some patients receiving mRNA-4157 in combination with pembrolizumab. We and our strategic collaborator Merck have a Phase 2 trial of adjuvant mRNA-4157 in combination with pembrolizumab in patients with melanoma ongoing.

PCV (mRNA-4157 and NCI-4650): Our product concept

Rapid, personalized current good manufacturing practice, or cGMP, manufacturing to bring personalized cancer vaccines to patients

As tumors grow they acquire mutations, some of which create new protein sequences, or neoantigens, that can be presented on HLA molecules in the tumor and recognized as non-self by T cells. These neoantigens can be shared, as in mRNA-5671, or are completely unique to an individual patient’s tumor. In addition to the neoantigens being unique and patient specific, the presentation of those neoantigens is also dependent on a patient’s specific HLA type. Identification of patient-specific HLA type and tumor neoantigens through next generation sequencing paired with our proprietary, in silico design of each patient’s mRNA vaccine and rapid manufacturing for a specific patient allows us to rapidly deliver a completely unique and personalized medicine to patients.

We believe that antigen-encoded mRNA is an attractive technology platform for neoantigen vaccination for cancer patients for the following reasons:

• mRNA vaccines can deliver multiple unique and personalized neoantigens in a single mRNA molecule;

• mRNA vaccines unique to each particular patient can be rapidly designed in silico and manufactured with automation in personalized, individual cGMP batches; and

• mRNA encoding for neoantigens is translated and processed by patients’ endogenous cellular processing and presentation to the immune system.

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Our personalized cancer vaccine program, mRNA-4157, consists of an mRNA that encodes up to 34 neoantigens, predicted to elicit both class I (CD8) and class II (CD4) responses, designed against each individual patient’s tumor mutations and specific to their HLA type. NCI-4650 includes both neoantigens known to be immunogenic as identified through ex vivo experimentation on the patient’s immune cells and neoantigens predicted by the NCI bioinformatics algorithm. For both mRNA-4157 and NCI-4650, the neoantigens are encoded in a single mRNA sequence and therefore termed a neoantigen concatemer. Each patient-specific mRNA-4157 and NCI-4650 is formulated in our proprietary LNPs designed for intramuscular injection. An illustration of the intended design of mRNA-4157 and NCI-4650 is shown in the figure below.

Each mRNA-4157 and NCI-4650 is produced using an integrated batch manufacturing process that is the same regardless of the sequence of the neoantigens to be produced. The overall process involves five major steps that are highly integrated and intended to enable a robust chain of custody and chain of identity. An overview of the system is provided in the figure below.

The process includes the following steps:

1. Tumor sample;

2. Next generation sequencing, or NGS, of tumor DNA and RNA;

3. Vaccine design using our proprietary bioinformatics algorithm for up to 34 patient-specific neoantigens;

4. Manufacture of the designed mRNA; and

5. Administration of the mRNA to the same patient that provided the tumor sample.

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Specifically, for each patient, the tumor sample and peripheral blood samples are collected and immediately sent for NGS analysis. Whole exome sequencing, or WES, data are generated from both the tumor and blood samples, with the blood sample serving as the germline (un-mutated) reference. WES results from the blood sample are also to be used to determine the patient’s HLA-type using an NGS-based approach. The tumor transcriptome is determined by mRNA sequencing, or RNA-Seq. The HLA typing, WES, and RNA-Seq results for each patient are provided as inputs to our proprietary vaccine design algorithm which predicts which neoantigens could be the most immunogenic. The mRNA sequence is then manufactured using an automated workflow to enable a rapid turnaround time. The final drug product is shipped to the clinical site for administration to the same patient that provided the original biopsy.

PCV (mRNA-4157 and NCI-4650): Preclinical information

We have utilized model antigens as surrogates for PCV to demonstrate the ability to elicit a robust T cell response with a single mRNA

We have completed preclinical studies to characterize the ability of an mRNA vaccine to induce a robust and specific T cell response to multiple antigens. Specifically, the ability of our mRNA vaccines to elicit:

• Specific and robust T cell responses to murine neoantigens were observed by vaccinating mice with mRNA vaccines that encode previously published immunogenic epitopes from the MC38 mouse tumor cell line and measuring T cell responses to mutant but not wild type antigens. The responses to mRNA vaccination were also significantly higher than responses to the adjuvanted peptide as per a study we conducted. In this study, mice were vaccinated with either empty LNP, adjuvanted peptides corresponding to previously published data or mRNAs encoding the same neoantigen sequences formulated in LNPs. Mice were vaccinated on day 1, 8, and 15 and T cell responses were measured on day 18 using flow cytometry by re-stimulating splenocytes with either control (medium), wild type or mutant (neoantigens) peptides. In an ideal case, one would see a high T cell response when re-stimulated with mutant neoantigen and would not see an equivalent response for re-stimulation with media and wild type peptide. We believe this would indicate a clear specific response for mutant neoantigens with no response to self. As shown in the figure below, the T cell response by mRNA encoding for neoantigens was much higher than that for peptides. The T cell response for mRNA vaccine re-stimulated with wild type was higher than baseline and close to that with control (medium). The T cell responses for mutant peptide were significantly higher than those against wild type peptide.

T-cell response for our mRNA PCV in mouse study

• Specific and robust T cell responses to multiple antigens encoded in a single mRNA sequence. The T cell response after vaccinating mice with mRNA vaccine encoding for 16 specific antigens previously reported to be immunogenic in mice as shown in the figure below. mRNA was formulated in a proprietary LNP and delivered intramuscularly to mice on day 1 and day 8. T cell responses were measured on day 15 by re-stimulating splenocytes with either control (medium) or peptides corresponding to each antigen (1, 2, 6, 9, and 12) in the mRNA vaccine and measured by interferon gamma. Measurements are in spot forming units, or SFU, per 1 million cells per well.

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• An mRNA concatemer encoding distinct class I (antigens 6, 9, and 12) and class II antigens (antigen 2) can elicit specific T cell responses to each antigen as shown in the figure below.

Unique T cell response to specific antigens encoded by mRNA in mouse study

PCV (mRNA-4157 and NCI-4650): Clinical data

Our Phase 1 trial for PCV is currently ongoing in the United States and our Phase 2 trial for PCV is currently ongoing in the United States and Australia

The Phase 1 trial is an open-label, multicenter study to assess the safety, tolerability, and immunogenicity of mRNA-4157 alone in subjects with resected solid tumors and in combination with the CPI, pembrolizumab (marketed in the United States as KEYTRUDA), in subjects with inoperable solid tumors. The study is sponsored by us. mRNA-4157 is administered by intramuscular injection on the first day of each 21-day cycle and for a maximum of 9 doses. mRNA-4157 is administered as monotherapy (Part A) or in combination with pembrolizumab (Parts, B, C, and D) in the United States. Four mRNA-4157 dose levels of 0.04 mg, 0.13 mg, 0.39 mg, and 1 mg will be explored in Part A and Part B through dose escalation. The following cancers are being investigated: non-small cell lung cancer (subject to certain entry criteria), small cell lung cancer, melanoma, bladder urothelial carcinoma, human papillomavirus-negative head and neck squamous cell carcinoma, and a variety of solid malignancies.

The key objectives of the study include:

• for Part A—To determine the safety and tolerability of mRNA-4157 monotherapy in subjects with resected solid tumors and to assess the immunogenicity of mRNA-4157;

• for Parts B, C and D—To determine the safety, tolerability, and recommended Phase 2 dose of mRNA-4157 administered in combination with pembrolizumab; and

• for Part D—To assess the immunogenicity of mRNA-4157 with pembrolizumab from apheresis samples in certain subjects.

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A schematic of the trial is shown in the figure below.

As of February 12, 2020, 15 patients with resected solid tumors (melanoma, colon and lung cancers) received mRNA-4157 as adjuvant monotherapy after resection of their primary tumor. An additional 56 patients with metastatic, unresected solid tumors (melanoma, bladder, lung, colon, prostate, head and neck and endometrial cancers) received at least one dose of mRNA-4157 in combination with pembrolizumab.

In our dose escalation of mRNA-4157 in Part A (monotherapy), we have detected antigen specific T cell responses. This is measured by restimulating unexpanded peripheral blood mononuclear cells with sets of peptides corresponding to neoantigens encoded by the patient-specific mRNA-4157 and is shown in the figure below. Individual data points indicate technical replicates.

Antigen-specific T cell responses for one patient at the 0.13 mg dose level in Part A of the Phase 1 clinical trial for PCV vaccine (mRNA-4157)

As of June 2019, mRNA-4157 was well-tolerated at all dose levels studied with no dose-limiting toxicities or grade 3 or 4 adverse events (AEs) or SAEs reported when administered as a monotherapy or in combination with pembrolizumab. The most common grade 2 adverse events were fatigue, soreness at the injection site, colitis and myalgias. A cohort of patients at the top dose level (1 mg) are undergoing apheresis and deeper characterization of immunogenicity responses. Data from one such patient as of June 2019 showed neoantigen-specific CD8 T-cell responses were detected to 10 out of 18 class I neoantigens after the 4^th dose of the vaccine (compared to 0/18 at baseline). Clinical responses (one complete response + five partial responses) at doses ranging from 0.04-1.0 mg were observed in 6 out of 20 patients receiving at least one dose of mRNA-4157 in combination with pembrolizumab. The complete response occurred to pembrolizumab monotherapy before mRNA-4157 was administered. Of the five partial responses, two were seen in patients previously treated with a checkpoint inhibitor. Of the 13 patients who received adjuvant mRNA-4157 monotherapy, all patients have completed a full course of vaccination per the study protocol. Eleven patients remained disease free up to 75 weeks on study.

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NCI-4650 is in an investigator-initiated, single-arm, open-label trial involving up to 12-patients with advanced metastatic disease sponsored by National Cancer Institute. This trial has been completed as of November 2019.

We and our strategic collaborator Merck are conducting a randomized Phase 2 study to assess whether post-operative adjuvant therapy with mRNA-4157, in combination with pembrolizumab, improves relapse-free survival compared to pembrolizumab alone. The study has a primary endpoint of relapse free survival with a primary analysis at 12 months and will be conducted with patients that have had complete resection of cutaneous melanoma but remain at high risk of recurrence. As of February 12, 2020, 25 patients have been dosed with either mRNA-4157 in combination with pembrolizumab or pembrolizumab alone.

A schematic of the Phase 2 trial is shown in the figure below.

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KRAS vaccine (mRNA-5671): Summary

In collaboration with Merck, we are developing a cancer vaccine (mRNA-5671) with mRNAs encoding for a concatemer of mutations in the KRAS oncogene protein

Although monotherapy checkpoint inhibitor treatment can provide significant benefit for some cancer patients, many have incomplete or no response to therapy, presenting a need for alternative therapies to stimulate antitumor immunological responses. Finding oncogenic driver mutations that encode targetable T cell epitopes has considerable therapeutic implications. Point mutations in the KRAS gene occur in about 22% of human cancers, such as colorectal, non-small cell lung and pancreatic cancers. Direct inhibition of KRAS has proven challenging and to date, there are no successful KRAS-targeted cancer therapies. It has been reported that KRAS-mutant neoantigens can be presented on certain human HLAs. Therefore, one approach is to immunize the body to naturally synthesize neoantigen peptides that contain common KRAS mutations for presentation to the immune system by mRNA. We have designed an mRNA to generate and present KRAS neoantigens to the immune system from the four most common KRAS mutations. We transferred the IND to Merck since Merck is the sponsor of the Phase 1 trial. The Phase 1 trial is being conducted by Merck and is currently ongoing in the United States. Patients will either be dosed with mRNA-5671 as monotherapy or in combination with the checkpoint inhibitor pembrolizumab.

KRAS vaccine (mRNA-5671): Our product concept

Our approach is to encode multiple mutations of KRAS in our mRNA vaccine administered together with a checkpoint inhibitor.

Oncogenic driver mutations that encode targetable T cell neoantigens have considerable potential therapeutic implications: (1) driver mutations are subject to positive selection, as they confer survival advantages for the tumor, and (2) such neoantigens could be shared between patients, enabling an easier approach to developing and manufacturing such therapeutic or curative interventions.

KRAS is a frequently mutated oncogene in epithelial cancers, primarily lung, colorectal cancer, or CRC, and pancreatic cancers. The four most prevalent KRAS mutations associated with these malignancies are G12D, G12V, G13D, and G12C, which constitute 80% to 90% of KRAS mutations. KRAS has multiple downstream signaling pathways, and although drugs have been developed to target individual effectors, direct inhibition of KRAS could be more efficacious. Direct inhibition of KRAS has proven challenging, as have past efforts at generating a cancer vaccine against KRAS. These attempts have proven to be ineffective, likely due to either the lack of concomitant administration of a checkpoint inhibitor or vaccines which have been only minimally immunogenic. None of the historic attempts at a KRAS vaccine used mRNA.

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Immune stimulators are often incorporated in vaccines to improve immune response to the antigens of interest. STimulator of INterferon Gene, or STING, is a cytosolic nucleotide sensor known to trigger type 1 interferon responses and has been reported to promote antigen specific T cell responses. STING has been reported to promote antitumor immunity and vaccines including STING agonists (e.g., cyclic dinucleotides) show overall improvement of immune responses to poorly immunogenic antigens. Merck has opted to advance mRNA-5671 without STING mRNA and may choose to include STING mRNA in further clinical development of this vaccine.

In order to drive T cell mediated antitumor responses, our mRNA vaccine includes an mRNA encoding for a concatemer of sequences encoding the four most common KRAS mutations, encapsulated in our proprietary LNP. Our mRNA vaccine will be dosed either as monotherapy or in combination with a checkpoint inhibitor. An illustration of one approach for mRNA-5671 is shown in the figure below.

KRAS vaccine (mRNA-5671): Preclinical information

We have observed the utility of KRAS mRNA vaccine in vivo

The immunogenicity of our KRAS vaccine is supported by several preclinical studies in which we observed that our mRNA encoding for KRAS mutations can be made in cells and presented in transgenic mice with specific HLA I alleles.

One of these models was a transgenic mouse model expressing a specific human HLA. This is shown in the figure below. These transgenic mice were vaccinated with either mRNA encoding A11-positive control antigens (control), single mutant KRAS neoantigen or the concatemer of the four most common mutant KRAS neoantigens, plus mRNA encoding STING. mRNA was formulated in our proprietary LNP and delivered intramuscularly on day 1 and day 15, T cell responses were measured on day 22 by re-stimulating splenocytes with either medium, or wild type or mutant KRAS peptides (panel A—KRAS mutation 1 and panel B – KRAS mutation 2). Robust and specific antigen specific CD8+IFNγ+ T cell responses were detected in splenocytes after re-stimulation with KRAS mutation 1 peptide and KRAS mutation 2 peptide.

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T-cell response to restimulation with KRAS mutation 1 peptide in mouse model study with mRNA vaccine encoding for KRAS mutation 1 peptide

Panel (A)

T-cell response to restimulation with KRAS mutation 2 peptide in mouse model study with mRNA vaccine encoding for KRAS mutation 2 peptide

Panel (B)

KRAS vaccine (mRNA-5671): Clinical plan

Merck is leading the clinical development of the KRAS vaccine program and has a Phase 1 trial ongoing

Merck is conducting an open-label, multi-center, dose-escalation and dose expansion Phase 1 study to evaluate the safety and tolerability of mRNA-5671 administered as an intramuscular injection both as a monotherapy and in combination with pembrolizumab. This Phase 1 trial is being conducted in the United States.

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III. PROGRAM DESCRIPTIONS IN OUR INTRATUMORAL IMMUNO-ONCOLOGY MODALITY

We designed our intratumoral immuno-oncology modality to treat or cure cancer by transforming the tumor microenvironment to drive anti-cancer T cell responses against tumors. This modality currently has three programs. Our mRNA technology within this modality allows for the combination of multiple therapeutics that can be directly injected into a tumor with the goal of activating the tumor microenvironment to kill cancer cells in the injected tumor as well as in distal tumors, known as the abscopal effect. Intratumoral administration allows for localized effect of these therapeutics that could be toxic if administered systemically.

Our pipeline is shown in two formats, with a cell map illustrating the diversity of biology addressed by our mRNA pipeline programs, and a traditional format that shows the current stages of development of our pipeline programs, in the section of this Annual Report on Form 10-K titled “Business—Our Pipeline.”

Opportunity

More than 1.6 million new cancer cases and approximately 600,000 deaths due to cancer were predicted in the United States for 2017. There have been several advances in the treatment of cancer through immune-mediated therapies in recent years. However, the outlook for many patients with advanced cancer remains poor, especially in tumors that have little immune system engagement and are therefore termed immunologically “cold.” We aim to activate the tumor microenvironment with our mRNA therapeutics, in conjunction with a checkpoint inhibitor, to activate the immune system against these otherwise immunologically cold tumors.

Our approach

Our intratumoral immuno-oncology modality is focused on driving robust, specific anti-cancer T cell responses, transforming cold tumors with an immunosuppressive microenvironment into one that is immunologically “hot” thereby resulting in a productive anti-cancer immune response. Our goal is to discover and develop locally administered, or intratumoral, immune-mediated therapies to deliver mRNA encoding for potent immune-stimulatory proteins that can act at the site of the injected tumor, reduce systemic toxicities, and potentially create an “abscopal effect” where distal tumor sites are also impacted. These may be combined with checkpoint inhibitors to boost the response. All of the mRNAs utilized in this modality are designed to decrease the amount of protein that could be made in hepatocytes through incorporation of microRNA binding sites, thus potentially reducing off-target effects and resulting in better tolerability.

Earlier efforts by others on the utility of intratumoral immune-mediated therapies have been established in murine models of cancer. In many of our preclinical studies focusing on demonstrating bioactivity and efficacy in mice, we have employed surrogate mRNAs encoding murine homologs, given that human proteins may not be sufficiently cross-reactive in mice, and that the use of human proteins in mice would be expected to elicit anti-foreign protein immune responses.

OX40L (mRNA-2416): Summary

Our immuno-oncology approach to enhance specific T cell responses in the tumor microenvironment via expression of the membrane T cell co-stimulator OX40L by intratumoral injection of OX40L mRNA

There have been several recent advances in the treatment of cancer through activation of the immune system. However, many patients with advanced stages of cancer respond to few therapies and continue to face a poor outlook. Alternative strategies to activate an immunologic anti-tumor response, while at the same time reducing systemic toxicities, are required. To this end, we have developed an investigational mRNA therapeutic coding for wildtype OX40 ligand, or OX40L, protein, a membrane protein normally expressed on antigen presenting cells upon immune stimulation that augments an activated immune response. mRNA-2416 encodes for wild-type OX40L which is a membrane protein, a class of proteins that we believe cannot be manufactured for administration to tumor cells by recombinant technologies. mRNA-2416 is being developed for the treatment of solid tumors following local intratumoral injection. We are currently sponsoring a Phase 1/2 trial that is ongoing in the United States. We amended the protocol to add a Phase 1 dose escalation cohort in combination with durvalumab followed by a Phase 2 expansion cohort in patients with advanced ovarian carcinoma as part of the current trial as we anticipate synergistic activity of mRNA-2416 in combination with durvalumab.

As of February 12, 2020, 41 patients were dosed with mRNA-2416 (39 patients in monotherapy and 2 patients in combination with durvalumab). As of October 22, 2018, 26 patients were evaluated for response with mRNA-2416 monotherapy, and the best overall response was stable disease (n=6). Two patients with ovarian cancer have demonstrated clinical observations of tumor shrinkage in injected and/or uninjected lesions. Based on these clinical observations, we have opted to expand the trial to a Phase 2 expansion cohort in patients with advanced ovarian carcinoma.

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OX40L (mRNA-2416): Mechanistic overview

OX40L is a T cell co-stimulator

The generation of optimal T cell responses requires T cell receptor, or TCR, engagement by presented epitopes (e.g., cancer antigens) and a positive secondary signal achieved through co-stimulatory molecules like OX40. OX40 receptor (also known as TNFRSF4, or CD134) is a member of the tumor necrosis factor, or TNF, receptor superfamily and is upregulated on activated immune effector cells upon TCR activation. OX40 is endogenously stimulated via OX40L, a homotrimeric membrane protein normally expressed on professional antigen presenting cells. Binding of OX40 by OX40L in the presence of a recognized antigen enhances the expansion of CD4 and CD8 T cells, increases T cell effector function, and enhances survival of experienced T cells for increased memory capacity. Prior clinical attempts of activating OX40 with agonist antibodies may have been hampered via antibody interactions with other cells. We believe that introduction of OX40L in tumor sites via mRNA may serve to boost T cell responses, and we believe intratumoral administration of mRNA encoding for OX40L may be an attractive method of enhancing anti-cancer immunity.

OX40L (mRNA-2416): Our product concept

Our approach is to deliver OX40L mRNA in a lipid nanoparticle intratumorally to produce a membrane T cell co-stimulator

Our product consists of mRNA coding for the human sequence of OX40L formulated in our proprietary LNP. mRNA-2416 was designed to decrease the amount of protein that could be made in hepatocytes through incorporation of a microRNA binding site, thus potentially reducing off-target effects and resulting in better tolerability. Following intratumoral injection, a specific anti-tumor immune response is expected to be induced via proliferation and migration of T cell clones with specificity for the cancer that may also result in systemic anti-tumor responses. An illustration of our approach for this program is shown in the figure below. An earlier concept of this development candidate included a legacy LNP. However, we observed sufficient toxicity findings in an IND-enabling GLP toxicology study to abandon the legacy LNP. Toxicity findings were largely diminished when the development candidate was switched from a legacy LNP to our proprietary LNP.

OX40L (mRNA-2416): Preclinical information

We have demonstrated the ability to inhibit tumor growth in mouse models of cancer using our approach

Intratumoral administration of mouse OX40L mRNA in our proprietary LNP resulted in production of OX40L protein in the tumor microenvironment and draining lymph node in mice. The activity of mouse OX40L, or mOX40L, was evaluated in syngeneic models, including an H22 hepatocellular carcinoma model. With this model, H22 cancer cells were subcutaneously implanted on the flank of BALB/c mice. Following tumor growth, mice were randomized into treatment groups and treated with weekly intratumoral injections of formulated mRNA encoding mOX40L or a negative control mRNA. Repeated weekly intratumoral injections of mOX40L mRNA in a syngeneic H22 mouse model resulted in 50% of the mRNA-treated mice with no measurable disease at the end of the study. Survival of mice treated with negative control mRNA and mRNA encoding murine OX40L are depicted in gray and red respectively in the figure below. Mice with subcutaneous H22 tumors were treated intratumorally with 7.5 µg of mRNA formulated in LNPs on Days 8, 16, and 24 post cancer cell implant. 6 of 12 mice treated with mOX40L mRNA were complete responders with no detectable tumor burden at day 100, whereas negative control mRNA formulated in LNPs yielded no complete responders. Survival curves were plotted by considering any reason a mouse was removed from study, including the predetermined tumor burden endpoint of 2,000 mm ³, as a survival event.

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We further demonstrated generation of anti-cancer immunological memory after OX40L mRNA treatment, as no tumor growth was observed in mice in the six initial complete responders that were re-injected with the same H22 cancer cells.

50% complete responders (n=12) with mouse OX40L mRNA in H22 syngeneic mouse model study

The potential ability of intratumoral OX40L mRNA to yield benefit in a largely checkpoint inhibitor (CPI)-refractory setting was tested in the MC38-S colon carcinoma tumor mouse model. In this study, mice were treated with mRNA (6 weekly intratumoral injection of 5.0 µg of mOX40L mRNA or negative control mRNA) or CPI antibody (5 twice-weekly intraperitoneal injections of 10 mg/kg of an anti‑PD-L1 antibody or isotype control antibody) monotherapies or with a combination of mOX40L mRNA + anti-PD‑L1. Shown below, the combination of mOX40L mRNA + anti-PD‑L1 antibody resulted in complete tumor regression in 8 of 15 animals (53% CRs), whereas only 0 to 2 of 15 mice exhibited complete responses to active mOX40L mRNA or anti‑PD‑L1 monotherapies (and negative controls).

We further demonstrated generation of anti-cancer immunological memory after OX40L mRNA + αPD-L1 treatment, as no tumor growth was observed in mice in the eight initial complete responders that were re-injected with the same MC38 cancer cells.

53% complete responders (n=15) with mouse OX40L mRNA + αPD-L1 in MC38 (CPI refractory) syngeneic

mouse model study

OX40L (mRNA-2416): Clinical data

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Our interim data indicate that intratumoral treatment with OX40L mRNA has no dose limiting toxicities, and has led to clinical observations of tumor regression in two patients with ovarian cancer but the tumor regression at the doses studied do not meet RECIST criteria for partial responses in the Phase 1/2 trial in the United States

The Phase 1/2 trial for mRNA-2416 is an open-label, multicenter study of repeated intratumoral injections of mRNA-2416 in patients with advanced relapsed/refractory solid tumor malignancies and lymphomas in the United States. mRNA-2416 will be administered at day 1 and day 15 of a 28-day cycle with a maximum of 6 cycles. The objectives of this Phase 1/2 study include evaluating safety and tolerability of mRNA-2416 administered intratumorally, and to define the maximum tolerated dose and recommended dose for expansion. Other endpoints include pharmacokinetic analyses as well as assessment of biomarkers of immunological response in tumor. The dose levels being tested in the monotherapy arm of the trial were 1 mg, 2 mg, 4 mg, and 8 mg. The monotherapy arm of the study has been completed and we are not planning an expansion cohort of mRNA-2416 as a monotherapy. We have initiated a dose-finding cohort at 4 mg mRNA-2416 given in combination with durvalumab (IMFINZI®) followed by a Phase 2 expansion cohort in ovarian cancer.

In the monotherapy arm of the study, following completion of the safety cohort, patients were enrolled into one of the following three biopsy cohorts:

A. Baseline biopsy in abscopal distal, untreated tumor, second biopsy within cycle 1 at day 22 to 28 at distal tumor

B. Baseline biopsy in primary tumor to be treated, second biopsy 24 to 48 hours post-dose cycle 1 day 1 in injected tumor

C. Baseline biopsy in primary tumor to be treated, second biopsy 24 to 48 hours post-dose cycle 2 day 1 in injected tumor

A schematic of the trial design is shown in the figure below.

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As of February 12, 2020, 41 patients were dosed with mRNA-2416 (39 patients in monotherapy and 2 patients in combination with durvalumab). As of November 15, 2018, safety was reported on 28 patients treated with monotherapy mRNA-2416. In approximately 18% of patients, we have observed rapid onset of multiple grade 2 and a single grade 3 transient reversible injection related reactions, all of which were resolved with antihistamines, corticosteroids, or supplemental oxygen. Three suspected unexpected serious adverse reactions, or SUSARs, were reported. Of the three, one was the grade 3 serious adverse event, or SAE, described above. A second case was reported for a grade 2 non-infectious systemic inflammatory response syndrome, and the patient was kept overnight at the hospital. In the third case, a patient, diagnosed with Stage IIIC ovarian carcinoma, experienced a skin ulceration during treatment, deemed to be a non-serious adverse event, located within the injected tumor, which had begun to regress following treatment with mRNA-2416. After the last administered dose of mRNA-2416, and after the patient withdrew from the trial for personal reasons, the wound was smaller in size. Subsequently, the patient underwent additional treatment for disease progression with Cytoxan/Avastin, the wound increased significantly in size, and Avastin was discontinued due to patient preference and wound healing concerns. The patient was then hospitalized due to worsening of the skin ulceration, by which time the injected tumor was noted to be absent (though other lesions were present). Although no longer in the study, this hospitalization was deemed by the investigator as a suspected unexpected serious adverse reaction related to study drug, but deemed by us as possibly related to study drug. After discharge from the hospital, the patient died. This death was reported to be due to disease progression, not study drug. After the intratumoral injection of mRNA-2416 in other patients, no other skin ulceration has been observed related to study drug.

Of the 26 patients dosed with mRNA-2416 as of October 22, 2018, the best overall response was stable disease (n=6), including two patients with ovarian cancer, in which there was tumor shrinkage in injected and/or uninjected lesions.

We have collected and analyzed eight paired biopsies of tumors pre- and post-injection of mRNA-2416 through October 22, 2018. Of these eight, six paired biopsies are from injected lesions and two are from uninjected lesions. In three of the six paired biopsies from injected lesions where tumors showed evidence of the location of the injection site and had viable tissue from the biopsy to analyze, we have observed an increase in OX40L protein after mRNA administration. In one of these cases, we have observed OX40L protein expression in the injected lesion for a biopsy collected at cycle 1 day 2 as shown by quantitative immunofluorescence staining in the figure below. Staining in red denotes OX40L protein and 4’,6-diamidino-2-phenylindole, or DAPI, stains DNA to indicate nuclei in blue. Cytokeratin staining in green indicates keratin filaments often used to mark epithelial cancer cells.

OX40L protein production in tumor cells of a patient with ovarian cancer dosed with mRNA-2416

Before treatment with mRNA-2416	After treatment with mRNA-2416

In the remaining three of the six paired biopsies from injected lesions, we did not observe OX40L protein increase, possibly because there was no noted evidence of injection site or there was extensive tissue necrosis.

OX40L/IL-23/IL-36γ (Triplet) (mRNA-2752): Summary

Our immuno-oncology approach to transform the tumor microenvironment: intratumoral injection of OX40L/IL-23/IL-36γ

Despite recent advances in immune-mediated therapies for cancer, the outlook for many patients with advanced cancer is poor. We are developing Triplet (mRNA-2752) and other programs to drive anti-cancer T cell responses by transforming cold tumor microenvironments into productive, “hotter” immune landscapes with local intratumoral therapies. Triplet (mRNA-2752) utilizes the intrinsic advantage of mRNA to multiplex and to produce membrane and secreted proteins with mRNA in a single investigational medicine. Triplet (mRNA-2752) includes three mRNAs encoding human OX40L, interleukin 23, or IL-23, and

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interleukin 36 gamma, or IL-36γ, that are encapsulated in our proprietary LNP and administered intratumorally. OX40L is a membrane protein, whereas IL-23 and IL-36γ are secreted cytokines. We believe our approach has the advantage of localized high concentration gradients of IL-23 and IL-36γ compared to recombinant proteins administered systemically or intratumorally. Additionally, the mRNA for OX40L encodes for the wild type membrane protein, which we believe recombinant protein technologies cannot enable. The combination of OX40L, IL-23, and IL-36γ has shown robust activity in preclinical cancer models and is synergistic with checkpoint inhibitors. In addition, this combination elicits an anti-tumor response on distal tumors (via the “abscopal effect”), as well as treated tumors in preclinical studies. A Phase 1 trial of Triplet (mRNA-2752) is ongoing.

OX40L/IL-23/IL-36γ (Triplet) (mRNA-2752): Mechanistic overview

Triplet (mRNA-2752) is designed and tailored to activate the immune system in two ways

This potential mRNA medicine is a novel mRNA-based therapeutic agent containing multiple mRNAs that code for the wild type human OX40L, IL-23, and IL-36γ proteins that have distinct functions yet work synergistically in mediating anti-cancer responses. Triplet (mRNA-2752) brings two approaches into a single multi-mechanism therapy:

• T cell co-stimulation that could strengthen specific anti-cancer adaptive immune responses (mediated by OX40L); and

• pro-inflammatory cytokines/chemokines to ignite or transform an inflammatory response within the tumor microenvironment (IL-23 and IL-36γ).

The generation of optimal T cell responses requires T cell receptor, or TCR, engagement by presented epitopes (e.g., cancer antigens) and a positive secondary signal achieved through co-stimulatory molecules like OX40. OX40 receptor (also known as TNFRSF4 and CD134) is a member of the tumor necrosis factor, or TNF, receptor superfamily and is upregulated on activated immune effector cells upon TCR activation. OX40 is endogenously stimulated via OX40L, a homotrimeric membrane protein normally expressed on professional antigen presenting cells. Binding of OX40 by OX40L in the presence of a recognized antigen enhances the expansion of CD4 and CD8 T cells, increases T cell effector function, and enhances survival of experienced T cells for increased memory capacity. Therefore, introduction of OX40L via mRNA may serve to boost T cell responses. We believe that in addition to boosting T cell responses via OX40L expression, the expression of pro-inflammatory cytokines within a treated tumor may serve to ignite and transform an immunologically cold tumor microenvironment into a productive anti-cancer immune response. The initial focus was on cytokines with well-established roles in initiating inflammation and bridging innate to adaptive immunity in humans; namely the IL-1 and IL-12 families, respectively. Specifically, anti-cancer effects have been observed by introduction of IL-1 family member IL-36γ in preclinical mouse models of cancer. IL-12 family members, including IL-23, are often referred to as central coordinators of immune responses, largely due to their capacity to bridge innate to adaptive immunity.

OX40L/IL-23/IL-36γ (Triplet) (mRNA-2752): Our product concept

The potential advantage of mRNA to target multiple immuno-stimulatory pathways in tumors

We are developing Triplet (mRNA-2752) for the treatment of advanced or metastatic solid tumor malignancies or lymphoma as a single agent or in combination with checkpoint inhibitors. Triplet (mRNA-2752) includes three mRNAs encoding OX40L, IL-23, and IL-36γ, encapsulated in our proprietary LNP. Triplet (mRNA-2752) is designed to make these proteins in cells of the local tumor environment or lymph node. Our approach potentially has the advantage of localized gradients of two important cytokines IL-23 and IL-36γ, rather than a systemic administration or intratumoral injection of cytokine proteins that would lead to quick diffusion away from the tumor. Additionally, the mRNA for OX40L encodes for the wild type membrane protein, which would be challenging to administer to either a tumor or systemically as a recombinant membrane protein capable of co-stimulation of T cells. mRNA for IL-23 produces a single-chain fusion protein of the IL-12B and IL-23A subunits, with a linker between the subunits. mRNA for IL-36γ produces a protein with introduced signal peptide to bypass a need for upstream processing for release and activity. In addition, all three mRNA were designed to decrease the amount of protein that could be made in hepatocytes through incorporation of microRNA binding sites, thus potentially reducing off-target effects and resulting in better tolerability. An illustration of our approach for Triplet (mRNA-2752) is shown in the figure below.

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OX40L/IL-23/IL-36γ (Triplet) (mRNA-2752): Preclinical information

The OX40L/IL-23/IL-36γ combination promotes tumor killing in mice of injected and non-injected tumors, along with a lasting T cell effect

As described earlier, preclinical work was conducted using mouse homologs. The combination local therapy of OX40L/IL-23/IL-36γ mRNAs achieved 70-100% complete response rates in two MC38 syngeneic mouse models of cancer, one that is normally relatively responsive and the other completely refractory to systemic checkpoint inhibitor treatment. The triple combination therapy had better results than individual and doublet mRNA combinations. In one study, mice carrying bilateral MC38-S tumors received 5 µg total mRNA injected into the right flank tumor only (2.5 µg each mRNA administered for doublets and 1.67 µg each for triplet combinations). The survival plots are graphed in the figure below. Survival events were triggered when animals surpassed the predetermined tumor burden endpoint of 2,000 mm ³ (for both tumors combined). Animals removed from study for other reasons were censored and indicated below as horizontal lines prior to Day 100. 20 mice were included in each cohort depicted, and there were 10, 11, and 20 complete responders (i.e., no measurable disease at either tumor site) for the IL-23/IL-36γ, IL-23+OX40L and OX40L/IL-23/IL-36γ treatment groups, respectively, at 100 days post cancer cell implant. We also found that a single dose of OX40L/IL-23/IL-36γ mRNA was able to induce complete disease control at both treated and distal sites, sometimes known as an abscopal effect. This underscores the potential of our approach to lead to a well-tolerated and broadly active therapy for treatment of multilesional and metastatic cancers.

100% (n=20) complete responders with mouse OX40L/IL-23/IL-36γ mRNA in MC38 dual flank syngeneic mouse model study

In addition to OX40L/IL-23/IL-36γ mRNA monotherapy activity, we have further observed that a single suboptimal dose of OX40L/IL-23/IL-36γ mRNA therapy was synergistically active with systemically administered anti-PD-1/PD-L1 as well as anti-CTLA4 antibodies, again demonstrating complete response rates of > 70%.

OX40L/IL-23/IL-36γ (Triplet) (mRNA-2752): Clinical plan

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The Phase 1 trial for Triplet (mRNA-2752) is ongoing in the United States and Israel

We have an ongoing Phase 1 study that is designed as an open-label, multicenter study of intratumoral injections of Triplet (mRNA-2752) alone or in combination with durvalumab (anti-PD-L1). The objectives of this study include:

• assessment of safety and tolerability of Triplet (mRNA-2752) administered alone and in combination with durvalumab;

• define the maximum tolerated dose, or MTD, and recommended dose for expansion, or RDE, for intratumoral injections of Triplet (mRNA-2752) alone and in combination with durvalumab; and

• assessment of anti-tumor activity, protein expression in tumors, and pharmacokinetics, and exploratory endpoints that include assessment of immunological responses.

A schematic of the clinical trial design is shown in the figure below. We have filed a protocol amendment to the FDA to remove arm C, mRNA-2752 in combination with tremelimumab.

• arm A-Triplet (mRNA-2752) alone; and

• arm B-Triplet (mRNA-2752) in combination with durvalumab, a PD-L1 inhibitor.

The study consists of 2 dose escalation and 2 dose confirmation parts followed by a dose expansions for Arms B. mRNA-2752 will be evaluated at 0.25, 0.5, 1, 2, 4, and 8 mg. mRNA-2752 is administered once every two weeks for cycle 1 followed by once every four weeks for cycles 2 through 6. Durvalumab is administered every 4 weeks. Biopsy and blood samples to be collected pre- and post-treatment with mRNA in both dose escalation and dose expansion to assess protein expression and changes in tumor immune landscape.

As of February 12, 2020, 26 patients have been dosed with mRNA-2752 including 16 patients in monotherapy and 10 patients in combination with durvalumab.

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IL-12 (MEDI1191): Summary

Our immuno-oncology approach to transform the tumor microenvironment: IL-12 as a localized secreted protein in collaboration with AstraZeneca

Another strategy for cancer patients with immunologically cold tumors is to transform the tumor microenvironment by introducing pro-inflammatory cytokines directly into tumors or draining lymph nodes. In collaboration with AstraZeneca, we are developing MEDI1191 that is an mRNA for IL-12 encapsulated in our proprietary LNP to be delivered intratumorally. Systemic administration of recombinant IL-12 protein was poorly tolerated in early clinical trials and exhibited generally low response rates. MEDI1191 can enhance the immune response by positively impacting both antigen presenting cells and T cells, and local, intratumoral expression of IL-12 can potentially improve tolerability compared to systemic protein treatments. AstraZeneca is conducting a Phase 1 clinical trial for MEDI1191, which is to be co-administered with a checkpoint inhibitor.

IL-12 (MEDI1191): Mechanistic overview

IL-12 is a powerful immune-modulator that bridges innate and adaptive responses

The IL-12 family members are often referred to as central controllers of immune responses due to their capacity to bridge from innate to adaptive immunity. IL-12 is a potent immune-modulator typically associated with a type 1 immune response and production of interferon-gamma. While preclinical studies using IL-12 have resulted in dramatic antitumor effects in syngeneic cancer models, clinical development of systemically administered recombinant IL-12 has been hampered by systemic toxicity.

IL-12 (MEDI1191): Our product concept

In collaboration with AstraZeneca, we are developing intratumoral delivery of IL-12 in combination with a checkpoint inhibitor

Intratumoral delivery of IL-12 has been observed to be a feasible approach to overcome the toxicity associated with systemic IL-12 administration. For example, intratumoral delivery of an IL-12 containing DNA plasmid by injection followed by electroporation has shown promising activity in combination with pembrolizumab in a Phase 1 study with patients with metastatic melanoma. Such an approach may be limited to accessible lesions amenable to electroporation. In contrast, it may be more feasible to inject our mRNA delivered by our proprietary LNP into both accessible and visceral tumors.

MEDI1191 is being developed for the treatment of advanced or metastatic solid tumors in combination with a checkpoint inhibitor. MEDI1191 consists of our proprietary LNP encapsulating an mRNA for human IL-12B (p40) and IL-12A (p35) subunits. The mRNA produces a single-chain fusion protein of the IL-12B and IL-12A subunits, with a linker between the subunits. The mRNA sequence has been engineered to enhance protein production and is designed to decrease the amount of protein that might be made in hepatocytes for better tolerability. An illustration of our approach for IL-12 is shown in the figure below.

IL-12 (MEDI1191): Preclinical information

We have conducted several preclinical studies in which we observed activity with our approach

As described earlier, our preclinical work was conducted with a mouse homolog of IL-12. In a tumor model that we have characterized as completely refractory to checkpoint therapy and associated with an immunosuppressive tumor microenvironment,

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treatment with IL-12 transformed the tumor microenvironment, with notable activation of natural killer and dendritic cells, and an increase in cytotoxic lymphocytes. In this checkpoint inhibitor refractory mouse model of cancer, a single dose of IL-12 mRNA yielded around 30% complete response rates as an mRNA monotherapy as shown in panel A below and was synergistically active with systemically administered anti-PD-L1 antibody, or α PD-L1, demonstrating complete response rates of > 70%, as shown in panel B of the figure below. The x-axis represents days after subcutaneous implantation of MC38-R tumor cells. Test articles were administered on Day 11 for mRNA treatments and on Days 11, 14, 18, and 21 for antibody treatments. All antibody treatments were administered at 20 mg/kg. There were 15 mice per group in this study. Survival curves were plotted by considering any reason a mouse was removed from study, including the predetermined tumor burden endpoint of 2,000 mm³, as a survival event. NTC is a non-translating control mRNA. Synergy of locally administered IL-12 mRNA with systemic α PD-L1 treatment was also observed on distal tumors that were not directly administered mRNA.

Approximately 30% (n=15) complete responders with highest dose

tested for mouse IL-12 mRNA in MC38 mouse model study

Panel (A)

Approximately 70% (n=15) complete responders at highest dose tested

for mouse IL-12 mRNA with α PD-L1 antibody in MC38 mouse model study

Panel (B)

IL-12 (MEDI1191): Clinical plan

AstraZeneca is the sponsor and leading the clinical development for MEDI1191

We are responsible for generating a preclinical data package to support IND/CTA filing and clinical supply for early clinical development. AstraZeneca will lead the early clinical development. We expect a lower starting dose for MEDI1191 in the clinical trial compared to our other intratumoral programs.

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An open-label multicenter Phase 1 clinical trial of intratumoral injections of MEDI1191 alone and in combination with a checkpoint inhibitor, durvalumab is ongoing.

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IV. PROGRAM DESCRIPTIONS IN OUR LOCALIZED REGENERATIVE THERAPEUTICS MODALITY

We designed our localized regenerative therapeutics modality to develop mRNA medicines to address injured or diseased tissues. Our mRNA technology in this modality allows for the local production of proteins that provide a therapeutic benefit in the targeted tissue. The development of our program in this modality, AZD8601 for the local production of VEGF-A, is being led by our strategic collaborator AstraZeneca. This program recently completed a Phase 1a/b clinical trial in which we observed both a dose-dependent protein production and a pharmacologic effect, as measured by changes in local blood flow in patients. We believe these data provide clinical proof of mechanism for our mRNA technology outside of the vaccine setting as a potential therapeutic.

Our pipeline is shown in two formats, with a cell map illustrating the diversity of biology addressed by our mRNA pipeline programs, and a traditional format that shows the current stages of development of our pipeline programs, in the section of this Annual Report on Form 10-K titled “Business—Our Pipeline.”

Localized regenerative therapeutics modality: Opportunity

There are multiple applications for tissue regeneration. With AstraZeneca, we have focused on ischemic heart failure for the first program. Coronary artery disease, the primary cause of ischemic heart failure, affects the arteries providing blood supply to the cardiac muscle. In 2015, coronary artery disease resulted in 366,000 deaths in the United States, and 8.9 million deaths globally.

VEGF-A (AZD8601): Program summary

Addressing ischemic heart failure—VEGF-A as a localized therapeutic in collaboration with AstraZeneca

Heart disease is the leading cause of death in the United States, accounting for one in every four deaths, and is often due to the inability of adult humans to regenerate heart tissue. Current approved therapies do not specifically address heart regeneration. Previous attempts at cardiac regeneration have included stem cell grafting and gene therapy, but have faced challenges with safety or efficacy. In collaboration with AstraZeneca, we are pioneering a unique approach to treating ischemic heart failure, a condition where the cardiac muscle does not get enough blood supply to perform its contractile function. Vascular Endothelial Growth Factor A, or VEGF-A, can promote cardiac tissue revascularization. The goal of this program is to promote recovery of cardiac function through partial tissue regeneration. The mRNA in this program is in a saline formulation without LNPs and is expected to act locally. Our strategic collaborator AstraZeneca has conducted a Phase 1a/b clinical study in diabetic patients in Europe. The study has met its primary objectives of describing safety and tolerability and secondary objectives of dose-dependent protein production and changes in blood flow. AstraZeneca has moved this program to a Phase 2a trial that is being conducted in Europe and is designed to test safety and tolerability of epicardial injections for patients undergoing coronary artery bypass grafting surgery.

VEGF-A (AZD8601): Disease overview

VEGF-A can promote blood vessel growth to potentially address ischemic heart failure

Heart disease is the leading cause of death in the United States, accounting for one in every four deaths. Coronary artery disease, or CAD, the primary cause of ischemic heart failure, affects the arteries providing blood supply to the cardiac muscle. CAD resulted in 366,000 deaths in the United States, and 8.9 million deaths globally in 2015.

Several treatments are available for patients with ischemic heart failure. Current treatments include revascularization of the coronary arteries to relieve symptoms and improve cardiac function; and therapies that reduce blood pressure or potentially help eliminate excess fluids in congested tissues, including: beta-blockers, angiotensin-converting enzyme inhibitors, angiotensin II inhibitors, and aldosterone receptor blockers as diuretics. However, adult humans are unable to regenerate myocardium tissue following injury and the treatment options described above cannot compensate for this.

VEGF-A is a potent angiogenic factor that promotes growth of blood vessels. Preclinical data suggests that expression of this growth factor in the ischemic heart could increase blood flow and partially restore cardiac function.

VEGF-A (AZD8601): Our product concept

Local delivery of VEGF-A mRNA to increase local concentration of VEGF-A protein while reducing systemic distribution of therapeutic VEGF-A protein

VEGF-A protein acts as a powerful promoter of blood vessel growth. Systemic injection of VEGF-A protein increases VEGF-A exposure throughout the body, which can lead to side effects, but is very short-lived in circulation. Therefore, any therapy involving VEGF-A needs to be localized to elevate local protein concentration and drive revascularization while minimizing systemic side effects. AstraZeneca has opted to pursue the localized application of VEGF-A mRNA in a simple saline formulation in the heart muscle to elevate local protein concentration for longer periods due to increased local protein production. This

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potentially allows for an extended pharmacodynamic effect at the specific site of injection compared to systemic or local administration of a recombinant protein version of VEGF-A. Some of the early animal work for mRNA VEGF-A was published by our academic co-founder Dr. Kenneth Chien in Nature Biotechnology in 2013, showing improved cardiac function with increased survival with treatment.

VEGF-A (AZD8601): Preclinical information

AstraZeneca has observed the activity of VEGF-A for ischemic heart failure in several preclinical animal models

Preclinical work has been conducted at AstraZeneca in models of ischemic heart failure. In mouse, rat, and pig models of myocardial infarction, direct injection in the heart muscle (myocardium) of VEGF-A mRNA led to elevated cardiac VEGF-A protein levels and improved cardiac function. The data have been published by AstraZeneca in Molecular Therapy in 2018. The table below illustrates the beneficial effects of AZD8601 in the mini pig, two months after the myocardial infarct procedure and injection of the VEGF-A mRNA. In this table, left ventricular ejection fraction, or LVEF, was measured using echocardiography two months after intracardial mRNA administered 7 days after myocardial infarction. The data are means ± standard error of the means.

Significant improvement in LVEF with VEGF mRNA measured 2 months after administration in mini pig study

	LVEF, %	p-value
Control—Citrate saline	47.0 ± 0.8
AZD8601 1 mg dose	51.0 ± 0.9	<0.01
AZD8601 10 mg dose	52.0 ± 1.0	<0.01

VEGF-A (AZD8601): Clinical data

AstraZeneca has completed a Phase 1a/b trial in Germany; A Phase 2a trial is currently ongoing in Finland and an additional clinical trial application has been filed in the Netherlands for this study.

The Phase1a/b clinical trial for the AZD8601 program has met its primary objectives of describing safety and tolerability and secondary objectives of protein production and changes in blood flow post AZD8601 administration. AstraZeneca has moved this program to a Phase 2a trial.

The Phase 1a/b study was a randomized, double-blind, placebo-controlled study in men with type 2 diabetes mellitus. VEGF-A mRNA was administered by intradermal injection into the forearm skin in single ascending doses. The study was conducted in Europe. The primary objective was to evaluate the safety and tolerability of the drug product into the forearm skin, with safety follow-up for 6 months.

The study was divided into Part A (single ascending-dose cohorts) and Part B (pharmacodynamic cohort). There were three treatment regimens in Part A. Regimens were either AZD8601 at site 1 and placebo at site 2, placebo at site 1 and AZD8601 at site 2, or placebo at both sites. Each regimen comprised six 50 µL injections at one site and six 50 µL injections at a second site on the forearm. In part B, the regimen comprised one 50 µL intradermal injection of either AZD8601 or placebo at each of four sites on the forearm.

There were 27 patients in Part A with 18 receiving AZD8601 in at least one site of the forearm and 9 patients receiving placebo. There were three dose cohorts in Part A, each with 9 patients. In the first cohort, AZD8601 dose was at 24 µg per patient (4 µg per injection). The AZD8601 dose was increased to 72 µg and 360 µg in the next two dose cohorts. There were 15 patients in Part B receiving AZD8601 in at least two sites on the forearm per patient. In Part B, each patient received 200 µg of AZD8601 or placebo.

VEGF-A protein post injection of mRNA was produced at a high level, above the set expected threshold, as shown in the figure below. Expression was measured by skin microdialysis. At each sampling time, mean VEGF-A protein levels across all mRNA treated sites from patients across all cohorts were higher than that of placebo up to the 24-26 hour time point. Data are means with error bars showing standard error of the mean, or SEM. Asterisk indicates p-value <0.05.

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VEGF-A protein levels in patients in Part A of the Phase 1a/b trial

The bioactivity of the VEGF-A protein post injection of mRNA was observed by an increase in blood flow at injection sites up to 7 days following a single injection, as shown in the figure below. Measurements were made using laser doppler imaging 7 and 14 days after administration (study part A, n = 27). Data shown are means with error bars showing SEM. Asterisk indicates p-value <0.05.

VEGF-A led to increase in blood flow at day 7 and day 14 in patients in the Phase 1a/b trial

As shown above, administration of AZD8601 demonstrated protein production and changes in local blood flow in diabetic patients. Tolerability of our mRNA injected intradermally was demonstrated for all dose levels. The only causally treatment-related adverse events were mild injection-site reactions, occurring in 32 of 33 participants receiving VEGF-A mRNA across both parts of the study design. All adverse events of injection-site reaction were of mild intensity. No deaths, serious adverse events, or adverse events leading to discontinuation occurred. A list of adverse events is provided in the table below.

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Adverse events for the Phase 1a/b trial for AZD8601

	Part A (n = 27)		Part B (n = 15)
	Placebo only (1) (n = 9)	VEGF-A mRNA/ placebo (1)  (n =  18)	VEGF-A mRNA/ placebo (2)  (n =  15)
Participants with any AE, n (%)	5 (55.6)	18 (100.0)	14 (93.3)
Causally treatment-related, n (%)	0	18 (100.0)	14 (93.3)
Treatment-unrelated, n (%)	5 (55.6)	0	0
Participants with causally treatment-related AEs, n (%)
Injection-site reaction [mild]	0	18 (100.0)	14 (93.3)
Participants with treatment-unrelated AEs, n (%)
Injection-site reaction [mild]	1 (11.1)	0	0
Injection-site erythema [mild]	1 (11.1)	2 (11.1)	0
Asthenia [mild]	0	1 (5.6)	0
Tinea pedis [mild]	0	0	1 (6.7)
Arthropod bite [mild]	0	1 (5.6)	1 (6.7)
Injury [moderate]	0	1 (5.6)	0
Skin abrasion [mild]	0	1 (5.6)	0
Muscle spasms [mild]	0	1 (5.6)	0
Back pain [mild or moderate]	2 (22.2)	0	0
Myalgia [moderate]	0	0	1 (6.7)
Dizziness [mild]	0	1 (5.6)	0
Headache [mild]	1 (11.1)	0	0
Pruritus [mild]	0	1 (5.6)	0
Tooth extraction [mild]	0	1 (5.6)	0
Nasopharyngitis [moderate]	1 (11.1)	0	0

⁽¹⁾  There are two injection sites and it can be either VEGF-A mRNA/placebo, placebo/VEGF-A mRNA, or placebo/placebo at injection sites 1/2.

⁽²⁾  Randomized order of VEGF-A and placebo injections.

The program is currently in a Phase 2a clinical trial. It is a randomized, double-blind, placebo-controlled, multi-center, Phase 2a study to evaluate safety and tolerability of epicardial injections of AZD8601 during coronary artery bypass grafting surgery. Some of the outcomes to be monitored in the Phase 2a study include adverse and serious adverse events, electrocardiogram, or ECG, and LVEF. The study is being conducted in Europe. The study is intentionally designed to provide initial safety and tolerability data in about 24 coronary artery bypass patients.

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V. PROGRAM DESCRIPTIONS IN OUR SYSTEMIC SECRETED AND CELL SURFACE THERAPEUTICS MODALITY

We designed our systemic secreted and cell surface therapeutics modality to increase levels of desired proteins in circulation or in contact with the extracellular environment. We aim to use cells in the human body to produce proteins encoded by mRNA that are secreted to achieve a therapeutic effect in one or more tissues or cell types. The goal of this modality is to provide secreted proteins, such as antibodies or enzyme replacement therapies across a wide range of diseases, such as heart failure, infectious diseases, and rare genetic diseases. This modality has benefitted from our strategic alliances with AstraZeneca, DARPA, and the Bill & Melinda Gates Foundation.

In early 2020, we changed the name of the systemic secreted therapeutics modality to the systemic secreted & cell surface therapeutics modality. Like our prophylactic vaccine modality, we have designated this as a core modality based on the Phase 1 clinical data we have reported, specifically in our antibody against the chikungunya virus (mRNA-1944) program.

This modality currently has five programs. Our pipeline is shown in two formats, with a cell map illustrating the diversity of biology addressed by our mRNA pipeline programs, and a traditional format that shows the current stages of development of our pipeline programs, in the section of this Annual Report on Form 10-K titled “Business—Our Pipeline.”

Systemic secreted and cell surface therapeutics modality: Opportunity

The ability to systemically deliver mRNA for a therapeutic effect would allow us to address a number of diseases of high unmet medical need. Systemically delivered, secreted therapeutics address conditions often treated with recombinant proteins that are typically administered to the blood stream. These current therapies include:

• Enzyme replacement therapies, or ERTs, for rare diseases;

• Antibodies for membrane and extracellular soluble targets; and

• Circulating modulation factors for common and rare diseases such as growth factors and insulin.

Our approach

Our systemic secreted and cell surface therapeutics modality comprises programs where mRNAs instruct various cells of the human body to secrete proteins for therapeutic effect. For systemic therapeutic programs that utilize cells in the liver, the liver is a highly productive tissue for secreted protein production. The human liver can make tens of grams of proteins per day, well above the amounts necessary for the pharmacologic effect for virtually all protein therapeutics. We have demonstrated that mRNA can make and secrete monoclonal antibodies and soluble modulating factors in non-human primates. These proteins made in non-human primates can exert their pharmacological activity by binding to targets with biological effect.

The antibody against Chikungunya virus is our first systemic secreted therapeutic and patients are currently being dosed in a Phase 1 study. It will help us understand the fundamental relationship between mRNA dose and secreted protein production. The secreted human antibody is also a protein complex, not ordinarily made by the liver, which will be a test case for making human proteins in liver normally made by other cell types.

This modality also includes engineered proteins such as our Relaxin and PKU programs and is not limited to native forms of proteins. Recombinant protein therapeutics, which focus on secreted proteins, generate over $200 billion in annual worldwide sales.

Antibody against Chikungunya virus (mRNA-1944): Summary

Systemic mRNA administration to instruct cells to secrete antibodies, in this case for passive immunization to prevent Chikungunya infection

We are using this program to help understand how mRNA can be used to make complex secreted proteins in the human body and to address the potential health threat of Chikungunya virus, particularly for the military and others exposed to this virus. This program highlights a potentially important advancement of our platform and expansion of our modalities.

Chikungunya is a serious health problem with and is estimated to have caused at least three million cases during the 2005-2015 epidemic. There are no vaccines or prophylactic treatments for this disease. This virus can cause severe arthritic-like conditions in approximately 15% of the infected people. This program offers a passive immunization approach using antibodies to prevent infection, to complement our vaccine approach. In this program, we utilize two mRNAs encoding for light chain and heavy chain of an antibody against the envelope glycoprotein E. We plan to administer these mRNAs encapsulated in our proprietary LNPs

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intravenously to people to prevent infection by the Chikungunya virus. We are being financially supported for specific activities by DARPA and have an open IND for mRNA-1944.

Antibody against Chikungunya virus (mRNA-1944): Disease overview

Addressing a significant global health need

Chikungunya virus is a mosquito-borne alphavirus posing a significant public health problem in tropical and subtropical regions. While Chikungunya has been present in Africa for centuries, recent outbreaks and epidemics in new regions have arisen due to the expanding distribution of the Aedes mosquito in which it resides. A Chikungunya epidemic beginning in 2004 in Kenya spread to India and was exported to nearly all regions of the world and brought Chikungunya to the attention of the western world. As of April 2016, Chikungunya cases had been reported in 103 countries and territories around the world, including 46 countries and territories throughout the Americas. Chikungunya virus infection is characterized by an acute onset of fever, rash, myalgia, and sometimes debilitating polyarthralgia, giving the virus its name, which means “that which bends up” when translated from Makonde. It is rarely fatal, but neurological sequelae such as Guillain-Barre syndrome and chronic arthritis have been recognized.

Chikungunya virus is an alphavirus of the Togaviridae family with a positive-strand RNA genome. The viral structural proteins are naturally expressed as a single polyprotein followed by subsequent cleavage by viral and cellular proteases into capsid (C) and envelope (E) glycoproteins E3, E2, 6k, and E1. The E proteins are major targets of protective neutralizing antibody responses that can be tested for in assays.

There are currently no effective therapies or approved vaccines to treat or prevent Chikungunya infection or disease, and effective mosquito control has proven challenging, even in higher income countries. Currently, infected individuals are treated with non-steroidal anti-inflammatory drugs to relieve some symptoms. Therefore, in addition to an effective prophylactic vaccine, we believe there is a need for systemic secreted antibody for passive immunity to the Chikungunya virus.

Antibody against Chikungunya virus (mRNA-1944): Our product concept

A systemically delivered mRNA instructing cells to secrete an antibody to glycoprotein E to neutralize Chikungunya

The mRNA-1944 development candidate contains two mRNAs that encode the heavy and light chains of the Chikungunya antibody and utilizes our proprietary LNPs. The mRNA-1944 development candidate encodes a fully human IgG antibody isolated from B cells of a patient with a prior history of Chikungunya infection. Thus mRNA-1944 encodes a fully human IgG antibody against the envelope protein E2. The systemic antibody against Chikungunya virus titers can be evaluated in clinical trials by enzyme-linked immunosorbent assay, or ELISA, to quantify the amount of expressed IgG. A neutralization assay can be used to ensure that the mRNA expressed antibody was properly folded and functional.

Antibody against Chikungunya virus (mRNA-1944): Preclinical information

Systemic mRNA administration results in antibody production and protection from Chikungunya infection in animals

In immunodeficient AG129 mice (lacking the IFN-α/ß and -γ receptors) Chikungunya causes a lethal disease and mice succumb to infection within 3-4 days with ruffled fur and weight loss. Protection in this model is mediated by antibodies against the Chikungunya viral proteins that must provide complete protection or sterilizing immunity. Therefore, this challenge model was used to establish a correlate of protection using activity and systemic IgG concentration data.

An in vivo study in AG129 mice was completed to determine the activity of mRNA encoded antibody against Chikungunya virus. The test article was administered to mice as prophylaxis at 0.02, 0.1, and 0.5 mg/kg by IV tail injection. A subset of animals (n=10) were challenged 24 hours post prophylaxis with Chikungunya virus strain LR006 and monitored for morbidity and mortality. Complete survival of mice was observed after treatment with the highest dose of 0.5 mg/kg of mRNA-1944.

In addition, the pharmacokinetics were evaluated in cynomolgus monkeys through intravenous infusion at 0.3, 1.0, and 3.0 mg/kg. The average serum antibody level was quantified at various time points to demonstrate a half-life of 23 days. The maximum serum concentration of the antibody was found to be 16.2 µg/mL with dose 1 and 28.8 µg/mL with dose 2, as shown in the figure below.

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Expression of antibody against Chikungunya virus with repeat dosing of mRNA-1944 or placebo in non-human primate study

In addition, mRNA-1944 was tested in rats and non-human primates in a repeat-dose study via IV infusion up to 5 and 3 mg/kg, respectively. There were no dose-limiting toxicities related to mRNA-1944 observed and all other observations were generally reversible.

Antibody against Chikungunya virus (mRNA-1944): Clinical data

We recently announced positive interim data from the first analysis of safety and activity in the Phase 1 study of mRNA-1944 administered via intravenous infusion in healthy adults.

We are conducting a Phase 1 dose-escalation study in healthy adults that is randomized and placebo-controlled. The objective is to evaluate the safety and tolerability of escalating doses (0.1, 0.3, 0.6, mg/kg dose levels, without dexamethasone included in the premedication regimen, a dose level cohort at 0.6 mg/kg dose level, with dexamethasone included in the premedication regimen, with 8 subjects per cohort) of mRNA-1944 administered via intravenous infusion. In addition, there is a dose level cohort in which subjects will be administered two IV infusions of 0.3mg/kg, one infusion on Day 1 and another subsequent infusion on Day 8, without dexamethasone in the premedication regimen. No further dose escalation beyond 0.6 mg/kg is planned. Other objectives are to determine the pharmacokinetics of all dose levels of mRNA-1944, to determine if the antibodies produced are sufficiently active to neutralize viral infection in assays and to determine the pharmacodynamics of anti-Chikungunya virus IgG levels. Each of the dose level cohorts initially doses three sentinel subjects, with a seven-day interval between each sentinel subject. Safety data on each sentinel subject as well as cumulative safety data are reviewed by the internal safety team, or IST, seven days following infusion of mRNA-1944 prior to the second and third sentinel subjects are dosed, as per the schematic described below. The IST will also review safety data for the three sentinels and recommend expansion to five subjects at that dose level with an overall randomization ratio of 3:2 (mRNA-1944:placebo). The safety monitoring committee, or SMC, reviews the safety data for the dose level and recommend escalation to the next dose level. A schematic of the trial design is shown below.

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As of February 12, 2020, dose level cohorts 0.1, 0.3, 0.6 mg/kg without dexamethasone in the premedication regimen and dose level cohort 0.6 mg/kg with dexamethasone in the premedication regimen have been completed.

As of September 2019, at all dose levels tested (0.1, 0.3 and 0.6 mg/kg), all participants exceeded the levels of antibody expected to be protective against chikungunya infection (> 1 μg/mL) following a single dose, with the middle and high doses projected to maintain antibody levels above protective levels for at least 16 weeks as shown in the panel below. The average serum antibody level was quantified at various time points to demonstrate a half-life of 62 days. No significant adverse events were observed at the low and middle doses; infusion-related adverse events were observed at the high dose, which resolved spontaneously without treatment.

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Mean serum concentration of antibody against Chikungunya virus (mRNA_1944) at three dose levels without steroid premedication in Phase 1 clinical trial

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Relaxin (AZD7970): Summary

In collaboration with AstraZeneca we are developing a secreted systemic engineered protein for heart failure

Chronic heart failure continues to be a leading cause of death worldwide. While numerous treatments are currently available, the needs of many heart failure patients are not met. Relaxin is a well-studied natural protein hormone that is known to have cardiovascular protective effects. Earlier attempts at developing relaxin as a protein therapeutic have failed. Serelaxin, a recombinant relaxin protein therapeutic with a short 30 minute half-life recently failed to meet its primary endpoints in a Phase 3 trial. We believe that engineering the Relaxin protein for a longer duration and repeat dosing might overcome the shortcomings of earlier attempts. In collaboration with AstraZeneca, we use mRNA encoding for a relaxin protein designed for a long duration of action. It is also designed to be produced by the body with human post-translational modifications.

Relaxin (AZD7970): Disease overview

Heart failure continues to be a major health concern despite multiple treatment options

Heart failure is the inability of the heart to pump blood efficiently and presents itself as either an impairment of ejection of the blood (systolic heart failure) or defective ventricular filling (diastolic heart failure). It is associated with fluid retention in peripheral tissues, including the lungs, leading to tissue congestion, dyspnea, fatigue, and ultimately death. Heart failure is a major unmet medical need as it is the leading cause of hospitalization in the elderly worldwide and accounts for 1.1 million cases annually in the United States. The aging population and the improved survival rates from myocardial infarcts have increased the lifetime risk of developing heart failure to one in five.

Current treatments for heart failure include therapies that reduce blood pressure or potentially help eliminate the excess of fluid in congested tissues (beta-blockers, angiotensin-converting enzyme inhibitors, angiotensin II inhibitors, and aldosterone receptor blockers). Despite long-term combined treatments, the needs for these patients are often unmet, as evidenced by the high mortality rate in this patient population (i.e., 36.5% in a median 3-year follow-up).

Relaxin is a naturally occurring hormone, present in both men and women, that has been shown to promote vasodilation and angiogenesis, regulate extracellular matrix turnover, and suppress arrhythmias post myocardial infarction. Though prior studies have failed to demonstrate long-term benefit in clinical studies, we believe that our novel approach can overcome potential flaws of previous approaches.

Relaxin (AZD7970): Our product concept

We have engineered a long-acting Relaxin to extend its otherwise short half-life

AZD7970 is an mRNA encoding a human relaxin protein designed and engineered to have an extended half-life. We have also utilized our proprietary LNPs to enable repeat dosing. We believe AZD7970 can address the short half-life of serelaxin. AZD7970 is intended for IV-administered repeat dosing.

Relaxin (AZD7970): Preclinical information

We have observed extended exposure with our mRNA encoding for an engineered version of Relaxin

We have observed that relaxin mRNA gives rise to a long-lasting systemic and functional protein following IV dosing with proprietary LNPs. Prolonged duration of relaxin protein production was observed both in rodents and non-human primates. Systemic protein levels of the Relaxin protein in plasma of IV dosed cynomolgus monkeys following a single injection of mRNA were assessed using a commercially available antibody. Exposure to the fusion protein made from our mRNA was considerably extended (up to 10 days), as shown in the figure below. In contrast, earlier published studies described the half-life of relaxin administered as a recombinant protein to be of a few minutes. An IND-enabling GLP toxicology program for Relaxin (AZD7970) is ongoing.

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Relaxin protein levels in serum upon administration of mRNA encoding for

relaxin in our proprietary LNP in non-human primate study

Relaxin (AZD7970): Clinical plan

AstraZeneca may conduct a Phase 1 trial.

Fabry disease (mRNA-3630): Summary

Our approach to Fabry disease with a secreted alpha galactosidase protein

Fabry disease is an X-linked hereditary defect in glycosphingolipid metabolism caused by mutations in the GLA gene, which encodes for the lysosomal protein alpha galactosidase, or α-GAL. It is one of several lysosomal storage diseases. Decreased activity of α-GAL results in the lysosomal accumulation of substrates (Gb3 and Lyso-Gb3) within cells and tissues, ultimately impairing cell/tissue function. Currently, there are several approved therapies for the treatment of Fabry disease including enzyme replacement therapy, or ERT, and chaperone therapy. However, patients continue to suffer from renal decline and have immunogenic side effects with ERT usage. In addition, patient eligibility with chaperone therapy is limited to amenable mutation status. With our platform technology, the cells in the human body can be instructed to produce α-GAL from the liver and other tissues to properly target α-GAL into lysosomes. Additionally, these tissues can secrete it into circulation for delivery to the lysosomes of other tissues. We are developing an intravenously administered mRNA that encodes α-GAL enzyme and we plan to conduct a Phase 1/2 clinical trial to evaluate the safety and efficacy of mRNA-3630 in Fabry patients.

Fabry disease (mRNA-3630): Disease overview

Fabry disease is a lysosomal storage disorder

Fabry disease is a progressive, multiorgan, X-linked lysosomal storage disorder with an annual incidence of approximately 1:80,000. Affected individuals have a deficiency in α-GAL, resulting in a reduced or complete inability to metabolize glycosphingolipids in the lysosomes. Thus, patients accumulate glycosphingolipids such as Gb3 within lysosomes, which ultimately results in cellular and tissue dysfunction. In Fabry patients, multiple organs are impacted including the vasculature, kidney, heart; and the gastrointestinal and neurological systems. The severity of the disease is related to the lack of enzyme activity in patient cells. Classic Fabry patients are the most affected individuals, and generally retain <1% of normal enzyme activity. Diagnosis of Fabry disease occurs generally during childhood, but in some patients, it is diagnosed later in life, usually after the patient presents with a stroke or renal complications.

Currently, there are several approved therapies for the treatment of Fabry disease. Agalsidase beta, which is marketed as Fabrazyme by Sanofi Genzyme, and Agalsidase alpha, which is approved and marketed as Replagal outside the United States by Shire, are enzyme replacement therapies, or ERTs, administered to most Fabry patients. Both of those therapies are versions of α-GAL ERTs that are administered intravenously, often require long infusion times and can lead to undesired immune reactions. These enzymes are effective at decreasing substrate accumulation in some tissues and slowing disease progression, however patients that have been on ERTs for 10 years still have renal function decline at a rate greater than normal healthy individuals. In addition to ERTs, Amicus Therapeutics has received marketing approval in many jurisdictions including the United States and European Union for migalastat, a small molecule chaperone therapy which treats a subset of patients.

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Fabry disease (mRNA-3630): Our product concept

We intend to utilize the cells in the human body to produce and secrete α-GAL

The mRNA encoding α-GAL is designed to instruct the cells of the human body to produce complex functional intracellular proteins for utilization in the lysosome and secretion out of the cell for uptake by other tissues. This is intended to replace the enzyme α-GAL insufficient or missing in Fabry patients. Our mRNA-3630 program consists of an mRNA encoding human α-GAL encapsulated in our proprietary LNP. The mRNA sequence is optimized for protein expression. mRNA-3630 will be administered intravenously to encode enzymatically-active α-GAL protein to restore this deficient or defective enzyme.

An illustration of our approach is shown in the figure below. The mRNA encoding for α-GAL, once inside the cell, is translated to α-GAL protein by ribosomes and translocated to the endoplasmic reticulum. The protein sequences traverse the secretory pathway of the cell. The protein is either sent to the lysosome where it reduces the level of Gb3 in target cells or is directed for secretion outside the cells, allowing for broad distribution of the protein.

Fabry disease (mRNA-3630): Preclinical information

With a single dose of our mRNA encoding for α-GAL, we observed a sustained reduction in lyso-Gb3

We have conducted several in vivo pharmacology studies to demonstrate nonclinical proof-of-concept for α-GAL therapy. Administration of proprietary LNP formulated α-GAL mRNA to the Fabry mouse model resulted in a significant and durable reduction of globotriaosylsphingosine, or lyso-Gb3, in tissue and serum for 12 weeks following a single dose, as shown in the figure below. In this study, there were 3 Fabry GLA -/- mice per group. Data was normalized to the control sequence group for the specific time point.

Reduction in lyso-Gb3 in tissue with single administration of α-GAL mRNA in mouse model study

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In addition, we have evaluated plasma α-GAL in non-human primates following IV administration of 0.5 mg/kg mRNA-3630 every other week for four doses. There were four animals per group. These data indicate consistent circulation of enzyme in circulation following repeated administrations as shown in the figure below.

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Repeat dosing of α-GAL mRNA in non-human primate study

Anti α-GAL antibodies were not detected in these animals. Non-human primate tissues were examined after the last dose and showed greater than wild-type levels of enzyme as determined by activity assessment and shown in the figure below. The IND-enabling GLP toxicology program for mRNA-3630 is ongoing.

Increase inα-Galactosidase level in key tissues after repeat dosing ofα-GAL mRNA in non-human primate study

Fabry disease (mRNA-3630): Clinical plan

We plan to conduct a Phase 1/2 open label clinical trial with multiple ascending doses to evaluate the safety, tolerability, and efficacy of our development candidate in patients.

Autoimmune Therapeutic Area (mRNA-6981 and mRNA-6231) Introduction

Our company strategy continues to be to invest in our platform technology and scalable infrastructure to pursue a pipeline of potential medicines that reflect the breadth of the mRNA opportunity. In January 2020, we announced the entry into a fifth therapeutic area, autoimmune diseases, building on the clinical validation of the systemic delivery of mRNA provided by the Phase 1 clinical proof of concept of the chikungunya antibody program. Autoimmune diseases are characterized by immune activation in response to antigens normally present in the body, reflecting a loss of tolerance. Within this therapeutic area, we are developing two potential medicines, mRNA-6981 and mRNA-6231, designed to engage peripheral tolerance pathways to dampen autoimmune activation and help restore immune homeostasis, thereby reducing autoimmune pathology. In this modality, mRNA is delivered systemically to create proteins that are either secreted or expressed on the cell surface.

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Our approach to the treatment of autoimmune diseases is to leverage mechanisms of peripheral tolerance to modulate the immune system’s reaction to self-antigens.

Scientific and technical advances enable our expansion into new therapeutic areas, the latest of which is autoimmune disease. Autoimmune diseases are defined by pathology resulting from an adaptive immune response against an antigen or antigens normally present within the body. Pathology is present in a variety of organs across autoimmune diseases such as rheumatoid arthritis, systemic lupus erythematosus, inflammatory bowel disease, psoriasis, type 1 diabetes, multiple sclerosis, autoimmune hepatitis and related disorders such as graft vs host disease. Autoimmune diseases affect millions of patients worldwide, many of whose disease is not well-controlled by existing treatment options, and represent billions of dollars in healthcare costs.

In healthy people, autoimmune reactions are prevented or controlled by mechanisms of tolerance. Lymphocytes (e.g., T and B cells) that are reactive against self-antigens are deleted during development, thus establishing central tolerance. Central tolerance is not completely protective, and so other mechanisms, collectively known as peripheral tolerance, act on any self-reactive lymphocytes that escape central tolerance to control potential autoimmune pathology. These mechanisms of peripheral tolerance include induction of a reversible state of cellular non-responsiveness in self-reactive cells called anergy, and expression of inhibitory receptors or cytokines by other cells, such as dendritic cells, macrophages, and regulatory T cells (“Tregs”). The immune system works constantly to maintain balance between a state of immune activation and immune tolerance, sometimes called homeostasis. We are developing two potential medicines we believe have the potential to engage peripheral tolerance mechanisms to dampen autoimmune activation and help restore immune homeostasis. PD-L1 (mRNA-6981) aims to induce the expression of this inhibitory receptor on myeloid cells, and IL-2 (mRNA-6231) aims to preferentially increase the number of Tregs.

PD-L1 (mRNA-6981): Mechanistic overview

PD-L1 is a co-inhibitory receptor that can induce anergy in programmed cell death protein 1 (“PD-1”)-expressing T cells.

Antigen presenting cells, such as dendritic cells, form stable cell-cell junctions with T and B cells, called immune synapses, to communicate in three ways: Signal 1 (antigen presentation and recognition), Signal 2 (co-stimulatory signals to activate the cell) and Signal 3 (cytokines, chemokines, and certain metabolites to activate, repress, or modulate the immune response). When immune synapses occur in the context of high levels of co-inhibition, such as high levels of PD-L1 expressed on antigen presenting cells, this may result in the induction of peripheral regulatory T cells, induction of a reversible non-responsive state called anergy, or death of autoreactive lymphocytes due to removal of critical survival signals. Given their role in adaptive immune responses and their involvement in autoimmune disorders, dendritic cells and other myeloid populations have become a target of recent immunotherapies.

The PD-L1/PD-1 pathway has a critical function in immune regulation and promotes development and function of Tregs. PD-L1 is a transmembrane protein expressed on antigen presenting cells, such as dendritic cells and macrophages, activated T cells, B cells, and monocytes as well as peripheral tissues. Its cognate receptor, PD-1, is a co-inhibitory transmembrane protein expressed on T cells, B cells, natural killer cells and thymocytes. Engagement of PD-1 to PD-L1 results in decreased IL-2 production and glucose metabolism, with continued engagement leading to induction of T cell anergy or conversion of naïve cells into peripheral regulatory T cells. Engagement of PD-L1 with PD-1 also inhibits T cell proliferation, cytotoxic activity and cytokine production, and suppresses the reactivation of previously activated T effector cells.

Preclinical mouse models deficient in PD-1 spontaneously develop a variety of autoimmune diseases such as arthritis, myocarditis, lupus-like glomerulonephritis and type 1 diabetes, demonstrating the critical role of the PD-L1/PD-1 interaction in maintaining tolerance to self-antigens. Additionally, treatment of cancer patients with PD-1 or PD-L1 inhibitors sometimes results in immune-related adverse events, including the development of hepatitis, dermatitis and colitis, demonstrating the role of PD-1/PD-L1 in human autoimmune reactions.

We believe our PD-L1 therapy may augment PD-L1 expression on cell types similar to those that endogenously express it, and by reducing immune activation, potentially reduce the clinical manifestations of a variety of autoimmune diseases.

PD-L1 (mRNA-6981): Our product concept

We intend to induce expression of PD-L1 on myeloid cells to send a tolerizing signal to immune cells in their environment in order to treat autoimmune diseases.

Our intent is to use our platform to influence myeloid cells, including dendritic cells, to provide additional co-inhibitory signals by augmenting endogenous expression of PD-L1. We believe that this tolerizing signal to lymphocytes may limit autoreactivity in the context of ongoing autoimmune pathology without severe and global suppression of the immune system. Given that our platform allows us to modify myeloid cells in situ, our approach to the creation of a tolerogenic environment may provide unique benefits in

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treating autoimmune diseases by seeking to restore immune homeostasis. We believe the platform technologies used have already been substantially validated in humans; mRNA-6981 employs the same delivery technology used in clinical trials for our chikungunya antibody therapeutic, mRNA-1944. Results with mRNA-1944 demonstrate predictable dose-dependent pharmacology that translated effectively from preclinical species into humans.

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PD-L1 (mRNA-6981): Preclinical information

We have observed disease modification in a range of preclinical models.

We have investigated the effect of mRNA-6981 in multiple disease models. In one example we evaluated mRNA-6981 in a rat model of arthritis. Animals were given a single injection of chicken collagen type II in incomplete Freund’s adjuvant in order to induce chronic arthritis-like symptoms. mRNA-6981 was dosed subcutaneously at four times per week and compared to a negative PBS control and a positive control of daily high dose dexamethasone (Dex). Arthritis-like symptoms included paw swelling and joint rigidity, which were scored as a proxy for disease severity. Compared to animals treated with PBS, animals treated with PD-L1 mRNA presented with consistently less severe disease similar to animals treated daily with dexamethasone for at least three weeks.

Collagen-Induced Arthritis model

We have investigated mRNA-6981 in a range of other preclinical models of autoimmune and related diseases, including type 1 diabetes, colitis and graft-versus-host disease, and observed disease-modifying activity.

PD-L1 (mRNA-6981): Clinical plan

We are planning a Phase 1 clinical trial for patients with type 1 autoimmune hepatitis (“AIH”).

AIH is an autoimmune condition involving inflammation in the liver, which over time can lead to cirrhosis and liver failure. Type 1 AIH is characterized by a specific autoantibody profile and afflicts more than 75,000 patients in the U.S. Type 1 AIH is typically treated with steroids and azathioprine but some patients either do not respond to these treatments or are unable to tolerate them and are therefore in need of alternatives. A specific role for PD-L1 therapy in treating type 1 AIH is supported by clinical observations in cancer patients receiving PD-1/PD-L1 checkpoint inhibitor treatment: a noted adverse event is the development of AIH, which responds to discontinuation of checkpoint inhibitor therapy and treatment with corticosteroids. Checkpoint inhibitor-induced AIH has an identical histological and clinical manifestation compared to non-drug induced type 1 AIH. We believe that mRNA-6981 may provide benefit to type 1 AIH patients by increasing PD-L1 expression and plan to pursue proof-of-concept in type 1 AIH as a first step to addressing a range of autoimmune indications. We are planning a clinical trial to evaluate the safety, tolerability, pharmacology, and duration of the effect of mRNA-6981 in type 1 AIH patients refractory or intolerant to the standard of care

IL-2 Mutein (mRNA-6231): Mechanistic overview

IL-2 is a critical cytokine for Treg activation and expansion.

Cytokines are potent modulators of the immune system, directing function and homeostasis. IL-2 is critically important to T cell survival and function. IL-2 acts through a receptor complex that can be dimeric, IL-2Rß (“CD122”) plus the common γ chain (“CD132”), or trimeric, which is formed through the addition of IL-2Rα (“CD25”) to the dimeric form. The trimeric form has 10-

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fold to 100-fold greater affinity for IL-2. Under low or homeostatic IL-2 conditions, those cells which preferentially express the trimeric receptor, or IL-2R, such as Tregs and very recently activated effector T cells, are activated. Conversely, those cells that express the dimeric form, such as naïve or antigen-experienced cytotoxic T cells and natural killer cells (“NK cells”), are only activated by much higher concentrations of IL-2. Tregs play an obligate role in maintaining peripheral tolerance through the control of effector T cell responses, and several strategies are being developed to exploit IL-2 to treat autoimmune disease by selectively enhancing Treg function. These include recombinant protein forms of IL-2/mAb complexes, IL-2 Muteins and low-dose IL-2.

IL-2 Mutein (mRNA-6231): Our product concept

We intend to utilize subcutaneous mRNA administration to produce a version of IL-2 that is potentially longer acting and more selective for the trimeric IL-2 receptor (“IL-2R”) in order to treat autoimmune diseases.

IL-2-based therapeutics are being clinically evaluated for a wide range of immune-mediated disorders, including rheumatoid arthritis, systemic lupus erythematosus, graft versus host disease, inflammatory bowel diseases, and autoimmune hepatitis. We believe that our platform can be exploited to produce a modified IL-2 for the treatment of autoimmune conditions. Our modified IL-2 is engineered with mutations that selectively decrease binding to the dimeric IL-2 receptor present on CD4+ and CD8+ T effector cells and NK cells, and increase reliance upon CD25 of the trimeric IL-2 receptor complex to trigger the signaling cascade in regulatory T cells. Our modified IL-2 is also expressed as a fusion protein to extend its half-life in the serum. This will be the first demonstration of subcutaneous administration of the delivery technology used in clinical trials for our chikungunya antibody therapeutic, mRNA-1944.

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IL-2 Mutein (mRNA-6231): Preclinical information

We have observed preferential expansion of Tregs in non-human primates.

Preclinical work has been conducted using mouse homologs as well as cynomolgus monkeys. In one example, monkeys were dosed subcutaneously with a single dose of mRNA-6231 and T cells in the peripheral blood were monitored on days 1, 3, 5, 8, and 14. The percentage of Tregs (CD4+ T cells that were also FoxP3+) increased about 12-fold (average across N=4 animals) at their maximum (day 8 post-dosing). Conversely, the percentage of activated CD8+ conventional T cells (that co-express CD25) did not significantly increase over baseline at any time during the monitoring period, illustrating the preferential expansion of Tregs by the IL-2 Mutein.

IL-2 Mutein (mRNA-6231): Clinical plan

We are planning a Phase 1 clinical trial in normal healthy volunteers to assess safety, tolerability, pharmacokinetics and pharmacodynamics.

We plan to conduct a Phase 1 dose escalation study of mRNA-6231 in adult healthy volunteers. The objectives of this study are to evaluate the safety and tolerability of mRNA-6231, to assess the pharmacodynamic response through Treg selective expansion, activation and duration, and to characterize the pharmacokinetic profile of mRNA-6231 in expressing IL-2 in the serum following subcutaneous administration.

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VI. PROGRAM DESCRIPTIONS IN OUR SYSTEMIC INTRACELLULAR THERAPEUTICS MODALITY

We designed our systemic intracellular therapeutics modality to increase levels of intracellular proteins. We aim to use cells in the human body to produce proteins encoded by mRNA that are located in the cytosol or specific organelles of the cell to achieve a therapeutic effect in one or more tissues or cell types. The goal of this modality is to provide intracellular proteins, such as intracellular enzymes and organelle-specific proteins, as safe, tolerable, and efficacious therapies. Our initial focus within this modality is on rare genetic diseases.

This modality currently has four programs. Our pipeline is shown in two formats, with a cell map illustrating the diversity of biology addressed by our mRNA pipeline programs, and a traditional format that shows the current stages of development of our pipeline programs, in the section of this Annual Report on Form 10-K titled “Business—Our Pipeline.”

Systemic intracellular therapeutics modality: Opportunity

Systemically delivered, intracellular therapeutics focus on areas currently not addressable with recombinant proteins, which are typically administered systemically and cannot reach the inside of the cell. Objectives for potential new therapies in this area include increasing the levels of:

• intracellular pathway proteins;

• soluble organelle-specific proteins; and

• organelle-specific membrane proteins.

Methylmalonic acidemia (mRNA-3704): Summary

Program aims to produce an intracellular, mitochondrial enzyme to treat a pediatric, genetic, metabolic disorder

Isolated methylmalonic academia, or MMA, is a rare, life-threatening, inherited metabolic disorder that is primarily caused by a defect in the mitochondrial enzyme methylmalonyl-coenzyme A mutase, or MUT. It primarily affects the pediatric population. There is no approved therapy that addresses the underlying disorder, including no approved enzyme replacement therapy, due to the complexity of the protein and its mitochondrial localization. Liver or combined liver-kidney transplant is one option for severely affected individuals. Our platform may allow the cells in the human body to produce these and other complex mitochondrial enzymes. Therefore, we are developing an intravenously (IV)-administered mRNA encoding MUT in our proprietary LNP, in order to restore this deficient or defective mitochondrial enzyme in the liver and other cells. We have observed preclinical proof-of-concept in two different MMA mouse models, notably with a marked improvement in survival and reduction of biochemical abnormalities in a severe MMA mouse model. We have received Rare Pediatric Disease Designation and Orphan Drug Designation from the FDA and Orphan Drug Designation from the European Commission. The FDA has also designated the investigation of mRNA-3704 for the treatment of isolated MMA due to MUT deficiency as a Fast Track development program. We have initiated a Phase 1/2 clinical trial in MMA patients with MUT deficiency, and as of February 12, 2020, we have enrolled the first patient in the trial. This patient has entered an observational period prior to treatment, which evaluates the patient’s baseline disease prior to starting the treatment period.

Methylmalonic acidemia (mRNA-3704): Disease overview

MMA is a rare, life-threatening pediatric disorder with no approved therapies that address the underlying defect

MMA associated with MUT deficiency is a serious inborn error of metabolism disorder with significant morbidity and mortality. There are approximately 500-2,000 MMA MUT deficiency patients in the United States based on estimated birth prevalence (0.3-1.2:100,000 newborns) and mortality rates. Mortality is significant, with mortality rates of 50% for MMA patients with complete MUT deficiency (mut ⁰) (median age of death 2 years) and 40% for MMA patients with partial MUT deficiency (mut ^-) (median age of death 4.5 years) reported in a large European study.

MMA mainly affects the pediatric population and usually presents in the first few days or weeks of life. The occurrence of acute metabolic decompensations is the hallmark of the disorder and decompensations are typically more frequent in the first few years of life. Each decompensation is life-threatening and often requires hospitalization and management at an intensive care unit. Surviving patients often suffer from numerous complications including chronic renal failure and neurologic complications such as movement disorders, developmental delays, and seizures. Consequently, the health-related quality of life for MMA patients and their families is significantly impaired.

The disorder is autosomal recessive and primarily caused by loss-of-function mutations in the gene encoding MUT, a mitochondrial enzyme that metabolizes certain proteins and fats, resulting in complete (mut ⁰) or partial (mut ^-) enzyme deficiency.

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Over 250 mutations have been reported to date for MUT, with many MMA patients carrying private mutations. The most frequent mutations include p.N219Y and p.R369H, occurring with allelic frequencies of 8% in a large European cohort (n=151). Population-specific mutations have been reported, such as the p.R108C and p.G717V mutations identified in Hispanic and African-American patients, respectively. Due to a deficiency in the MUT enzyme resulting in a blockage in a metabolic pathway, the disorder is biochemically characterized by the accumulation of toxic metabolites such as methylmalonic acid in all body fluids and tissues.

There are currently no approved therapies that address the underlying defect for MMA. Carglumic acid (marketed as Carbaglu) is approved in the EU for the acute treatment of hyperammonemia due to various organic acidemias including MMA. Liver transplant and combined liver-kidney transplant have emerged as effective treatment options for severely affected individuals, resulting in substantial reductions in metabolic decompensations and circulating methylmalonic acid concentrations.

Methylmalonic acidemia (mRNA-3704): Our product concept

We are utilizing our ability to produce a complex intracellular enzyme (MUT) that is localized to the mitochondria

MUT is a complex intracellular enzyme that exists as a homodimer, and requires mitochondrial localization and engagement with its cofactor (a derivative of vitamin B ₁₂ ) to be enzymatically active. mRNA has the capability to encode any type of protein, including a functional, intracellular protein that is trafficked to the proper subcellular localization within target cells.

We are developing an mRNA encoding human MUT encapsulated in our proprietary LNPs for intravenous, or IV, administration for the treatment of isolated MMA associated with MUT deficiency. The sequence has been engineered to improve protein translation. To function, the mRNA-encoded MUT protein is translocated to its site of action in the mitochondria as shown in the figure below.

Methylmalonic acidemia (mRNA-3704): Preclinical information

We have observed pronounced improvement in survival due to mRNA treatment in an MMA mouse model

We have conducted a series of in vitro and in vivo pharmacology studies to demonstrate preclinical proof-of-concept for human MUT mRNA in two different mouse models of MMA representing the spectrum of MUT deficiency (mut ⁰ and mut ^- ) as published by us in Cell Reports in 2017. As an example, a 12-week repeat-dose study in MMA mut ⁰ mice (Mut ^-/-; Tg ^{INS-MCK- Mut}) at 0.5 mg/kg IV every other week has shown a pronounced improvement in survival due to human MUT mRNA treatment, with all treated mice surviving 12 weeks in contrast to control mice which all perished within a few weeks. The figure below shows the Kaplan-Meier curve of PBS-injected (n=6 mice) and human MUT mRNA (n=6 mice) treated MMA mut ⁰ mice and PBS-injected (n=6 mice) healthy heterozygote mice. The three asterisks indicate p-value < 0.001 for human MUT mRNA vs. PBS-injected MMA mut⁰ mice from the log-rank test.

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Improved survival in a 12-week study with mRNA encoding for human MUT in mouse disease model study

In addition, the data indicated that the treated MMA mut⁰ mice doubled their body weights and approached the body weights of PBS-injected healthy mice in this 12-week repeat dose study. In contrast, surviving PBS-injected MMA mut ⁰ mice did not gain weight.

Increase in body weight in a 12-week study with mRNA encoding human MUT in mouse disease model study

hMUT mRNA treated MMA mut⁰ mice showed significant and sustained reductions in the toxic disease metabolites, including plasma methylmalonic acid, compared to pre-treatment levels, in a 6-week repeat dose study in MMA mut⁰ mice. This is shown in the figure below. Arrows denote weekly IV administration of human MUT mRNA (0.2 mg/kg). Plasma was collected 4 days prior to treatment and 3 days after each dose administration. Washout levels were for the 10-day washout following 5 ^th dose administration of human MUT mRNA. The asterisk indicates a p-value < 0.01 from paired t-tests of post-treatment vs. pre-treatment levels.

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Decrease in plasma methylmalonic acid in 6-week repeat dose study with mRNA encoding for human MUT in MMA mut ⁰ mouse model study

Additionally, a pharmacokinetic study performed in wild type mice demonstrated that human MUT can be elevated above wild type level MUT levels. Specifically, human MUT protein expression in liver peaked at 16 hours after a single IV injection of human MUT mRNA (0.5 mg/kg) with a concentration of 85 ng/mg protein, ~2-3 fold higher than endogenous human and mouse MUT in liver.

There were no dose-limiting toxicities related to mRNA-3704 in juvenile rats and immature non-human primates in a repeat IV dose one-month IND-enabling GLP toxicology study up to the top doses tested. An independent IND-enabling GLP cardiovascular safety study in non-human primates also indicated mRNA-3704 showed no dose-limiting toxicities.

Methylmalonic acidemia (mRNA-3704): Clinical plan

We are conducting a global natural history study and a Phase 1/2 clinical trial in the United States and Europe

We are conducting a global natural history study in methylmalonic acidemia, or MMA, and propionic acidemia, or PA, that was initiated in 2018. Some of the patients participating in the natural history study may enter our interventional clinical trials.

Our natural history study aims to identify and correlate clinical and biomarker endpoints for both MMA and PA. We also have a PA program (mRNA-3927) that addresses a disease closely related to MMA. There is synergy in combining the natural history study for MMA and PA. The natural history study is a global, multi-center, non-interventional study for patients with confirmed diagnosis of MMA due to MUT deficiency or PA. Up to 60 MMA patients and up to 60 PA patients in the United States and Europe will be followed prospectively for 1-3 years. Enrollment in the study has been completed. Retrospective data are also being collected as available.

We have initiated an open-label, multi-center, dose escalation Phase 1/2 study of multiple ascending doses of mRNA-3704 in patients with isolated MMA due to MUT deficiency between 1 to 18 years of age with elevated plasma methylmalonic acid concentrations. The objectives of this study are to evaluate the safety, pharmacodynamics (as assessed by changes in plasma methylmalonic acid), and pharmacokinetic profile of mRNA-3704 in patients affected by MMA.

During the dose-escalation phase, three dose levels of mRNA-3704 are planned to be investigated in this study. The first dose level will enroll adolescents aged 8 and older. Once safety and tolerability is determined, we intend to enroll patients aged 1 and older. An additional cohort to evaluate a fourth dose level may be considered. Patients will receive twelve doses of mRNA-3704 administered via IV infusion every 3 weeks.

Three patients will be enrolled sequentially within each dose level cohort. Enrollment of the first three patients within each dose cohort will be staggered by 21 days using a sentinel dosing strategy approach to allow for safety observation after dosing. For the evaluation of safety data prior to escalation to the next dose level, a modified 3+3 design using predefined dose limiting toxicity criteria will be used. Dose escalation recommendations to open the next dose level cohort will be made by an independent SMC and will include review of safety and pharmacodynamic activity through at least 21 days following the first dose administration of mRNA-3704, the dose limiting toxicity window, for all patients.

Upon establishment of a dose with acceptable safety and pharmacodynamic activity in dose escalation, additional patients will be enrolled in a dose-expansion phase to allow for further characterization of the safety and pharmacodynamic activity of

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mRNA-3704. Patients in both phases of study will enter into a pre-dosing observational period to characterize baseline (pre-treatment) biomarker levels, followed by a treatment period, and then a two-year follow-up period after withdrawal of treatment. A schematic of the trial is shown in the figure below. We have enrolled the first patient in the trial. This patient has entered an observational period prior to treatment, which evaluates the patient’s baseline disease prior to starting the treatment period.

Propionic acidemia (mRNA-3927): Summary

We aim to produce an intracellular, mitochondrial enzyme complex to treat a pediatric metabolic disorder

Propionic acidemia, or PA, is a rare, life-threatening, inherited metabolic disorder due to a defect in the mitochondrial enzyme propionyl-CoA carboxylase, or PCC. It primarily affects the pediatric population. There is no approved therapy for PA, including no approved enzyme replacement therapy, due to the complexity of the enzyme, which comprises six copies each of two different subunits (PCCA and PCCB), and its mitochondrial localization. The only effective treatment for severely affected individuals is liver transplant, aimed at increasing enzyme activity to reduce the occurrence of life-threatening acute metabolic crises. Our platform is uniquely positioned to potentially address this disease by enabling synthesis of this complex enzyme that is localized in the mitochondria of the cell. We are developing an IV-administered mRNA therapeutic comprising two different mRNAs encoding PCCA and PCCB in our proprietary LNP to replace the defective PCC enzyme with functional enzyme in liver and other cells. We have received Rare Pediatric Disease Designation and Orphan Drug Designation from the FDA and Orphan Drug Designation from the European Commission for the PA program. The FDA has also granted Fast Track designation to mRNA-3927.

We expect to initiate a Phase 1/2 clinical trial in PA patients.

Propionic acidemia (mRNA-3927): Disease overview

PA is an inherited metabolism disorder with significant morbidity and mortality and no approved therapy

PA is a serious inborn error of metabolism disorder, closely related to MMA, with significant morbidity and mortality. There are approximately 325-2,000 PA patients in the United States based on estimated birth prevalence (0.2-1.2:100,000 newborns) and mortality rates. The vast majority of patients present with life-threatening metabolic crises during the first days or weeks of life, with mortality rates ranging from 13-53% during the neonatal period. Similar to MMA, the cardinal feature of the disorder is the occurrence of life-threatening acute metabolic decompensations that are more frequent in the first few years of life. Longer term sequelae include cardiac complications (cardiomyopathy, arrhythmias) and severe neurologic complications.

The disorder is caused by a defect or deficiency in PCC, an enzyme that is one step upstream in the same metabolic pathway as the MUT enzyme that is deficient in MMA. PCC is a complex hetero-dodecamer enzyme composed of six alpha subunits (PCCA) and six beta subunits (PCCB). The disorder is autosomal recessive, with PA patients generally having loss-of-function mutations in either PCCA or PCCB (and in rare instances, mutations in both PCCA and PCCB). To date, over 100 mutations have been identified for both PCCA and PCCB genes and, similar to MMA, most of the mutations are private. Also similar to MMA, due to this enzyme deficiency resulting in a metabolic block, the disorder is biochemically characterized by the accumulation of toxic metabolites such as 3-hydroxypropionic acid and 2-methylcitrate, among others, and these metabolites may be used as biomarkers of disease.

There is no approved therapy for PA to treat the underlying defect, including no enzyme replacement therapy, due to the complexity of PCC and mitochondrial localization. Carglumic acid (marketed as Carbaglu) is approved in the EU for the acute treatment of hyperammonemia due to various organic acidemias, including PA. Management of the disorder is otherwise limited to strict dietary restrictions and other supportive measures similar to MMA. Liver transplant is a radical yet effective treatment, with the aim of increasing PCC enzyme activity in liver for severely affected individuals.

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Propionic acidemia (mRNA-3927): Our product concept

We are utilizing the strength of our platform to produce a complex enzyme comprising two different proteins that localize to the mitochondria

The ability of our platform to encode for large, multimeric complexes such as PCC and enable production of intracellular, mitochondrial proteins makes mRNA especially suited to potentially address PA. We are developing an IV-administered combination mRNA approach, which contains two mRNAs, one for each of the subunits of PCC (PCCA and PCCB) encapsulated in our proprietary LNP. The intent is to potentially treat the entire PA population, regardless of whether an individual has a defect or deficiency in the PCC alpha or beta subunit. The mRNA sequences have been engineered to improve protein translation and encode enzymatically-active PCC with the proper subcellular localization in the mitochondria. An illustration of our approach is shown in the figure below.

Propionic acidemia (mRNA-3927): Preclinical information

We have demonstrated activity in a PA mouse model in a long-term repeat dose study

A series of in vitro and in vivo pharmacology studies have been performed to demonstrate preclinical proof-of-concept for the combined PCCA and PCCB mRNA therapy. PCCA and PCCB mRNAs administered in PA patient fibroblasts (both PCCA and PCCB-deficient) showed production of active PCC enzyme with the proper subcellular localization in mitochondria at concentrations above wild-type levels. In vivo studies in PA (PCCA ^-/- [A138T]) mice have resulted in a dose-dependent increase in hepatic PCC activity with a concomitant decrease in disease biomarkers. Notably, a reduction in plasma ammonia levels was observed 3-4 weeks after a single IV administration (1 mg/kg) of PCCA and PCCB mRNA encapsulated in our proprietary LNP in PA mice (n=4-5/group). The data are shown in panel A of the figure below. Additionally, a 6-month repeat-dose study in PA mice showed decreased heart weight (normalized to body weight) in mice treated with monthly IV administration of PCCA and PCCB mRNA (1 mg/kg) compared to control mRNA (n=6/group). This is shown in panel B of the figure below. Data in both panels is presented as mean ± standard deviation.

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Reduction in plasma ammonia with PCCA+PCCB mRNA in PA mouse model study

Panel (A)

Decrease in heart weight with PCCA+PCCB mRNA in 6 month repeat dose study in PA mouse model study

Panel (B)

In the 6-month repeat dose study in PA mice, a significant and sustained lowering of additional disease biomarkers (e.g., 2-methylcitrate, or 2MC) was observed throughout the duration of the 6-month study. A comparison of 2-methylcitrate levels as a result of monthly IV administration of PCCA and PCCB mRNAs (0.5-1 mg/kg) compared to control mice injected with a control (luciferase) mRNA is shown in the figure below (n=6/group). Data are presented as mean ± standard deviation. The IND-enabling GLP toxicology program for PA (mRNA-3927) has been completed.

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Plasma 2-methylcitrate levels with repeat dosing of PCCA+PCCB mRNA in PA mouse model study

Propionic acidemia (mRNA-3927): Clinical plan

We are conducting a global natural history study and are planning a Phase 1/2 clinical trial

The clinical development plan for mRNA-3927 includes a global, natural history study that was initiated in 2018 and a planned Phase 1/2 study in pediatric patients diagnosed with PA.

We have launched a natural history study aimed at identifying and correlating clinical and biomarker endpoints. This is a global, multi-center, non-interventional study for patients with confirmed diagnosis of PA or MMA due to MUT deficiency. Up to 60 PA and 60 MMA patients in the United States and Europe will be followed prospectively for 1-3 years. Enrollment in this study has been completed. Retrospective data are being collected as available.

We plan to conduct an open-label, multi-center, dose escalation Phase 1/2 study of multiple ascending doses of mRNA-3927 in pediatric patients with PA in the United States and Europe. The objectives of this study are to evaluate the safety and tolerability of mRNA-3927 administered via IV infusion, to assess the pharmacodynamic response from changes in plasma biomarkers, to characterize the pharmacokinetic profile of mRNA-3927.

Phenylketonuria (mRNA-3283): Summary

Our approach to Phenylketonuria with an mRNA encoding for an intracellular protein

Phenylketonuria, or PKU, is a rare inherited metabolic disease resulting from a deficiency in the metabolism of phenylalanine, or PHE, due to mutations within the enzyme phenylalanine hydroxylase, or PAH. The most effective treatment is a restrictive diet of low protein, which controls PHE intake. Approximately 20-56% of PKU patients respond to sapropterin dihydrochloride (marketed as Kuvan in the United States), a synthetic BH4 cofactor for PAH which improves PHE metabolism, but does not fully cure patients. In addition, Biomarin has received approval for pegylated phenylalanine lyase, or PAL, marketed as Palynziq. Palynziq is a pegylated recombinant bacterial enzyme which metabolizes PHE in the blood. We believe the immune risk is, at least in part, driven by bacterial PAL. With our mRNA technology, cells in the human body can be instructed to produce functional PAH, decreasing PHE levels in the blood and restoring production of tyrosine. We are developing an intravenously administered mRNA which encodes for the PAH enzyme and is encapsulated in our proprietary LNP. We plan to conduct a Phase 1 clinical trial for mRNA-3283.

Phenylketonuria (mRNA-3283): Disease overview

There are options to treat PKU which are not widely applicable, and efforts by other companies are likely to face hurdles

PKU occurs in approximately 1:10,000-15,000 live births in the United States. Based on current population estimates that would translate into approximately 21,000-32,000 PKU patients in the United States. Affected individuals have a deficiency in the enzyme PAH, resulting in a reduced or complete inability to metabolize the essential amino acid phenylalanine into tyrosine. Thus,

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PKU patients suffer from a phenylalanine intoxication and a subsequent deprivation of tyrosine, leading to severe mental disability if left untreated.

PAH is expressed as a monomer, but functions as a tetramer and requires tetrahydrobiopterin (BH4) as a cofactor to complete the conversion of PHE to tyrosine, thereby maintaining adequate PHE:TYR ratios within circulation. To date, greater than 950 gene variants have been identified in the PAH gene, resulting in PKU.

Diagnosis of PKU occurs primarily through newborn screening in available countries, followed by genetic confirmation. Newly diagnosed patients receive medical formulas containing protein with low PHE content to control blood PHE and provide adequate nutrition for growing infants. As patients age they are tested for sensitivity to synthetic BH4 and may transition to Kuvan. Approximately 20% of patients respond favorably to Kuvan, which can aid in PHE control. Nonresponsive patients are treated mainly with restricted diet; however, adherence to the diet is challenging, resulting in poor compliance. When PHE levels are not adequately controlled, patients begin to show multiple signs of disease, including depression, anxiety, poor executive function, and attention deficit hyperactivity disorder, or ADHD. In May 2018, Biomarin received approval to market Palynziq.

One option for PKU patients may be treatment with gene therapy. We believe there are potential advantages for mRNA therapeutics for this disorder over gene therapy as described in the systemic intracellular therapeutics modality section.

Phenylketonuria (mRNA-3283): Our product concept

We intend to utilize the cells in the human body to produce PAH intracellularly

We believe mRNA therapy is a viable therapeutic modality for PKU patients due to its ability to instruct cells in the human body to produce complex functional intracellular proteins such as PAH. Our program mRNA-3283 consists of an mRNA encoding human PAH encapsulated in our proprietary LNPs. The mRNA sequence is optimized for protein synthesis and contains a microRNA binding site to reduce or potentially eliminate synthesis of protein outside of the target tissues. mRNA-3283 is designed to be administered intravenously to encode enzymatically-active PAH protein in liver to restore this deficient or defective enzyme as illustrated in the figure below.

Phenylketonuria (mRNA-3283): Preclinical information

We have demonstrated the ability to impact PHE levels by repeat dosing of our mRNA in preclinical studies

We have conducted several in vitro and in vivo pharmacology studies to demonstrate preclinical proof-of-concept for PAH therapy. A PKU mouse model demonstrated a significant reduction of blood PHE levels post dose as shown in the figure below. The study included IV administration of PAH mRNA every 7 days at 0.5 mg/kg in a PAH-/- mouse model. Data point with asterisk is marked zero since it was not collected due to a snow storm. PHE level was measured using liquid chromatography with a combination of two mass analyzers (LC-MS/MS). The IND-enabling GLP toxicology program for PKU (mRNA-3283) is ongoing.

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PHE reduction with repeat dosing of PAH mRNA in PKU mouse model study

Phenylketonuria (mRNA-3283): Clinical plan

We plan to conduct a Phase 1 open label clinical trial with single ascending dose to evaluate the safety, tolerability, and activity of our development candidate in patients.

Glycogen storage disease type 1a (mRNA-3745): Summary

Our approach to glycogen storage disease type 1a using an mRNA encoding for intracellular human glucose 6-phosphatase

Glycogen storage disease type 1a ("GSD1a") is an inherited metabolic disease caused by the deficiency in the catalytic activity of glucose 6-phosphatase (“G6Pase”), which is encoded by the glucose 6-phosphatase gene (“G6PC”). The G6Pase enzyme is involved in the metabolic pathways of glycogenolysis and gluconeogenesis which allow the liver and kidney to release glucose into the blood. Those affected by GSD1a present with life-threatening hypoglycemia and a wide range of severe metabolic derangements and long-term complications such as hyperlipidemia, lactic acidemia, hepatomegaly, hepatocellular adenomas, and end-stage renal disease. The standard of care consists of strict diet control. Enzyme replacement therapy (“ERT”) is not an option for these patients due to challenges associated with delivering an enzyme inside the cell. Strict diet control via the frequent consumption of uncooked cornstarch is effective in improving hypoglycemia. However, the underlying pathologies continue and its efficacy in preventing the long-term metabolic complications has yet to be established. With our mRNA platform, cells in the liver may be instructed to produce functional G6Pase, with the goal of restoring the homeostasis of glycogenolysis and gluconeogenesis pathways and correcting the underlying pathologies. We are developing an intravenously administered mRNA which encodes for G6Pase and is encapsulated in our proprietary lipid nanoparticle ("LNP"). We have demonstrated activity in mouse models in the form of reduction in both liver and serum biomarkers and improvements in liver morphology. We plan to conduct a Phase 1 clinical trial for mRNA-3745.

Glycogen storage disease type 1a (mRNA-3745): Disease overview

There are no approved therapies for GSD1a that address the enzymatic deficiency

GSD1a is an inherited metabolic disorder caused by a deficiency in the catalytic activity of G6Pase, an enzyme encoded by G6PC gene and involved in two metabolic pathways associated with glucose homeostasis. G6Pase catalyzes the hydrolysis of glucose-6-phosphate to glucose and inorganic phosphate, the final step of glycogenolysis and gluconeogenesis that mainly takes place in liver and kidney. GSD1a patients suffer from severe fasting hypoglycemia, hepatomegaly, nephromegaly, lactic acidemia, hypertriglyceridemia, hyperuricemia, hypercholesterolemia, hepatic steatosis, and growth retardation. In addition, hepatocellular adenomas occur in 70% to 80% of GSD1a patients by their third decade of life and carries risk of transformation into hepatocellular carcinomas. Proteinuria has been observed in over half of patients above 25 years of age.

GSD1a occurs in approximately 1:100,000 live births in the United States and European Union but is more common in Ashkenazi Jews where the incidence is reported to be 1:20,000 live births. There are an estimated 2,500 people in the United States and over

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4,000 people in the European Union with GSD1a. Although strict diet therapy, including frequent feeding with uncooked cornstarch, allows GSD1a patients to live into adulthood by preventing hypoglycemia, the underlying pathological processes remain uncorrected resulting in the development of many long-term complications including liver adenomas and hepatocellular carcinoma. While gene therapy is being investigated for treatment of GSD1a, we believe there are potential advantages for mRNA therapeutics for this disorder over gene therapy.

Glycogen storage disease type 1a (mRNA-3745): Our product concept

We intend to utilize the cells in the human body to produce G6Pase intracellularly

We believe that our platform can address GSD1a with its ability to instruct cells in the human body to produce complex functional intracellular membrane proteins such as G6Pase. Our program, mRNA-3745, consists of an mRNA encoding for modified human G6Pase encapsulated in our proprietary LNPs. The human G6Pase sequence is modified for improved protein production and G6Pase activity. mRNA-3745 is designed to be administered intravenously and encodes G6Pase protein to restore this deficient or defective enzyme as illustrated in the figure below.

Glycogen storage disease type 1a (mRNA-3745): Preclinical information

We have demonstrated the ability to improve hypoglycemia and other metabolic abnormalities associated with GSD1a in a mouse model

We have conducted several in vitro and in vivo pharmacology studies to demonstrate preclinical proof-of-concept for GSD1a therapy. mRNA encoding for G6Pase introduced in human cells resulted in robust production of active G6Pase with subcellular localization into endoplasmic reticulum. We have examined the activity of mRNA encoding for human G6Pase in a liver-specific G6Pase -/- mouse model (G6PC.LKO). Like GSD1a patients, the G6PC.LKO mice are unable to produce endogenous glucose, leading to severe hypoglycemia during the fasting state.

In a dose-response study performed in G6PC.LKO mice, we treated the mice with three different doses of 0.2, 0.5, and 1 mg/kg of G6Pase mRNA encapsulated in our proprietary LNP and examined fasting glucose, serum triglycerides, and liver enzymes (n=5-8). Of note, mice treated with G6Pase mRNA showed a dose-dependent improvement in fasting glycemia and a reduction in serum triglycerides, without a significant increase in liver enzymes (e.g. alanine transaminase - ALT). Fasting blood glucose and triglycerides are shown in the figure below. Each bar represents the mean ± standard deviation. Single and double asterisk denotes p < 0.05 and p < 0.0001, respectively, by one-way ANOVA, followed by Dunnett’s post-hoc test for multiple comparisons.

Serum biomarkers after single dose of G6Pase mRNA in G6PC.LKO mice

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In the same study, a reduction in liver weight compared to the control-treated group was observed after 24 hours of administration of G6Pase encoded mRNA in LNP. The reduction in liver weight was associated with significant improvement in liver morphology presumably due to reduction in liver glucose 6-phosphate, glycogen, and triglycerides.

Reduction in liver weight 24 hours after IV administration of G6Pase mRNA in G6PC.LKO mice

In addition, data for a 7-week repeat-dose study in G6PC.LKO mice receiving G6Pase mRNA in LNP at 0.25 mg/kg IV every other week have shown a pronounced improvement in fasting glycemia, in comparison with the G6PC.LKO mice receiving a control mRNA treatment as shown below (n=7-9).

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Restoration of blood glucose above therapeutic threshold with repeat dosing of G6Pase mRNA in G6PC.LKO mice

Glycogen storage disease type 1a (mRNA-3745): Clinical plan

We are planning a Phase 1 clinical trial

We plan to conduct an open-label, dose escalation Phase 1 study of mRNA-3745 in adolescent and adult patients with GSD1a in the United States. The objectives of this study are to evaluate the safety and tolerability of mRNA-3745, to assess the pharmacodynamic response through changes in maintenance of euglycemia, and to characterize the pharmacokinetic profile of mRNA-3745.

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MANUFACTURING (PRODUCT SUPPLY AND TECHNICAL DEVELOPMENT)

We believe manufacturing plays a critical role in our value chain and ability to develop a new class of medicines. Our manufacturing capabilities currently support the Research Engine and the Early Development Engine, while in connection with preparing for our upcoming Phase 3 clinical trial with our CMV vaccine, we are establishing capabilities to support the Late Stage Development and Commercial Engine. Within the Research Engine, our manufacturing provides mRNA drug substance and formulated drug product for platform research and therapeutic area drug discovery. For the Early Development Engine, we manufacture mRNA and drug product for IND-enabling GLP toxicology studies and initial human clinical studies. For Late Stage Development, we manufacture mRNA and drug product for phase 3 studies. Our approach to date has been to proactively build capacity in anticipation of demand from internal research and development, as well as from our strategic collaborators. We have done so by making significant investments in our internal manufacturing capability and in a network of external manufacturing partners.

Overview of our manufacturing operating model

Our manufacturing activities focus on the following:

• Manufacturing Technology. Our manufacturing technology development includes state-of-the-art technologies for mRNA and drug product manufacturing and testing to attain robust, consistent supply that matches target product profiles. Manufacturing technology also needs to support scale-up and industrialization of products for ultimate commercial approval.

• Supply. The product supply for the Research Engine enables platform research and drug discovery in our therapeutic areas. Within the Early Development Engine, supply is directed towards IND-enabling GLP toxicology programs or current good manufacturing practice, or cGMP, supplies for early clinical studies of our investigational medicines.

We have invested in a dedicated in-house manufacturing facility in Norwood, MA, Moderna Technology Center (MTC), given our expectations for significant ongoing pipeline expansion and the long lead time required in building manufacturing infrastructure. The facility is approximately 200,000 square feet; can scale up to 100 cGMP lots per year; and can accommodate over 200 of our employees. This facility is expected to support our Research Engine supply, IND-enabling GLP toxicology study supplies, our Phase 1 and Phase 2 pipeline activities, later-stage clinical development activities, particularly in connection with our Phase 3 CMV vaccine clinical trials, as well as certain commercial activities.

The MTC includes the following areas:

• five cGMP suites for the manufacture of mRNA drug substance and bulk drug product;

• dedicated cGMP suites for sterile filling;

• cGMP suites for the manufacture of personalized cancer vaccines, or PCVs;

• cGMP suites for the manufacture of critical raw materials;

• space for packaging, labeling, and storage of vialed products;

• temperature-controlled warehouse for incoming and outgoing products;

• quality control laboratories;

• pilot scale manufacturing space for scale-up and manufacture of toxicology supplies;

• space for the manufacture of research grade mRNA; and

• clean utilities including purified water and water for injection generation and controlled distribution.

The facility has been designed with a high level of automation and digital integration of manufacturing records and data. In addition, we have deployed an automated material and resource management system, a manufacturing execution system, a laboratory execution system, a laboratory information management system, and an asset and document management system, to ensure the digital integration of our manufacturing, product testing and release, and regulatory filings.

Manufacturing technology development

In order to support our broad pipeline of products spanning multiple therapeutic areas and multiple routes of administration, the technology underpinning product manufacturing is critical to our success. Over the last few years, we have invested heavily in this technology to enable the breadth and depth of our pipeline, and to prepare us to meet future needs and requirements as our programs enter later phases of development and commercialization.

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Our technology efforts are intended to span the development of robust and consistent manufacturing processes, assays to fully characterize the product, and fit-for-purpose formulations and product presentations. In addition, manufacturing activities include the development of novel hardware platforms that incorporate significant automation and robotics which are applicable broadly across programs but also specifically to personalized cancer vaccines. All of these activities are being developed with a focus on achieving appropriate cost of goods and scalability.

Our advances over the last few years have enabled us to more efficiently scale our mRNA and drug product manufacturing at successfully larger production yields. We have made significant investments in analytical characterization to determine critical product quality attributes and enable manufacturing site and scale changes over the course of development. In addition, pharmaceutical readiness of our drug product has enabled a wide variety of routes of administration (e.g., intramuscular, intratumoral, and intravenous).

We have also invested in the establishment of technology for the manufacture of some of our key raw materials, including DNA plasmid and many small molecules. This vertical integration allows us to exert significant control over the value chain, though we will continue to use a combination of internal and external manufacture of these raw materials.

Supply of mRNA for the Research Engine and Early Development Engine

Supply for the Research Engine

We believe that our internal manufacturing capacity is key to the advancement of our platform technology development and therapeutic area discovery efforts. High throughput automation and custom-engineered equipment enable us to produce multiple high quality mRNA and formulated constructs within a limited timeframe from order to delivery. We currently have infrastructure capable of producing up to 1,000 lots of mRNA sequences and formulations per month with a turnaround time of a few weeks from sequence to final product. The typical scale of mRNA manufactured by this team is 1-1000 mg.

Supply for the Early Development Engine

Analogous to the Research Engine, we have proactively established manufacturing capabilities for the Early Development Engine. We started supplying product to enable IND-enabling GLP toxicology studies, and for human clinical studies, meeting required cGMP standards, with a combination of internal manufacturing at our Cambridge headquarters and external manufacturing at well-established contract manufacturing organizations, or CMOs. Our MTC facility has the capability and capacity to produce research and clinical supply for our programs as well as to enable technology development and scale-up for future needs. We will continue to selectively use CMOs to complement our internal capacity to provide supply contingency and expanded capability where needed.

This extensive capacity has helped enable our broad pipeline of 24 development candidates, including the significant output necessary to supply our toxicological and human clinical studies. Though the underpinnings of the technology utilized across these 23 programs are the same, each program typically requires customization driven in part by its target product profile. These custom features range from varying molecular architecture to different routes of administration, and often necessitate multivalent products. For example, our CMV vaccine (mRNA-1647) requires six different mRNA sequences to be manufactured for inclusion in an intramuscular mRNA medicine, whereas OX40L (mRNA-2416) requires a single mRNA sequence for inclusion in an intratumoral mRNA medicine. All programs, with the exception of PCV, require that we scale up supply over time to meet the clinical demand required in the different phases of development and prepare the process for regulatory approval and eventually commercial supply, where bigger batch sizes will be required. In contrast, the PCV program is designed to provide each patient with a cancer vaccine that is designed and manufactured for that specific patient, thus increasing the number of batches to match the number of patients treated. As we scale the manufacturing output for particular programs, we plan to continuously improve yield, purity, and the pharmaceutical properties of our development candidates from IND-enabling GLP toxicology studies through commercial launch, including improvement to shelf life stability and solubility properties of drug product and drug substance. Typically after a change in process, more time may be required for pharmaceutical property testing, such as 6- or 12-month stability testing. This time lag may necessitate resupplying clinical materials, or making additional cGMP batches to meet clinical trial demand, before such pharmaceutical property testing is completed.

Supply of mRNA and formulated product for toxicology studies: Early on, we established the internal capability to produce mRNA and formulated product for IND-enabling GLP toxicology studies for our development candidates under GLP standards.

Supply of cGMP mRNA and formulated product for human clinical studies: We have incrementally built the capability to produce and supply mRNA drug product for clinical development. In our early years, we outsourced cGMP supply. We selected specialized CMOs to support a total of five programs by the end of 2015. In 2016, we built and qualified two cGMP suites in our Cambridge facility for the manufacture of mRNA drug substance and formulated drug product. While we had the internal capability to produce drug product, we continued to work with our external CMO network for redundant capacity and to provide sterile filling capability.

cGMP manufacture of PCV: Due to the specialized nature of personalized medicine, in which a batch is specifically manufactured for a single patient, the PCV program has unique requirements. In this program, we digitally integrate patient-specific data from

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sequencing tumor samples and automatically design PCVs for patients. We have developed proprietary bioinformatics design algorithms, and have linked them to an automated manufacturing process for rapid production of formulated mRNA that can be turned around in a matter of weeks. The PCV manufacturing capability is termed Personalized Vaccine Unit, or PVU. PCV manufacturing is conducted using custom automated and engineering solutions utilizing single-use systems with fast “needle-to-needle” turnaround time. We have operationalized PCV manufacture within our external CMO network to meet our Phase 1 supply needs, while in parallel working to internalize manufacturing. Unlike traditional process development, where the product is scaled up in quantity for later phases of development and commercialization, each PCV is manufactured for a single patient and thus scaled-out with extensive use of automation and robotics for the larger numbers of patients involved in later phases of development and commercialization.

Supply for the Late Stage Development and Commercialization Engine

As our pipeline advances to later stage development and potential commercialization, we will need to evolve our manufacturing suites and other capabilities at our MTC facility. The modular nature of the MTC suites is permitting us to manufacture drug substance and drug product for our upcoming phase 3 CMV clinical trial and potentially other registrational trials, and potentially drug substance and drug product for commercialization for certain rare disease indications. In other instances, we may build additional capabilities to support our Late Stage Development and Commercialization Engine.

Quality unit

Quality is core to the way we operate. We seek to ensure quality at Moderna through a combination of a robust Quality Management System, or QMS, our quality culture, and through our people. In accordance with applicable regulations we have established, documented, and implemented a QMS to assure continued compliance with the requirements therein. The QMS facilitates cGMP compliance by implementing practices that identify the various processes required by the QMS, their application throughout the organization, and the sequence of interaction of these processes.

The primary mode of documenting these key practices is through policies, standard operating procedures, forms, and other quality records, which include an overarching Quality Policy and Quality Manual. We have implemented measurement tools and metrics to monitor, measure, and analyze these practices to support cGMP operations, achieve planned results, and support continuous improvement. We monitor these quality metrics through formal governance processes, including Quality Management Review, or QMR, and our Quality Council to enable continuous improvement. We have also established an independent Quality Unit that fulfills quality assurance and quality control responsibilities.

While the Quality Unit is ultimately accountable and responsible for quality, quality is everyone’s responsibility. All cGMP personnel are empowered to ensure quality systems are appropriately maintained and executed.

We have established a culture that encourages transparency, accountability, and ownership of quality at all levels in the organization. As we scale the quality organization, we have focused on hiring the best talent with the required experience, training, and education.

Supply chain unit

We have established a robust supply chain to enable sufficient supply of the raw materials used to produce our mRNAs and components of our formulations. We have worked with our supply chain vendors to characterize critical raw materials and to understand their impact on the quality of mRNA drug substance and formulated drug product. We have also assessed the quality system and performance of our supply chain vendors and worked with them to comply with regulatory requirements.

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DIGITAL INFRASTRUCTURE

We believe that digital technologies, such as robotics, automation, artificial intelligence, and cloud computing, are critical to operationalize our strategy, accelerate our pace of learning and execute at scale. Our approach to bring these digital technologies into our workflows and processes has involved the following:

• utilization of a consistent set of digital building blocks;

• application of digital technologies in multiple business processes; and

• rapid iterations for maximum optimization.

We have seen several benefits from our investments in digitization, most importantly through the depth of our platform technology and breadth of our pipeline. Other benefits include:

• Quality: Reduction in human errors by enabling automation, repeatability, and seamless integration;

• Scalability: Growth in our pipeline to 23 programs;

• Speed: Rapid manufacture of research-grade mRNA from the Research Engine; and

• Cost efficiencies: Digital infrastructure utilized across our platform, drug discovery, clinical development, and manufacturing to maximize efficiencies.

Our digital building blocks

We utilize six building blocks for our digital infrastructure:

• Cloud enablement is a critical component of our digital infrastructure. We are at the forefront of mRNA technology. We generate complex data sets, and our scientists need computational power and agility to operate without being limited by traditional computing technology. Maintaining digital infrastructure in the cloud provides the benefits of lower costs by simplifying provisioning and administration, flexibility, scalability, ease of maintenance, disaster recovery, and information security.

• Integration of business processes enables us to streamline processes and bring data together in a consistent manner, avoiding caches of information and manual intervention. This efficient flow of data between systems enables the automation of our business processes.

• Internet of things allows for smart interconnected devices that provide real-time synchronization of operations. The data from equipment provides real-time guidance to our scientists and engineers.

• Automation allows us to scale our operations reliably and reproducibly. With the help of custom hardware solutions and state-of-the-art robotics, we can continue to increase our operating efficiency, reduce errors, and improve our quality and compliance.

• Advanced analytics enable us to draw insights from our data. We are constantly generating large data sets that can provide important insights if mined appropriately and regularly.

• Artificial intelligence, or AI, is enabling key breakthroughs in predictive modeling. It will allow us to improve our mRNA design algorithms based on machine learning, and will provide us with critical insights into research, supply chain, manufacturing, and other processes.

Digital technologies to enable our Research Engine

We have deployed multiple digital technologies across our Research Engine to drive a rapid pace of learning, enable efficient workflows and business processes, and draw insights from vast amounts of data. Our aim is to provide our platform and discovery scientists with access to an environment that helps them through each step of their research cycle.

Drug Design Studio: Our proprietary in-house digital application suite contains a Sequence Designer module to tailor an entire mRNA, with ever-improving rule sets that contain our accumulated learning about mRNA design. Drug Design Studio utilizes cloud-based computational capacity to run various algorithms we have developed to design each mRNA sequence. The utility of cloud-based capacity allows us to provide flexible computational capacity on demand, allowing the Research Engine to power parallel intake and design of multiple mRNA sequences. Once a sequence is designed, it can be ordered digitally using an internal order form application within Drug Design Studio.

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Manufacture of research grade mRNA: Once an order is optimized, the mRNA production process is triggered. We have developed proprietary interfaces that allow the manufacturing team to track production orders at every stage. We have automated several manufacturing steps using both off-the-shelf and custom automation. The equipment used in the manufacture of research-grade mRNA is integrated with the digital interfaces to capture, extract, and interpret the data generated at each step of the manufacturing process, building digital traceability on each mRNA order. We have also embedded real-time algorithms and analytics tools to allow for automated decision-making at some stages, accelerate the quality control workflows, and provide for continuous improvement of manufacturing processes.

Dispatching and shipping mRNA: Because we produce large quantities of research-grade mRNA, we require digital tools to track their shipment to our scientists and to external contract research organizations, or CROs, conducting in vivo studies. Our dispatching and shipping application automatically generates bar-coded labels, allowing for traceability of product.

Inventory and registry: Material used in research and created in production, including mRNA, cell lines, chemicals, and reagents, is tracked in our Inventory application. This application supports numerous workflow tools such as consumption, aliquoting, material transfer, and stock alerts. Critical material types are assigned unique registry identification by our Registry application.

Study design: Using our Drug Design Studio, our scientists can design their in vivo studies using our proprietary Study Design application. This application captures in vivo study protocol design parameters, including dose amount, number of doses, frequency, samples, and assays for each sample. This application serves two purposes. It allows our scientists to maintain and track their in vivo study designs and associated research grade mRNA. Our Study Design application also allows our in vivo pharmacology teams to track the various ongoing studies and leverage external CROs to manage the in vivo demand as needed.

Experiment management: We have deployed Electronic Lab Notebooks for experiment management, allowing our scientists to streamline documentation of their experiments and track it in a standardized, searchable repository. We have also integrated Electronic Lab Notebooks further with our other research tools to connect inventory, in vivo studies, and instrument data.

Advanced analytics and AI to accelerate the pace of learning: We utilize AI to enable various parts of our platform and drug discovery. Examples include:

• Neural networks for protein engineering: One way to optimize the efficacy of the proteins encoded by our mRNA is to engineer the sequence of the protein itself. We use neural networks to analyze and model protein sequences. We train these models by inputting orthologous sequences from thousands of organisms, from which we can generate potential protein sequences optimized for specific attributes.

• Neural networks for mRNA engineering: The redundancy in the genetic code allows for a large number of mRNA sequences that encode the same protein. mRNA sequence may impact translation, thereby impacting the amount of protein produced in circulation. We are developing AI tools to predict mRNA sequences that can enhance protein expression.

• Bayesian AI for sequencing mRNA: We analyze the mRNA sequence produced in our Research Engine as part of our quality control requirements. Analysis of sequencing data can be cumbersome and time-consuming. We are developing Bayesian models to accelerate the assessment of sequencing data and more rapidly provide our scientists with high quality mRNA.

Digital technologies to enable our Early Development Engine

We have deployed multiple digital technologies across our Early Development Engine to drive the rapid pace of advancement, in parallel, of our development candidates into the clinic.

Digital systems for cGMP manufacture: We are committed to having integrated systems connected with robotics to drive our manufacturing in a paperless environment, and have designed and deployed automation to drive efficient manufacturing operations. We have also deployed digital tools within manufacturing process development that give us the ability to track, analyze, and rapidly deploy manufacturing process improvements. Additionally, we have implemented several digital systems across manufacturing process development, quality, supply chain, and operations, including:

• enterprise Quality Management System, or QMS, to electronically manage deviations, investigation, and correction and preventive actions;

• Laboratory Information Management System, or LIMS, to manage our analytical development data and automate our manufacturing quality control;

• computerized maintenance management system to manage equipment maintenance and calibration; and

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• SAP/S4 Hana system for enterprise resource planning, or ERP, manufacturing execution system, and manufacturing control system to manage inventories, track raw material consumption, digitally integrate equipment with manufacturing recipes in batch records, and control automated equipment.

Digital systems for clinical development and clinical operations: In order to track the timelines of various development candidates through the Early Development Engine, we have created a set of integrated applications. Workflows include timelines for regulatory filings, planning for IND-enabling GLP toxicology studies, scheduling for cGMP manufacturing, and clinical operations management. Below is a summary of our applications:

• Our portfolio application is a digital interface that maintains and tracks the timelines across multiple workstreams for each of our development candidates.

• The supply application manages the manufacturing schedule of IND-enabling GLP toxicology supplies and cGMP manufacture of clinical supplies to support our programs. This application helps us see how the manufacturing schedule changes over time, identifies supply/demand mismatches, and enables resource planning with real-time alerts should we have any issues.

• The GLP toxicology application tracks the planned and ongoing IND-enabling GLP toxicology studies and allows us to manage timelines with our external vendors.

• The regulatory application tracks timelines related to regulatory affairs including, pre-IND meetings, IND/CTA submission dates, and other planned regulatory interactions.

• Our clinical operations application allows us to track our ongoing trials by accessing clinical operations information in real-time from our CROs. It also has multiple tools and analytics to draw key insights, including, for example, enrollment by trial and enrollment by site to maintain our program timelines.

Digital systems for PCV: The PCV program aims to design, manufacture, and deliver a drug product that includes an mRNA sequence encoding for each patient’s specific neoantigens. The personalized nature of the PCV program adds additional steps and complexity in the overall patient treatment process. We have addressed those additional steps and complexity by digitizing and automating steps within the process, as described below.

• Each patient is provided a unique identifier. We track the entire workflow using a single integrated tracker based on this unique identifier. This is one of many ways we ensure that each patient receives the specific drug product lot manufactured for them.

• We use neural networks to design the mRNA sequences for the PCV program. Our proprietary vaccine design algorithm selects the top twenty neoantigens to be used and determines their amino acid sequences to trigger the desired immune response.

• We utilize Monte Carlo simulations of PCV supply/demand to manage our capacity. Since each drug product lot is personalized to a patient, there is a need to manage supply and demand to avoid bottlenecks at any stage of the workflow.

Digital technologies to support our business processes

We have deployed several digital systems across finance, manufacturing, and human resources to automate our business processes and drive efficiencies. We have implemented the SAP S4/Hana system for ERP. In December 2016 we implemented the finance, procurement and inventory management modules and further scaled the ERP to support manufacturing, quality and supply chain in September 2017 and added the MTC facility and processes in July 2018. We have implemented various cloud-based solutions to improve business processes and drive efficiencies. For example, we have implemented the Workday system for human resource planning and management and integrated various applications across payroll, 401k services, equity plan management and expense reporting.

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THIRD-PARTY STRATEGIC ALLIANCES

Strategic alliances

To accelerate the discovery and advancement of potential mRNA medicines across therapeutic areas, we have entered into, and intend to seek other opportunities to form, alliances with a diverse group of strategic collaborators. We have forged productive strategic alliances with pharmaceutical and biotechnology companies, government agencies, academic laboratories, foundations and research institutes with therapeutic area expertise and resources in an effort to advance our discovery and development programs, while leveraging our platform and our Research and Early Development Engines.

One key principle of our approach to strategic alliances is to share the rewards and risks of developing a new mRNA modality, where we may have early research data and desire a strategic collaborator to join us in advancing early development candidates within such modality into the clinic. Representative relationships and associated programs include the following:

• AstraZeneca for the localized regenerative therapeutics modality, such as the VEGF-A program (AZD8601) currently in Phase 2a;

• AstraZeneca for the intratumoral immuno-oncology modality, such as the IL-12 program (MEDI1191) currently in Phase 1;

• AstraZeneca for the systemic secreted therapeutics modality, such as the Relaxin program (AZD7970);

• Merck for the prophylactic vaccines modality, such as the RSV vaccine program (mRNA-1172) currently in Phase 1;

• Merck for the cancer vaccines modality, such as the personalized cancer vaccine program (mRNA-4157) currently in Phase 2 using a workflow that enables a rapid turnaround time to bring personalized vaccines to patients, and the KRAS vaccine program (mRNA-5671) currently in Phase 1;

• DARPA for the systemic secreted therapeutics modality, such as the antibody against Chikungunya virus program (mRNA-1944) currently in Phase 1; and

• Vertex for the lung delivery modality, such as the cystic fibrosis, or CF, and cystic fibrosis transmembrane conductance regulator, or CFTR program currently in research.

We view strategic alliances as important drivers for accelerating execution of our goal of rapidly developing mRNA medicines to treat patients across a wide range of medical and disease challenges. To maintain the integrity of our platform, the terms of our agreements with our strategic collaborators generally provide that our strategic collaborators receive rights to develop and commercialize potential mRNA medicines that we design and manufacture, as opposed to rights to use our platform to generate new mRNA, and that we generally own mRNA-related intellectual property arising from research activities performed under the strategic alliance.

We plan to continue to identify potential strategic collaborators who can contribute meaningful resources and insights to our programs and allow us to more rapidly expand our impact to broader patient populations.

AstraZeneca (NYSE: AZN)—Strategic Alliances in Cardiovascular and Oncology

We have three alliances with AstraZeneca. Our first strategic alliance established in 2013 and amended and restated in 2018, was to discover, develop, and commercialize potential mRNA medicines for the treatment of cardiovascular and cardiometabolic diseases, as well as selected targets for cancer. The relationship with AstraZeneca was expanded in 2016 by entering into a new immuno-oncology strategic alliance which is now focused on the joint development of an mRNA investigational medicine to make the IL-12 protein. It was further expanded in 2017 by entering into another strategic alliance which is focused on the joint development of a potential mRNA medicine to make the relaxin protein, following discovery and preclinical development of the relevant development candidate internally. Additionally, AstraZeneca has made several equity investments in Moderna, which total approximately $290.0 million through December 31, 2019.

2013 Agreements with AstraZeneca, amended and restated in 2018

In March 2013, we entered into an Option Agreement and a related Services and Collaboration Agreement with AstraZeneca, which were amended and restated in June 2018. We refer to these amended and restated agreements as the 2018 A&R Agreements. Under the

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2018 A&R Agreements, we granted AstraZeneca certain exclusive rights and licenses to research, develop and commercialize potential therapeutic mRNA medicines directed at certain targets for the treatment of cardiovascular and cardiometabolic diseases and cancer, and agreed to provide related services to AstraZeneca. The activities to be performed by the parties under the 2018 A&R Agreements are limited to defined biological targets in the cardiovascular and cardiometabolic fields and one defined target in the cancer field.

Pursuant to the 2018 A&R Agreements, AstraZeneca is responsible for all research, development and commercialization activities and associated costs, while we provide specified research and manufacturing services, at AstraZeneca’s expense, during a research and evaluation period, as described below, to further AstraZeneca’s activities conducted pursuant to an agreed upon services plan. AstraZeneca may request we provide additional services, at AstraZeneca’s expense. Subject to customary “back-up” supply rights granted to AstraZeneca, we exclusively manufacture (or have manufactured) mRNA for all research, development and commercialization purposes under the 2018 A&R Agreements until, on a product-by-product basis, the expiration of the time period for which we are entitled to receive earn-out payments with respect to such product pursuant to the 2018 A&R Agreements.

As of the effective date of the original Option Agreement and Services and Collaboration Agreement in 2013, and as further reflected in the 2018 A&R Agreements, AstraZeneca acquired forty options that it may exercise to obtain exclusive rights to clinically develop and commercialize identified development candidates (and related back-up candidates) directed to specified targets that arise during the research and evaluation period. During the research and evaluation period for research candidates, AstraZeneca may elect to designate a limited number of research candidates as development candidates in order to continue preclinical development on such development candidates (and related back-up candidates). From such pool of development candidates designated by AstraZeneca, during a specified option exercise period, AstraZeneca may then exercise one of its options to obtain exclusive rights to clinically develop and commercialize an identified development candidate (and related back-up candidates) in certain fields. If AstraZeneca does not exercise one of its options to acquire exclusive rights to clinically develop and commercialize a particular development candidate during the defined option exercise period for such development candidate, AstraZeneca’s rights to exercise an option and other rights granted under the 2018 A&R Agreements with respect to such development candidate (and related back-up candidates) will terminate, all rights to exploit such development candidate (and related back-up candidates) will be returned to us and all data and results generated by AstraZeneca with respect to such development candidate (and related back-up candidates) will be either assigned or licensed to us. Upon the earlier of termination of the 2018 A&R Agreements for any reason and a specified anniversary of the effective date of the original Option Agreement and Services and Collaboration Agreement in 2013, all unexercised options, and the right to exercise any and all options if not previously exercised by AstraZeneca, will automatically terminate.

On a target-by-target basis, we and AstraZeneca have agreed to certain defined exclusivity obligations under the 2018 A&R Agreements with respect to the research, development and commercialization of mRNA medicines for such target in certain fields. In addition, we and AstraZeneca have agreed to certain defined exclusivity obligations with respect to the research, development and commercialization of mRNA medicines coding for the same polypeptide as any development candidate being developed under the 2018 A&R Agreements.

As of the effective date of the original Option Agreement and Services and Collaboration Agreement in 2013, AstraZeneca made upfront cash payments to us totaling $240.0 million in exchange for the acquired options and our performance of certain research-related services, each as described above. AstraZeneca will pay us a $10.0 million option exercise payment with respect to each development candidate (and related back-up candidates) for which it exercises an option. We are also eligible to receive, on a product-by-product basis, up to $400.0 million in aggregate contingent option exercise payments upon the achievement of certain development, regulatory and commercial milestone events. Additionally, we are entitled to receive, on a product-by-product basis, earn-out payments on worldwide net sales of products ranging from a high-single digit percentage to 12%, subject to certain reductions, with an aggregate minimum floor. As of December 31, 2019, we have received from AstraZeneca an option exercise payment of $10.0 million and a clinical milestone payment of $30.0 million with respect to AstraZeneca’s VEGF-A product (AZD8601) that is currently being developed in a Phase 2a clinical trial in the cardiovascular and cardiometabolic fields. Additionally, as of December 31, 2019, we have received $120.0 million from AstraZeneca under the 2018 A&R Agreements for the achievement of specified technical milestones.

Unless earlier terminated, the 2018 A&R Agreements will continue until the expiration of AstraZeneca’s earn-out and contingent option exercise payment obligations for optioned product candidates. Either party may terminate the 2018 A&R Agreements upon the other party’s material breach, either in its entirety or in certain circumstances, with respect to relevant candidates, subject to a defined materiality threshold and specified notice and cure provisions. If AstraZeneca has the right to terminate the 2018 A&R Agreements for our material breach, then AstraZeneca may elect, in lieu of terminating the 2018 A&R Agreements, in their entirety or with respect to such candidates, to have the 2018 A&R Agreements remain in effect, subject to reductions in certain payments we are eligible to receive and certain adjustments to AstraZeneca’s obligations under the 2018 A&R Agreements. AstraZeneca may terminate the 2018 A&R Agreements in full, without cause, upon 90 days’ prior notice to us.

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2016 Strategic Alliance with AstraZeneca—IL-12

In January 2016, we entered into a new Strategic Drug Development Collaboration and License Agreement, which we refer to as the 2016 AZ Agreement, with AstraZeneca to discover, develop and commercialize potential mRNA medicines for the treatment of a range of cancers.

Under the terms of the 2016 AZ Agreement, we and AstraZeneca have agreed to work together on an immuno-oncology program focused on the intratumoral delivery of a potential mRNA medicine to make the IL-12 protein. The 2016 AZ Agreement initially included research activities with respect to a second discovery program. During a limited period of time, each party had an opportunity to propose additional discovery programs to be conducted under the 2016 AZ Agreement. We are responsible for conducting and funding all discovery and preclinical development activities under the 2016 AZ Agreement in accordance with an agreed upon discovery program plan for the IL-12 program and any other discovery program the parties agree to conduct under the 2016 AZ Agreement. For the IL-12 program and any other discovery program the parties agree to conduct under the 2016 AZ Agreement, during a defined election period that commenced as of the effective date of the 2016 AZ Agreement (for the IL-12 program) and otherwise will commence on initiation of any such new discovery program, AstraZeneca may elect to participate in the clinical development of a development candidate arising under the 2016 AZ Agreement from such program. If AstraZeneca so elects (as it has for the IL-12 program), AstraZeneca will lead clinical development activities worldwide and we will be responsible for certain activities, including being solely responsible for manufacturing activities, all in accordance with an agreed upon development plan. AstraZeneca will be responsible for funding all Phase 1 clinical development activities (including costs associated with our manufacture of clinical materials in accordance with the development plan), and Phase 2 clinical development activities (including costs associated with our manufacture of clinical materials in accordance with the development plan) up to a defined dollar threshold. We and AstraZeneca will equally share the costs of Phase 2 clinical development activities in excess of such dollar threshold, all Phase 3 clinical development activities and certain other costs of late-stage clinical development activities, unless we elect not to participate in further development and commercialization activities and instead receive tiered royalties, as described below.

We and AstraZeneca will co-commercialize products in the United States in accordance with an agreed upon commercialization plan and budget, and on a product-by-product basis will equally share the U.S. profits or losses arising from such commercialization. Notwithstanding, on a product-by-product basis, prior to a specified stage of development of a given product, we have the right to elect not to participate in the further development and commercialization activities for such product. If we make such election, instead of participating in the U.S. profits and losses share with respect to such product, we are obligated to discuss future financial terms with AstraZeneca. If we are unable to agree on future financial terms within a short defined period of time, we are entitled to receive tiered royalties at default rates set forth in the 2016 AZ Agreement, ranging from percentages in the mid-single digits to 20% on worldwide net sales of products, subject to certain reductions with an aggregate minimum floor. AstraZeneca has sole and exclusive responsibility for all ex-U.S. commercialization efforts. Unless we have elected to not to participate in further development (in which case royalties on ex-U.S. net sales will be at the default rates as described above, unless otherwise agreed by the parties), we are entitled to tiered royalties at rates ranging from 10% to 30% on ex-U.S. net sales of the products, subject to certain reductions with an aggregate minimum floor. Subject to customary “back-up” supply rights granted to AstraZeneca, we exclusively manufacture (or have manufactured) products for all development and commercialization purposes. We and AstraZeneca have agreed to certain defined exclusivity obligations with each other under the 2016 AZ Agreement with respect to the development and commercialization of mRNA medicines for IL-12.

Unless earlier terminated, our strategic alliance under the 2016 AZ Agreement will continue on a product-by-product basis (i) until both parties cease developing and commercializing such product without the intention to resume, if we have not elected our right not to participate in further development and commercialization of such product or (ii) on a country-by-country basis, until the end of the applicable royalty term for such product in such country, if we have elected our right not to participate in further development and commercialization of such product.

Either party may terminate the 2016 AZ Agreement upon the other party’s material breach, subject to specified notice and cure provisions. Each party may also terminate the 2016 AZ Agreement in the event the other party challenges such party’s patent rights, subject to certain defined exceptions. AstraZeneca has the right to terminate the 2016 AZ Agreement in full or with respect to any program for scientific, technical, regulatory or commercial reasons at any time upon 90 days’ prior written notice to us. On a product-by-product basis, we have the right to terminate the 2016 AZ Agreement in certain cases if AstraZeneca has suspended or is no longer proceeding with the development or commercialization of such product for a period of twelve consecutive months, subject to specified exceptions, including tolling for events outside of AstraZeneca’s control. On a product-by-product basis, if the 2016 AZ Agreement is terminated with respect to a given product, AstraZeneca’s rights in such product will terminate and, to the extent we terminated for AstraZeneca’s breach, patent challenge or cessation of development or AstraZeneca terminated in its discretion, AstraZeneca will grant us reversion licenses and take certain other actions so as to enable us to continue developing and commercializing such product in the oncology field.

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If we continue developing and commercializing a given product following termination of the 2016 AZ Agreement by AstraZeneca in its discretion with respect to such product, AstraZeneca is entitled to receive a mid-single digit royalty on our worldwide net sales of such product and a high-single digit percentage of the amounts received by us from a third party in consideration of a license to such third party to exploit such product, in each case, until AstraZeneca recovers an amount equal to specified development costs incurred by AstraZeneca under the 2016 AZ Agreement with respect to such product prior to such termination. Such percentages increase by a low to mid-single digit amount to the extent such termination occurs after such product achieves a specified stage of development.

2017 Strategic Alliance with AstraZeneca—Relaxin

In October 2017, we entered a new Collaboration and License Agreement, which we refer to as the 2017 AZ Agreement, under which AstraZeneca may clinically develop and commercialize a development candidate, now known as AZD7970, which is comprised of an mRNA construct for the relaxin protein designed by us and encapsulated in one of our proprietary LNPs. We discovered and performed preclinical development activities for AZD7970 prior to the initiation of the strategic alliance with AstraZeneca under the 2017 AZ Agreement.

Under the terms of the 2017 AZ Agreement, we will fund and be responsible for conducting preclinical development activities for AZD7970 through completion of IND-enabling GLP toxicology studies and AstraZeneca will lead pharmacological studies, each in accordance with an agreed upon discovery program plan. During a defined election period that commences as of the effective date of the 2017 AZ Agreement, AstraZeneca may elect to participate in further development and commercialization of AZD7970. Upon such election, AstraZeneca will lead clinical development activities for AZD7970 worldwide and we will be responsible for manufacturing AZD7970, certain regulatory matters and any other development activities that we agree to perform and that are set forth in an agreed upon development plan. AstraZeneca will be responsible for funding Phase 1 clinical development activities (including costs associated with our manufacture of clinical materials in accordance with the development plan, up to a cap above which such costs are shared), and Phase 2 clinical development activities (including costs associated with our manufacture of clinical materials in accordance with the development plan, up to a cap above which such costs are shared) up to a defined dollar threshold. Thereafter, we and AstraZeneca will equally share the costs of Phase 2 clinical development activities in excess of such defined dollar threshold, all Phase 3 clinical development activities and certain other costs of late-stage clinical development activities, unless we elect not to participate in further development and commercialization activities and instead receive tiered royalties as described below. If the development candidate is determined to be IND-ready, and AstraZeneca does not timely elect to participate in the clinical development of AZD7970, AstraZeneca is obligated to reimburse us for certain costs we incurred in the manufacture and development of AZD7970 since execution of the 2017 AZ Agreement.

We and AstraZeneca will co-commercialize AZD7970 in the United States in accordance with an agreed upon commercialization plan and budget, and will equally share U.S. profits or losses arising from such commercialization. Notwithstanding, prior to a specified stage of development of AZD7970, we have the right to elect not to participate in the further development and commercialization activities for AZD7970. If we make such election, instead of participating in the U.S. operating profits and losses share with respect to AZD7970, we are obligated to discuss future financial terms with AstraZeneca. If we are unable to agree on future financial terms within a short, defined period of time, we are entitled to receive tiered royalties at default rates set forth in the 2017 AZ Agreement, ranging from percentages in the mid-single digits to the low 20s on worldwide net sales by AstraZeneca of AZD7970, subject to certain reductions with an aggregate minimum floor. AstraZeneca has sole and exclusive responsibility for all ex-U.S. commercialization efforts. Unless we have elected not to participate in further development (in which case royalties on ex-U.S. net sales will be at the default rates as described above, unless otherwise agreed by the parties), we are entitled to receive tiered royalties at rates ranging from 10% to 30% on annual ex-U.S. net sales of AZD7970, subject to certain reductions, with an aggregate minimum floor. Subject to customary “back-up” supply rights granted to AstraZeneca, we exclusively manufacture (or have manufactured) products for all development and commercialization purposes. Additionally, we and AstraZeneca have agreed to certain defined exclusivity obligations under the 2017 AZ Agreement with respect to the development and commercialization of mRNA medicines for Relaxin.

Unless earlier terminated, our strategic alliance under the 2017 AZ Agreement will continue (i) until the expiration of AstraZeneca’s election period, if it does not elect to participate in the clinical development of AZD7970, (ii) until both parties cease developing and commercializing AZD7970 without the intention to resume, if we have not elected our right not to participate in further development and commercialization of AZD7970, (iii) on a country-by-country basis, until the end of the applicable royalty term for AZD7970 in such country, if we have elected our right not to participate in further development or commercialization of AZD7970 or (iv) following completion of IND-enabling studies with respect to AZD7970, if we provide AstraZeneca with written notice that we do not reasonably believe that the product is IND-ready.

Either party may terminate the 2017 AZ Agreement upon the other party’s material breach, subject to specified notice and cure provisions. Each party may also terminate the 2017 AZ Agreement in the event the other party challenges the validity or enforceability of such party’s patent rights, subject to certain defined exceptions. AstraZeneca has the right to terminate the 2017 AZ Agreement in

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full for scientific, technical, regulatory or commercial reasons at any time upon 90 days’ prior written notice to us. We have the right to terminate the 2017 AZ Agreement in certain cases if AstraZeneca has suspended or is no longer proceeding with the development or commercialization of AZD7970 for a period of twelve consecutive months, subject to specified exceptions, including tolling for events outside of AstraZeneca’s control. If AstraZeneca does not timely elect to participate in clinical development of AZD7970, or the Agreement is terminated, AstraZeneca’s rights in AZD7970 will terminate and, to the extent we terminated for AstraZeneca’s breach, patent challenge or cessation of development or AstraZeneca terminated in its discretion, AstraZeneca will grant us reversion licenses and take certain other actions so as to enable us to continue developing and commercializing AZD7970 in the cardiovascular and cardiometabolic fields.

If we continue developing and commercializing AZD7970 following a termination of the 2017 AZ Agreement by AstraZeneca in its discretion, AstraZeneca is entitled to receive a mid-single digit royalty on our worldwide net sales of AZD7970 and a high-single digit percentage of the amounts received by us from a third party in consideration for a license to such third party to exploit AZD7970, in each case until AstraZeneca recovers an amount equal to specified development costs incurred by AstraZeneca under the 2017 AZ Agreement with respect to AZD7970 prior to such termination. Such percentages increase by a low to mid-single digit amount to the extent such termination occurs after such product achieves a specified stage of development.

Merck (NYSE: MRK)—Strategic Alliances in Infectious Diseases and Cancer Vaccines

We have established a multi-faceted relationship with Merck Sharp & Dohme Corp., or Merck, that includes distinct strategic alliances directed to the research, development, and commercialization of mRNA medicines for the prevention and treatment of viral infections and for the treatment of cancer. Merck has also made several equity investments in Moderna totaling approximately $182.0 million.

2015 Strategic Alliance with Merck—Infectious Disease

In January 2015, we entered into a Master Collaboration and License Agreement with Merck, which we refer to as the 2015 Merck Agreement, to research, develop, and commercialize potential mRNA medicines for the prevention and treatment of infections by RSV. As a part of the May 2019 amendment of the 2015 Merck Agreement, we and Merck agreed to conclude the collaboration as it relates to development of potential mRNA medicines for other viruses, including mRNA-1278 for the prevention of VZV infection. Pursuant to the 2015 Merck Agreement, Merck is primarily responsible for research, development and commercialization activities and associated costs. We are responsible for designing and, at Merck's cost, manufacturing all mRNA constructs for preclinical and Phase 1 and Phase 2 clinical development purposes. Responsibility for manufacturing mRNA constructs for late stage clinical development and commercialization purposes is to be determined.

The focus of the initial four-year period of the 2015 Merck Agreement, which ended in January 2019, was the discovery and development of mRNA vaccines and antibodies directed to the four viruses that were the subject of the 2015 Merck Agreement. The 2015 Merck Agreement also includes an additional three-year period during which Merck may continue to preclinically and clinically develop product candidates using mRNA constructs that were initially developed during the initial four-year research period. Merck may, prior to January 12, 2022, elect to exclusively develop and commercialize up to five product candidates.

During the four-year discovery and development phase of the alliance, we and Merck agreed to work exclusively with each other to develop potential mRNA medicines for the prevention and treatment of infections by the four viruses that were the subject of the 2015 Merck Agreement. Additionally, we and Merck have agreed to certain defined exclusivity obligations following the four-year discovery and development phase of the alliance. As part of the May 2019 amendment of the 2015 Merck Agreement, we and Merck agreed to certain exceptions to the existing exclusivity obligations, pursuant to which we will no longer be restricted from researching, developing, and commercializing an mRNA investigational medicine for the prevention of a specific set of respiratory infections, including RSV, for the pediatric population.

Under the terms of the 2015 Merck Agreement, we received a $50.0 million upfront payment. We are eligible to receive, on a product-by-product basis, up to $300.0 million in aggregate milestone payments upon the achievement of certain development, regulatory and commercial milestone events. To date, we have received from Merck a clinical milestone payment of $5.0 million with respect to the initiation of a Phase 1 clinical trial for a Merck RSV vaccine product candidate. On a product-by-product basis, we are also entitled to receive royalties on Merck’s net sales of products at rates ranging from the mid-single digits to low teens, subject to certain reductions, with an aggregate minimum floor. Additionally, concurrent with entering into the 2015 Merck Agreement, Merck made a $50.0 million equity investment in us.

Unless earlier terminated, the 2015 Merck Agreement will continue on a product-by-product and country-by-country basis for so long as royalties are payable by Merck on a given product in a given country. Either party may terminate the 2015 Merck Agreement upon the other party’s material breach, either in its entirety or with respect to a particular program, product candidate, product or country, subject to specified notice and cure provisions. Merck may terminate the 2015 Merck Agreement in full or with respect to a particular

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product candidate or product upon certain advance notice to us for any reason, or earlier if Merck determines the alliance or product is no longer commercially practicable. If Merck has the right to terminate the 2015 Merck Agreement, in its entirety or with respect to a program, product candidate or product, for our material breach, then Merck may elect, in lieu of terminating the 2015 Merck Agreement, to have the 2015 Merck Agreement remain in effect, subject to reductions in certain payments we are eligible to receive with respect to the terminable rights. Upon a termination of the 2015 Merck Agreement with respect to a program, all licenses and other rights granted to Merck with respect to such program will terminate and the continued development and commercialization of product candidates and products will revert to us. If the 2015 Merck Agreement is terminated with respect to a given product candidate or product, all licenses and other rights granted to Merck with respect to such product candidate or product will terminate and, to the extent we terminated for Merck’s breach, Merck will grant us licenses under select Merck technology for our continued development and commercialization of such product candidate or product.

2016 Expansion of the Infectious Disease Strategic Alliance with Merck

In January 2016, we expanded our infectious disease strategic alliance with Merck. Specifically, we and Merck agreed to amend the original 2015 Merck Agreement to include the research, development, and commercialization of mRNA medicines for the prevention and treatment of infection by the varicella zoster virus in place of one of the viruses initially included under the 2015 Merck Agreement. Under the terms of the amended 2015 Merck Agreement, we received an upfront payment of $10.0 million from Merck for the inclusion of the new program and we agreed with Merck to increase the tiered royalty rates ranging from the mid-single digits to low-teens for net sales of products directed to this virus.

2016 Cancer Vaccine Strategic Alliance—Personalized mRNA Cancer Vaccines with Merck

In June 2016, we entered into a personalized mRNA cancer vaccines (PCV) Collaboration and License Agreement with Merck, which we refer to as the PCV Agreement, to develop and commercialize PCVs for individual patients using our mRNA vaccine and formulation technology. Under the strategic alliance, we identify genetic mutations present in a particular patient’s tumor cells, synthesize mRNA for these mutations, encapsulate the mRNA in one of our proprietary LNPs and administer to each patient a unique mRNA cancer vaccine designed to specifically activate the patient’s immune system against her or his own cancer cells.

Pursuant to the PCV Agreement, we are responsible for designing and researching PCVs, providing manufacturing capacity and manufacturing PCVs, and conducting Phase 1 and Phase 2 clinical trials for PCVs, alone and in combination with KEYTRUDA (pembrolizumab), Merck’s anti-PD-1 therapy, all in accordance with an agreed upon development plan and budget. We received an upfront payment of $200.0 million from Merck, which we will use to fund the performance of our activities set forth in the agreed upon development plan and budget. In November 2017, we and Merck announced the achievement of a key milestone for the first-in-human dosing of a PCV (mRNA-4157) as a part of the alliance.

Until the expiration of a defined period of time following our completion of Phase 1 and Phase 2 clinical trials for PCVs under the PCV Agreement and delivery of an associated data package to Merck, Merck has the right to elect to participate in future development and commercialization of PCVs by making a $250.0 million participation payment to us. If Merck exercises its election and pays the participation payment, then the parties will equally co-fund subsequent clinical development of PCVs, with Merck primarily responsible for conducting clinical development activities under a jointly agreed development plan and budget. Each party may also conduct additional clinical trials for PCVs that are not included in the jointly agreed development plan and budget, in which case the non-conducting party will reimburse the conducting party for half of the total costs for such trials, plus interest, from its share of future profits resulting from sales of such PCVs, if any. Merck will lead worldwide commercialization of PCVs, subject to Moderna’s option to co-promote PCVs in the United States, and the parties will equally share the profits or losses arising from worldwide commercialization. Until a PCV becomes profitable, we may elect to defer payment of our share of the commercialization and related manufacturing costs and instead reimburse Merck for such costs, plus interest, from our share of future profits resulting from sales of such PCV, if any. Subject to customary “back-up” supply rights granted to Merck, we will manufacture (or have manufactured) PCVs for preclinical and clinical purposes. Manufacture of PCVs for commercial purposes will be determined by the parties in accordance with the terms of the PCV Agreement.

If Merck does not exercise its right to participate in future development and commercialization of PCVs, then we will retain the exclusive right to develop and commercialize PCVs developed during the strategic alliance, subject to Merck’s rights to receive a percentage in the high teens to the low 20s, subject to reductions, of our net profits on sales of such PCVs. During a limited period following such non-exercise, Merck has the right to perform clinical trials of such PCVs in combination with KEYTRUDA, for which we agree to use reasonable efforts to supply such PCVs. During such limited period, we also have the right to perform clinical studies of PCVs in combination with KEYTRUDA, for which Merck agrees to use reasonable efforts to supply KEYTRUDA. In addition, following its non-exercise, Merck is also entitled to receive a percentage in the high teens to the low 20s, subject to reductions, of our net profits on sales of certain PCVs first developed by us following such non-exercise and reaching a specified development stage within a defined period of time.

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We and Merck have agreed to certain defined, limited exclusivity obligations with respect to the development and commercialization of PCVs.

2018 Expansion of the Cancer Vaccine Strategic Alliance with Merck—Shared Neoepitope Cancer Vaccines

In April 2018, we and Merck agreed to expand our cancer vaccine strategic alliance to include the development and commercialization of our KRAS vaccine development candidate, mRNA-5671, and potentially other shared neoantigen mRNA cancer vaccines (SAVs). We preclinically developed mRNA-5671 prior to its inclusion in the cancer vaccine strategic alliance and it is comprised of a novel mRNA construct designed by us and encapsulated in one of our proprietary LNPs. The PCV Agreement was amended and restated to include the new SAV strategic alliance, which we refer to as the PCV/SAV Agreement.

We and Merck have agreed to certain exclusivity obligations with respect to SAVs and particular SAV programs, which obligations are subject to termination or expiration upon certain triggering events.

Under the PCV/SAV Agreement, Merck will be responsible for conducting Phase 1 and Phase 2 clinical trials for mRNA-5671 and for all costs associated with such activities, in accordance with a jointly agreed development plan and budget, and we will be responsible for manufacturing and supplying all mRNA-5671 required to conduct such trials and for all costs and expenses associated with such manufacture and supply. Under the PCV/SAV Agreement, our budgeted commitment for PCVs increased to $243.0 million. Until the expiration of a defined period of time following our completion of Phase 1 and Phase 2 clinical trials for mRNA-5671 under the PCV/SAV Agreement and delivery of an associated data package to Merck, Merck has the right to elect to participate in future development and commercialization of mRNA-5671 by making a participation payment to us. If Merck exercises its participation rights, then the parties will equally co-fund subsequent clinical development of mRNA-5671, with Merck primarily responsible for conducting clinical development activities under a jointly agreed development plan and budget. If Merck declines to participate in future development and commercialization activities following the initial Phase 1 and Phase 2 clinical trials for mRNA-5671, then we will retain the rights to develop and commercialize mRNA-5671. If Merck elects to participate in future development and commercialization of mRNA-5671, Merck may also conduct additional clinical trials for mRNA-5671 that are not included in the jointly agreed development plan and budget, in which case we will reimburse Merck for half of the total development costs for such clinical trials, plus interest, from our share of future profits resulting from sales of mRNA-5671, if any. Merck will lead worldwide commercialization of mRNA-5671, subject to our option to co-promote mRNA-5671 in the United States, and the parties will equally share the profits or losses arising from worldwide commercialization. Until mRNA-5671 becomes profitable, we may elect to defer payment of our share of the commercialization and related manufacturing costs and instead reimburse Merck for such costs, plus interest, from our share of future profits resulting from sales of mRNA-5671, if any. Subject to “back-up” supply rights granted to Merck, we will manufacture (or have manufactured) mRNA-5671 and other SAVs for preclinical and clinical purposes. After Merck exercises its right to participate in future development and commercialization of mRNA-5671 and other SAVs, the parties are obligated to discuss responsibility for future manufacturing, giving consideration to applicable criteria.

Pursuant to the PCV/SAV Agreement, for a defined period of time, either party may propose that the parties conduct additional programs for the research and development of SAVs directed to different shared neoantigens. If the parties agree to conduct any such programs, then we will be responsible for conducting and funding pre-clinical discovery and research activities for such SAVs, and otherwise the programs would be conducted on substantially the same terms as the mRNA-5671 program. If we or Merck propose a new SAV program and the other party does not agree to conduct such program, then the PCV/SAV Agreement includes provisions allowing the proposing party to proceed with such development, at the proposing party’s expense. In such case, the non-proposing party will have the right to opt-in to such SAV program any time before the proposing party commits to performing Good Laboratory Practice (GLP)-toxicity studies. Until the expiration of a defined period of time following our completion of Phase 1 and Phase 2 clinical trials for any SAV program mutually agreed by the parties under the PCV/SAV Agreement and delivery of an associated data package to Merck, Merck has the right to elect to participate in future development and commercialization of such SAV by making a participation payment to us.

Unless earlier terminated, the PCV/SAV Agreement will continue on a program-by-program basis until Merck terminates its participation in such program. Following any such termination, we will retain the exclusive right to develop and commercialize PCVs or SAVs developed as a part of such program, subject to restrictions and certain limited rights retained by Merck.

In connection with the amendment of the PCV Agreement to include the development and commercialization of mRNA-5671 and potentially other SAVs, Merck made a $125.0 million equity investment in us.

Vertex (Nasdaq: VRTX)—2016 Strategic Alliance in Cystic Fibrosis

In July 2016, we entered into a Strategic Collaboration and License Agreement, with Vertex Pharmaceuticals Incorporated, and Vertex Pharmaceuticals (Europe) Limited, together, Vertex, which we refer to as the Vertex Agreement. The Vertex Agreement is aimed at the

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discovery and development of potential mRNA medicines for the treatment of cystic fibrosis, or CF, by enabling cells in the lungs of people with CF to produce functional CFTR proteins.

Pursuant to the Vertex Agreement, we lead discovery efforts during an initial research period that currently extends until March 2020, leveraging our Platform technology and mRNA delivery expertise along with Vertex’s scientific experience in CF biology and the functional understanding of CFTR. Vertex is responsible for conducting development and commercialization activities for candidates and products that arise from the strategic alliance, including the costs associated with such activities. Vertex is also obligated to pay us for research services in connection with our performance of activities during the research period in accordance with a jointly agreed research plan. Subject to customary “back-up” supply rights granted to Vertex, we exclusively manufacture (or have manufactured) mRNA for pre-clinical, clinical, and commercialization purposes.

Under the terms of the Vertex Agreement, we received a $20.0 million upfront payment from Vertex. In July 2019, Vertex elected to extend the initial research period by six months by making a $2.0 million payment to us pursuant to the 2019 Vertex Amendment. Vertex has the right to extend the initial research period by an additional 18-month period by making an additional payment to us. Vertex has rights to further extend the research period for two additional one-year periods by making an additional payment to us for each one-year extension. We are eligible to receive up to $275.0 million in aggregate milestone payments upon the achievement of certain development and regulatory milestone events, and Vertex will also pay us tiered royalties at rates ranging from the low- to high-teens on worldwide net sales of products arising from the strategic alliance, subject to certain reductions, with an aggregate minimum floor. In connection with the strategic alliance, Vertex also made a $20.0 million equity investment in us.

During the term of the Vertex Agreement, we and Vertex have agreed to certain defined exclusivity obligations under the Vertex Agreement with respect to the development and commercialization of certain mRNA medicines.

Unless earlier terminated, the Vertex Agreement will continue until the expiration of all royalty terms. Vertex may terminate the Vertex Agreement for convenience upon 90 days’ prior written notice, except if termination relates to a product in a country where Vertex has received marketing approval, which, in such case, Vertex must provide 180 days’ prior written notice. Either party may terminate the Vertex Agreement upon the other party’s material breach, subject to specified notice and cure provisions. Each party may also terminate the Vertex Agreement in the event that the other party challenges the validity or enforceability of such party’s patent rights, subject to certain exceptions, or if the other party becomes insolvent.

Strategic alliances with government organizations and foundations

Defense Advanced Research Projects Agency (DARPA)

In October 2013, DARPA awarded Moderna up to approximately $24.6 million under Agreement No. W911NF-13-1-0417 to research and develop potential mRNA medicines as a part of DARPA’s Autonomous Diagnostics to Enable Prevention and Therapeutics, or ADEPT, program, which is focused on assisting with the development of technologies to rapidly identify and respond to threats posed by natural and engineered diseases and toxins. As of December 31, 2019, $19.7 million of the award amount has been funded. This award followed an initial award from DARPA of approximately $1.4 million given in March 2013 under Agreement No. W31P4Q-13-1-0007. The DARPA awards have been deployed primarily in support of our vaccine and antibody programs to protect against Chikungunya infection.

Biomedical Advanced Research and Development Authority (BARDA)

In September 2016, we received an award of up to approximately $125.8 million under Agreement No. HHSO100201600029C from BARDA, a component of the Office of the Assistant Secretary for Preparedness and Response, or ASPR, within the U.S. Department of Health and Human Services, or HHS, to help fund our Zika vaccine program. Under the terms of the agreement with BARDA, an initial base award of approximately $8.2 million supported toxicology studies, a Phase 1 clinical trial, and associated manufacturing activities. Additionally, four contract options were awarded under the agreement with BARDA. Three out of four of these options have been exercised, bringing the total current award to approximately $117.6 million to support an additional Phase 1 study of an improved Zika vaccine candidate, Phase 2 and Phase 3 clinical studies, as well as large-scale manufacturing for the Zika vaccine.

The Bill & Melinda Gates Foundation

In January 2016, we entered a global health project framework agreement with the Bill & Melinda Gates Foundation to advance mRNA-based development projects for various infectious diseases. The Bill & Melinda Gates Foundation has committed up to $20.0 million in grant funding to support our initial project related to the evaluation of antibody combinations in a preclinical setting as well as the conduct of a first-in-human Phase 1 clinical trial of a potential mRNA medicine to help prevent human immunodeficiency virus, or HIV, infections. Follow-on projects which could bring total potential funding under the framework agreement up to $100.0 million

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(including the HIV antibody project) to support the development of additional mRNA-based projects for various infectious diseases can be proposed and approved until the sixth anniversary of the framework agreement, subject to the terms of the framework agreement, including our obligation to grant to the Bill & Melinda Gates Foundation certain non-exclusive licenses.

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INTELLECTUAL PROPERTY

Our patent estate and approach, a strategic asset

Since our inception, we have considered the creation and building of our intellectual property, or IP, portfolio as a critical part of our mission. In a relatively short amount of time, we have built a significant patent estate that includes over 560 world-wide pending patent applications and over 210 issued or allowed U.S. and foreign patents covering key components of our proprietary platform technology, investigational medicines, and development candidates. The figure below shows our internally developed estate and indicates the number of patents approved since 2010.

We regularly identify inventions and trade secrets as we surmount various challenges with our platform to create modalities. We seek to protect our proprietary position by, among other means, filing U.S. and certain foreign patent applications related to our platform, modality, and program inventions. Our company trade secrets and know-how are appropriately guarded to maintain our business advantage. We also seek to identify and obtain third party licenses where useful to maintain our advantageous IP position in the mRNA medicines field. We seek to obtain and maintain, and intend to strategically enforce, patents in appropriate jurisdictions for our platform technologies, modalities, and programs, in particular, in instances where insurmountable business competition threatens advancement of future commercial products. 

Protecting our platform, modality, and program investments: Building an expansive, multi-layered IP estate

We have built a substantial IP estate that includes numerous patents and patent applications related to the development and commercialization of mRNA vaccine and therapeutic development candidates, including related platform technologies. Our platform IP protects advances in mRNA design and engineering, proprietary LNP components, delivery systems, processes for the manufacture and purification of drug substances and products, and analytical methods. A significant portion of our platform IP estate further provides multi-layered protection for our modalities and programs.

With respect to our IP estate, our solely-owned patent portfolio consists of more than 115 issued or allowed U.S. patents or patent applications and more than 100 granted or allowed patents in jurisdictions outside of the U.S. covering certain of our proprietary platform technology, inventions, and improvements, and covering key aspects of our clinical and most advanced development candidates. Additional patent applications are also pending that, in many cases, are counterparts to the foregoing U.S. and foreign patents.

Most of the patents and applications (if issued) in our portfolio have or will have expiry dates extending out to 2033 at the earliest and at least 2040-2041 for patents ultimately granting based on our more recently filed patent applications.

We also rely on trademarks, trade secrets, and know-how relating to our proprietary technology and programs, continuing innovation, and in-licensing opportunities to develop, strengthen, and maintain our proprietary position in the field of mRNA therapeutic and vaccine technologies. We additionally plan to rely on data exclusivity, market exclusivity, and patent term extensions when available, and plan to seek and rely on regulatory protection afforded through orphan drug designations. We also possess substantial proprietary know-how associated with related manufacturing processes and expertise.

IP protecting our platform

We have a broad IP estate covering key aspects of our platform. This estate provides multiple layers of protection covering the making and use of the mRNA drug substance and delivery technologies.

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With respect to our platform, we have a portfolio that includes approximately 90 issued or allowed U.S. patents or patent applications, and approximately 100 granted foreign patents and pending foreign patent applications covering platform innovations that are directly related to the design, formulation and manufacturing of mRNA medicines.

For example, these patents and patent applications include claims directed to:

• mRNA chemistry imparting improved properties for vaccine and therapeutic uses;

• methods for mRNA sequence optimization to enhance the levels and fidelity of proteins expressed from our mRNA medicines;

• methods for identifying epitopes having superior suitability in cancer vaccine contexts;

• engineering elements tailored to enhance stability and the in vivo performance of mRNA medicines;

• proprietary lipid nanoparticle, or LNP, delivery systems, including novel lipid components designed for optimal expression of both therapeutic and vaccine mRNAs, in particular, prophylactic infectious disease and cancer vaccine mRNAs, intratumoral immuno-oncology therapeutics, local regenerative therapeutics, systemic secreted therapeutics, and systemic intracellular therapeutics; and

• innovative processes for the manufacture and analysis of mRNA drug substance and formulated drug product.

IP protection for modalities

Our IP estate provides protection for the multiple programs within our modalities both at the product-specific level and at various broader levels. For example, we have patent coverage for LNP-encapsulated mRNAs having specific chemical modification suited for vaccine and therapeutic mRNA use. Our estate also includes IP covering certain LNP-encapsulated mRNAs coding for infectious disease antigens for use in prophylactic vaccination. Our mRNA chemistry, formulation and manufacturing patent applications and related know-how and trade secrets may also provide us with additional IP protection relating to our development candidates.

Our patent portfolio for our investigational medicines and development candidates features at least 25 issued or scheduled-to-issue patents, with many additional pending applications in the U.S. and foreign jurisdictions directed to our development candidates.

Prophylactic vaccines

For programs within our prophylactic vaccines modality, we typically pursue patent protection featuring composition of matter and method of use claims. Our global patent protection strategy may vary based on the unique geographic prevalence of various infectious diseases.

One of our earliest investigational medicines in the infectious disease pipeline, a vaccine containing mRNA encoding the H7 HA antigen for the prevention of human infection with the influenza H7N9 avian influenza A virus is protected by a patent family that includes two issued U.S. patents, three pending U.S. patent applications and pending patent applications in Europe, Canada, Australia, Brazil, China, Hong Kong, India, Japan, Russia, and Singapore. Issued U.S. Patent No. 9,872,900 includes claims to H7 mRNA vaccine compositions. Issued U.S. Patent No. 10,022,435 features claims directed to methods of vaccinating subjects against infection with lipid nanoparticle-encapsulated mRNAs encoding infectious disease antigens. Also pending are patent applications in the U.S., China and Europe covering certain prophylactic vaccination methods relating to our influenza H7N9 mRNA vaccine.

We filed patent applications in several jurisdictions covering RSV vaccines. At least two U.S. and two European patent applications are pending, as are applications in several African, Asian, European, Middle Eastern, South American, and other jurisdictions. Also pending is a provisional application featuring our pediatric RSV vaccine.

Patent coverage for our human CMV vaccine, which includes mRNAs encoding several surface glycoproteins of the CMV virus, can be found in pending applications in Australia, Canada, Europe and Japan. In the United States, our CMV vaccine is covered in issued U.S. Patent No. 10,064,935, in issued U.S. Patent No. 10,383,937, and in two recently allowed and soon to be issued U.S. patent applications.

Patent applications directed to our hMPV/PIV3 vaccine are pending in the United States, Europe and Hong Kong. Three U.S. patents have issued featuring hMPV/PIV3 vaccines with U.S. Patent No. 10,064,934 having claims covering LNP-encapsulated mRNA vaccines that encode the PIV3 and hMPV fusion proteins, U.S. Patent No. 10,272,150 having claims covering administration methods for these LNP-encapsulated mRNA vaccines, and U.S. Patent No. 10,543,269 having claims covering vaccines that include HMPV-encoding mRNA formulated in LNPs.

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Our Zika mRNA vaccine is covered in a series of patent families directed to mosquito-borne viruses. These patent families include two issued U.S. Patents that cover our Zika vaccines, U.S. Patent No. 10,124,055 and U.S. Patent No. 10,449,244, several pending U.S. patent applications, one of which is recently allowed and soon to be issued as a U.S. patent, and pending European and Hong Kong patent applications.

Cancer vaccines

Composition of matter and method claims also protect programs within our cancer vaccines modality. Proprietary methods around the making and therapeutic use of our PCVs and resulting vaccine compositions are described and claimed in three pending U.S. patent applications, two pending PCT applications, three pending European patent applications, two pending patent applications in each of Australia, Canada, China, and Japan, and a pending patent application in each of South Korea, New Zealand, Russia, Singapore and South Africa. These applications also relate to various vaccine design formats, in particular, polyepitopic vaccine formats, and methods of treating cancer with such personalized cancer vaccines. We also possess substantial know-how and trade secrets relating to the development and commercialization of our cancer vaccine programs, including related manufacturing process and technology.

Likewise, our KRAS antigen cancer vaccine and methods of treating cancer featuring such vaccines are covered in a pending U.S. patent application and pending applications in Australia, Canada, Europe, and Japan, as well as in several other European, South American, Asian and Middle Eastern jurisdictions.

Intratumoral immuno-oncology

To protect programs within our intratumoral immuno-oncology modality, we have filed numerous patent applications featuring claims to mRNAs encoding immune-stimulatory proteins and methods of treating cancer using such compositions.

Three of our immuno-oncology programs are designed to be administered intratumorally to alter the tumor microenvironment in favor of mounting an immune response against tumors. Our OX40L mRNA program and our mRNA program that includes mRNAs that encode OX40L, IL-23 and IL-36γ are covered by eight issued U.S. patents, U.S. Patent Nos. 10,143,723, 10,172,808, 10,285,950, 10,322,090, 10,322,191, 10,379,767, 10,383,951 and 10,406,113, by several pending U.S. patent applications, and by several pending patent applications in foreign jurisdictions including European, Asian, South American and other jurisdictions. These applications feature claims to the mRNA therapeutics as compositions of matter, formulations that include such mRNAs and methods of reducing tumors and treating cancer featuring these development candidates. Similar claims cover our IL-12 development candidate which can be found in a pending patent applications in the United States, Australia, Canada, China, Europe and Japan, as well as several other jurisdictions in Asia, South America and the Middle East.

Localized regenerative therapeutics

Our localized regenerative therapeutics modality is focused on regenerative therapeutics. Our sole program, VEGF-A, is being developed in collaboration with AstraZeneca and is covered by a pending U.S. patent application and by several national phase patent applications filed in South American, Asian and Middle Eastern jurisdictions. The VEGF patent applications are solely-owned by Moderna.

Systemic intracellular therapeutics

Within our systemic intracellular therapeutics modality, we have four programs featuring expression of intracellular enzymes for the treatment of rare diseases. For our rare disease programs, we generally pursue patent protection featuring composition of matter and method of use claims, for example, pharmaceutical composition and method of treatment claims. Our most advanced rare disease development candidate, MMA, is covered by a patent family that includes two issued U.S. Patents, U.S. Patent No. 10,406,112 and U.S. Patent No. 10,426,738, two pending U.S. patent applications, a pending U.S. provisional patent application, and foreign patent applications filed in Australia, Canada, Japan, Europe and the Middle East.

For our PA development candidate, we have two pending PCT patent applications covering mRNA encoding the alpha and beta subunits of the enzyme propionyl-CoA carboxylase (PCCA and PCCB, respectively), for the treatment of PA.

For our PKU development candidate, we have a pending PCT patent application covering mRNA encoding phenylalanine hydroxylase, or PAH, for the treatment of PKU.

For our Glycogen Storage Disorder, Type 1a (GSD1a) development candidate, we have 2 pending PCT patent applications covering mRNA encoding glucose 6-phosphatase (G6Pase) for the treatment of this disorder.

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Any U.S. and foreign patents that may issue from these four patent families would be expected to expire in 2036 for the earliest of the MMA patents and 2038-2039 for the remaining MMA, PA, PKU and GSD1a patents, excluding any patent term adjustments and any patent term extensions.

As further described below, we have filed or intend to file patent applications on these and other aspects of our technology and development candidates, and as we continue the development of our intended products, we plan to identify additional means of obtaining patent protection that would potentially enhance commercial success, including protection for additional methods of use, formulation, or manufacture.

Systemic secreted and cell-surface therapeutics

Our systemic secreted and cell-surface therapeutics modality features programs directed to expression of secreted or cell-surface proteins including antibodies, circulating modulation factors, secreted enzymes and transmembrane proteins. Our mRNA-encoded antibody against Chikungunya virus reported positive interim Phase 1 results in clinical trials and utilizes the same lipid nanoparticle (LNP) formulation being advanced for our MMA program and other rare disease programs. Patent protection for mRNA-encoded antibody against Chikungunya virus is being sought by way of a pending PCT patent application, in which we share joint ownership rights.

Our Relaxin development candidate is being developed in collaboration with AstraZeneca and is covered by several pending foreign patent applications outside the United States, for example, in several Asian, European, Middle Eastern, South American and other jurisdictions, and by a pending U.S. application undergoing accelerated examination in the USPTO.

For our Fabry development candidate, we have two issued U.S. patents, U.S. Patent No. 10,494,636 and U.S. Patent No. 10,519,455, as well as pending applications in the United States, Australia, Canada, Europe and Japan covering mRNA encoding alpha-galactosidase A.

Our PD-L1 and IL-2 development candidates are covered in three recently filed U.S. provisional patent applications.

Trademarks

Our registered trademark portfolio currently contains approximately 100 registered trademarks, consisting of at least 10 registrations in the United States and approximately 90 registrations in Australia, Canada, China, the EU, Japan, Singapore, Sweden, and under the Madrid Protocol. In addition, we have other pending trademark applications, consisting of trademark applications in the United States, Australia, Canada, China, the EU, Japan, Singapore, and under the Madrid Protocol.

In-licensed intellectual property

While we develop and manufacture our potential mRNA medicines using our internally created mRNA technology platform, we also seek out and evaluate third party technologies and IP that may be complementary to our platform.

Patent sublicense agreements with Cellscript and mRNA RiboTherapeutics

The Trustees of the University of Pennsylvania, or Penn, owns several issued U.S. patents, granted European patents and pending U.S. patent applications directed, in part, to nucleoside-modified mRNAs and their uses, or the Penn Modified mRNA Patents. mRNA RiboTherapeutics, Inc., or MRT, obtained an exclusive license to the Penn Modified mRNA Patents and granted its affiliate, Cellscript, LLC, or Cellscript, a sublicense to the Penn Modified mRNA Patents in certain fields of use.

In June 2017, we entered into two sublicense agreements, one with Cellscript, and one with MRT, which agreements we collectively refer to as the Cellscript-MRT Agreements. Together, the Cellscript-MRT Agreements grant us a worldwide, sublicensable sublicense to the Penn Modified mRNA Patents to research, develop, make, and commercialize products covered by the Penn Modified mRNA Patents, or licensed products, for all in vivo uses in humans and animals, including therapeutic, prophylactic, and diagnostic applications. The Cellscript-MRT Agreements are non-exclusive, although Cellscript and MRT are subject to certain time restrictions on granting additional sublicenses for in vivo uses in humans under the Penn Modified mRNA Patents.

We paid Cellscript and MRT aggregate sublicense grant fees of $28 million upon entering into the Cellscript-MRT Agreements, $25 million in early 2018, and $22 million in early 2019. Cellscript and MRT are collectively eligible to receive, on a licensed product-by-licensed product basis, milestone payments totaling up to $0.5 million upon the achievement of certain regulatory-based events for diagnostic products, and milestone payments totaling up to $1.5 million upon the achievement of certain development and regulatory-based events for either therapeutic or prophylactic products, and up to $24 million upon the achievement of certain commercial-based events for either therapeutic or prophylactic products. The Cellscript-MRT Agreements require us to pay royalties

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based on annual net sales of licensed products at rates in the low single digits for therapeutic, prophylactic, and diagnostic uses, and royalties based on annual net sales of licensed products sold for research uses at rates in the mid-single digits, subject to certain reductions, with an aggregate minimum floor. Following the first commercial sale of licensed products under a Cellscript-MRT Agreement, we are required to pay Cellscript or MRT, as applicable, minimum annual royalties ranging from $10,000—$400,000 depending on the use of such licensed product, with all such payments creditable against earned royalties on net sales.

The Cellscript-MRT Agreements will expire upon the expiration or abandonment of the last to expire or become abandoned of the Penn Modified mRNA Patents. Cellscript or MRT, as applicable, may terminate its respective Cellscript-MRT Agreement if we fail to make required payments or otherwise materially breach the applicable agreement, subject to specified notice and cure provisions. Cellscript or MRT, as applicable, may also terminate the applicable Cellscript-MRT Agreement upon written notice in the event of our bankruptcy or insolvency or if we challenge the validity or enforceability of the Penn Modified mRNA Patents. We have the right to terminate each Cellscript-MRT Agreement at will upon 60 days’ prior notice to Cellscript or MRT, as applicable, provided that we cease all development and commercialization of licensed products upon such termination. If rights to MRT or Cellscript under the Penn Modified mRNA Patents are terminated (e.g., due to bankruptcy of MRT or Cellscript), the terminated party will assign its interest in the respective Cellscript-MRT Agreement to the licensor from which it received rights under the Penn Modified mRNA Patents and our rights will continue under the new licensor.

Formulation technology in-licenses

Our development candidates use internally developed formulation technology that we own. We do, however, have rights to use and exploit multiple issued and pending patents covering formulation technologies under licenses from other entities. If in the future we elect to use or to grant our strategic collaborators sublicenses to use these in-licensed formulation technologies, we or our strategic collaborators may be liable for milestone and royalty payment obligations arising from such use. We consider the commercial terms of these licenses and their provisions regarding diligence, insurance, indemnification and other similar matters, to be reasonable and customary for our industry.

In addition, we have entered into material transfer agreements that have provided us with opportunities to evaluate third party delivery systems.

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EMPLOYEES

We have approximately 830 full-time employees, 51% of whom hold Ph.D., M.D., J.D., or Master’s degrees. Among our employees, 45% identify as female, 54% identify as male, and 1% have chosen not to identify themselves or selected other. None of our employees is represented by a labor union, and none of our employees has entered into a collective bargaining agreement with us. We consider our employee relations to be good.

We believe that our employees are highly engaged, and we and our employees have been recognized by surveys conducted by external groups. Science magazine ranked us as a top employer for the last five years; we were ranked #7 in 2015, #3 in 2016, #6 in 2017, #4 in 2018 and #11 in 2019.

Our approach to attracting and retaining talent within Moderna

We are committed to ensuring that our employees find that their careers at Moderna are filled with purpose, growth and fulfillment. We believe that a career at Moderna provides opportunity for:

• Impact: Our people will have the opportunity to do work that is unparalleled in terms of its innovation and scope of impact on people’s lives.

• Growth: For the intellectually curious, we provide incredible opportunities for growth. We invest in the development of our people as scientists and as leaders.

• Wellness: We are committed to the health and wellbeing of our employees and their families by providing family friendly benefits and opportunities to be healthy.

• Inclusive environment: We believe in the benefits of bringing together a diverse set of perspectives and backgrounds, and creating an environment where differences are celebrated and leveraged.

• Compelling rewards: To attract and retain the best talent, we provide competitive rewards that help to drive groundbreaking work and allow employees to share in the value we will create together.

Our approach to training our employees

We have established a structured training curriculum for our employees called Moderna University and have a full-time team dedicated to developing the curriculum and conducting activities for Moderna University. The objective of Moderna University is for every employee to be deeply familiar with our core technology and able to learn about technologies that might further enable our science. In addition, Moderna University is also focused on creating strong leaders within the company through management and leadership training. There are four core areas wi