10-Q

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549

FORM 10-Q

(Mark One)

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

For the quarterly period ended March 31, 2022

OR

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

For the transition period from to .

Commission File No. 001-36276

ULTRAGENYX PHARMACEUTICAL INC.

(Exact name of registrant as specified in its charter)

Delaware	27-2546083
(State or other jurisdiction of incorporation or organization)	(I.R.S. Employer Identification No.)

60 Leveroni Court Novato, California	94949
(Address of principal executive offices)	(Zip Code)

(415) 483-8800

(Registrant’s telephone number, including area code)

Not Applicable

(Former Name, Former Address and Former Fiscal Year, if Changed Since Last Report)

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

Title of each class	Trading Symbol	Name of each exchange on which registered
Common Stock, $0.001 par value	RARE	The Nasdaq Global Select Market

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 ☑ No ☐

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 ☑ No ☐

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	☑	Accelerated filer	☐
Non-accelerated filer	☐	Smaller reporting company	☐
		Emerging growth company	☐

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. ☐

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

As of May 2, 2022, the registrant had 69,930,191 shares of common stock issued and outstanding.

ULTRAGENYX PHARMACEUTICAL INC.

FORM 10-Q FOR THE QUARTER ENDED MARCH 31, 2022

INDEX

			Page
CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS			1
Part I –	Financial Information
	Item 1.	Financial Statements
		Condensed Consolidated Balance Sheets	2
		Condensed Consolidated Statements of Operations	3
		Condensed Consolidated Statements of Comprehensive Loss	4
		Condensed Consolidated Statements of Stockholders’ Equity	5
		Condensed Consolidated Statements of Cash Flows	6
		Notes to Condensed Consolidated Financial Statements	7
	Item 2.	Management’s Discussion and Analysis of Financial Condition and Results of Operations	20
	Item 3.	Quantitative and Qualitative Disclosures About Market Risk	31
	Item 4.	Controls and Procedures	32
Part II –	Other Information
	Item 1.	Legal Proceedings	32
	Item 1A.	Risk Factors	32
	Item 2.	Unregistered Sales of Equity Securities and Use of Proceeds	69
	Item 3.	Defaults Upon Senior Securities	69
	Item 4.	Mine Safety Disclosures	69
	Item 5.	Other Information	69
	Item 6.	Exhibits	69
	Signatures		70

CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS

This Quarterly Report on Form 10-Q (the Quarterly Report) contains forward-looking statements that involve risks and uncertainties. We make such forward-looking statements pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995 and other federal securities laws. All statements other than statements of historical facts contained in this Quarterly Report are forward-looking statements. In some cases, you can identify forward-looking statements by words such as “anticipate,” “believe,” “contemplate,” “continue,” “could,” “estimate,” “expect,” “forecast,” “intend,” “may,” “plan,” “potential,” “predict,” “project,” “seek,” “should,” “target,” “will,” “would,” or the negative of these words, or other comparable terminology. These forward-looking statements include, but are not limited to, statements about:

•our commercialization, marketing, and manufacturing capabilities and strategy;

•our expectations regarding the timing of clinical study commencements and reporting results from same;

•the timing and likelihood of regulatory approvals for our product candidates;

•the anticipated indications for our product candidates, if approved;

•the potential market opportunities for commercializing our products and product candidates;

•our expectations regarding the potential market size and the size of the patient populations for our products and product candidates, if approved for commercial use;

•the impact of the COVID-19 pandemic and related health measures on our business, financial condition and liquidity;

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

•our ability to develop, acquire, and advance product candidates into, and successfully complete, clinical studies;

•the implementation of our business model and strategic plans for our business, products and product candidates and the integration and performance of any businesses we have acquired or may acquire;

•the initiation, timing, progress, and results of ongoing and future preclinical and clinical studies, and our research and development programs;

•the scope of protection we are able to establish and maintain for intellectual property rights covering our products and product candidates;

•our ability to maintain and establish collaborations or strategic relationships or obtain additional funding;

•our ability to maintain and establish relationships with third parties, such as contract research organizations, contract manufacturing organizations, suppliers, and distributors;

•our financial performance and the expansion of our organization;

•our ability to obtain supply of our products and product candidates;

•the scalability and commercial viability of our manufacturing methods and processes;

•developments and projections relating to our competitors and our industry; and

•other risks and uncertainties, including those listed under Part II, Item 1A. Risk Factors.

Any forward-looking statements in this Quarterly Report reflect our current views with respect to future events or to our future 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. Factors that may cause actual results to differ materially from current expectations include, among other things, those discussed under Part II, Item 1A. Risk Factors and elsewhere in this Quarterly Report. Given these uncertainties, you should not place undue reliance on these forward-looking statements. Except as required by law, we assume no obligation to update or revise these forward-looking statements for any reason, even if new information becomes available in the future.

This Quarterly Report also contains estimates, projections, and other information concerning our industry, our business, and the markets for certain diseases, including data regarding the estimated size of those markets, and the incidence and prevalence of certain medical conditions. Information that is based on estimates, forecasts, projections, market research, or similar methodologies is inherently subject to uncertainties and actual events or circumstances may differ materially from events and circumstances reflected in this information. Unless otherwise expressly stated, we obtained this industry, business, market, and other data from reports, research surveys, studies, and similar data prepared by market research firms and other third parties, industry, medical and general publications, government data, and similar sources.

1

PART I. FINANCIAL INFORMATION

Item 1. Financial Statements

ULTRAGENYX PHARMACEUTICAL INC.

CONDENSED CONSOLIDATED BALANCE SHEETS

(Unaudited)

(In thousands, except share amounts)

	March 31,			December 31,
	2022			2021
Assets
Current assets:
Cash and cash equivalents	$	153,988		$	307,584
Marketable debt securities		444,333			432,612
Accounts receivable, net		28,369			28,432
Inventory		17,809			16,231
Prepaid expenses and other current assets		63,020			71,745
Total current assets		707,519			856,604
Property, plant, and equipment, net		177,073			141,247
Equity investments		25,596			34,925
Marketable debt securities		215,526			258,933
Right-of-use assets		32,699			34,936
Intangible assets, net		159,992			130,788
Goodwill		44,406			44,406
Other assets		21,218			20,558
Total assets	$	1,384,029		$	1,522,397
Liabilities and Stockholders’ Equity
Current liabilities:
Accounts payable	$	23,685		$	17,138
Accrued liabilities		126,356			145,555
Contract liabilities		5,867			7,609
Lease liabilities		11,323			11,066
Total current liabilities		167,231			181,368
Contract liabilities		—			1,467
Lease liabilities		28,043			30,904
Deferred tax liabilities		33,306			33,306
Liability related to the sale of future royalties		355,633			351,786
Other liabilities		3,392			1,005
Total liabilities		587,605			599,836
Stockholders’ equity:
Preferred stock — 25,000,000 shares authorized; nil outstanding as of March 31, 2022 and    December 31, 2021		—			—
Common stock — 250,000,000 shares authorized; 69,796,940 and 69,344,998 shares issued    and outstanding as of March 31, 2022 and December 31, 2021, respectively		70			69
Additional paid-in capital		3,028,829			2,997,497
Accumulated other comprehensive loss		(6,554	)		(1,404	)
Accumulated deficit		(2,225,921	)		(2,073,601	)
Total stockholders’ equity		796,424			922,561
Total liabilities and stockholders’ equity	$	1,384,029		$	1,522,397

See accompanying notes.

2

ULTRAGENYX PHARMACEUTICAL INC.

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS

(Unaudited)

(In thousands, except share and per share amounts)

	Three Months Ended March 31,
	2022			2021
Revenues:
Collaboration and license	$	48,413		$	79,010
Product sales		26,684			16,513
Non-cash collaboration royalty revenue		4,838			3,872
Total revenues		79,935			99,395
Operating expenses:
Cost of sales		6,100			5,188
Research and development		143,155			147,518
Selling, general and administrative		67,312			53,258
Total operating expenses		216,567			205,964
Loss from operations		(136,632	)		(106,569	)
Interest income		494			639
Change in fair value of equity investments		(9,329	)		(20,619	)
Non-cash interest expense on liability related to the sale of future     royalties		(6,584	)		(8,418	)
Other income (expense)		289			(795	)
Loss before income taxes		(151,762	)		(135,762	)
Provision for income taxes		(558	)		(379	)
Net loss	$	(152,320	)	$	(136,141	)
Net loss per share, basic and diluted	$	(2.19	)	$	(2.03	)
Weighted-average shares used in computing net loss per share,     basic and diluted		69,516,668			67,102,342

See accompanying notes.

3

ULTRAGENYX PHARMACEUTICAL INC.

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS

(Unaudited)

(In thousands)

	Three Months Ended March 31,
	2022			2021
Net loss	$	(152,320	)	$	(136,141	)
Other comprehensive loss:
Foreign currency translation adjustments		(60	)		(285	)
Unrealized loss on available-for-sale securities		(5,090	)		(348	)
Other comprehensive loss:		(5,150	)		(633	)
Total comprehensive loss	$	(157,470	)	$	(136,774	)

See accompanying notes.

4

ULTRAGENYX PHARMACEUTICAL INC.

CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY

(Unaudited)

(In thousands, except share amounts)

	Common Stock				Additional Paid-In		Accumulated Other Comprehensive			Accumulated			Total Stockholders'
	Shares		Amount		Capital		Income (Loss)			Deficit			Equity
Balance as of December 31, 2021		69,344,998	$	69	$	2,997,497	$	(1,404	)	$	(2,073,601	)	$	922,561
Stock-based compensation		—		—		29,578		—			—			29,578
Issuance of common stock under    equity plan awards, net of tax		451,942		1		1,754		—			—			1,755
Other comprehensive loss		—		—		—		(5,150	)		—			(5,150	)
Net loss		—		—		—		—			(152,320	)		(152,320	)
Balance as of March 31, 2022		69,796,940	$	70	$	3,028,829	$	(6,554	)	$	(2,225,921	)	$	796,424

	Common Stock				Additional Paid-In		Accumulated Other Comprehensive			Accumulated			Total Stockholders'
	Shares		Amount		Capital		Income (Loss)			Deficit			Equity
Balance as of December 31, 2020		66,818,520	$	67	$	2,773,195	$	689		$	(1,619,576	)	$	1,154,375
Stock-based compensation		—		—		24,220		—			—			24,220
Issuance of common stock under    equity plan awards, net of tax		620,957		—		12,761		—			—			12,761
Other comprehensive loss		—		—		—		(633	)		—			(633	)
Net loss		—		—		—		—			(136,141	)		(136,141	)
Balance as of March 31, 2021		67,439,477	$	67	$	2,810,176	$	56		$	(1,755,717	)	$	1,054,582

See accompanying notes.

5

ULTRAGENYX PHARMACEUTICAL INC.

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS

(Unaudited)

(In thousands)

	Three Months Ended March 31,
	2022			2021
Operating activities:
Net loss	$	(152,320	)	$	(136,141	)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation		29,396			24,254
Amortization of premium on marketable debt securities, net		1,894			940
Depreciation and amortization		4,088			3,367
Change in fair value of equity investments		9,329			20,619
Non-cash collaboration royalty revenue		(4,838	)		(3,872	)
Non-cash interest expense on liability related to the sale of future royalties		6,584			8,418
Other		35			325
Changes in operating assets and liabilities:
Accounts receivable		33			(1,993	)
Inventory		(1,475	)		474
Prepaid expenses and other assets		9,126			(10,656	)
Accounts payable, accrued, and other liabilities		(16,164	)		(23,602	)
Contract liabilities		(3,209	)		(41,479	)
Net cash used in operating activities		(117,521	)		(159,346	)
Investing activities:
Purchase of property, plant, and equipment		(32,184	)		(16,414	)
Purchase of marketable debt securities		(203,710	)		(405,230	)
Proceeds from sale of marketable debt securities		39,422			14,980
Proceeds from maturities of marketable debt securities		188,990			224,240
Purchase of mutual funds related to nonqualified deferred compensation plan		(2,458	)		—
Payment for intangible asset		(30,000	)		—
Other		2,578			—
Net cash used in investing activities		(37,362	)		(182,424	)
Financing activities:
Proceeds from the issuance of common stock from equity plan awards, net		1,755			12,761
Other		(143	)		(112	)
Net cash provided by financing activities		1,612			12,649
Effect of exchange rate changes on cash		(108	)		(771	)
Net decrease in cash, cash equivalents and restricted cash		(153,379	)		(329,892	)
Cash, cash equivalents and restricted cash at beginning of period		309,585			726,294
Cash, cash equivalents and restricted cash at end of period	$	156,206		$	396,402
Supplemental disclosures of non-cash information:
Acquired lease liabilities arising from obtaining right-of-use assets	$	132		$	—
Non-cash interest expense on liability related to the sale of future royalties capitalized into ending property, plant and equipment	$	2,101		$	—

See accompanying notes.

6

ULTRAGENYX PHARMACEUTICAL INC.

Notes to Condensed Consolidated Financial Statements

1. Organization

Ultragenyx Pharmaceutical Inc. (the Company) is a biopharmaceutical company incorporated in Delaware.

The Company is focused on the identification, acquisition, development, and commercialization of novel products for the treatment of serious rare and ultra-rare genetic diseases. The Company operates as one reportable segment. The Company has four commercially approved products.

Crysvita® (burosumab) is approved in the United States (U.S.) by the U.S. Food and Drug Administration (FDA) and in Canada for the treatment of X-linked hypophosphatemia (XLH) in adult and pediatric patients one year of age and older, and is approved in the European Union (EU) and the United Kingdom, for the treatment of XLH with radiographic evidence of bone disease in children one year of age and older, adolescents, and adults. In Brazil, Colombia, and Mexico, Crysvita is approved for treatment of XLH in adult and pediatric patients one year of age and older. Crysvita is also approved in the U.S. by the FDA for the treatment of fibroblast growth factor 23 (FGF23)-related hypophosphatemia in tumor-induced osteomalacia (TIO), associated with phosphaturic mesenchymal tumors that cannot be curatively resected or localized in adults and pediatric patients 2 years of age and older.

Mepsevii® (vestronidase alfa) is approved by the FDA as the first medicine for the treatment of children and adults with mucopolysaccharidosis VII (MPS VII), also known as Sly syndrome. In the European Union and the United Kingdom, Mepsevii is approved under exceptional circumstances for patients of all ages for the treatment of non-neurological manifestations of MPS VII. In Brazil, Mepsevii is approved for the treatment of MPS VII for patients of all ages.

Dojolvi® (triheptanoin) is approved in the U.S., Canada, and Brazil for the treatment of pediatric and adult patients severely affected by long-chain fatty acid oxidation disorders (LC-FAOD).

On January 7, 2022, the Company announced a collaboration with Regeneron Pharmaceuticals (Regeneron) to commercialize Evkeeza® (evinacumab) outside of the U.S. Evkeeza is approved in the U.S. and the European Economic Area (EEA) for the treatment of homozygous familial hypercholesterolemia (HoFH).

In addition to the approved products, the Company has the following ongoing clinical development programs:

•DTX401 is an adeno-associated virus 8 (AAV8) gene therapy product candidate for the treatment of patients with glycogen storage disease type Ia (GSDIa);

•DTX301 is an AAV8 gene therapy product candidate in development for the treatment of patients with ornithine transcarbamylase (OTC) deficiency, the most common urea cycle disorder;

•UX143 (setrusumab), which is subject to the Company's collaboration agreement with Mereo BioPharma 3 (Mereo), is a fully human monoclonal antibody that inhibits sclerostin, a protein that acts on a key bone-signaling pathway and inhibits the activity of bone-forming cells for the treatment of patients with osteogenesis imperfect (OI);

•GTX-102 is an antisense oligonucleotide (ASO), which the Company is collaborating on the development with GeneTx Biotherapeutics LLC (GeneTx) for the treatment of Angelman syndrome, a debilitating and rare neurogenetic disorder caused by loss-of-function of the maternally inherited allele of the UBE3A gene;

•UX701 is an AAV type 9 gene therapy designed to deliver stable expression of a truncated version of the ATP7B copper transporter following a single intravenous infusion to improve copper distribution and excretion from the body and reverse pathological findings of Wilson liver disease; and

•UX053 is a messenger RNA (mRNA) product candidate designed for the treatment of patients with Glycogen Storage Disease Type III (GSDIII), a disease caused by a glycogen debranching enzyme (AGL) deficiency that results in glycogen accumulation in the liver and muscle.

The Company has sustained operating losses and expects such annual losses to continue over the next several years. The Company’s ultimate success depends on the outcome of its research and development and commercialization activities, for which it expects to incur additional losses in the future. Management recognizes that the Company will likely need to raise additional capital to fully implement its business plans. Through March 31, 2022, the Company has relied primarily on its sale of equity securities, its revenues from commercial products, its sale of future royalties, and strategic collaboration arrangements to finance its operations.

The Company will likely raise additional capital through the issuance of equity, borrowings, or strategic alliances with partner companies. However, if such financing is not available at adequate levels, the Company would need to reevaluate its operating plans.

7

2. Summary of Significant Accounting Policies

Basis of Presentation

The accompanying unaudited Condensed Consolidated Financial Statements include the accounts of the Company and its wholly-owned subsidiaries and have been prepared in accordance with U.S. generally accepted accounting principles (GAAP) for interim financial information and in accordance with the instructions to Form 10-Q and Rule 10-01 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. The unaudited interim Condensed Consolidated Financial Statements have been prepared on the same basis as the annual financial statements. In the opinion of management, the accompanying unaudited Condensed Consolidated Financial Statements reflect all adjustments (consisting only of normal recurring adjustments) considered necessary for a fair presentation. These financial statements should be read in conjunction with the audited financial statements and notes thereto for the preceding fiscal year contained in the Company’s Annual Report on Form 10-K filed on February 15, 2022 (Annual Report) with the United States Securities and Exchange Commission (the SEC).

The results of operations for the three months ended March 31, 2022 are not necessarily indicative of the results to be expected for the year ending December 31, 2022. The Condensed Consolidated Balance Sheet as of December 31, 2021 has been derived from audited financial statements at that date, but does not include all of the information required by GAAP for complete financial statements.

Use of Estimates

The accompanying Condensed Consolidated Financial Statements have been prepared in accordance with GAAP. The preparation of the Condensed Consolidated Financial Statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent liabilities and the reported amounts of expenses in the Condensed Consolidated Financial Statements and the accompanying notes. On an ongoing basis, management evaluates its estimates, including those related to clinical trial accruals, fair value of assets and liabilities, income taxes, stock-based compensation, revenue recognition, and the liability related to the sale of future royalties. Management bases its estimates on historical experience and on various other market-specific and relevant assumptions that management believes to be reasonable under the circumstances. Actual results could differ from those estimates.

Cash, Cash Equivalents and Restricted Cash

Restricted cash primarily consists of money market accounts used as collateral for the Company’s obligations under its facility leases and the gene therapy building construction project. The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the Condensed Consolidated Balance Sheets that sum to the total of the same such amounts shown in the Condensed Consolidated Statement of Cash Flows (in thousands):

	March 31,
	2022		2021
Cash and cash equivalents	$	153,988	$	383,794
Restricted cash included in prepaid expenses and     other current assets		217		10,687
Restricted cash included in other assets		2,001		1,921
Total cash, cash equivalents, and restricted cash     shown in the statements of cash flows	$	156,206	$	396,402

Credit Losses

The Company is exposed to credit losses primarily through receivables from customers and collaborators and through its available-for-sale debt securities. For trade receivables and other instruments, the Company uses a forward-looking expected loss

8

model that generally results in the earlier recognition of allowances for losses. For available-for-sale debt securities with unrealized losses, the losses are recognized as allowances rather than as reductions in the amortized cost of the securities.

The Company’s expected loss allowance methodology for the receivables is developed using historical collection experience, current and future economic market conditions, a review of the current aging status and financial condition of the entities. Specific allowance amounts are established to record the appropriate allowance for customers that have a higher probability of default. Balances are written off when determined to be uncollectible. The Company’s expected loss allowance methodology for the debt securities is developed by reviewing the extent of the unrealized loss, the size, term, geographical location, and industry of the issuer, the issuers’ credit ratings and any changes in those ratings, as well as reviewing current and future economic market conditions and the issuers’ current status and financial condition. There were no material credit losses recorded for receivables and available-for-sale debt securities for the three months ended March 31, 2022 and 2021.

Revenue Recognition

Collaboration and license revenue

The Company has certain license and collaboration agreements that are within the scope of Accounting Standards Codification (ASC) 808, Collaborative Agreements, which provides guidance on the presentation and disclosure of collaborative arrangements. Generally, the classification of the transactions under the collaborative arrangements is determined based on the nature of contractual terms of the arrangement, along with the nature of the operations of the participants. The Company records its share of collaboration revenue, net of transfer pricing related to net sales in the period in which such sales occur, if the Company is considered as an agent in the arrangement. The Company is considered an agent when the collaboration partner controls the product before transfer to the customers and has the ability to direct the use of and obtain substantially all of the remaining benefits from the product. Funding received related to research and development services and commercialization costs is generally classified as a reduction of research and development expenses and selling, general and administrative expenses, respectively, in the Condensed Consolidated Statement of Operations, because the provision of such services for collaborative partners are not considered to be part of the Company’s ongoing major or central operations.

In order to record collaboration revenue, the Company utilizes certain information from its collaboration partners, including revenue from the sale of the product, associated reserves on revenue, and costs incurred for development and sales activities. For the periods covered in the financial statements presented, there have been no material changes to prior period estimates of revenues and expenses.

The Company sold the right to receive certain royalty payments from net sales of Crysvita to RPI Finance Trust (RPI), an affiliate of Royalty Pharma, as further described in Note 7. The Company records the royalty revenue from the net sales of Crysvita in the applicable European territories on a prospective basis as non-cash royalty revenue in the Condensed Consolidated Statements of Operations over the term of the arrangement.

The terms of the Company’s collaboration and license agreements may contain multiple performance obligations, which may include licenses and research and development activities. The Company evaluates these agreements under ASC 606, Revenue from Contracts with Customers (ASC 606), to determine the distinct performance obligations. The Company analogizes to ASC 606 for the accounting for distinct performance obligations for which there is a customer relationship. Prior to recognizing revenue, the Company makes estimates of the transaction price, including variable consideration that is subject to a constraint. Amounts of variable consideration are included in the transaction price to the extent that it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur and when the uncertainty associated with the variable consideration is subsequently resolved. Total consideration may include nonrefundable upfront license fees, payments for research and development activities, reimbursement of certain third-party costs, payments based upon the achievement of specified milestones, and royalty payments based on product sales derived from the collaboration.

If there are multiple distinct performance obligations, the Company allocates the transaction price to each distinct performance obligation based on its relative standalone selling price. The standalone selling price is generally determined based on the prices charged to customers or using expected cost-plus margin. The Company estimates the efforts needed to complete the performance obligations and recognizes revenue by measuring the progress towards complete satisfaction of the performance obligations using input measures.

Product sales

The Company sells its approved products through a limited number of distributors. Under ASC 606, revenue from product sales is recognized at the point in time when the delivery is made and when title and risk of loss transfers to these distributors. The Company also recognizes revenue from sales of certain products on a “named patient” basis, which are allowed in certain countries prior to the commercial approval of the product. Prior to recognizing revenue, the Company makes estimates of the transaction

9

price, including any variable consideration that is subject to a constraint. Amounts of variable consideration are included in the transaction price to the extent that it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur and when the uncertainty associated with the variable consideration is subsequently resolved. Product sales are recorded net of estimated government-mandated rebates and chargebacks, estimated product returns, and other deductions.

Provisions for returns and other adjustments are provided for in the period the related revenue is recorded, as estimated by management. These reserves are based on estimates of the amounts earned or to be claimed on the related sales and are reviewed periodically and adjusted as necessary. The Company’s estimates of government mandated rebates, chargebacks, estimated product returns, and other deductions depends on the identification of key customer contract terms and conditions, as well as estimates of sales volumes to different classes of payors. If actual results vary, the Company may need to adjust these estimates, which could have an effect on earnings in the period of the adjustment.

3. Financial Instruments

Financial assets and liabilities are recorded at fair value. The carrying amount of certain financial instruments, including cash and cash equivalents, accounts receivable, accounts payable and accrued liabilities approximate fair value due to their relatively short maturities. Assets and liabilities recorded at fair value on a recurring basis in the balance sheets are categorized based upon the level of judgment associated with the inputs used to measure their fair values. Fair value is defined as the exchange price that would be received for an asset or an exit price that would be paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The authoritative guidance on fair value measurements establishes a three-tier fair value hierarchy for disclosure of fair value measurements as follows:

Level 1—Inputs are unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date;

Level 2—Inputs are observable, unadjusted quoted prices in active markets for similar assets or liabilities, unadjusted quoted prices for identical or similar assets or liabilities in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the related assets or liabilities; and

Level 3—Unobservable inputs that are significant to the measurement of the fair value of the assets or liabilities that are supported by little or no market data.

The Company determines the fair value of its equity investments in Arcturus Therapeutics Holdings Inc. (Arcturus) and Solid Biosciences Inc. (Solid) by using the quoted market prices, which are Level 1 fair value measurements.

The following tables set forth the fair value of the Company’s financial assets remeasured on a recurring basis based on the three-tier fair value hierarchy (in thousands):

	March 31, 2022
	Level 1		Level 2		Level 3		Total
Money market funds	$	113,600	$	—	$	—	$	113,600
Certificate of deposits and time deposits		—		27,101		—		27,101
Corporate bonds		—		384,474		—		384,474
Commercial paper		—		120,685		—		120,685
Asset-backed securities		—		12,875		—		12,875
U.S. Government Treasury and agency securities		7,172		106,344		—		113,516
Debt securities in government-sponsored entities		—		19,328		—		19,328
Investments in Arcturus and Solid common stock		22,871		—		—		22,871
Other		—		3,400		—		3,400
Total	$	143,643	$	674,207	$	—	$	817,850

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	December 31, 2021
	Level 1		Level 2		Level 3		Total
Money market funds	$	266,765	$	—	$	—	$	266,765
Certificate of deposits and time deposits		—		16,000		—		16,000
Corporate bonds		—		349,691		—		349,691
Commercial paper		—		187,624		—		187,624
Asset-backed securities		—		41,245		—		41,245
U.S. Government Treasury and agency securities		—		87,435		—		87,435
Debt securities in government-sponsored entities		—		19,549		—		19,549
Investments in Arcturus and Solid common stock		32,200		—		—		32,200
Other		—		942		—		942
Total	$	298,965	$	702,486	$	—	$	1,001,451

4. Balance Sheet Components

Cash Equivalents and Investments

The fair values of cash equivalents and investments classified as available-for-sale securities consisted of the following (in thousands):

	March 31, 2022
				Gross Unrealized
		Amortized Cost		Gains		Losses			Estimated Fair Value
Money market funds		$	113,600	$	—	$	—		$	113,600
Certificates of deposit and time deposits			27,101		—		—			27,101
Corporate bonds			389,619		1		(5,146	)		384,474
Commercial paper			120,686		—		(1	)		120,685
Asset-backed securities			12,924		—		(49	)		12,875
U.S. Government Treasury and agency securities			114,445		29		(958	)		113,516
Debt securities in government-sponsored entities			19,577		—		(249	)		19,328
Total		$	797,952	$	30	$	(6,403	)	$	791,579

	December 31, 2021
				Gross Unrealized
		Amortized Cost		Gains		Losses			Estimated Fair Value
Money market funds		$	266,765	$	—	$	—		$	266,765
Certificates of deposit and time deposits			16,000		—		—			16,000
Corporate bonds			350,667		3		(979	)		349,691
Commercial paper			187,624		—		—			187,624
Asset-backed securities			41,282		1		(38	)		41,245
U.S. Government Treasury and agency securities			87,642		1		(208	)		87,435
Debt securities in government-sponsored entities			19,612		—		(63	)		19,549
Total		$	969,592	$	5	$	(1,288	)	$	968,309

At March 31, 2022, the remaining contractual maturities of available-for-sale securities were less than three years. There have been no significant realized gains or losses on available-for-sale securities for the three months ended March 31, 2022 and 2021. The unrealized losses on the Company’s investments in marketable debt securities were caused by interest rate increases. The contractual terms of these investments do not permit the issuers to settle the securities at a price less than the par value.

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Accordingly, it is expected that the securities would not be settled at a price less than the amortized cost basis of these investments. The Company does not intend to sell the investments and it is not more likely than not that the Company will be required to sell the investments before recovery of their amortized cost basis. All marketable securities with unrealized losses at March 31, 2022 have been in a loss position for less than twelve months.

Inventory

Inventory consists of the following (in thousands):

	March 31,		December 31,
	2022		2021
Work-in-process	$	11,989	$	10,504
Finished goods		5,820		5,727
Total inventory	$	17,809	$	16,231

Accrued Liabilities

Accrued liabilities consist of the following (in thousands):

	March 31,		December 31,
	2022		2021
Research, clinical study, and manufacturing expenses	$	40,092	$	40,880
Payroll and related expenses		41,638		62,591
Other		44,626		42,084
Total accrued liabilities	$	126,356	$	145,555

5. Revenue

The following table disaggregates total revenues from customers (in thousands):

	Three Months Ended
	March 31,
	2022		2021
Collaboration and license revenue:
Crysvita collaboration revenue in profit-     share territory	$	45,164	$	36,260
Daiichi Sankyo		3,249		42,750
Total collaboration and license revenue		48,413		79,010
Product sales:
Crysvita		9,394		5,872
Mepsevii		4,861		3,607
Dojolvi		12,429		7,034
Total product sales		26,684		16,513
Crysvita non-cash collaboration royalty     revenue		4,838		3,872
Total revenues	$	79,935	$	99,395

The following table disaggregates total revenues based on geographic location (in thousands):

	Three Months Ended
	March 31,
	2022		2021
U.S. and Canada	$	61,917	$	87,742
Europe		8,227		5,637
Latin America		9,791		6,016
Total revenues	$	79,935	$	99,395

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The following table presents changes in the contract liabilities (in thousands):

	Three Months Ended March 31,
	2022			2021
Balance of contract liabilities at beginning of period	$	(9,076	)	$	(66,568	)
Additions		(40	)		(1,271	)
Deductions		3,249			42,750
Balance of contract liabilities at end of period	$	(5,867	)	$	(25,089	)

See Note 6 for additional details on contract liabilities activities.

The Company’s largest accounts receivable balance accounted for 61% and 71% of the total accounts receivable balance as of March 31, 2022 and December 31, 2021, respectively, and was due from a collaboration partner.

6. License and Research Agreements

Kyowa Kirin Collaboration and License Agreement

In August 2013, the Company entered into a collaboration and license agreement with Kyowa Kirin Co., Ltd. (KKC or formerly Kyowa Hakko Kirin Co., Ltd. or KHK). Under the terms of this collaboration and license agreement, as amended, the Company and KKC collaborate on the development and commercialization of Crysvita in the field of orphan diseases in the U.S. and Canada, or the profit-share territory, and in the European Union, United Kingdom, and Switzerland, or the European territory, and the Company has the right to develop and commercialize such products in the field of orphan diseases in Mexico and Central and South America, or Latin America.

Development Activities

In the field of orphan diseases, and except for ongoing studies being conducted by KKC, the Company is the lead party for development activities in the profit-share territory and in the European territory until the applicable transition date. The Company shares the costs for development activities in the profit-share territory and the European territory conducted pursuant to the development plan before the applicable transition date equally with KKC. In April 2023, which is the transition date for the profit-share territory, KKC will become the lead party and be responsible for the costs of the development activities. However, the Company will continue to share the costs of the studies commenced prior to the applicable transition date equally with KKC.

The collaboration and license agreements are within the scope of ASC 808, which provides guidance on the presentation and disclosure of collaborative arrangements.

Collaboration revenue related to sales in profit-share territory

The Company and KKC share commercial responsibilities and profits in the profit-share territory until April 2023. Under the collaboration agreement, KKC manufactures and supplies Crysvita for commercial use in the profit-share territory and charges the Company the transfer price of 35% of net sales through December 31, 2022, and 30% thereafter. The remaining profit or loss after supply costs from commercializing products in the profit-share territory are shared between the Company and KKC on a 50/50 basis until April 2023. Thereafter, the Company will be entitled to receive a tiered double-digit revenue share in the mid-to-high 20% range.

As KKC is the principal in the sale transaction with the customer, the Company recognizes a pro-rata share of collaboration revenue, net of transfer pricing, in the period the sale occurs. The Company concluded that its portion of KKC’s sales in the profit-share territory is analogous to a royalty and therefore recorded its share as collaboration revenue, similar to a royalty.

Royalty revenue related to sales in European territory

KKC has the commercial responsibility for Crysvita in the European territory. In December 2019, the Company sold its right to receive royalty payments based on sales in the European territory to Royalty Pharma, effective January 1, 2020, as further described in Note 7. Prior to the Company’s sale of the royalty, the Company received a royalty of up to 10% on net sales in the European territory, which was recognized as the underlying sales occur. Beginning in 2020, the Company recorded the royalty revenue as non-cash royalty revenues.

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The Company’s share of collaboration and royalty revenue related to Crysvita was as follows (in thousands):

	Three Months Ended March 31,
	2022		2021
Company's share of revenue in profit-     share territory	$	45,164	$	36,260
Non-cash royalty revenue in European     territory		4,838		3,872
Total	$	50,002	$	40,132

Product revenue related to sales in other territories

The Company is responsible for commercializing Crysvita in Latin America and Turkey. The Company is considered the principal in these territories as the Company controls the product before it is transferred to the customer. Accordingly, the Company records revenue on a gross basis related to the sale of Crysvita once the product is delivered and the risk and title of the product is transferred to the distributor. The Company recorded product sales of $9.4 million and $5.9 million for the three months ended March 31, 2022 and 2021, respectively, net of estimated product returns and other deductions. KKC has the option to assume responsibility for commercialization efforts in Turkey from the Company, after a certain minimum period.

Under the collaboration agreement, KKC manufactures and supplies Crysvita, which is purchased by the Company for sales in its territories and is based on 35% of the net sales through December 31, 2022 and 30% thereafter. The Company also pays to KKC a low single-digit royalty on net sales in Latin America.

Cost sharing payments

Under the collaboration agreement, KKC and the Company share certain development and commercialization costs. As a result, the Company was reimbursed for these costs and operating expenses were reduced as follows (in thousands):

	Three Months Ended March 31,
	2022		2021
Research and development	$	4,619	$	6,185
Selling, general and administrative		9,196		7,495
Total	$	13,815	$	13,680

Collaboration receivable and payable

The Company had accounts receivable from KKC in the amount of $17.4 million and $20.2 million from profit-share revenue and royalties and other receivables recorded in prepaid expenses and other current assets of $3.8 million and $16.0 million and accrued liabilities of $4.2 million and $2.3 million from commercial and development activity reimbursements, as of March 31, 2022 and December 31, 2021, respectively.

GeneTx

In August 2019, the Company entered into a Program Agreement and a Unitholder Option Agreement with GeneTx to collaborate on the development of GeneTx’s GTX-102, an ASO for the treatment of Angelman syndrome.

Pursuant to the terms of the Unitholder Option Agreement, the Company made an upfront payment of $20.0 million for an exclusive option to acquire GeneTx, which was exercisable any time prior to 30 days following FDA acceptance of the IND for GTX-102. Pursuant to the agreement, upon acceptance of the IND, which occurred in January 2020, the Company elected to extend the option period by paying an option extension payment of $25.0 million (option extension premium) during the quarter ended March 31, 2020, which was recorded as an in-process research and development expense. In April 2022, the parties entered into an amendment to the Unitholder Option Agreement (the “Amendment”) which provides the Company with an additional, earlier option to acquire GeneTx for a payment of $75.0 million based on the earlier of receipt of interim data in the Phase 1/2 study or a specified date (such option, the “Interim Option”). After such date, the Company has the right to acquire GeneTx for a payment of $125.0 million until the earlier of 30 months from the first dosing of a patient in the Phase 1/2 study (subject to extensions) or 90 days after results are available from that study. This exclusive option to acquire GeneTx can be extended under certain circumstances by one additional three month period, by paying an additional extension fee. Pursuant to the Amendment, in the event the Company acquires GeneTx by exercising the Interim Option, the Company will be required to make a milestone payment to GeneTx in an amount up to $30.0 million upon achievement of the earlier of a Phase 3 clinical study start and product approvals in Canada and the U.K.

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During the exclusive option period, GeneTx is responsible for conducting the program based on the development plan agreed between the parties and, subject to the terms in the Program Agreement, has the decision-making authority on all matters in connection with the research, development, manufacturing and regulatory activities with respect to the Program. The Company will provide support, at its discretion, including strategic guidance and clinical expertise. The Company and GeneTx will collaborate on the management of the Phase 1/2 study in patients with Angelman syndrome. If the Company acquires GeneTx, the Company would then be responsible for all development and commercialization activities from the date of acquisition. The Company would also be required to make payments upon achievement of certain development and commercial milestones, as well as royalties, depending upon the success of the program.
 

Daiichi Sankyo

In March 2020, the Company executed a License and Technology Access Agreement (the License Agreement) with Daiichi Sankyo Co., Ltd. (Daiichi Sankyo). Pursuant to the License Agreement, the Company granted Daiichi Sankyo a non-exclusive license to intellectual property, including know-how and patent applications, with respect to its Pinnacle PCLTM producer cell line platform (Pinnacle PCL Platform), and HEK293 transient transfection manufacturing technology platforms for AAV-based gene therapy products.

Under the terms of the License Agreement, Daiichi Sankyo made an upfront payment of $125.0 million and an additional $25.0 million upon completion of the technology transfer of the Pinnacle PCL Platform and HEK293 platform. Daiichi Sankyo reimbursed the Company for all costs associated with the transfer of the manufacturing technology and will pay single-digit royalties on net sales of products manufactured in either system.

The Company also entered into a Stock Purchase Agreement (SPA) with Daiichi Sankyo, pursuant to which Daiichi Sankyo purchased 1,243,913 shares of the Company’s common stock in exchange for $75.0 million in cash during the first quarter of 2020. The fair market value of the common stock issued to Daiichi Sankyo was $55.3 million based on the stock price of $44.43 per share on the date of issuance, resulting in a $19.7 million premium on the SPA. Daiichi Sankyo is also subject to a three-year standstill and restrictions on sale of the shares (subject to customary exceptions or release).

In June 2020, the Company executed a subsequent license agreement (the Sublicense Agreement) with Daiichi Sankyo for transfer of certain technology in consideration for an upfront payment of $8.0 million and annual maintenance fees, milestone payments, and royalties on any net sales of products incorporating the licensed intellectual property.

The License Agreement, the Sublicense Agreement, and the SPA are being accounted for as one arrangement because they were entered into at or near the same time and negotiated in contemplation of one another. The Company evaluated the License Agreement and the Sublicense Agreement under ASC 606 and determined that the performance obligations under the agreements are (i) intellectual property with respect to its Pinnacle PCL Platform and HEK293 transient transfection manufacturing technology platform together with the initial technical assistance and technology transfer services, which was completed in the first quarter of 2022, and (ii) the transfer of any know-how and improvements after the completion of the initial technology transfer through the end of the three year technology transfer period ending March 2023.

As of March 31, 2022, the Company has determined that the total transaction price of the License Agreement was $183.3 million which was comprised of the $19.7 million premium from the SPA, the $125.0 million upfront payment, the $25.0 million in unconstrained milestone payments, $8.0 million from the Sublicense Agreement, and the $5.6 million estimated reimbursement amount for delivering the license and technology services. Total revenue recognized under the license agreement through March 31, 2022 was $177.5 million.

The Company allocated the total transaction price to the two performance obligations on a relative stand-alone selling price basis. Revenue allocated to the intellectual property and the technology transfer services was recognized over an initial period which was completed during the first quarter of 2022, measuring the progress toward complete satisfaction of the individual performance obligation using an input measure. Revenue for know-how and improvements after the completion of technology transfer is being recognized on a straight-line basis over the remaining technology transfer period, which ends in March 2023, as it is expected that Daiichi Sankyo will receive and consume the benefits consistently throughout the period. Royalties from commercial sales will be accounted for as revenue upon achievement of such sales, assuming all other revenue recognition criteria are met.

The Company recognized $3.2 million and $42.8 million for the three months ended March 31, 2022 and 2021, respectively, in revenue related to this arrangement. Accordingly, the Company had recorded $5.9 and $9.1 million of contract liabilities, net, as of March 31, 2022 and December 31, 2021, respectively. The Company recorded an accounts receivable related to the above agreements of nil and $0.1 million as of March 31, 2022 and December 31, 2021, respectively.

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Mereo BioPharma 3 Limited

In December 2020, the Company entered into a License and Collaboration Agreement with Mereo BioPharma 3 Limited, or Mereo, to collaborate on the development of setrusumab. Under the terms of the agreement, the Company will lead future global development of setrusumab in both pediatric and adult patients with Osteogenesis Imperfecta, or OI. The Company was granted an exclusive license to develop and commercialize setrusumab in the U.S., Turkey, and the rest of the world, excluding the European Economic Area, United Kingdom, and Switzerland, or the Mereo territory, where Mereo retains commercial rights. Each party will be responsible for post-marketing commitments and commercial supply in their respective territories.

Upon the closing of the transaction in January 2021, the Company made a payment of $50.0 million to Mereo and will be required to make payments of up to $254.0 million upon the achievement of certain clinical, regulatory, and commercial milestones. The Company will pay for all global development costs as well as tiered double-digit percentage royalties to Mereo on net sales in the U.S., Turkey, and the rest of the world (excluding the Mereo Territory), and Mereo will pay the Company a fixed double-digit percentage royalty on net sales in the Mereo Territory.

Although Mereo is a variable interest entity, the Company is not the primary beneficiary as it does not have the power to direct the activities that would most significantly impact the economic performance of Mereo. Prior to the achievement of certain development milestones, all consideration paid to Mereo represents rights to potential future benefits associated with Mereo’s in-process research and development activities, which have not reached technological feasibility and have no alternative future use. Accordingly, for the three months ended March 31, 2021, the Company recorded the upfront payment of $50.0 million as in-process research and development expense.

Regeneron Pharmaceuticals, Inc.

In January 2022, the Company announced a collaboration with Regeneron Pharmaceuticals, Inc., or Regeneron, to commercialize Evkeeza for HoFH outside of the U.S. Evkeeza is approved in the U.S., where it is marketed by Regeneron and in the European Economic Area, or EEA, as a first-in-class therapy for use together with diet and other low-density lipoprotein-cholesterol- lowering therapies to treat adults and adolescents aged 12 years and older with HoFH. Pursuant to the terms of the agreement, the Company received the rights to develop, commercialize and distribute the product for HoFH in countries outside of the U.S. The Company will share in certain costs for global trials led by Regeneron and also have the right to opt into other potential indications. The Company may be obligated to pay up to $63.0 million in future milestone payments, contingent upon the achievement of certain regulatory and sales milestones.

The collaboration agreement is within the scope of ASC 808 which provides guidance on the presentation and disclosure of collaborative arrangements. As the Company would be the principal in future sale transactions with the customer, the Company will recognize product sales and cost of sales in the period the related sale occurs and the related revenue recognition criteria are met. Under the collaboration agreement, Regeneron will supply the product and will charge the Company a transfer price from the low 20% range up to 40% on net sales, which will be recognized as cost of sales in the Company's Statement of Operations.

Upon the closing of the transaction in January 2022, the Company paid Regeneron a $30.0 million upfront payment. As the upfront payment was related to the Company's usage of intellectual property related to Evkeeza for HoFH, the upfront payment was recorded on the Consolidated Balance Sheet as an intangible asset, which is being amortized over its useful life of 10.5 years.

The Company recorded costs of goods sold of $0.7 million for the three months ended March 31, 2022, related to the amortization of the intangible asset. Further, the Company reimbursed Regeneron for certain development costs of $0.6 million for the three months ended March 31, 2022. No sales of Evkeeza were recorded for the three months ended March 31, 2022.

Other Arrangements

The Company has also entered into several collaborations and/or licensing arrangements in prior periods. Except as disclosed above, there have not been material changes in these arrangements as disclosed in Note 7 to the Consolidated Financial Statements in the Annual Report.

Under the financial terms of these arrangements, the Company may be required to make payments upon achievement of developmental, regulatory, and commercial milestones, which could be significant. Future milestone payments, if any, will be reflected in the Condensed Consolidated Statements of Operations upon the occurrence of the contingent event. In addition, the Company may be required to pay royalties on future sales if products related to these arrangements are commercialized. The payment of these amounts, however, is contingent upon the occurrence of various future events, which have a high degree of uncertainty of occurrence.

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As described in the Annual Report, in connection with the Company’s collaborations with Solid Biosciences, Inc. (Solid) and Arcturus Therapeutic Holding, Inc. (Arcturus), the Company holds certain equity interests in each entity. The changes in the fair value of the Company’s equity investments in the common stock of Solid and Arcturus were as follows (in thousands ):

 

	Common stock
As of December 31, 2020		154,756
Change in fair value		(42,713	)
Sale of shares		(79,843	)
December 31, 2021		32,200
Change in fair value		(9,329	)
March 31, 2022	$	22,871

7. Liability Related to the Sale of Future Royalties

In December 2019, the Company entered into a Royalty Purchase Agreement with RPI. Pursuant to the agreement, RPI paid $320.0 million to the Company in consideration for the right to receive royalty payments effective January 1, 2020, arising from the net sales of Crysvita in the European Union, the United Kingdom, and Switzerland under the terms of the Company’s Collaboration and License Agreement with KKC dated August 29, 2013, as amended. The agreement with RPI will automatically terminate, and the payment of royalties to RPI will cease, in the event aggregate royalty payments received by RPI are equal to or greater than $608.0 million prior to December 31, 2030, or in the event aggregate royalty payments received by RPI are less than $608.0 million prior to December 31, 2030, when aggregate royalty payments received by RPI are equal to $800.0 million.

Proceeds from the transaction were recorded as a liability (liability related to sale of future royalties on the Consolidated Balance Sheets). The Company amortizes $320.0 million, net of transaction cost of $5.8 million, using the effective interest method over the estimated life of the arrangement. In order to determine the amortization of the liability, the Company is required to estimate the total amount of future royalty payments to be received by the Company and paid to RPI, subject to the capped amount, over the life of the arrangement. The excess of future estimated royalty payments (subject to the capped amount), over the $314.2 million of net proceeds, is recorded as non-cash interest expense over the life of the arrangement. Consequently, the Company estimates an imputed interest on the unamortized portion of the liability and records interest expense relating to the transaction. The Company records the royalty revenue arising from the net sales of Crysvita in the applicable European territories as non-cash royalty revenue in the Consolidated Statements of Operations over the term of the arrangement.

The Company periodically assesses the expected royalty payments using a combination of historical results, internal projections and forecasts from external sources. To the extent such payments are greater or less than the Company’s initial estimates or the timing of such payments is materially different than its original estimates, the Company will prospectively adjust the amortization of the liability and the effective interest rate. The Company's effective annual interest rate was approximately 9.6% as of March 31, 2022.

There are a number of factors that could materially affect the amount and timing of royalty payments from KKC in the applicable European territories, most of which are not within the Company’s control. Such factors include, but are not limited to, the success of KKC’s sales and promotion of Crysvita, changing standards of care, delays or disruptions related to the COVID-19 pandemic, the introduction of competing products, pricing for reimbursement in various European territories, manufacturing or other delays, intellectual property matters, adverse events that result in governmental health authority imposed restrictions on the use of Crysvita, significant changes in foreign exchange rates as the royalty payments are made in U.S. dollars (USD) while significant portions of the underlying European sales of Crysvita are made in currencies other than USD, and other events or circumstances that could result in reduced royalty payments from European sales of Crysvita, all of which would result in a reduction of non-cash royalty revenue and the non-cash interest expense over the life of the arrangement. Conversely, if sales of Crysvita in Europe are more than expected, the non-cash royalty revenue and the non-cash interest expense recorded by the Company would be greater over the term of the arrangement.

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The following table shows the activity within the liability account (in thousands):

	Liability related to the sale of future royalties
December 31, 2020	$	335,665
Non-cash collaboration royalty revenue		(17,951	)
Non-cash interest expense		34,072
December 31, 2021		351,786
Non-cash collaboration royalty revenue		(4,838	)
Non-cash interest expense		8,685
March 31, 2022	$	355,633

8. Stock-Based Awards

The 2014 Incentive Plan (the 2014 Plan) provides for automatic annual increases in shares available for grant, beginning on January 1, 2015 through January 1, 2024. As of March 31, 2022, there were 2,008,628 shares reserved under the 2014 Plan for the future issuance of equity awards, 4,698,895 shares reserved for the 2014 Employee Stock Purchase Plan, and 436,063 shares reserved for the Employment Inducement Plan.

The table below sets forth the stock-based compensation expense for the periods presented (in thousands):

	Three Months Ended March 31,
	2022		2021
Cost of sales	$	175	$	379
Research and development		16,907		13,489
Selling, general and administrative		12,305		10,430
Total stock-based compensation expense	$	29,387	$	24,298

9. Net Loss Per Share

Basic net loss per share has been computed by dividing the net loss by the weighted-average number of shares of common stock outstanding during the period. Diluted net loss per share is calculated by dividing net loss by the weighted-average number of shares of common stock and potential dilutive securities outstanding during the period.

The following weighted-average outstanding common stock equivalents were excluded from the computation of diluted net loss per share for the periods presented because including them would have been antidilutive:

	Three Months Ended March 31,
	2022		2021
Options to purchase common stock,     restricted stock units, and performance stock units		9,363,681		8,084,585
Employee stock purchase plan		23,276		33,636
		9,386,957		8,118,221

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10. Equity Transactions

In May 2021, the Company entered into an Open Market Sale Agreement with Jefferies LLC, (Jefferies), pursuant to which the Company may offer and sell shares of the Company’s common stock having an aggregate offering proceeds up to $350.0 million, from time to time, in at-the-market (ATM) offerings through Jefferies. As of March 31, 2022, the Company has sold 1,050,372 shares under the arrangement resulting in net proceeds of approximately $78.9 million. No shares were sold under the arrangement for the three months ended March 31, 2022.

11. Accumulated Other Comprehensive Loss

Total accumulated other comprehensive loss consisted of the following (in thousands):

	March 31,			December 31,
	2022			2021
Foreign currency translation adjustments	$	(181	)	$	(121	)
Unrealized loss on available-for-sale securities		(6,373	)		(1,283	)
Total accumulated other comprehensive loss	$	(6,554	)	$	(1,404	)

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Item 2. Management’s Discussion and Analysis of Financial Condition and Results of Operations

The following discussion and analysis of our financial condition and results of operations should be read in conjunction with the accompanying unaudited Condensed Consolidated Financial Statements and related notes in Item 1 and with the audited Consolidated Financial Statements and the related notes included in our Annual Report on Form 10-K for the year ended December 31, 2021 (“Annual Report”).

Overview

Ultragenyx Pharmaceutical Inc. (we or the Company) is a biopharmaceutical company focused on the identification, acquisition, development, and commercialization of novel products for the treatment of serious rare and ultra-rare genetic diseases. We target diseases for which the unmet medical need is high, the biology for treatment is clear, and for which there are typically no approved therapies treating the underlying disease. Our strategy, which is predicated upon time- and cost-efficient drug development, allows us to pursue multiple programs in parallel with the goal of delivering safe and effective therapies to patients with the utmost urgency.

Impact of COVID-19 Pandemic

Our business operations have been and continue to be affected by the COVID-19 pandemic. In addition to some impact on our preclinical manufacturing activities and certain regulatory interactions, we have experienced interruptions to our clinical trial activities, primarily due to delays or disruptions to patient enrollment and dosing as a result of the diversion of clinic and hospital staff and resources to COVID-19 patients. The continuing outbreak has caused delays in delivery of ancillary clinical trial materials as certain of our third-party manufacturers or suppliers prioritized and allocated more resources and capacity to supply drug product or raw materials to other companies engaged in the study or manufacture of treatments or vaccinations for COVID-19. Staffing shortages and other effects from the pandemic have also made it difficult for us to identify new patients for our commercialized products, which may result in loss of revenue.

As the COVID-19 global pandemic continues, we may experience lower revenue and increased expenses as a result of disruptions to our clinical trial, commercialization and regulatory activities, in addition to delays or shortages of drug product and raw materials. The magnitude and extent to which the pandemic may impact our business operations and operating results will continue to remain highly dependent on future developments, which are very uncertain and cannot be predicted with confidence. As a result, we cannot reliably estimate the extent to which the COVID-19 pandemic will impact our financial statements in 2022 and beyond. See Item 1A: "Risk Factors" for additional details.

Approved Therapies and Clinical Product Candidates

Our current approved therapies and clinical-stage pipeline consist of four product categories: biologics, small molecules, gene therapy, and nucleic acid product candidates. See section entitled “Recent Program Updates” below for a description of recent updates to certain of our approved therapies and clinical-stage pipeline products.

Our biologic products include approved therapies Crysvita® (burosumab), Mepsevii® (vestronidase alfa), and Evkeeza® (evinacumab) and UX143 in clinical development:

•Crysvita is an antibody administered via subcutaneous injection that targets fibroblast growth factor 23 (FGF23), developed for the treatment of XLH, a rare, hereditary, progressive and lifelong musculoskeletal disorder characterized by renal phosphate wasting caused by excess FGF23 production. There are approximately 48,000 patients with XLH in the developed world, including approximately 36,000 adults and 12,000 children. Crysvita is the only approved treatment that addresses the underlying cause of XLH. Crysvita is approved in the U.S. and Canada for the treatment of XLH in adult and pediatric patients six months of age and older. In the European Union, or the EU, and the United Kingdom, Crysvita is approved for the treatment of XLH with radiographic evidence of bone disease in children one year of age and older, adolescents, and adults. In Brazil, Colombia, and Mexico, Crysvita is approved for treatment of XLH in adult and pediatric patients one year of age and older. We have submitted regulatory filings in various other Latin American countries.

Crysvita is also approved in the U.S. and Canada for the treatment of FGF23-related hypophosphatemia in tumor-induced osteomalacia, or TIO, associated with phosphaturic mesenchymal tumors that cannot be curatively resected or localized in adults and pediatric patients 2 years of age and older. TIO can lead to severe hypophosphatemia, osteomalacia, fractures, fatigue, bone and muscle pain, and muscle weakness.

We are collaborating with Kyowa Kirin Co., Ltd., or KKC (formerly Kyowa Hakko Kirin Co., Ltd., or KHK), and Kyowa Kirin, a wholly owned subsidiary of KKC, on the development and commercialization of Crysvita globally.

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•Mepsevii is an intravenous, or IV, enzyme replacement therapy, developed for the treatment of Mucopolysaccharidosis VII, also known as MPS VII or Sly syndrome, a rare lysosomal storage disease that often leads to multi-organ dysfunction, pervasive skeletal disease, and death. MPS VII is one of the rarest MPS disorders, affecting an estimated 200 patients in the developed world. Mepsevii is approved in the U.S. for the treatment of children and adults with MPS VII. In the EU and the United Kingdom, Mepsevii is approved under exceptional circumstances for the treatment of non-neurological manifestations of MPS VII for patients of all ages. In Italy, Mepsevii received reimbursement approval for the treatment of pediatric and adult patients with MPS VII. In Brazil and Mexico, Mepsevii is approved for the treatment of MPS VII for patients of all ages.

•Evkeeza is a fully human monoclonal antibody that binds to and blocks the function of angiopoietin-like 3 (ANGPTL3), a protein that plays a key role in lipid metabolism. Evkeeza is an approved therapy for the treatment of homozygous familial hypercholesterolemia, or HoFH, a rare inherited condition. HoFH occurs when two copies of the familial hypercholesterolemia (FH)-causing genes are inherited, one from each parent, resulting in dangerously high levels (>400 mg/dL) of LDL-C, or bad cholesterol. Patients with HoFH are at risk for premature atherosclerotic disease and cardiac events as early as their teenage years. Evkeeza is approved in the U.S., where it is marketed by our partner Regeneron Pharmaceuticals (Regeneron), and the European Economic Area (EEA) as a first-in-class therapy for use together with diet and other low-density lipoprotein-cholesterol (LDL-C) lowering therapies to treat adults and adolescents aged 12 years and older with HoFH. There are approximately 3,000 to 5,000 patients with HoFH in the Ultragenyx key markets.

•UX143 (setrusumab), which is subject to our collaboration agreement with Mereo Biopharma 3 (Mereo), and the lead clinical asset in our bone endocrinology franchise, is a fully human monoclonal antibody that inhibits sclerostin, a protein that acts on a key bone-signaling pathway by inhibiting the activity of bone-forming cells and promoting bone resorption. Setrusumab is being studied for the treatment of osteogenesis imperfecta (OI) and has received orphan drug designation from the U.S. Food and Drug Administration (FDA) and European Medicines Agency (EMA), rare pediatric disease designation from the FDA, and was accepted into the EMA’s Priority Medicines program (PRIME). There are an estimated 60,000 patients in the developed world affected by OI. A Phase 2/3 study of setrusumab in pediatric and young adult patients with OI was initiated in April 2022 and a separate study is currently being planned for younger children and an extension study for adults with OI.

Our small molecule products include the approved therapy Dojolvi® (triheptanoin):

•Dojolvi is a highly purified, synthetic, 7-carbon fatty acid triglyceride specifically designed to provide medium-chain, odd-carbon fatty acids as an energy source and metabolite replacement for people with long-chain fatty acid oxidation disorders, or LC-FAOD, which is a set of rare metabolic diseases that prevents the conversion of fat into energy and can cause low blood sugar, muscle rupture, and heart and liver disease. Dojolvi is approved and commercially available in the U.S. and Canada as a source of calories and fatty acids for the treatment of pediatric and adult patients with molecularly confirmed LC-FAOD. We have received marketing authorization from the Brazilian Health Regulatory Agency (ANVISA) and are in the process of seeking reimbursement approval. There are approximately 8,000 to 14,000 patients in the developed world with LC-FAOD.

Our clinical-stage gene therapy pipeline includes DTX401, DTX301, DTX201 and UX701:

•DTX401 is an adeno-associated virus 8, or AAV8, gene therapy clinical candidate for the treatment of patients with glycogen storage disease type Ia, or GSDIa, a disease that arises from a defect in G6Pase, an essential enzyme in glycogen and glucose metabolism. GSDIa is the most common genetically inherited glycogen storage disease, with an estimated 6,000 patients in the developed world affected by GSDIa. A Pediatric Investigation Plan, or PIP, was accepted by the EMA. DTX401 has been granted Orphan Drug Designation in both the U.S. and in the EU, and Regenerative Medicine Advanced Therapy (RMAT) designation and Fast Track designation in the U.S. Patients are being enrolled and dosed in the Phase 3 study of DTX401.

•DTX301 is an AAV8 gene therapy product candidate designed for the treatment of patients with ornithine transcarbamylase, or OTC, deficiency. OTC is part of the urea cycle, an enzymatic pathway in the liver that converts excess nitrogen, in the form of ammonia, to urea for excretion. OTC deficiency is the most common urea cycle disorder, and there are approximately 10,000 patients in the developed world with OTC deficiency, of which we estimate approximately 80% are classified as late-onset, our target population. DTX301 has received Orphan Drug Designation in both the U.S. and in the EU and Fast Track Designation in the U.S. Phase 3 study start-up activities are ongoing with the first patients in the U.S. expected to enter a 4-to 8-week baseline screening period in mid-2022, after which they would receive a single dose of DTX301 or placebo.

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•DTX201 is a Factor VIII gene therapy program for the treatment of hemophilia A that is being developed in collaboration with Bayer Healthcare LLC, or Bayer. Hemophilia A is the most common form of hemophilia with approximately 144,000 patients in the developed world. A number of patients across multiple cohorts have been dosed with DTX201.

•UX701 is an AAV type 9 gene therapy product candidate designed to deliver stable expression of a truncated version of the ATP7B copper transporter following a single intravenous infusion to patients with Wilson disease. Wilson disease affects more than 50,000 individuals in the developed world. UX701 was granted Orphan Drug Designation in the U.S. and EU. Patients with Wilson disease are currently being enrolled and dosed in the seamless Phase 1/2/3 study of UX701, the Cyprus2+study.

Our clinical-stage nucleic acid pipeline includes GTX-102 for the treatment of Angelman syndrome, and UX053 for the treatment of GSDIII:

•GTX-102 is an antisense oligonucleotide, or ASO, that is being developed for the treatment of Angelman syndrome, a debilitating and rare neurogenetic disorder caused by loss-of-function of the maternally inherited allele of the UBE3A gene. There are an estimated 60,000 patients in the developed world affected by Angelman syndrome. GTX-102 was granted Fast Track designation, Orphan Drug Designation and Rare Pediatric Disease Designation from the FDA. GTX-102 is being developed in collaboration with GeneTx Biotherapeutics LLC (GeneTx) in an ongoing Phase 1/2 clinical study in the U.S., Canada, and the U.K.

•UX053 is an mRNA product candidate designed for the treatment of patients with GSDIII, a disease caused by a glycogen debranching enzyme (AGL) deficiency that results in glycogen accumulation in the liver and muscle. GSDIII affects more than 10,000 patients in the developed world. UX053 was granted Orphan Drug Designation in the U.S. and EU. The single-dose portion of a Phase 1/2 study of UX053 is ongoing.

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The following table summarizes our approved products and clinical product candidate pipeline:

 

Recent Program Updates

Evkeeza for the treatment of HoFH

In January 2022, we announced a collaboration with Regeneron Pharmaceuticals (Regeneron) to commercialize Evkeeza outside of the U.S. Evkeeza is a fully human monoclonal antibody that binds to and blocks the function of angiopoietin-like 3 (ANGPTL3), a protein that plays a key role in lipid metabolism, and is approved for the treatment of homozygous familial hypercholesterolemia, or HoFH, a rare inherited condition.

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Clinical Product Candidates

DTX401 for the treatment of glycogen storage disease type Ia, or GSDIa

We are enrolling and dosing patients in the Phase 3 study of DTX401. The Phase 3 study has a 48-week primary efficacy analysis period and we plan to enroll approximately 50 patients eight years of age and older, randomized 1:1 to DTX401 (1.0 x 10^13 GC/kg dose) or placebo. The primary endpoint is the reduction in oral glucose replacement with cornstarch while maintaining glucose control.

DTX301 for the treatment of ornithine transcarbamylase, or OTC, deficiency

We are currently in the process of initiating a Phase 3 study that will include a 64-week primary efficacy analysis period and plan to enroll approximately 50 patients 12 years of age and older, randomized 1:1 to DTX301 (1.7 x 10^13 GC/kg dose) or placebo. The co-primary endpoints are the percentage of patients who achieve a response as measured by discontinuation or reduction in baseline disease management and the 24-hour plasma ammonia levels. The first patients in the U.S. are expected to enter an approximate 4-to 8-week baseline screening period in mid-2022, after which they are expected to receive a single dose of DTX301 or placebo.

UX701 for the treatment of Wilson Disease

We are enrolling and dosing patients with Wilson disease in the seamless Phase 1/2/3 study of UX701, or the Cyprus2+ study.

During the first stage of the study, the safety and efficacy of up to three dose levels of UX701 will be evaluated over the course of 52 weeks and a dose will be selected for further evaluation in stage 2. In this first stage, 27 patients will be randomized into three cohorts in a 2:1 ratio per cohort to receive UX701 at the dose level assigned for the cohort or a placebo. The sequential doses to be evaluated are 5.0 x 10^12 GC/kg, 1.0 x 10^13 GC/kg, and 2.0 x 10^13 GC/kg. In stage 2, a new cohort of patients will be randomized 2:1 to receive the selected dose of UX701 or placebo. The primary safety and efficacy analyses will be conducted at Week 52 of stage 2. The primary efficacy endpoints are change in 24-hour urinary copper concentration and percent reduction in standard of care medication by Week 52. After the initial 52-week study period, all patients will receive long term follow up in stage 3. Patients randomized to placebo in stages 1 and 2 will become eligible to receive UX701 in stage 3.

UX143 (setrusumab) for the treatment of Osteogenesis Imperfecta (OI), in collaboration with Mereo BioPharma 3 Limited, or Mereo

We are dosing patients in a pediatric and young adult Phase 2/3 study. The objective of the Phase 2/3 study will first focus on determining the optimal dose based on increases in collagen production using serum P1NP levels and an acceptable safety profile. Following determination of the dose, we currently intend to adapt the study into a pivotal Phase 3 stage, evaluating fracture reduction over an estimated 15 to 24 months as the primary endpoint, subject to regulatory review. We currently expect a separate Phase 2 study of patients under age five with OI to start in the second half of 2022. We will also continue to evaluate adult patients who were previously treated in the Phase 2b ASTEROID study that was conducted by Mereo.

GTX-102 for the treatment of Angelman Syndrome, partnered with GeneTx

In January 2022, we provided an initial update on the first four patients treated in Canada and the U.K. under the amended protocol for the phase 1/2 study of GTX-102. As of the update, all four patients had received multiple doses of GTX-102 with no treatment-related serious adverse events of any type nor adverse events related to lower extremity weakness. As of January 2022, three patients had received a preliminary assessment of clinical response and all have shown early signs of clinical activity. The data safety monitoring board (DSMB) for Cohort 4 recommended dose escalation for the first two patients and enrollment of the additional four patients in this cohort. Later in January 2022, the DSMB for Cohort 5 met and also recommended dose escalation and expansion of that cohort.

As of February 14, 2022, patients naïve to prior treatment with GTX-102 have been screened in the U.S. and dosing has begun.

We plan to provide an additional update on patients in Cohorts 4 and 5 in Canada and the U.K. in mid-2022.

UX053 for the treatment of glycogen storage disease type III, or GSDIII

We are dosing patients in a Phase 1/2 study of UX053 for the treatment of GSDIII. Part 1 of the study is open label with single-ascending doses. Part 2 is double-blind and will evaluate repeat doses at escalating levels. We currently expect preliminary data from Part 1 of the study and to initiate Part 2 of the study in the second half of 2022.

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Other Development

In April 2022, we announced the appointment of Amrit Ray, M.D., M.B.A. to the company’s Board of Directors, effective April 19, 2022. Dr. Ray currently serves as Chief Patient Officer at Biohaven Pharmaceuticals. He is also currently a member of the board of directors of CorEvitas, LLC and a member of the board of directors at EveryLife Foundation for Rare Diseases.

Financial Operations Overview

We are a biopharmaceutical company with a limited operating history. To date, we have invested substantially all of our efforts and financial resources in identifying, acquiring, and developing our products and product candidates, including conducting clinical studies and providing selling, general and administrative support for these operations. To date, we have funded our operations primarily from the sale of our equity securities, revenues from our commercial products, the sale of certain future royalties, and strategic collaboration arrangements.

We have incurred net losses in each year since inception. Our net loss was $152.3 million and $136.1 for the three months ended March 31, 2022 and 2021, respectively. Net loss for the three months ended March 31, 2022 and 2021 included losses of $9.3 million and $20.6 million, respectively, resulting from changes in fair value of our investments in Arcturus Therapeutics Holdings Inc. (Arcturus) and Solid Biosciences Inc. (Solid) equity securities. Other than changes in the fair value of our investments, substantially all of our net losses have resulted from costs incurred in connection with our research and development programs and from selling, general and administrative costs associated with our operations.

For the three months ended March 31, 2022 our total revenues were $79.9 million, compared to $99.4 million for the same period in 2021. Revenue for the three months ended March 31, 2022 included $3.2 million from our collaboration and license agreement with Daiichi Sankyo Co., Ltd. (Daiichi Sankyo), as compared to $42.8 million for the same period in 2021. The decrease in collaboration revenue with Daiichi Sankyo was partially offset by higher revenue from Crysvita collaboration revenue in the profit-share territory, an increase in revenue for our approved products, and an increase in collaboration royalty revenue.

As of March 31, 2022, we had $813.8 million in available cash, cash equivalents, and marketable debt securities.

Critical Accounting Estimates

Our management’s discussion and analysis of our financial condition and results of operations is based on our Condensed Consolidated Financial Statements, which have been prepared in accordance with U.S. generally accepted accounting principles, or GAAP. The preparation of these Condensed Consolidated Financial Statements requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements, as well as the reported expenses incurred during the reporting periods. Our estimates are based on our historical experience and on various other factors that we believe are reasonable under the circumstances, the results of which form the basis for making judgments about the carrying value of assets and liabilities that are not readily apparent from other sources. Actual results may differ from these estimates under different assumptions or conditions. There have been no material changes in our critical accounting policies during the three months ended March 31, 2022, as compared to those disclosed in “Management’s Discussion and Analysis of Financial Condition and Results of Operations — Critical Accounting Policies and Significant Judgments and Estimates” in our Annual Report.

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Results of Operations

Comparison of the three months ended March 31, 2022 to the three months ended March 31, 2021:

Revenue (dollars in thousands)

	Three Months Ended March 31,				Dollar			%
	2022		2021		Change			Change
Collaboration and license revenue:
Crysvita collaboration revenue in profit-share     territory	$	45,164	$	36,260	$	8,904			25	%
Daiichi Sankyo		3,249		42,750		(39,501	)		-92	%
Total collaboration and license revenue		48,413		79,010		(30,597	)		-39	%
Product sales:
Crysvita		9,394		5,872		3,522			60	%
Mepsevii		4,861		3,607		1,254			35	%
Dojolvi		12,429		7,034		5,395			77	%
Total product sales		26,684		16,513		10,171			62	%
Crysvita non-cash collaboration royalty revenue		4,838		3,872		966			25	%
Total revenues	$	79,935	$	99,395	$	(19,460	)		-20	%

For the three months ended March 31, 2022, our share of Crysvita collaboration revenue in the profit-share territory increased by $8.9 million, as compared to the same period in 2021. The increase primarily reflects the continuing increase in demand for Crysvita due to an increase in the number of patients on therapy.

In March 2020, we executed a license agreement with Daiichi Sankyo. For the three months ended March 31, 2022, the collaboration and license revenue from this arrangement decreased by $39.5 million, as compared to the same period in 2021. The decrease in the three months period ended March 31, 2022 was related to the relative progress toward complete satisfaction of the individual performance obligation using an input measure of the technology transfer period, which was completed as of March 31, 2022.

The increase in product sales of $10.2 million for the three months ended March 31, 2022, compared to the same period in 2021 was primarily due to continued momentum from the commercial launch of Dojolvi in the U.S., continuing increase in demand for our other approved products, and an increase in sales of our products under our named patient program in certain countries.

The increase in Crysvita non-cash collaboration royalty revenue of $1.0 million for the three months ended March 31, 2022, compared to the same period in 2021 primarily reflects the launch progress by our collaboration partner in European countries and an increase in the number of patients on therapy.

Cost of Sales (dollars in thousands)

	Three Months Ended March 31,				Dollar		%
	2022		2021		Change		Change
Cost of sales	$	6,100	$	5,188	$	912		18	%

Cost of sales increased by $0.9 million for the three months ended March 31, 2022, compared to the same period in 2021. The increase was due to increased demand for our approved products, and amortization of the intangible asset related to our license from Regeneron for Evkeeza. This was offset by lower reserves for excess inventory write-downs with $0.1 million recorded for the three months ended March 31, 2022, compared to $1.7 million recorded for the same period in 2021.

Research and Development Expenses (dollars in thousands)

Research and development expenses include internal and external costs incurred for research and development of our programs and program candidates and expenses related to certain technology that we acquire or license through business development transactions. These expenses consist primarily of clinical studies performed by contract research organizations, manufacturing of drug substance and drug product performed by contract manufacturing organizations, materials and supplies, fees from collaborative and other arrangements including milestones, licenses and other fees, personnel costs including salaries, benefits and stock-based compensation, and overhead allocations consisting of various support and infrastructure costs.

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Commercial programs include costs for disease monitoring programs and certain regulatory and medical affairs support activities for programs after commercial approval. Clinical programs include study conduct and manufacturing costs related to clinical program candidates. Translational research includes costs for preclinical study work and costs related to preclinical programs prior to IND filing. Upfront license and milestone fees include any significant expenses related to strategic licensing agreements. Infrastructure costs include direct costs related to laboratory, IT, and equipment depreciation costs, and overhead allocations for human resources, IT and other allocable costs.

The following table provides a breakout of our research and development expenses by major program type and business activities:

	Three Months Ended March 31,				Dollar			%
	2022		2021		Change			Change
Commercial programs	$	13,064	$	13,661	$	(597	)		-4	%
Clinical programs:
Gene therapy programs		40,280		21,362		18,918			89	%
Nucleic acid and other biologic         programs		20,474		9,024		11,450			127	%
Translational research		20,327		12,613		7,714			61	%
Upfront license and milestone fees		—		50,000		(50,000	)		-100	%
Infrastructure		16,384		14,862		1,522			10	%
Stock-based compensation		16,907		13,489		3,418			25	%
Other research and development		15,719		12,507		3,212			26	%
Total research and development expenses	$	143,155	$	147,518	$	(4,363	)		-3	%

Total research and development expenses decreased $4.4 million for the three months ended March 31, 2022, compared to the same period in 2021. The change in research and development expenses was primarily due to:

•for commercial programs, a decrease of $0.6 million for the three months ended March 31, 2022, primarily related to reduced R&D personnel allocations to commercial programs;

•for gene therapy programs, an increase of $18.9 million for the three months ended March 31, 2022, primarily related to increases in clinical manufacturing expenses for DTX401 and DTX301;

•for nucleic acid and other biologic programs, an increase of $11.5 million for the three months ended March 31, 2022, primarily related to the addition of expenses related to UX053, following its IND approval in March 2021, and UX143 as we entered into a License and Collaboration Agreement with Mereo BioPharma 3 Limited, or Mereo, to collaborate on the development of UX143 effective January 2021. The increase was partially offset by the classification of expenses for the TIO indication for Crysvita to commercial programs for the three months ended March 31, 2022;

•for translational research, an increase of $7.7 million for the three months ended March 31, 2022, primarily related to IND-enabling development costs for multiple research projects;

•for upfront license and milestone fees, a decrease of $50.0 million for the three months ended March 31, 2022 due to no fees incurred for the three months ended March 31, 2022, as compared to the $50.0 million upfront fee recognized for the Mereo license for the three months ended March 31, 2021;

•for infrastructure, an increase of $1.5 million for the three months ended March 31, 2022, primarily related to increased expenses for support of our clinical and research program pipeline, expansion of laboratory space, implementation of COVID-related policies and safety protocols, depreciation of laboratory-related leasehold improvements and equipment, and IT-related expenses;

•for stock-based compensation, an increase of $3.4 million for the three months ended March 31, 2022, primarily related to an increase in employee headcount; and

•for other research and development expenses, an increase of $3.2 million for the three months ended March 31, 2022, primarily related to increased staffing to support internal manufacturing, increased travel, and increased administrative and general support.

We expect our annual research and development expenses to continue to increase in the future as we advance our product candidates through clinical development. The timing and amount of expenses incurred will depend largely upon the outcomes of current or future clinical studies for our product candidates as well as the related regulatory requirements, manufacturing costs, and any costs associated with the advancement of our preclinical programs.

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Selling, General and Administrative Expenses (dollars in thousands)

	Three Months Ended March 31,				Dollar		%
	2022		2021		Change		Change
Selling, general and administrative	$	67,312	$	53,258	$	14,054		26	%

Selling, general and administrative expenses increased by $14.1 million for the three months ended March 31, 2022, compared to the same period in 2021. The increases in selling, general and administrative expenses were primarily due to increases in personnel costs resulting from an increase in the number of employees in support of our commercial activities, commercialization costs, and professional services costs.

We expect selling, general and administrative expenses to continue to increase in the future to support our organizational growth related to our approved products and multiple clinical-stage product candidates.

Interest Income (dollars in thousands)

	Three Months Ended March 31,				Dollar			%
	2022		2021		Change			Change
Interest income	$	494	$	639	$	(145	)		-23	%

Interest income decreased by $0.1 million for the three months ended March 31, 2022, compared to the same periods in 2021, primarily due to lower average balances in our marketable debt securities.

Change in Fair Value of Equity Investments (dollars in thousands)

	Three Months Ended March 31,						Dollar		%
	2022			2021			Change		Change
Change in fair value of equity investments	$	(9,329	)	$	(20,619	)	$	11,290		-55	%

For the three months ended March 31, 2022, we recorded a net decrease in the fair value of our equity investments of $9.3 million. The fair value of our equity investments in Arcturus and Solid decreased by $5.0 million and $4.3 million, respectively during the period.

For the three months ended March 31, 2021, we recorded a net decrease in the fair value of our equity investments of $20.6 million. The fair value of our equity investments in Arcturus and Solid decreased by $4.6 million and $16.0 million, respectively, during the period.

Given the historic volatility of the publicly traded stock price of Arcturus and Solid, the fair value adjustments of our equity investments may be subject to wide fluctuations which may have a significant impact on our earnings in future periods.

Non-cash Interest Expense on Liability Related to the Sale of Future Royalties (dollars in thousands)

	Three Months Ended March 31,						Dollar		%
	2022			2021			Change		Change
Non-cash interest expense on liability related to the     sale of future royalties	$	(6,584	)	$	(8,418	)	$	1,834		-22	%

The non-cash interest expense on liability related to the sale of future royalties decreased by $1.8 million for the three months ended March 31, 2022, compared to the same periods in 2021 due to the capitalization of interest related to the construction-in-progress for the gene therapy manufacturing plant, slightly offset by the increase in the liability related to the sale of future royalties for net sales of Crysvita in the European territory. To the extent the royalty payments are greater or less than our initial estimates or the timing of such payments is materially different than our original estimates, we will prospectively adjust the effective interest rate.

Other Income (Expense) (dollars in thousands)

	Three Months Ended March 31,					Dollar		%
	2022		2021			Change		Change
Other income (expense)	$	289	$	(795	)	$	1,084		-136	%

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Other income increased by $1.1 million for the three months ended March 31, 2022, compared to the same period in 2021. The increase was primarily due to fluctuations in foreign exchange rates.

Provision for Income Taxes (dollars in thousands)

	Three Months Ended March 31,						Dollar			%
	2022			2021			Change			Change
Provision for income taxes	$	(558	)	$	(379	)	$	(179	)		47	%

The provision for incomes taxes increased by a nominal amount for the three months ended March 31, 2022, compared to the same period in 2021.

Liquidity and Capital Resources

To date, we have funded our operations primarily from the sale of our equity securities, revenues from our commercial products, the sale of certain future royalties, and strategic collaboration arrangements.

As of March 31, 2022, we had $813.8 million in available cash, cash equivalents, and marketable debt securities. We believe that our existing capital resources will be sufficient to fund our projected operating requirements for at least the next twelve months. Our cash, cash equivalents, and marketable debt securities are held in a variety of deposit accounts, interest-bearing accounts, corporate bond securities, commercial paper, U.S government securities, asset-backed securities, debt securities in government-sponsored entities, and money market funds. Cash in excess of immediate requirements is invested with a view toward liquidity and capital preservation, and we seek to minimize the potential effects of concentration and credit risk.

In May 2021, we entered into an Open Market Sale Agreement with Jefferies LLC, (Jefferies), pursuant to which we may offer and sell shares of our common stock having an aggregate offering proceeds up to $350.0 million, from time to time, in at-the-market (ATM) offerings through Jefferies. As of March 31, 2022, net proceeds from shares sold under the arrangement were approximately $78.9 million. No shares were sold under this arrangement for the three months ended March 31, 2022.

The following table summarizes our cash flows for the periods indicated (in thousands):

	Three Months Ended March 31,
	2022			2021
Cash used in operating activities	$	(117,521	)	$	(159,346	)
Cash used in investing activities		(37,362	)		(182,424	)
Cash provided by financing activities		1,612			12,649
Effect of exchange rate changes on cash		(108	)		(771	)
Net decrease in cash, cash equivalents and restricted cash	$	(153,379	)	$	(329,892	)

Cash Used in Operating Activities

Our primary use of cash is to fund operating expenses, which consist primarily of research and development and commercial expenditures. Due to our significant research and development expenditures, we have generated significant operating losses since our inception. Cash used to fund operating expenses is affected by the timing of when we pay these expenses, as reflected in the change in our outstanding accounts payable and accrued expenses.

Cash used in operating activities for the three months ended March 31, 2022 was $117.5 million and primarily reflected a net loss of $152.3 million and $4.8 million for non-cash collaboration royalty revenues related to the sale of future royalties to RPI Finance Trust (RPI), an affiliate of Royalty Pharma, offset by non-cash charges of $29.4 million for stock-based compensation, $1.9 million for the amortization of the premium paid on purchased marketable debt securities, $4.1 million for depreciation and amortization, $9.3 million for a change in fair value of equity investments in Arcturus and Solid, and $6.6 million for non-cash interest incurred on the liability related to the sale of future royalties to RPI. Cash used in operating activities also reflected a $1.5 million decrease due to an increase in inventory for Mepsevii, a $16.2 million decrease due to a decrease in accounts payable, accrued liabilities, and other liabilities primarily due to the payout of the 2021 annual bonus, partially offset by an increase in accounts payable and general accrued liabilities related to timing differences, and a decrease of $3.2 million in contract liabilities, net, related to the revenue recognized from the license agreements with Daiichi Sankyo, offset by a $9.1 million increase due to a decrease in prepaid expenses and other assets primarily due to a decrease in receivables due from collaboration partners.

Cash used in operating activities for the three months ended March 31, 2021 was $159.3 million and reflected a net loss of $136.1 million and $3.9 million for non-cash collaboration royalty revenues related to the sale of future royalties to RPI, offset by non-cash charges of $24.3 million for stock-based compensation, $0.9 million for the amortization of the premium paid on purchased marketable debt securities, $3.4 million for depreciation, $20.6 million for a change in fair value of equity investments

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from Arcturus and Solid, and $8.4 million for non-cash interest incurred on the liability related to the sale of future royalties to RPI. Cash used in operating activities also reflected a $2.0 million decrease due to an increase in accounts receivable primarily related to higher revenues, a $10.7 million decrease in prepaid expenses and other assets primarily due to an increase in prepaid manufacturing, insurance, and subscriptions, a $23.6 million decrease in accounts payable, accrued liabilities, and other liabilities primarily due to the payout of 2020 annual bonuses, and a decrease of $41.5 million in contract liabilities, net primarily related to the revenue recognized from the license agreements with Daiichi Sankyo, offset by a $0.5 million increase due to a decrease in inventory.

Cash Used in Investing Activities

Cash used in investing activities for the three months ended March 31, 2022 was $37.4 million and was primarily related to purchases of property, plant, and equipment of $32.2 million, purchases of marketable debt securities of $203.7 million, purchases of mutual funds related to our nonqualified deferred compensation plan of $2.5 million, and the payment to Regeneron for an intangible asset of $30.0 million, offset by proceeds from the sale of marketable debt securities of $39.4 million and maturities of marketable debt securities of $189.0 million.

Cash used in investing activities for the three months ended March 31, 2021 was $182.4 million and related to purchases of property and equipment of $16.4 million and purchases of marketable debt securities of $405.2 million, offset by proceeds from the sale of marketable debt securities of $15.0 million and maturities of marketable debt securities of $224.2 million.

Cash Provided by Financing Activities

Cash provided by financing activities for the three months ended March 31, 2022 was $1.6 million and was primarily comprised of $1.8 million in net proceeds from the issuance of common stock pursuant to equity plan awards.

Cash provided by financing activities for the three months ended March 31, 2021 was $12.6 million and was primarily comprised of $12.8 million in net proceeds from the issuance of common stock pursuant to equity plan awards.

Funding Requirements

We anticipate that, excluding non-recurring items, we will continue to generate annual losses for the foreseeable future as we continue the development of, and seek regulatory approvals for, our product candidates, and continue with commercialization of approved products. We will require additional capital to fund our operations, to complete our ongoing and planned clinical studies, to commercialize our products, to continue investing in early-stage research capabilities to promote our pipeline growth, to continue to acquire or invest in businesses or products that complement or expand our business, and to further develop our general infrastructure, including construction of our GMP gene therapy manufacturing facility, and such funding may not be available to us on acceptable terms or at all.

If we are unable to raise additional capital in sufficient amounts or on terms acceptable to us, we may be required to delay, limit, reduce the scope of, or terminate one or more of our clinical studies, research and development programs, future commercialization efforts, or grant rights to develop and market product candidates that we would otherwise prefer to develop and market ourselves.

Our future funding requirements will depend on many factors, including the following:

•the scope, rate of progress, results and cost of our clinical studies, nonclinical testing, and other related activities;

•the cost of manufacturing clinical supplies, and establishing commercial supplies, of our product candidates, products that we have begun to commercialize, and any products that we may develop in the future, including the construction of our own GMP gene therapy manufacturing plant;

•the number and characteristics of product candidates that we pursue;

•the cost, timing, and outcomes of regulatory approvals;

•the cost and timing of establishing our commercial infrastructure, and distribution capabilities;

•the magnitude and extent to which the COVID-19 pandemic impacts our business operations and operating results, as described in “Management’s Discussion and Analysis of Financial Condition and Results of Operations” and “Risk Factors – Risks Related to Our Business Operations;” and

•the terms and timing of any collaborative, licensing, marketing, distribution, acquisition (including whether and when we exercise our option to acquire GeneTx pursuant to the terms of our Unitholder Option Agreement with them) and other arrangements that we may establish, including any required upfront milestone, royalty, reimbursements or other payments thereunder.

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We expect to satisfy future cash needs through existing capital balances, revenue from our commercial products, and through some combination of public or private equity offerings, debt financings, collaborations, strategic alliances, licensing arrangements, and other marketing and distribution arrangements. Please see “Risk Factors—Risks Related to Our Financial Condition and Capital Requirements.”

Contractual Obligations and Commitments

Material contractual obligations arising in the normal course of business primarily consist of operating and finance leases and manufacturing and service contract obligations.

Manufacturing and service contract obligations primarily relate to manufacturing of inventory for our approved products, the majority of which are due in the next 12 months.

The terms of certain of our licenses, royalties, development and collaboration agreements, as well as other research and development activities, require us to pay potential future milestone payments based on product development success. The amount and timing of such obligations are unknown or uncertain.

There have been no material changes in our contractual obligations and commitments during the three months ended March 31, 2022, as compared to those disclosed in “Management’s Discussion and Analysis of Financial Condition and Results of Operations — Contractual Obligations” in our Annual Report.

Off-Balance Sheet Arrangements

We have not engaged in any off-balance sheet arrangements, as contemplated by the rules and regulations of the SEC.

Item 3. Quantitative and Qualitative Disclosures about Market Risk

Equity Risk

We have exposure to equity risk with respect to the equity investments that we hold in Arcturus and Solid. The carrying value of our equity investments held in Arcturus and Solid were $13.5 million and $9.4 million as of March 31, 2022, respectively, A hypothetical 10 percent decrease in the market price for our equity investments in Arcturus and Solid as of March 31, 2022 would decrease the fair value by $1.4 million and $0.9 million, respectively. Given the historic volatility of the publicly traded stock price of Arcturus and Solid, the fair value of our investments in Arcturus and Solid is subject to wide fluctuations which may have a significant impact on our net income (loss) in future periods.

Interest Rate Risk

Our exposure to market risk for changes in interest rates relates primarily to interest earned on our cash equivalents and marketable debt securities. The primary objective of our investment activities is to preserve our capital to fund operations. A secondary objective is to maximize income from our investments without assuming significant risk. Our investment policy provides for investments in low-risk, investment-grade debt instruments. As of March 31, 2022, we had cash, cash equivalents, and marketable debt securities totaling $813.8 million, compared to $999.1 million as of December 31, 2021, which include bank deposits, money market funds, U.S. government treasury and agency securities, and investment-grade corporate bond securities which are subject to default, changes in credit rating, and changes in market value. The securities in our investment portfolio are classified as available for sale and are subject to interest rate risk and will decrease in value if market interest rates continue to increase. A hypothetical 100 basis point change in interest rates during any of the periods presented would not have had a material impact on the fair market value of our cash equivalents and marketable debt securities as of March 31, 2022 or December 31, 2021. To date, we have not experienced a loss of principal on any of these investments and as of March 31, 2022, we did not record any allowance for credit loss from our investments.

Foreign Currency Risk

We face foreign exchange risk as a result of entering into transactions denominated in currencies other than U.S. dollars. Due to the uncertain timing of expected payments in foreign currencies, we do not utilize any forward exchange contracts. All foreign transactions settle on the applicable spot exchange basis at the time such payments are made. Volatile market conditions arising from the COVID-19 pandemic or global political instability may result in significant changes in exchange rates, and in particular a weakening of foreign currencies relative to the U.S. dollar may negatively affect our revenue and operating income as expressed in U.S. dollars. An adverse movement in foreign exchange rates could have a material effect on payments made to foreign suppliers and for license agreements. For the three months ended March 31, 2022, a majority of our revenue and expense activities and capital expenditures were denominated in U.S. dollars. A hypothetical 10% change in foreign exchange rates during any of the periods presented would not have had a material impact on our Condensed Consolidated Financial Statements.

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Item 4. Controls and Procedures

Evaluation of Disclosure Controls and Procedures

Management carried out an evaluation, under the supervision and with the participation of our Chief Executive Officer and our Chief Financial Officer, of the effectiveness of our “disclosure controls and procedures” as of the end of the period covered by this Quarterly Report, pursuant to Rules 13a-15(b) and 15d-15(b) under the Securities Exchange Act of 1934, or the Exchange Act. In connection with that evaluation, our Chief Executive Officer and our Chief Financial Officer concluded that our disclosure controls and procedures were effective and designed to provide reasonable assurance that the information required to be disclosed is recorded, processed, summarized and reported within the time periods specified in the SEC rules and forms as of March 31, 2022. For the purpose of this review, disclosure controls and procedures means controls and procedures designed to ensure that information required to be disclosed by us in the reports that we file or submit is recorded, processed, summarized and reported within the time periods specified in the SEC’s rules and forms. These disclosure controls and procedures include, without limitation, controls and procedures designed to ensure that information required to be disclosed by us in the reports that we file or submit is accumulated and communicated to management, including our principal executive officer and principal financial officer, as appropriate to allow timely decisions regarding required disclosure. In designing and evaluating the disclosure controls and procedures, our management recognized that any controls and procedures, no matter how well designed and operated, can provide only reasonable assurance of achieving the desired control objectives, and our management necessarily was required to apply its judgment in evaluating the cost-benefit relationship of possible controls and procedures.

Changes in Internal Control over Financial Reporting

There have been no changes in our internal control over financial reporting (as defined in Rules 13a-15(f) and 15d-15(f) under the Exchange Act) during our quarter ended March 31, 2022, that has materially affected, or is reasonably likely to materially affect our internal control over financial reporting.

PART II. OTHER INFORMATION

Item 1. Legal Proceedings

We are not currently a party to any material legal proceedings. We may, however, in the ordinary course of business face various claims brought by third parties or government regulators and we may, from time to time, make claims or take legal actions to assert our rights, including claims relating to our directors, officers, stockholders, intellectual property rights, employment matters and the safety or efficacy of our products. Any of these claims could subject us to costly litigation and, while we generally believe that we have adequate insurance to cover many different types of liabilities, our insurance carriers may deny coverage, may be inadequately capitalized to pay on valid claims, or our policy limits may be inadequate to fully satisfy any damage awards or settlements. If this were to happen, the payment of any such awards could have a material adverse effect on our consolidated operations, cash flows and financial position. Additionally, any such claims, whether or not successful, could damage our reputation and business.

Item 1A. Risk Factors

Investing in our common stock involves a high degree of risk. You should carefully consider the following material risks, together with all the other information in this Quarterly Report, including our financial statements and notes thereto, before deciding to invest in our common stock. The risks and uncertainties described below are not the only ones we face. Additional risk and uncertainties not presently known to us or that we presently deem less significant may also impair our business operations. If any of the following risks actually materialize, our operating results, financial condition, and liquidity could be materially adversely affected. As a result, the trading price of our common stock could decline and you could lose part or all of your investment. Our company’s business, financial condition and operating results can be affected by a number of factors, whether currently known or unknown, including but not limited to those described below, any one or more of which could, directly or indirectly, cause our actual financial condition and operating results to vary materially from past, or from anticipated future, financial condition and operating results. Any of these factors, in whole or in part, could materially and adversely affect our business, prospects, financial condition, operating results and stock price.

Because of the following factors, as well as other factors affecting our financial condition and operating results, past financial performance should not be considered to be a reliable indicator of future performance, and investors should not use historical trends to anticipate results or trends in future periods.

The following description of the risk factors associated with our business includes any material changes to and supersedes the description of the risk factors associated with our business previously disclosed in Part I, Item 1A of the Annual Report.

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Risk Factor Summary

•We have a history of operating losses and anticipate that we will continue to incur losses for the foreseeable future.

•We have limited experience in generating revenue from product sales.

•We expect to need to raise additional capital to fund our activities.

•Clinical drug development is a lengthy, complex, and expensive process with uncertain outcomes.

•If we do not achieve our projected development goals in the time frames we announce and expect, we may experience delays in commercialization of our products and other adverse effects.

•We may experience difficulty in enrolling patients, which could delay or prevent clinical studies of our product candidates.

•The regulatory approval processes of the FDA and comparable foreign authorities are lengthy and inherently unpredictable.

•Our product candidates may cause undesirable or serious side effects that could delay or prevent their regulatory approval or result in other negative consequences.

•We face a multitude of manufacturing risks, particularly with respect to our gene therapy and mRNA product candidates.

•Our products will remain subject to regulatory scrutiny even if we obtain regulatory approval.

•Product liability lawsuits against us could cause us to incur substantial liabilities.

•We may not realize the full commercial potential of our product candidates if we are unable to source and develop effective biomarkers.

•We rely on third parties to conduct our nonclinical and clinical studies and perform other tasks for us.

•We are dependent on KKC for the clinical and commercial supply of Crysvita for all major markets and for the development and commercialization of Crysvita in certain major markets.

•We rely on third parties to manufacture our products and product candidates.

•The loss of, or failure to supply by, any of any of our single-source suppliers for our drug substance and drug product could adversely affect our business.

•The actions of distributors and specialty pharmacies could affect our ability to sell or market products profitably.

•A competitor could misappropriate or disclose our trade secrets.

•Our revenue may be adversely affected if the market opportunities for our products and product candidates are smaller than expected.

•Our competitors may develop therapies that are similar, more advanced, or more effective than ours.

•We may not successfully manage expansion of our company, including building an integrated commercial organization.

•Our exclusive rights to promote Crysvita in the U.S. and Canada will transition back to KKC.

•Commercial success of our products depends on the degree of market acceptance by physicians, patients, third-party payors, and others in the medical community.

•We face uncertainty related to insurance coverage and reimbursement status of our newly approved products.

•If we, or our third party partners, are unable to maintain effective proprietary rights for our products or product candidates, we may not be able to compete effectively.

•Claims of intellectual property infringement may prevent or delay our development and commercialization efforts.

•We may not be successful in obtaining or maintaining necessary rights to our product candidates through acquisitions and in-licenses.

•We may face competition from biosimilars of our biologics product and product candidates or from generic versions of our small-molecule product and product candidates, which may result in a material decline in sales of affected products.

•We could lose license rights that are important to our business if we fail to comply with our obligations in the agreements under which we license intellectual property and other rights from third parties.

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•We may become involved in lawsuits to protect or enforce our patents or the patents of our licensors, or be subject to claims that challenge the inventorship or ownership of our patents.

•Changes in U.S. patent law could diminish the value of patents in general, thereby impairing our ability to protect our products.

•We may not be able to protect our intellectual property rights throughout the world.

•The ongoing COVID-19 pandemic has impacted our operations and could materially and adversely affect our business and operating results.

•We have no experience as a company developing or operating a manufacturing facility.

•Our success depends in part on our ability to retain our President and Chief Executive Officer and other qualified personnel.

•Our revenue may be impacted if we fail to obtain or maintain orphan drug exclusivity for our products.

•Our operating results may be adversely impacted if our intangible assets become impaired.

•We may not be successful in identifying, licensing, developing, or commercializing additional product candidates, or we may fail to capitalize on opportunities that may be more profitable.

•We may fail to comply with laws and regulations or changes in laws and regulations could adversely affect our business.

•We are exposed to risks related to international expansion of our business outside of the U.S.

•Our business may be adversely affected in the event of computer system failures or security breaches.

•We or our third party partners may be adversely affected by earthquakes or other serious natural disasters that are not adequately protected by business continuity and disaster recovery plans.

•We may incur various costs and expenses and risks related to acquisition of companies or products or strategic transactions.

•The market price of our common stock is highly volatile.

•Future sales and issuances of our common stock could dilute the percentage ownership of our current stockholders and result in a decline in stock price.

•We do not intend to pay dividends on our common stock so any returns will be limited to the value of our stock.

•Provisions in our amended and restated certificate of incorporation and by-laws, as well as provisions of Delaware law, could make it more difficult for a third-party to acquire us or increase the cost of acquiring us or could limit our stockholders’ ability to obtain a favorable judicial forum for disputes with us or our directors, officers or employees.

•We face general risks related to our ability to maintain effective internal controls over financial reporting, additional tax liabilities related to our operations, our ability to use our net operating loss carryforwards and costs of litigation

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Risks Related to Our Financial Condition and Capital Requirements

We have a history of operating losses and anticipate that we will continue to incur losses for the foreseeable future.

We are a biopharmaceutical company with a history of operating losses, and anticipate continuing to incur operating losses for the foreseeable future. Biopharmaceutical product development is a highly speculative undertaking and involves a substantial degree of risk. We have devoted substantially all of our financial resources to identifying, acquiring, and developing our products and product candidates, including conducting clinical studies, developing manufacturing processes, manufacturing product candidates for clinical studies, and providing selling, general and administrative support for these operations. The amount of our future net losses will depend, in part, on non-recurring events, the success of our commercialization efforts, and the rate of our future expenditures. We anticipate that our expenses will increase substantially if and as we:

•continue our research and nonclinical and clinical development of our product candidates;

•expand the scope of our current clinical studies for our product candidates;

•advance our programs into more expensive clinical studies;

•initiate additional nonclinical, clinical, or other studies for our product candidates;

•pursue preclinical and clinical development for additional indications for existing products and product candidates;

•change or add additional manufacturers or suppliers;

•expand upon or build our own manufacturing-related facilities and capabilities, including construction of our own GMP gene therapy manufacturing plant;

•seek regulatory and marketing approvals for our product candidates that successfully complete clinical studies;

•continue to establish Medical Affairs field teams to initiate relevant disease education;

•continue to establish a marketing and distribution infrastructure and field force to commercialize our products and any product candidates for which we may obtain marketing approval;

•continue to manage our international subsidiaries and establish new ones;

•continue to operate as a public company and comply with legal, accounting and other regulatory requirements;

•seek to identify, assess, license, acquire, and/or develop other product candidates, technologies, and/or businesses;

•make milestone or other payments under any license or other agreements;

•seek to maintain, protect, and expand our intellectual property portfolio;

•seek to attract and retain skilled personnel;

•create additional infrastructure, including facilities and systems, to support the growth of our operations, our product development, and our commercialization efforts; and

•experience any delays or encounter issues with any of the above, including, but not limited to, failed studies, complex results, safety issues, inspection outcomes, or other regulatory challenges that require longer follow-up of existing studies, additional major studies, or additional supportive studies in order to pursue marketing approval.

The net losses we incur may fluctuate significantly from quarter to quarter and year to year, such that a period-to-period comparison of our results of operations may not be a good indication of our future performance.

We have limited experience in generating revenue from product sales.

Our ability to generate significant revenue from product sales depends on our ability, alone or with strategic collaboration partners, to successfully commercialize our products and to complete the development of, and obtain the regulatory and marketing approvals necessary to commercialize, our product candidates. Our ability to generate substantial future revenue from product sales, including named patient sales, depends heavily on our success in many areas, including, but not limited to:

•obtaining regulatory and marketing approvals with broad indications for product candidates for which we complete clinical studies;

•developing a sustainable and scalable manufacturing process for our products and any approved product candidates and establishing and maintaining supply and manufacturing relationships with third parties that can conduct the processes and provide adequate (in amount and quality) product supply to support market demand for our products and product candidates, if approved;

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•launching and commercializing our products and product candidates for which we obtain regulatory and marketing approval, either directly or with a collaborator or distributor;

•obtaining market acceptance of our products and product candidates as viable treatment options;

•obtaining adequate market share, reimbursement and pricing for our products and product candidates;

•our ability to sell our products and product candidates on a named patient basis or through an equivalent mechanism and the amount of revenue generated from such sales;

•our ability to find patients so they can be diagnosed and begin receiving treatment;

•addressing any competing technological and market developments;

•negotiating favorable terms, including commercial rights, in any collaboration, licensing, or other arrangements into which we may enter, any amendments thereto or extensions thereof;

•maintaining, protecting, and expanding our portfolio of intellectual property rights, including patents, trade secrets, and know-how; and

•attracting, hiring, and retaining qualified personnel.

If the number of our addressable rare disease patients is not as significant as we estimate, the indication approved by regulatory authorities is narrower than we expect, or the reasonably accepted population for treatment is narrowed by competition, physician choice, or treatment guidelines, or any other reasons, we may not generate significant revenue from sales of our products, even if they receive regulatory approval.

We expect to need to raise additional capital to fund our activities. This additional financing may not be available on acceptable terms, if at all. Failure to obtain this necessary capital when needed may force us to delay, limit, or terminate our product development efforts or other activities.

As of March 31, 2022, our available cash, cash equivalents, and marketable debt securities were $813.8 million. We expect we will need additional capital to continue to commercialize our products, and to develop and obtain regulatory approval for, and to commercialize, all of our product candidates. In addition, our operating plans may change as a result of many factors that may currently be unknown to us, and we may need to seek additional funds sooner than planned. Our future funding requirements will depend on many factors, including but not limited to:

•the scope, rate of progress, results, and cost of our clinical studies, nonclinical testing, and other related activities;

•the cost of manufacturing clinical and commercial supplies of our products and product candidates;

•the cost of creating additional infrastructure, including facilities and systems, such as our GMP gene therapy manufacturing plant;

•the number and characteristics of the product candidates that we pursue;

•the cost, timing, and outcomes of regulatory approvals;

•the cost and timing of establishing and operating our international subsidiaries;

•the cost and timing of establishing and operating field forces, marketing, and distribution capabilities;

•the cost and timing of other activities needed to commercialize our products; and

•the terms and timing of any collaborative, licensing, acquisition (including whether we exercise our option to acquire GeneTx pursuant to the terms of our Unitholder Option Agreement with them), and other arrangements that we may establish, including any required milestone, royalty, and reimbursements or other payments thereunder.

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Any additional fundraising efforts may divert our management’s attention from their day-to-day activities, which can adversely affect our ability to develop our product candidates and commercialize our products. In addition, we cannot guarantee that future financing will be available in sufficient amounts or on terms acceptable to us, if at all. The terms of any financing may adversely affect the holdings or the rights of our stockholders and the issuance of additional securities by us, whether equity or debt, or the possibility of such issuance, may cause the market price of our shares to decline. The sale of additional equity or convertible securities would dilute all of our stockholders. If we incur debt, it could result in increased fixed payment obligations and we may be required to agree to certain restrictive covenants, such as limitations on our ability to incur additional debt, limitations on our ability to acquire, sell, or license intellectual property rights, and other operating restrictions that could adversely impact our ability to conduct our business. We have in the past sought and may in the future seek funds through a sale of future royalty payments similar to our transaction with Royalty Pharma or through collaborative partnerships, strategic alliances, and licensing or other arrangements, such as our transaction with Daiichi Sankyo, and we may be required to relinquish rights to some of our technologies or product candidates, future revenue streams, research programs, and other product candidates or otherwise agree to terms unfavorable to us, any of which may have a material adverse effect on our business, operating results, and prospects. Even if we believe we have sufficient funds for our current or future operating plans, we may seek additional capital if market conditions are favorable or if we have specific strategic considerations.

If we are unable to obtain funding on a timely basis, or at all, we may be required to significantly curtail, delay, or discontinue one or more of our research or development programs or the commercialization of our products and any approved product candidates or be unable to expand our operations or otherwise capitalize on our business opportunities, as desired, which could materially affect our business, financial condition, and results of operations.

Risks Related to the Discovery and Development of Our Product Candidates

Clinical drug development involves a lengthy, complex, and expensive process with uncertain outcomes and the potential for substantial delays, and the results of earlier studies may not be predictive of future study results.

Before obtaining marketing approval from regulatory authorities for the sale of our product candidates, we must conduct extensive clinical studies to demonstrate the safety and efficacy of the product candidates in humans. Clinical testing is expensive, complex, time consuming, and uncertain as to outcome. We cannot guarantee that any clinical studies will be conducted as planned or completed on schedule, if at all. A failure of one or more clinical studies can occur at any stage of testing, and our future clinical studies may not be successful. Product candidates that have shown promising results in early-stage clinical studies may still suffer significant setbacks or fail in subsequent clinical studies. The safety or efficacy results generated to date in clinical studies do not ensure that later clinical studies will demonstrate similar results. Results from investigator-sponsored studies or compassionate-use studies may not be confirmed in company-sponsored studies or may negatively impact the prospects for our programs. Additionally, given the nature of the rare diseases we are seeking to treat, we often have to devise newly-defined endpoints to be tested in our studies, which can lead to some subjectivity in interpreting study results and could result in regulatory agencies not agreeing with the validity of our endpoints, or our interpretation of the clinical data, and therefore delaying or denying approval. Given the illness of the patients in our studies and the nature of their rare diseases, we may also be required or choose to conduct certain studies on an open-label basis. We have in the past, and may in the future elect to review interim clinical data at multiple time points during the studies, which could introduce bias into the study results and potentially result in denial of approval.

In the biopharmaceutical industry, there is a high failure rate for drugs and biologics proceeding through clinical studies, and product candidates in later stages of clinical studies may fail to show the desired safety and efficacy despite having progressed through nonclinical studies and initial clinical studies. A number of companies in the biopharmaceutical industry have suffered significant setbacks in advanced clinical studies due to lack of efficacy or adverse safety profiles, notwithstanding promising results in earlier studies.

Scenarios that can prevent successful or timely completion of clinical development include but are not limited to:

•delays or failures in generating sufficient preclinical, toxicology, or other in vivo or in vitro data to support the initiation or continuation of human clinical studies or filings for regulatory approval;

•failure to demonstrate a starting dose for our product candidates in the clinic that might be reasonably expected to result in a clinical benefit;

•delays or failures in developing gene therapy, messenger RNA (mRNA), DNA, small interfering RNA (siRNA) or other novel and complex product candidates, which are expensive and difficult to develop and manufacture;

•delays resulting from a shutdown, or uncertainty surrounding the potential for future shutdowns of the U.S. government, including the FDA;

•delays or failures in reaching a consensus with regulatory agencies on study design;

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•delays in reaching agreement on acceptable terms with contract research organizations, or CROs, clinical study sites, and other clinical trial-related vendors;

•failure or delays in obtaining required regulatory agency approval and/or IRB or EC approval at each clinical study site or in certain countries;

•failure to correctly design clinical studies which may result in those studies failing to meet their endpoints or the expectations of regulatory agencies;

•changes in clinical study design or development strategy resulting in delays related to obtaining approvals from IRBs or ECs and/or regulatory agencies to proceed with clinical studies;

•imposition of a clinical hold by regulatory agencies after review of an IND application or amendment, another equivalent application or amendment, or an inspection of our clinical study operations or study sites;

•delays in recruiting suitable patients to participate in our clinical studies;

•difficulty collaborating with patient groups and investigators;

•failure by our CROs, other third parties, or us to adhere to clinical study requirements;

•failure to perform in accordance with the FDA’s and/or ICH’s good clinical practices requirements or applicable regulatory guidelines in other countries;

•delays in patients’ completion of studies or their returns for post-treatment follow-up;

•patients dropping out of a study;

•adverse events associated with the product candidate occurring that are viewed to outweigh its potential benefits;

•changes in regulatory requirements and guidance that require amending or submitting new clinical protocols;

•greater than anticipated costs associated with clinical studies of our drug candidates, including as a result of hyperinflation;

•clinical studies of our drug candidates producing negative or inconclusive results, which may result in us deciding, or regulators requiring us, to conduct additional clinical or nonclinical studies or to abandon drug development programs;

•competing clinical studies of potential alternative product candidates or investigator-sponsored studies of our product candidates; and

•delays in manufacturing, testing, releasing, validating, or importing/exporting sufficient stable quantities of our product candidates for use in clinical studies or the inability to do any of the foregoing.

Any inability to successfully complete nonclinical and clinical development could result in additional costs to us or negatively impact our ability to generate revenue. In addition, if we make manufacturing or formulation changes to our product candidates, we may need to conduct additional toxicology, comparability or other studies to bridge our modified product candidates to earlier versions. Clinical study delays could also shorten any periods during which our products have commercial exclusivity and may allow our competitors to bring products to market before we do, which could negatively impact our ability to obtain orphan exclusivity and to successfully commercialize our product candidates and may harm our business and results of operations.

If we do not achieve our projected development goals in the time frames we announce and expect, the commercialization of our products may be delayed and the credibility of our management may be adversely affected and, as a result, our stock price may decline.

For planning purposes, we estimate the timing of the accomplishment of various scientific, clinical, regulatory, and other product development goals, which we sometimes refer to as milestones. These milestones may include the commencement or completion of scientific studies and clinical trials, the timing of patient dosing, the timing, type or clarity of data from clinical trials, the submission or acceptance of regulatory filings, and the potential approval of such regulatory filings. We periodically make public announcements about the expected timing of some of these milestones. All of these milestones are based on a variety of assumptions, but the actual timing of these milestones can vary dramatically from our estimates. If we do not meet these publicly announced milestones, the commercialization of our products may be delayed and the credibility of our management may be adversely affected and, as a result, our stock price may decline.

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We may find it difficult to identify and enroll patients in our clinical studies given the limited number of patients who have the diseases for which our product candidates are being studied. Difficulty in enrolling patients could delay or prevent clinical studies of our product candidates.

Identifying and qualifying patients to participate in clinical studies of our product candidates is critical to our success. The timing of our clinical studies depends in part on the speed at which we can recruit patients to participate in testing our product candidates, and we may experience delays in our clinical studies if we encounter difficulties in enrollment.

Each of the conditions for which we plan to evaluate our current product candidates is a rare genetic disease. Accordingly, there are limited patient pools from which to draw for clinical studies. For example, we estimate that approximately 6,000 patients worldwide suffer from GSDIa, for which DTX401 is being studied, and these all may not be treatable if they are immune to the AAV viral vector.

In addition to the rarity of these diseases, the eligibility criteria of our clinical studies will further limit the pool of available study participants as we will require patients to have specific characteristics that we can measure or to assure their disease is either severe enough or not too advanced to include them in a study. The process of finding and diagnosing patients is costly and time-consuming, especially since the rare diseases we are studying are commonly underdiagnosed. We also may not be able to identify, recruit, and enroll a sufficient number of appropriate patients to complete our clinical studies because of demographic criteria for prospective patients, the perceived risks and benefits of the product candidate under study, the proximity and availability of clinical study sites for prospective patients, and the patient referral practices of physicians. The availability and efficacy of competing therapies and clinical studies can also adversely impact enrollment. If patients are unwilling to participate in our studies for any reason (such as drug-related side effects), the timeline for and our success in recruiting patients, conducting studies, and obtaining regulatory approval of potential products may be delayed or impaired, the commercial prospects of our product candidates will be harmed, and our ability to generate product revenue from any of these product candidates could be delayed or prevented. Delays in completing our clinical studies will increase our costs, slow down our product candidate development and approval process, and jeopardize our ability to commence product sales and generate revenue.

The regulatory approval processes of the FDA and comparable foreign authorities are lengthy, time consuming, and inherently unpredictable. Even if we achieve positive results in our pre-clinical and clinical studies, if we are ultimately unable to obtain timely regulatory approval for our product candidates, our business will be substantially harmed.

Our future success is dependent on our ability to successfully commercialize our products and develop, obtain regulatory approval for, and then successfully commercialize one or more product candidates. We are not permitted to market or promote any of our product candidates before we receive regulatory approval from the FDA or comparable foreign regulatory authorities. We have only obtained regulatory approval for three products that we have developed, and it is possible that none of our existing product candidates or any product candidates we may seek to develop in the future will ever obtain regulatory approval. Further, as the clinical trial requirements of regulatory authorities and the criteria these regulators use to determine the safety and efficacy of a product candidate vary substantially according to the type, complexity, novelty and intended use and market of the product candidates, the regulatory approval process for novel product candidates, such as our gene therapy product candidates, can be more expensive and take longer than for other product candidates, leading to fewer product approvals. To date, very few gene therapy products have received regulatory approval in the U.S. or Europe. The regulatory framework and oversight over development of gene therapy products has evolved and may continue to evolve in the future. Within the FDA, the Center for Biologics Evaluation and Research (CBER) regulates gene therapy products. Within the CBER, the review of gene therapy and related products is consolidated in the Office of Cellular, Tissue and Gene Therapies, and the FDA has established the Cellular, Tissue and Gene Therapies Advisory Committee to advise CBER on its reviews. The CBER works closely with the National Institutes of Health (NIH). The FDA and the NIH have published guidance with respect to the development and submission of gene therapy protocols. For example, in January 2020, the FDA issued final guidance to set forth the framework for the development, review and approval of gene therapies. The final guidance pertains to the development of gene therapies for the treatment of specific disease categories, including rare diseases, and to manufacturing and long-term follow up issues relevant to gene therapy, among other topics. At the same time the FDA issued new draft guidance describing the FDA’s approach for determining whether two gene therapy products were the same or different for the purpose of assessing orphan drug exclusivity; the draft guidance was finalized by the FDA in September 2021.

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To obtain regulatory approval in the U.S. and other jurisdictions, we must comply with numerous and varying requirements regarding safety, efficacy, chemistry, manufacturing and controls, clinical studies (including good clinical practices), commercial sales, pricing, and distribution of our product candidates, as described in “Item 1. Business – Government Regulation” of our Annual Report. Even if we are successful in obtaining approval in one jurisdiction, we cannot ensure that we will obtain approval in any other jurisdictions. In addition, approval policies, regulations, positions of the regulatory agencies on study design and/or endpoints, or the type and amount of clinical data necessary to gain approval may change during the course of a product candidate’s clinical development, which may cause delays in the approval or the decision not to approve an application. Communications with the regulatory agencies during the approval process are also unpredictable; favorable communications early in the process do not ensure that approval will be obtained and unfavorable communications early on do not guarantee that approval will be denied. Applications for our product candidates could fail to receive regulatory approval, or could be delayed in receiving regulatory approval, for many reasons, including but not limited to the following:

•regulatory authorities may disagree with the design, implementation, or conduct of our clinical studies;

•regulatory authorities may change their guidance or requirements for a development program for a product candidate;

•the population studied in the clinical program may not be sufficiently broad or representative to assure efficacy and safety in the full population for which we seek approval;

•regulatory authorities may disagree with our interpretation of data from nonclinical studies or clinical studies;

•the data collected from clinical studies of our product candidates may not be sufficient to support the submission of an NDA, or biologics license application, or BLA, or other submission or to obtain regulatory approval;

•we may be unable to demonstrate to regulatory authorities that a product candidate’s risk-benefit ratio for its proposed indication is acceptable;

•regulatory authorities may fail to approve the manufacturing processes, test procedures and specifications, or facilities used to manufacture our clinical and commercial supplies;

•the U.S. government may be shut down, which could delay the FDA;

•the FDA may be delayed in responding to our applications or submissions due to competing priorities or limited resources, including as a result of the COVID-19 pandemic;

•failure of our nonclinical or clinical development to comply with an agreed upon Pediatric Investigational Plan (PIP), which details the designs and completion timelines for nonclinical and clinical studies and is a condition of marketing authorization in the EU; and

•the approval policies or regulations of regulatory authorities may significantly change in a manner rendering our clinical data insufficient for approval.

Furthermore, the disease states we are evaluating often do not have clear regulatory paths for approval and/or do not have validated outcome measures. In these circumstances, we work closely with the regulatory authorities to define the approval path and may have to qualify outcome measures as part of our development programs. Additionally, many of the disease states we are targeting are highly heterogeneous in nature, which may impact our ability to determine the treatment benefit of our potential therapies.

This lengthy and uncertain approval process, as well as the unpredictability of the clinical and nonclinical studies, may result in our failure to obtain regulatory approval to market any of our product candidates, or delayed regulatory approval.

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Our product candidates may cause undesirable side effects or have other properties that could delay or prevent their regulatory approval, limit the commercial profile of an approved label, or result in significant negative consequences following marketing approval, if any.

Undesirable side effects caused by our product candidates could cause us or regulatory authorities to interrupt, delay, or halt clinical studies or further development, and could result in a more restrictive label, the delay or denial of regulatory approval by the FDA or other comparable foreign authorities, or a Risk Evaluation and Mitigation Strategy, or REMS, plan, which could include a medication guide outlining the risks of such side effects for distribution to patients, restricted distribution, a communication plan for healthcare providers, and/or other elements to assure safe use. Our product candidates are in development and the safety profile has not been established. Further, as one of the goals of Phase 1 and/or 2 clinical trials is to identify the highest dose of treatment that can be safely provided to study participants, adverse side effects, including serious adverse effects, have occurred in certain studies as a result of changes to the dosing regimen during such studies and may occur in future studies. Results of our studies or investigator-sponsored trials could reveal a high and unacceptable severity and prevalence of these or other side effects. In such an event, our studies could be suspended or terminated, and the FDA or comparable foreign regulatory authorities could order us to cease further development of or deny or withdraw approval of our product candidates for any or all targeted indications.

Additionally, notwithstanding our prior or future regulatory approvals for our product candidates, if we or others later identify undesirable side effects caused by such products, a number of potentially significant negative consequences could result, including but not limited to:

•regulatory authorities may withdraw approvals of such product;

•regulatory authorities may require additional warnings on the product’s label or restrict the product’s approved use;

•we may be required to create a REMS plan;

•patients and physicians may elect not to use our products, or reimbursement authorities may elect not to reimburse for them; and

•our reputation may suffer.

Any of these events could prevent us from achieving or maintaining market acceptance of the particular product candidate, if approved.

Serious adverse events in clinical trials involving gene therapy product candidates may damage public perception of the safety of our product candidates, increase government regulation, and adversely affect our ability to obtain regulatory approvals for our product candidates or conduct our business.

Gene therapy remains a novel technology. Public perception may be influenced by claims that gene therapy is unsafe, and gene therapy may not gain the acceptance of the public or the medical community. For example, certain gene therapy trials using AAV8 vectors (although at significantly higher doses than those used in our gene therapy product candidates) and other vectors led to several well-publicized adverse events, including cases of leukemia and death. The risk of cancer or death remains a concern for gene therapy and we cannot assure you that it will not occur in any of our planned or future clinical studies. In addition, there is the potential risk of delayed adverse events following exposure to gene therapy products due to persistent biological activity of the genetic material or other components of products used to carry the genetic material. Serious adverse events in our clinical trials, or other clinical trials involving gene therapy products, particularly AAV gene therapy products such as candidates based on the same capsid serotypes as our product candidates, or occurring during use of our competitors’ products, even if not ultimately attributable to the relevant product candidates, and the resulting publicity, could result in increased government regulation, unfavorable public perception, potential regulatory delays in the testing or approval of our gene therapy product candidates, stricter labeling requirements for those gene therapy product candidates that are approved and a decrease in demand for any such gene therapy product candidates.

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Gene therapy and mRNA, DNA and siRNA product candidates are novel, complex, expensive and difficult to manufacture. We could experience manufacturing problems that result in delays in developing and commercializing these programs or otherwise harm our business.

The manufacturing process used to produce our gene therapy, mRNA, DNA and siRNA product candidates is novel, complex, and has not been validated for commercial use. Several factors could cause production interruptions, including equipment malfunctions, regulatory inspections, facility contamination, raw material shortages or contamination, natural disasters, disruption in utility services, human error or disruptions in the operations of our suppliers. Further, given that cGMP gene therapy, mRNA, DNA and siRNA manufacturing is a nascent industry, there are a small number of CMOs with the experience necessary to manufacture our gene therapy product candidates and we may have difficulty finding or maintaining relationships with such CMOs or hiring experts for internal manufacturing and accordingly, our production capacity may be limited.

Our gene therapy, mRNA, DNA and siRNA product candidates require processing steps that are more complex than those required for most small molecule drugs. Moreover, unlike small molecules, the physical and chemical properties of a biologic such as gene therapy, mRNA, DNA and siRNA product candidates generally cannot be fully characterized. As a result, assays of the finished product candidate may not be sufficient to ensure that the product candidate is consistent from lot to lot or will perform in the intended manner. Accordingly, we employ multiple steps to control the manufacturing process to assure that the process works reproducibly, and the product candidate is made strictly and consistently in compliance with the process. Problems with the manufacturing process, even minor deviations from the normal process, could result in product defects or manufacturing failures that result in lot failures, noncompliance with regulatory requirements, product recalls, product liability claims or insufficient inventory. We may encounter problems achieving adequate quantities and quality of clinical-grade materials that meet FDA, the EMA or other applicable standards or specifications with consistent and acceptable production yields and costs.

In addition, FDA, the EMA and other foreign regulatory authorities may require us to submit samples of any lot of any approved product together with the protocols showing the results of applicable tests at any time. Under some circumstances, FDA, the EMA or other foreign regulatory authorities may require that we not distribute a lot until the agency authorizes its release. Slight deviations in the manufacturing process, including those affecting quality attributes and stability, may result in unacceptable changes in the product that could result in lot failures or product recalls. Lot failures or product recalls could cause us to delay product launches or clinical trials, which could be costly to us and otherwise harm our business, financial condition, results of operations and prospects.

Even if we obtain regulatory approval for our product candidates, our products will remain subject to regulatory scrutiny.

Our products and any product candidates that are approved in the future remain subject to ongoing regulatory requirements for manufacturing, labeling, packaging, storage, distribution, advertising, promotion, sampling, record-keeping, conduct of post-marketing studies, and submission of safety, efficacy, and other post-market information, including both federal and state requirements in the U.S. and requirements of comparable foreign regulatory authorities, as described in “Item 1. Business – Government Regulation” of our Annual Report.

Manufacturers and manufacturers’ facilities are required to comply with extensive FDA, and comparable foreign regulatory authority, requirements, including ensuring that quality control and manufacturing procedures conform to Good Manufacturing Practices (GMP) regulations. As such, we and our contract manufacturers are subject to continual review and inspection to assess compliance with GMP and adherence to commitments made in any NDA, BLA, MAA, or other comparable application for approval in another jurisdiction. Regulatory authorities may, at any time, audit or inspect a manufacturing facility involved with the preparation of our products, product candidates or the associated quality systems for compliance with the regulations applicable to the activities being conducted. If we, our collaborators, such as KKC, or any of our third-party manufacturers fail to maintain regulatory compliance, the FDA or other applicable regulatory authority can impose regulatory sanctions including, among other things, the temporary or permanent suspension of a clinical study or commercial sales, recalls or seizures of product or the temporary or permanent closure of a facility or withdrawal of product approval. If supply from one approved manufacturer is interrupted due to failure to maintain regulatory compliance, an alternative manufacturer would need to be qualified through an NDA or BLA supplement or MAA variation, or equivalent foreign regulatory filing, which could result in delays in product supply. The regulatory agencies may also require additional studies if a new manufacturer, material, testing method or standard is relied upon for commercial production. Switching manufacturers, materials, test methods or standards may involve substantial costs and may result in a delay in our desired clinical and commercial timelines. Accordingly, we and others with whom we work are required continue to expend time, money, and effort in all areas of regulatory compliance, including manufacturing, production, and quality control.

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Any regulatory approvals that we receive for our product candidates may be subject to limitations on the approved indicated uses for which the product may be marketed or other conditions of approval, or contain requirements for potentially costly post-marketing testing, including Phase 4 clinical studies, and surveillance to monitor the safety and efficacy of the product candidate. We could also be asked to conduct post-marketing clinical studies to verify the safety and efficacy of our products in general or in specific patient subsets. If original marketing approval was obtained via the accelerated approval or conditional marketing authorization pathways, we would be required to conduct a successful post-marketing clinical study to confirm clinical benefit for our products. An unsuccessful post-marketing study or failure to complete such a study could result in the withdrawal of marketing approval. We will be required to report certain adverse events and manufacturing problems, if any, to the FDA and comparable foreign regulatory authorities. The holder of an approved NDA, BLA, MAA, or other comparable application must submit new or supplemental applications and obtain approval for certain changes to the approved product, product labeling, or manufacturing process.

If we fail to comply with applicable regulatory requirements, or there are safety or efficacy problems with a product, a regulatory agency or enforcement authority may, among other things:

•issue warning or notice of violation letters;

•impose civil or criminal penalties;

•suspend or withdraw regulatory approval;

•suspend any of our ongoing clinical studies;

•refuse to approve pending applications or supplements to approved applications submitted by us;

•impose restrictions on our operations, including closing our contract manufacturers’ facilities;

•seize or detain products, or require a product recall; or

•require entry into a consent decree.

Any government investigation of alleged violations of law could require us to expend significant time and resources in response, and could generate negative publicity. Any failure to comply with ongoing regulatory requirements may significantly and adversely affect our ability to commercialize and generate revenue from our products. If regulatory sanctions are applied or if regulatory approval is withdrawn, the value of our company and our operating results will be adversely affected.

Product liability lawsuits against us could cause us to incur substantial liabilities and could limit commercialization of our approved products or product candidates.

We face an inherent risk of product liability exposure related to the testing of our approved products and product candidates in human clinical trials, as well as in connection with commercialization of our current and future products. If we cannot successfully defend ourselves against claims that any of our approved products or product candidates caused injuries, we could incur substantial liabilities. There can be no assurance that our product liability insurance, which provides coverage in the amount of $15.0 million per incident and $15.0 million in the aggregate, will be sufficient in light of our current or planned clinical programs. We may not be able to maintain insurance coverage at a reasonable cost or in sufficient amounts to protect us against losses due to liability, or losses may exceed the amount of insurance that we carry. A product liability claim or series of claims brought against us could cause our stock price to decline and, if judgments exceed our insurance coverage, could adversely affect our results of operations and business. In addition, regardless of merit or eventual outcome, product liability claims may result in impairment of our business reputation, withdrawal of clinical study participants, costs due to related litigation, distraction of management’s attention from our primary business, initiation of investigations by regulators, substantial monetary awards to patients or other claimants, the inability to commercialize our product candidates, and decreased demand for our product candidates, if approved for commercial sale.

If we are unable to identify, source, and develop effective biomarkers, or our collaborators are unable to successfully develop and commercialize companion diagnostics for our product candidates, or experience significant delays in doing so, we may not realize the full commercial potential of our product candidates.

We are developing companion diagnostic tests to identify the right patients for certain of our product candidates and to monitor response to treatment. In certain cases, diagnostic tests may need to be developed as companion diagnostics and regulatory approval obtained in order to commercialize some product candidates. We currently use and expect to continue to use biomarkers to identify the right patients for certain of our product candidates. We may also need to develop predictive biomarkers in the future. We can offer no assurances that any current or future potential biomarker will in fact prove predictive, be reliably measured, or be accepted as a measure of efficacy by the FDA or other regulatory authorities. In addition, our success may depend, in part, on the development and commercialization of companion diagnostics. We also expect the FDA will require the development

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and regulatory approval of a companion diagnostic assay as a condition to approval of our gene therapy product candidates. There has been limited success to date industrywide in developing and commercializing these types of companion diagnostics. Development and manufacturing of companion diagnostics is complex and there are limited manufacturers with the necessary expertise and capability. Even if we are able to successfully develop companion diagnostics, we may not be able to manufacture the companion diagnostics at a cost or in quantities or on timelines necessary for use with our product candidates. To be successful, we need to address a number of scientific, technical and logistical challenges. We are currently working with a third party to develop companion diagnostics, however, we have little experience in the development and commercialization of diagnostics and may not ultimately be successful in developing and commercializing appropriate diagnostics to pair with any of our product candidates that receive marketing approval. We rely on third parties for the automation, characterization and validation, of our bioanalytical assays, companion diagnostics and the manufacture of its critical reagents.

Companion diagnostics are subject to regulation by FDA and similar regulatory authorities outside the U.S. as medical devices and require regulatory clearance or approval prior to commercialization. In the U.S., companion diagnostics are cleared or approved through FDA’s 510(k) premarket notification or premarket approval, or PMA, process. Changes in marketing approval policies during the development period, changes in or the enactment of additional statutes or regulations, or changes in regulatory review for each submitted 510(k) premarket notification, PMA or equivalent application types in jurisdictions outside the U.S., may cause delays in the approval, clearance or rejection of an application. Given our limited experience in developing and commercializing diagnostics, we expect to rely in part or in whole on third parties for companion diagnostic design and commercialization. We and our collaborators may encounter difficulties in developing and obtaining approval or clearance for the companion diagnostics, including issues relating to selectivity/specificity, analytical validation, reproducibility, or clinical validation. Any delay or failure by us or our collaborators to develop or obtain regulatory approval of the companion diagnostics could delay or prevent approval of our product candidates.

Risks Related to our Reliance on Third Parties

We rely on third parties to conduct our nonclinical and clinical studies and perform other tasks for us. If these third parties do not successfully carry out their contractual duties, meet expected deadlines, or comply with regulatory requirements, we may be exposed to sub-optimal quality and reputational harm, we may not be able to obtain regulatory approval for or commercialize our product candidates, and our business could be substantially harmed.

We have relied upon and plan to continue to rely upon third parties, including CROs, collaborative partners, and independent investigators to analyze, collect, monitor, and manage data for our ongoing nonclinical and clinical programs. We rely on third parties for execution of our nonclinical and clinical studies, and for estimates regarding costs and efforts completed, and we control only certain aspects of their activities. For example, pursuant to the terms of our collaboration with GeneTx on the development of GeneTx’s GTX-102, an antisense oligonucleotide (ASO) for the treatment of Angelman syndrome, subject to certain limited rights we have, GeneTx retains the decision-making authority on all matters in connection with the research, development, manufacturing and regulatory activities with respect to the program. Nevertheless, we are responsible for ensuring that each of our studies is conducted in accordance with the applicable protocol, legal, regulatory, and scientific standards, and our reliance on the CROs and other third parties does not relieve us of our regulatory responsibilities. We and our CROs and other vendors and partners are required to comply with GMP, GCP, and GLP, which are regulations and guidelines enforced by the FDA, the Competent Authorities of the Member States of the European Economic Area, and comparable foreign regulatory authorities for all of our product candidates in development. Regulatory authorities enforce these regulations through periodic inspections of study sponsors, principal investigators, study sites, and other contractors. If we or any of our CROs or other vendors and partners, including the sites at which clinical studies are conducted, fail to comply with applicable regulations, the data generated in our nonclinical and clinical studies may be deemed unreliable and the FDA, EMA, or comparable foreign regulatory authorities may deny approval and/or require us to perform additional nonclinical and clinical studies before approving our marketing applications, which would delay the approval process. We cannot make assurances that upon inspection by a given regulatory authority, such regulatory authority will determine that any of our clinical studies comply with GCP regulations or that nonclinical studies comply with GLP regulations. In addition, our clinical studies must be conducted with products produced under GMP regulations. If the regulatory authorities determine that we have failed to comply with GLP, GMP, or GCP regulations, they may deny approval of our product candidates and/or we may be required to repeat clinical or nonclinical studies, which would delay the regulatory approval process.

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Our CROs and other vendors and partners are not our employees and we cannot control whether or not they devote sufficient time and resources to our on-going nonclinical and clinical programs, except for the limited remedies available to us under our agreements with such third parties. If our vendors and partners do not successfully carry out their contractual duties or obligations or meet expected deadlines, if they need to be replaced, or if the quality or accuracy of the data they obtain is compromised due to the failure to adhere to our protocols, regulatory requirements, or for other reasons, our clinical studies may be extended, delayed, or terminated, and we may not be able to obtain regulatory approval for or successfully commercialize our product candidates. CROs and other vendors and partners may also generate higher costs than anticipated as a result of changes in scope of work or otherwise. As a result, the commercial prospects for our product candidates would be harmed, our costs could increase, and our ability to generate revenue could be delayed.

If any of our relationships with these third parties terminate, we may not be able to enter into arrangements with alternative vendors or do so on commercially reasonable terms. Switching or adding additional vendors involves additional cost and requires management time and focus. In addition, there is a natural transition period when a new vendor commences work. As a result, delays may occur, which can materially impact our ability to meet our desired clinical development timelines. Our efforts to manage our relationships with our vendors and partners can provide no assurance that we will not encounter similar challenges or delays in the future or that these delays or challenges will not have a material adverse impact on our business, financial condition, and business prospects.

We also rely on third parties in other ways, including efforts to support patient diagnosis and identify patients, to assist our finance and legal departments, and to provide other resources for our business. Use of these third parties could expose us to sub-optimal quality, missed deadlines, and non-compliance with applicable laws, all of which could result in reputational harm to us and negatively affect our business.

We are dependent on KKC for the clinical and commercial supply of Crysvita for all major markets and for the development and commercialization of Crysvita in certain major markets, and KKC’s failure to provide an adequate supply of Crysvita or to commercialize Crysvita in those markets could result in a material adverse effect on our business and operating results.

Under our agreement with KKC, KKC has the sole right to commercialize Crysvita in Europe and, at certain specified times, in the U.S., Canada, and Turkey, subject to a limited promotion right we retained. Our partnership with KKC may not be successful, and we may not realize the expected benefits from such partnership, due to a number of important factors, including but not limited to the following:

•KKC has no obligation under our agreement to use diligent efforts to commercialize Crysvita in Europe. The timing and amount of any royalty payments that are made by KKC based on sales of Crysvita in Europe will depend on, among other things, the efforts, allocation of resources, and successful commercialization of Crysvita by KKC in Europe;

•the timing and amount of any payments we may receive under our agreement with KKC will depend on, among other things, the efforts, allocation of resources, and successful commercialization of Crysvita by KKC in the U.S. and Canada under our agreement;

•KKC may change the focus of its commercialization efforts or pursue higher-priority programs;

•KKC may make decisions regarding the indications for our product candidates in countries where it has the sole right to commercialize the product candidates that limit commercialization efforts in those countries or in countries where we have the right to commercialize our product candidates;

•KKC may make decisions regarding market access and pricing in countries where it has the sole right to commercialize our product candidates which can negatively impact our commercialization efforts in countries where we have the right to commercialize our product candidates;

•KKC may fail to manufacture or supply sufficient drug product of Crysvita in compliance with applicable laws and regulations or otherwise for our development and clinical use or commercial use (including as a result of the COVID-19 pandemic), which could result in program delays or lost revenue;

•KKC may elect to develop and commercialize Crysvita indications with a larger market than XLH and at a lower price, thereby reducing the profit margin on sales of Crysvita for any orphan indications, including XLH;

•if KKC were to breach or terminate the agreement with us, we would no longer have any rights to develop or commercialize Crysvita or such rights would be limited to non-terminated countries;

•KKC may terminate its agreement with us, adversely affecting our potential revenue from licensed products; and

•the timing and amounts of expense reimbursement that we may receive are uncertain, and the total expenses for which we are obligated to reimburse KKC may be greater than anticipated.

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We rely on third parties to manufacture our products and our product candidates and we are subject to a multitude of manufacturing risks, any of which could substantially increase our costs and limit the supply of our product and product candidates.

As we currently lack the resources and the capability to manufacture our products and most of our product candidates on a clinical or commercial scale, we rely on third parties to manufacture our products and product candidates. Although we oversee the contract manufacturers, we cannot control the manufacturing process of, and are substantially dependent on, our contract manufacturing partners for compliance with the regulatory requirements. See “- Even if we obtain regulatory approval for our product candidates, our products will remain subject to regulatory scrutiny” risk factor above. Further, we depend on our manufacturers to purchase from third-party suppliers the materials necessary to produce our products and product candidates. There are a limited number of suppliers for raw materials that we use to manufacture our drugs, placebos, or active controls, and there may be a need to identify alternate suppliers to prevent or mitigate a possible disruption of the manufacture of the materials necessary to produce our products and product candidates for our clinical studies, and, if approved, ultimately for commercial sale. We also do not have any control over the process or timing of the acquisition of these raw materials by our manufacturers. We may also experience interruptions in supply of product if the product or raw material components fail to meet our quality control standards or the quality control standards of our suppliers.

Further, manufacturers that produce our products and product candidates may not have experience producing our products and product candidates at commercial levels and may not produce our products and product candidates at the cost, quality, quantities, locations, and timing needed to support profitable commercialization. We have not yet secured manufacturing capabilities for commercial quantities of all of our product candidates and may be unable to negotiate binding agreements with manufacturers to support our commercialization activities on commercially reasonable terms. Even if our third-party product manufacturers develop acceptable manufacturing processes that provide the necessary quantities of our products and product candidates in a compliant and timely manner, the cost to us for the supply of our products and product candidates manufactured by such third parties may be high and could limit our profitability. For instance, KKC is our sole supplier of commercial quantities of Crysvita. The supply price to us for commercial sales of Crysvita in Latin America and the transfer price for commercial sales of the product in the U.S. and Canada is 35% of net sales through December 31, 2022 and 30% thereafter, which is higher than the typical cost of sales for companies focused on rare diseases.

The process of manufacturing our products and product candidates is complex, highly regulated, and subject to several risks, including but not limited to those listed below.

•The process of manufacturing our products and product candidates is extremely susceptible to product loss due to contamination, equipment failure or improper installation or operation of equipment, or vendor or operator error. Even minor deviations from normal manufacturing processes for our products and any of our product candidates could result in reduced production yields, product defects, and other supply disruptions. If microbial, viral, or other contaminations are discovered in our products and product candidates or in the manufacturing facilities in which our products and product candidates are made, such manufacturing facilities may need to be closed for an extended period of time to investigate and remedy the contamination.

•The manufacturing facilities in which our products and product candidates are made could be adversely affected by equipment failures, labor shortages, raw material shortages, natural disasters, power failures, actual or threatened public health emergencies, and numerous other factors.

Any adverse developments affecting manufacturing operations for our products and product candidates may result in shipment delays, inventory shortages, lot failures, withdrawals or recalls, or other interruptions in the supply of our products and product candidates. Due to their stage of development, small volume requirements, and infrequency of batch production runs, we carry limited amounts of safety stock for our products and product candidates. We have, and may in the future, be required to take inventory write-offs and incur other charges and expenses for products and product candidates that fail to meet specifications, undertake costly remediation efforts, or seek more costly manufacturing alternatives.

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The drug substance and drug product for our products and most of our product candidates are currently acquired from single-source suppliers. The loss of these suppliers, or their failure to supply us with the necessary drug substance or drug product, could materially and adversely affect our business.

We acquire most of the drug substances and drug products for our products and product candidates from single sources. If any single source supplier breaches an agreement with us, or terminates the agreement in response to an alleged breach by us or otherwise becomes unable or unwilling to fulfill its supply obligations, we would not be able to manufacture and distribute the product or product candidate until a qualified alternative supplier is identified, which could significantly impair our ability to commercialize such product or delay the development of such product candidate. For example, the drug substance and drug product for Crysvita are made by KKC pursuant to our license and collaboration agreement with KKC. The drug substance and drug product for Mepsevii are currently manufactured by Rentschler under a commercial supply and services agreement, accompanying purchase orders, and other agreements. We experienced disruptions related to the fill and finish activities for the drug product for Mepsevii during the fourth quarter of 2019 and as a result, we identified an alternative supplier to conduct such activities. We are currently in the process of qualifying and transferring the activities to such alternative supplier, which may take a significant amount of time and expense. If we fail to qualify our alternative supplier, we could experience delays or disruptions in the supply of Mepsevii, which would negatively impact sales of the product. Pharmaceutical-grade drug substance for Dojolvi is manufactured by IOI Oleo pursuant to a supply agreement, and the drug product for Dojolvi is prepared by Haupt Pharma AG, pursuant to a master services agreement. Single source suppliers are also used for our gene therapy programs. We cannot provide assurances that identifying alternate sources, if available at all, and establishing relationships with such sources would not result in significant expense or delay in the commercialization of our products or the development of our product candidates. Additionally, we may not be able to enter into supply arrangements with an alternative supplier on commercially reasonable terms or at all. The terms of any new agreement may also be less favorable or more costly than the terms we have with our current supplier. A delay in the commercialization of our products or the development of our product candidates or having to enter into a new agreement with a different third-party on less favorable terms than we have with our current suppliers could have a material adverse impact upon on our business.

The actions of distributors and specialty pharmacies could affect our ability to sell or market products profitably. Fluctuations in buying or distribution patterns by such distributors and specialty pharmacies could adversely affect our revenues, financial condition, or results of operations.

We rely on commercial distributors and specialty pharmacies for a considerable portion of our product sales and such sales are concentrated within a small number of distributors and specialty pharmacies. The financial failure of any of these parties could adversely affect our revenues, financial condition or results of operations. Our revenues, financial condition or results of operations may also be affected by fluctuations in buying or distribution patterns of such distributors and specialty pharmacies. These fluctuations may result from seasonality, pricing, wholesaler inventory objectives, or other factors.

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Risks Related to Commercialization of Our Products and Product Candidates

If the market opportunities for our products and product candidates are smaller than we believe they are, our revenue may be adversely affected, and our business may suffer. Because the target patient populations of our products and product candidates are small, and the addressable patient population potentially even smaller, we must be able to successfully identify patients and acquire a significant market share to achieve profitability and growth.

We focus our research and product development on treatments for rare and ultra-rare genetic diseases. Given the small number of patients who have the diseases that we are targeting, it is critical to our ability to grow and become profitable that we continue to successfully identify patients with these rare and ultra-rare genetic diseases. Some of our current products or clinical programs may be most appropriate for patients with more severe forms of their disease. For instance, while adults make up the majority of the XLH patients, they often have less severe disease that may reduce the penetration of Crysvita in the adult population relative to the pediatric population. Given the overall rarity of the diseases we target, it is difficult to project the prevalence of the more severe forms, or the other subsets of patients that may be most suitable to address with our products and product candidates, which may further limit the addressable patient population to a small subset. Our projections of both the number of people who have these diseases, as well as the subset of people with these diseases who have the potential to benefit from treatment with our products and product candidates, are based on our beliefs and estimates. These estimates have been derived from a variety of sources, including the scientific literature, surveys of clinics, patient foundations, or market research, and may prove to be incorrect. Further, new studies may change the estimated incidence or prevalence of these diseases. The number of patients may turn out to be lower than expected. The effort to identify patients with diseases we seek to treat is in early stages, and we cannot accurately predict the number of patients for whom treatment might be possible. Additionally, the potentially addressable patient population for each of our products and product candidates may be limited or may not be amenable to treatment with our products and product candidates, and new patients may become increasingly difficult to identify or access. Further, even if we obtain significant market share for our products and product candidates, because the potential target populations are very small, we may never become or remain profitable nor generate sufficient revenue growth to sustain our business.

We face intense competition and rapid technological change and the possibility that our competitors may develop therapies that are similar, more advanced, or more effective than ours, which may adversely affect our financial condition and our ability to successfully commercialize our product candidates.

The biotechnology and pharmaceutical industries are intensely competitive and subject to rapid and significant technological change. We are currently aware of various existing treatments that may compete with our products and product candidates. See “Item 1. Business – Competition” in our Annual Report.

We have competitors both in the U.S. and internationally, including major multinational pharmaceutical companies, specialty pharmaceutical companies, biotechnology companies, startups, academic research institutions, government agencies, and public and private research institutions. Many of our competitors have substantially greater financial, technical, and other resources, such as larger research and development staff and experienced marketing and manufacturing organizations. Additional mergers and acquisitions in the biotechnology and pharmaceutical industries may result in even more resources being concentrated in our competitors. As a result, these companies may obtain regulatory approval more rapidly than we are able to and may be more effective in selling and marketing their products as well. Smaller or early-stage companies may also prove to be significant competitors, particularly through collaborative arrangements with large, established companies. Competition may increase further as a result of advances in the commercial applicability of technologies and greater availability of capital for investment in these industries. Our competitors may succeed in developing, acquiring, or licensing on an exclusive basis, products that are more effective or less costly than any product candidate that we may develop, or achieve earlier patent protection, regulatory approval, product commercialization, and market penetration than we do. Additionally, technologies developed by our competitors may render our potential products and product candidates uneconomical or obsolete, and we may not be successful in marketing our products and product candidates against competitors.

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We may not be able to effectively manage the expansion of our organization, including building an integrated commercial organization. If we are unable to expand our existing commercial infrastructure or enter into agreements with third parties to market and sell our products and product candidates, as needed, we may be unable to increase our revenue.

We expect to need additional managerial, operational, marketing, financial, legal, and other resources to support our development and commercialization plans and strategies. In order to successfully commercialize our products as well as any additional products that may result from our development programs or that we acquire or license from third parties, we are building and expanding our commercial infrastructure in North America, Europe, Latin America and the Asia-Pacific region. This infrastructure consists of both office based as well as field teams with technical expertise, and will be expanded as we approach the potential approval dates of additional products that result from our development programs. Our management may need to divert a disproportionate amount of its attention away from our day-to-day activities and devote a substantial amount of time to managing these growth activities. We may not be able to effectively manage the expansion of our operations, which may result in weaknesses in our infrastructure, operational mistakes, loss of business opportunities, loss of employees, and reduced productivity among remaining employees. Our expected growth could require significant capital expenditures and may divert financial resources from other projects, such as the development of additional product candidates. If our management is unable to effectively manage our growth, our expenses may increase more than expected, our ability to generate and/or grow revenue could be reduced, and we may not be able to implement our business strategy. Our future financial performance and our ability to commercialize product candidates and compete effectively will depend, in part, on our ability to effectively manage any future growth.

We, as a company, have limited, recent experience selling and marketing our product and only some of our employees have prior experience promoting other similar products in the past while employed at other companies. As we increase the number and range of our commercialized products, we may experience additional complexities to our sales process and strategy and have difficulties in allocating sufficient resources to sales and marketing of certain products. Further, as we launch additional products or as demand for our products change, our initial estimate of the size of the required field force may be materially more or less than the size of the field force actually required to effectively commercialize our product candidates. As such, we may be required to hire large teams to adequately support the commercialization of our products and product candidates or we may incur excess costs in an effort to optimize the hiring of commercial personnel. With respect to certain geographical markets, we may enter into collaborations with other entities to utilize their local marketing and distribution capabilities, but we may be unable to enter into such agreements on favorable terms, if at all. If our future collaborators do not commit sufficient resources to commercialize our future products, if any, and we are unable to develop the necessary marketing capabilities on our own, we will be unable to generate sufficient product revenue to sustain our business. We may be competing with companies that currently have extensive and well-funded marketing and sales operations. Without a large internal team or the support of a third-party to perform key commercial functions, we may be unable to compete successfully against these more established companies.

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Our exclusive rights to promote Crysvita in the U.S. and Canada will transition back to KKC.

Pursuant to the terms of our collaboration and license agreement with KKC, or the collaboration agreement, we have the sole right to promote Crysvita in the U.S. and Canada, or the profit-share territory for a specified period of time, with KKC increasingly participating in the promotion of the product until the transition date of April 2023, which is the fifth anniversary of the commercial launch of the product in the U.S. After the transition date, KKC will have the right to promote the product, subject to a limited promotion right retained by us. The transition of responsibilities to KKC will require significant effort and may result in the diversion of management’s attention to transition activities. We may also encounter unexpected difficulties or incur unexpected costs in connection with such transition activities. Further, we cannot assure that we will have adequate commercial activity to support our North America field force and other aspects of our commercial infrastructure in the territory after the transition date and we may fail to retain members of our field teams due to such uncertainties. After the transition date, we will also solely bear the expenses related to the promotion of Crysvita in the profit-share territory pursuant to our limited promotion right, rather than share such expenses with KKC. Collaboration with KKC may not result in a seamless transition of responsibilities for KKC to promote the product in the profit-share territory after the transition date and the commercial success of Crysvita in the profit-share territory after the transition date will depend on, among other things, the efforts and allocation of resources of KKC.

The commercial success of any current or future product will depend upon the degree of market acceptance by physicians, patients, third-party payors, and others in the medical community.

Even with the requisite approvals from the FDA and comparable foreign regulatory authorities, the commercial success of our current and future products will depend in part on the medical community, patients, and payors accepting our current and future products as medically useful, cost-effective, and safe. Any product that we bring to the market may not gain market acceptance by physicians, patients, payors, and others in the medical community. The degree of market acceptance of any of our current and future products will depend on a number of factors, including:

•the efficacy of the product as demonstrated in clinical studies and potential advantages over competing treatments;

•the prevalence and severity of any side effects, including any limitations or warnings contained in a product’s approved labeling;

•the clinical indications for which approval is granted;

•relative convenience and ease of administration;

•the cost of treatment, particularly in relation to competing treatments;

•the willingness of the target patient population to try new therapies and of physicians to prescribe these therapies;

•the effectiveness of our field forces and marketing efforts;

•the strength of marketing and distribution support and timing of market introduction of competitive products;

•publicity concerning our products or competing products and treatments; and

•sufficient third-party insurance coverage and reimbursement.

Even if a potential product displays a favorable efficacy and safety profile in nonclinical and clinical studies, market acceptance of the product will not be fully known until after it is launched. Our efforts to educate the medical community and payors on the benefits of the product candidates require significant resources and may never be successful. If our current and future products fail to achieve an adequate level of acceptance by physicians, patients, payors, and others in the medical community, we will not be able to generate sufficient revenue to become or remain profitable.

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The insurance coverage and reimbursement status of newly approved products is uncertain. Failure to obtain or maintain adequate coverage and reimbursement for new or current products could limit our ability to market those products and decrease our ability to generate revenue.

Our target patient populations are small, and accordingly the pricing, coverage, and reimbursement of our products and product candidates, if approved, must be adequate to support our commercial infrastructure. Our per-patient prices must be sufficient to recover our development and manufacturing costs and potentially achieve profitability. We expect the cost of a single administration of gene therapy products, such as those we are developing, to be substantial, when and if they achieve regulatory approval. Accordingly, the availability and adequacy of coverage and reimbursement by governmental and private payors are essential for most patients to afford expensive treatments such as ours, assuming approval. Sales of our products and product candidates, if approved, will depend substantially, both domestically and abroad, on the extent to which their costs will be paid for by health maintenance, managed care, pharmacy benefit, and similar healthcare management organizations, or reimbursed by government authorities, private health insurers, and other payors. If coverage and reimbursement are not available, are available only to limited levels, or are not available on a timely basis, we may not be able to successfully commercialize our products and product candidates, if approved. For example, deteriorating economic conditions and political instability in certain Latin American countries and in Turkey continue to cause us to experience significant delays in receiving approval for reimbursement for our products and consequently impact our product commercialization timelines in such regions. Even if coverage is provided, the approved reimbursement amount may not be high enough to allow us to establish or maintain pricing sufficient to sustain our overall enterprise.

There is significant uncertainty related to the insurance coverage and reimbursement of newly approved products. In the U.S., the Centers for Medicare & Medicaid Services, or CMS, an agency within the U.S. Department of Health and Human Services, decides whether and to what extent a new drug will be covered and reimbursed under Medicare. Private payors tend to follow the coverage reimbursement policies established by CMS to a substantial degree. It is difficult to predict what CMS or private payors will decide with respect to reimbursement for products such as ours, especially our gene therapy product candidates as there is a limited body of established practices and precedents for gene therapy products.

Outside the U.S., international operations are generally subject to extensive governmental price controls and other market regulations, and we believe the increasing emphasis on cost-containment initiatives in Europe, Canada, and other countries will put pressure on the pricing and usage of our products and product candidates. In many countries, the prices of medical products are subject to varying price control mechanisms as part of national health systems. Other countries allow companies to fix their own prices for medicinal products, but monitor and control company profits. Additional foreign price controls or other changes in pricing regulation could restrict the amount that we are able to charge for our product candidates. Accordingly, in markets outside the U.S., the reimbursement for our products may be reduced compared with the U.S. and may be insufficient to generate commercially reasonable revenue and profits.

Moreover, increasing efforts by governmental and third-party payors in the U.S. and abroad to cap or reduce healthcare costs may cause such organizations to limit both coverage and the level of reimbursement for new products and, as a result, they may not cover or provide adequate payment for our products and product candidates. We expect to experience pricing pressures in connection with the sale of any of our products and product candidates due to the trend toward managed healthcare, the increasing influence of health maintenance organizations, additional legislative changes, and statements by elected officials. For example, proposals have been discussed to tie U.S. drug prices to the cost in other countries, several states in the U.S. have introduced legislation to require pharmaceutical companies to disclose their costs to justify the prices of their products, and an “Affordable Drug Pricing Task-Force” has been formed in the U.S. House of Representatives with the goal of combating the increased costs of prescription drugs. Drug pricing is also expected to remain a focus for the current Presidential Administration and Congress. The downward pressure on healthcare costs in general, and with respect to prescription drugs, surgical procedures, and other treatments in particular, has become very intense. As a result, increasingly high barriers are being erected to the entry of new products.

Risks Related to Our Intellectual Property

If we are unable to obtain and maintain effective patent rights for our products, product candidates, or any future product candidates, we may not be able to compete effectively in our markets.

We rely upon a combination of patents, trade secret protection, and confidentiality agreements to protect the intellectual property related to our technologies, our products, and our product candidates. Our success depends in large part on our and our licensors’ ability to obtain and maintain patent and other intellectual property protection in the U.S. and in other countries with respect to our proprietary technologies, our products, and our product candidates.

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We have sought to protect our proprietary position by filing patent applications in the U.S. and abroad related to our novel technologies, products and product candidates that are important to our business. This process is expensive and time consuming, and we may not be able to file and prosecute all necessary or desirable patent applications at a reasonable cost or in a timely manner. It is also possible that we will fail to identify patentable aspects of our research and development output before it is too late to obtain patent protection.

The patent position of biotechnology and pharmaceutical companies generally is highly uncertain and involves complex legal and factual questions for which legal principles remain unsolved. The patent applications that we own or in-license may fail to result in issued patents with claims that cover our products or product candidates in the U.S. or in other foreign countries. There is no assurance that all potentially relevant prior art relating to our patents and patent applications has been found, which can invalidate a patent or prevent a patent from issuing from a pending patent application. Third parties may challenge the validity, enforceability, or scope of any issued patents which may result in such patents being narrowed, found unenforceable, or invalidated. Furthermore, even if the patents and patent applications we own or in-license are unchallenged, they may not adequately protect our intellectual property, provide exclusivity for our products or product candidates, or prevent others from designing around our claims. Any of these outcomes could impair our ability to prevent competition from third parties.

We, independently or together with our licensors, have filed several patent applications covering various aspects of our products or product candidates. We cannot offer any assurances about which, if any, patents will issue, the breadth of any such patent, or whether any issued patents will be found invalid and unenforceable or will be threatened by third parties. Any successful opposition to these patents could impair the exclusivity position of our products or deprive us of rights necessary for the successful commercialization of any product candidates that are approved. Further, if we encounter delays in regulatory approvals, the period of time during which we could market a product candidate under patent protection could be reduced.

Our current patents or applications covering methods of use and certain compositions of matter do not provide complete patent protection for our products and product candidates in all territories. For example, there are no issued patents covering the Crysvita composition of matter in Latin America, where we have rights to commercialize the compound. Therefore, a competitor could develop the same antibody or a similar antibody as well as other approaches that target FGF23 for potential commercialization in Latin America, subject to any intellectual property rights or regulatory exclusivities awarded to us. If we cannot obtain and maintain effective patent rights for our products or product candidates, we may not be able to compete effectively and our business and results of operations would be harmed.

We may not have sufficient patent terms to effectively protect our products and business.

Patents have a limited lifespan. In the U.S., the natural expiration of a patent is generally 20 years after its effective filing date. Although various extensions may be available, the life of a patent, and the protection it affords, is limited. Even if patents covering our product candidates are obtained, once the patent life has expired for a product, we may be open to competition from generic or biosimilar medications.

Patent term extensions under the Hatch-Waxman Act in the U.S. and under supplementary protection certificates in Europe may not be available to extend the patent exclusivity term for our products and product candidates, and we cannot provide any assurances that any such patent term extension will be obtained and, if so, for how long. Furthermore, we may not receive an extension if we fail to apply within applicable deadlines, fail to apply prior to expiration of relevant patents, or otherwise fail to satisfy applicable requirements. Moreover, the length of the extension could be less than we request. If we do not have sufficient patent terms or regulatory exclusivity to protect our products, our business and results of operations may be adversely affected.

Patent policy and rule changes could increase the uncertainties and costs surrounding the prosecution of our patent applications and the enforcement or defense of our issued patents.

Changes in either the patent laws or interpretation of the patent laws in the U.S. and other countries may diminish the value of our patents or narrow the scope of our patent protection. The laws of foreign countries may not protect our rights to the same extent as the laws of the U.S. Publications of discoveries in the scientific literature often lag behind the actual discoveries, and patent applications in the U.S. and other jurisdictions are typically not published until 18 months after filing, or in some cases not at all. We therefore cannot be certain that we or our licensors were the first to make the invention claimed in our owned and in-licensed patents or pending applications, or that we or our licensor were the first to file for patent protection of such inventions.

In 2011, the Leahy-Smith America Invents Act (the Leahy-Smith Act) was signed into law and introduced significant changes to the prosecution of U.S. patent applications and to the procedures for challenging U.S. patents. The effects of these changes still remain unclear owing to the evolving nature of the law and the lengthy timelines associated with court system review and interpretation. However, the Leahy-Smith Act and its implementation could increase the uncertainties and costs surrounding the prosecution of our patent applications and the enforcement or defense of our issued patents, all of which could have a material adverse effect on our business and financial condition.

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If we are unable to maintain effective proprietary rights for our products, product candidates, or any future product candidates, we may not be able to compete effectively in our markets.

In addition to the protection afforded by patents, we rely on trade secret protection and confidentiality agreements to protect proprietary know-how that is not patentable or that we elect not to patent, processes for which patents are difficult to enforce and any other elements of our products or product candidate discovery and development processes that involve proprietary know-how, information, or technology that is not covered by patents. However, trade secrets can be difficult to protect. The confidentiality agreements entered into with our employees, consultants, scientific advisors, contractors and other third parties that we rely on in connection with the development, manufacture and commercialization of our products may not be sufficient to protect our proprietary technology and processes, which increase the risk that such trade secrets may become known by our competitors or may be inadvertently incorporated into the technology of others.

The physical security of our premises and physical and electronic security of our information technology systems may not preserve the integrity and confidentiality of our data and trade secrets. These individuals, organizations and systems, agreements or security measures may be breached, and we may not have adequate remedies for any breach. In addition, our trade secrets may otherwise become known or be independently discovered by competitors.

The assignment agreements we enter into with our employees and consultants to assign their inventions to us, and the confidentiality agreements we enter into with our employees, consultants, advisors, and any third parties who have access to our proprietary know-how, information, or technology may not have been duly executed and we cannot assure that our trade secrets and other confidential proprietary information will not be disclosed or that competitors will not otherwise gain access to our trade secrets or independently develop substantially equivalent information and techniques. Misappropriation or unauthorized disclosure of our trade secrets could impair our competitive position and may have a material adverse effect on our business. Additionally, if the steps taken to maintain our trade secrets are deemed inadequate, we may have insufficient recourse against third parties for misappropriating the trade secret.

Claims of intellectual property infringement may prevent or delay our development and commercialization efforts.

Our commercial success depends in part on our avoiding infringement of the patents and proprietary rights of others. There have been many lawsuits and other proceedings involving patent and other intellectual property rights in the biotechnology and pharmaceutical industries, including patent infringement lawsuits, interferences, inter partes reviews, post grant reviews, oppositions, and reexamination proceedings before the USPTO and corresponding foreign patent offices. Numerous U.S. and foreign issued patents and pending patent applications, which are owned by other parties, exist in the fields in which we are developing product candidates. As the biotechnology and pharmaceutical industries expand and more patents are issued, the risk increases that our products or product candidates may be subject to claims of infringement of the patent rights of these other parties.

Other parties may assert that we are employing their proprietary technology without authorization. There may be patents or patent applications with claims to materials, formulations, methods of manufacture, or methods for treatment relevant to the use or manufacture of our products or product candidates. We have conducted freedom to operate analyses with respect only to our products and certain of our product candidates, and therefore we do not know whether there are any patents of other parties that would impair our ability to commercialize all of our product candidates. We also cannot guarantee that any of our analyses are complete and thorough, nor can we be sure that we have identified each and every patent and pending application in the U.S. and abroad that is relevant or necessary to the commercialization of our products or product candidates. Because patent applications can take many years to issue, there may be currently pending patent applications that may later result in issued patents that are relevant to our products or product candidates.

We are aware of certain U.S. and foreign patents owned by third parties that a court might construe to be valid and relevant to one or more of our gene therapy product candidates, certain methods that may be used in their manufacture, or certain formulations comprising one or more of our gene therapy candidates. We are also aware of certain U.S. and foreign patents owned by third parties that relate to anti-sclerostin antibodies and their use, and which a court might construe to be valid and relevant to setrusumab. We are additionally aware of certain U.S. and foreign patents owned by third parties that relate to nucleic acid-containing lipid particles or to certain mRNA modifications, and which a court might construe to be valid and relevant to UX053. There is a risk that one or more of these third parties may choose to engage in litigation with us to enforce or to otherwise assert their patent rights against us. Even if we believe such claims are without merit, a court of competent jurisdiction could hold that one or more of these patents is valid, enforceable, and infringed, in which case the owners of any such patents may be able to block our ability to commercialize a product candidate unless we obtained a license under the applicable patents, or until such patents expire. However, such a license may not be available on commercially reasonable terms or at all.

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Parties making claims against us may obtain injunctive or other equitable relief, which could effectively block our ability to continue commercialization of our products, or block our ability to develop and commercialize one or more of our product candidates. Defense of these claims, regardless of their merit, would involve substantial litigation expense and would be a substantial diversion of employee resources from our business. In the event of a successful claim of infringement against us, we may have to pay substantial damages, including treble damages and attorneys’ fees for willful infringement, pay royalties, redesign our infringing products, or obtain one or more licenses from third parties, which may be impossible or require substantial time and monetary expenditure.
 

We may not be successful in obtaining or maintaining necessary rights to our product candidates through acquisitions and in-licenses.

Because our programs may require the use of proprietary rights held by third parties, the growth of our business will likely depend in part on our ability to acquire, in-license, or use these proprietary rights. For example, our product candidates may require specific formulations to work effectively and efficiently and the rights to these formulations may be held by others. We may be unable to acquire or in-license any compositions, methods of use, processes, or other third-party intellectual property rights from third parties that we identify as necessary for our product candidates. The licensing and acquisition of third-party intellectual property rights is a competitive area, and a number of more established companies are also pursuing strategies to license or acquire third-party intellectual property rights that we may consider attractive. These established companies may have a competitive advantage over us due to their size, cash resources, and greater clinical development and commercialization capabilities. In addition, companies that perceive us to be a competitor may be unwilling to assign or license rights to us. We also may be unable to license or acquire third-party intellectual property rights on terms that would allow us to make an appropriate return on our investment.

We sometimes collaborate with U.S. and foreign academic institutions to accelerate our preclinical research or development under written agreements with these institutions. Typically, these institutions provide us an option to negotiate a license to any of the institution’s rights in technology resulting from the collaboration. Regardless of such option, we may be unable to negotiate a license within the specified timeframe or under terms that are acceptable to us. If we are unable to do so, the institution may offer the intellectual property rights to other parties, potentially blocking our ability to pursue our program.

If we are unable to successfully obtain rights to required third-party intellectual property rights or maintain the existing intellectual property rights we have, we may have to abandon development of the corresponding program.

We may face competition from biosimilars, which may have a material adverse impact on the future commercial prospects of our biological products and product candidates.

Even if we are successful in achieving regulatory approval to commercialize a product candidate faster than our competitors, we may face competition from biosimilars with respect to our biological products (Crysvita, Mepsevii and Evkeeza) and our biological product candidates. In the U.S., the Biologics Price Competition and Innovation Act of 2009, or BPCI Act, was included in the Affordable Care Act and created an abbreviated approval pathway for biological products that are demonstrated to be “highly similar,” or biosimilar, to or “interchangeable” with an FDA-approved biological product. The BPCI Act prohibits the FDA from approving a biosimilar or interchangeable product that references a brand biological product until 12 years after the licensure of the reference product, but permits submission of an application for a biosimilar or interchangeable product to the FDA four years after the reference product was first licensed. The BPCI Act does not prevent another company from developing a product that is highly similar to the innovative product, generating its own data, and seeking approval. The law is complex and is still being interpreted and implemented by the FDA. As a result, its ultimate impact, implementation and meaning are subject to uncertainty. Modification of the BPCI Act, or changes to the FDA’s interpretation or implementation of the BPCI Act, could have a material adverse effect on the future commercial prospects for our biological products and product candidates.

In Europe, the European Commission has granted marketing authorizations for several biosimilars pursuant to a set of general and product class-specific guidelines for biosimilar approvals issued over the past few years. In Europe, a competitor may reference data supporting approval of an innovative biological product, but will not be able to get on the market until 10 years after the time of approval of the innovative product. This 10-year marketing exclusivity period will be extended to 11 years if, during the first eight of those 10 years, the marketing authorization holder obtains an approval for one or more new therapeutic indications that bring significant clinical benefits compared with existing therapies. In addition, companies may be developing biosimilars in other countries that could compete with our products.

If competitors are able to obtain marketing approval for biosimilars referencing our products, our products may become subject to competition from such biosimilars, with the attendant competitive pressure and consequences.

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Competitors could enter the market with generic versions of Dojolvi or our small-molecule product candidates, which may result in a material decline in sales of affected products.

Under the Hatch-Waxman Act, a pharmaceutical manufacturer may file an abbreviated new drug application, or ANDA, seeking approval of a generic copy of an approved innovator product. Under the Hatch-Waxman Act, a manufacturer may also submit an NDA under section 505(b)(2) that references the FDA’s finding of safety and effectiveness of a previously approved drug. A 505(b)(2) NDA product may be for a new or improved version of the original innovator product. Innovative small molecule drugs may be eligible for certain periods of regulatory exclusivity (e.g., five years for new chemical entities, three years for changes to an approved drug requiring a new clinical study, and seven years for orphan drugs), which preclude FDA approval (or in some circumstances, FDA filing and review of) an ANDA or 505(b)(2) NDA relying on the FDA’s finding of safety and effectiveness for the innovative drug. In addition to the benefits of regulatory exclusivity, an innovator NDA holder may have patents claiming the active ingredient, product formulation or an approved use of the drug, which would be listed with the product in the “Orange Book.” If there are patents listed in the Orange Book, a generic applicant that seeks to market its product before expiration of the patents must include in the ANDA or 505(b)(2) what is known as a “Paragraph IV certification,” challenging the validity or enforceability of, or claiming non-infringement of, the listed patent or patents. Notice of the certification must be given to the innovator, too, and if within 45 days of receiving notice the innovator sues to enforce its patents, approval of the ANDA is stayed for 30 months, or as lengthened or shortened by the court.

Accordingly, competitors could file ANDAs for generic versions of our small-molecule product, Dojolvi, or 505(b)(2) NDAs that reference Dojolvi. For the patents listed for Dojolvi in the Orange Book, those ANDAs and 505(b)(2) NDAs would be required to include a certification as to each listed patent indicating whether the ANDA applicant does or does not intend to challenge the patent. We cannot predict how any generic competitor would address such patents, whether we would sue on any such patents, or the outcome of any such suit.

We may not be successful in securing or maintaining proprietary patent protection for products and technologies we develop or license. Moreover, if any patents that are granted and listed in the Orange Book are successfully challenged by way of a Paragraph IV certification and subsequent litigation, the affected product could more immediately face generic competition and its sales would likely decline materially. Should sales decline, we may have to write off a portion or all of the intangible assets associated with the affected product and our results of operations and cash flows could be materially and adversely affected.

The patent protection and patent prosecution for some of our products and product candidates is dependent on third parties.

While we normally seek and gain the right to fully prosecute the patents relating to our products or product candidates, there may be times when patents relating to our products or product candidates are controlled by our licensors. This is the case with our license agreements with KKC and Regeneron, who are primarily responsible for the prosecution of certain patents and patent applications covering Crysvita and Evkeeza, respectively.

In addition, we have in-licensed patents and patent applications owned by the University of Pennsylvania, relating to the AAV8 vector used in DTX301 and DTX401, and the AAV9 vector used in UX701. These patents and patent applications are licensed or sublicensed by REGENX and sublicensed to us. We do not have the right to control the prosecution of these patent applications, or the maintenance of any of these patents. In addition, under our agreement with REGENX, we do not have the first right to enforce the licensed patents, and our enforcement rights are subject to certain limitations that may adversely impact our ability to use the licensed patents to exclude others from commercializing competitive products. Moreover, REGENX and the University of Pennsylvania may have interests which differ from ours in determining whether to enforce and the manner in which to enforce such patents.

We also have in-licensed patents and patent applications owned by Arcturus relating to the cationic lipid used in UX053. We do not have the right to control the prosecution of these patent applications, or the maintenance of any of these patents. In addition, under our agreement with Arcturus, we do not have the first right to enforce these patents, and our enforcement rights are subject to certain limitations that may adversely impact our ability to use these licensed patents to exclude others from commercializing competitive products. Moreover, Arcturus may have interests which differ from ours in determining whether to enforce and the manner in which to enforce such patents.

If KKC, Regeneron, the University of Pennsylvania, REGENX, Arcturus or any of our future licensing partners fail to appropriately prosecute, maintain, and enforce patent protection for the patents covering any of our products or product candidates, our ability to develop and commercialize those products or product candidates may be adversely affected and we may not be able to prevent competitors from making, using, and selling competing products. In addition, even where we now have the right to control patent prosecution of patents and patent applications we have licensed from third parties, we may still be adversely affected or prejudiced by actions or inactions of our licensors and their counsel that took place prior to us assuming control over patent prosecution.

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If we fail to comply with our obligations in the agreements under which we license intellectual property and other rights from third parties or otherwise experience disruptions to our business relationships with our licensors, we could lose license rights that are important to our business.

We are a party to a number of intellectual property license agreements that are important to our business and expect to enter into additional license agreements in the future. Our existing license agreements impose, and we expect that future license agreements will impose, various diligence, milestone payment, royalty, and other obligations on us. If we fail to comply with our obligations under these agreements, or we are subject to a bankruptcy, we may be required to make certain payments to the licensor, we may lose the exclusivity of our license, or the licensor may have the right to terminate the license, in which event we would not be able to develop or market products covered by the license. Additionally, the milestone and other payments associated with these licenses will make it less profitable for us to develop our product candidates.

In certain cases, we control the prosecution of patents resulting from licensed technology. In the event we breach any of our obligations related to such prosecution, we may incur significant liability to our licensing partners. Licensing of intellectual property is of critical importance to our business and involves complex legal, business, and scientific issues. Disputes may arise regarding intellectual property subject to a licensing agreement, including but not limited to:

•the scope of rights granted under the license agreement and other interpretation-related issues;

•the extent to which our technology and processes infringe on intellectual property of the licensor that is not subject to the licensing agreement;

•the sublicensing of patent and other rights;

•our diligence obligations under the license agreement and what activities satisfy those diligence obligations;

•the ownership of inventions and know-how resulting from the joint creation or use of intellectual property by our licensors and us and our collaborators; and

•the priority of invention of patented technology.

If disputes over intellectual property and other rights that we have licensed prevent or impair our ability to maintain our current licensing arrangements on acceptable terms, we may be unable to successfully develop and commercialize the affected product candidates.

We may become involved in lawsuits to protect or enforce our patents or the patents of our licensors, or be subject to claims that challenge the inventorship or ownership of our patents or other intellectual property, which could be expensive, time consuming, and result in unfavorable outcomes.

Competitors may infringe our patents or the patents of our licensors. If we or one of our licensing partners were to initiate legal proceedings against a third party to enforce a patent covering our products or one of our product candidates, the defendant could counterclaim that the patent covering our product or product candidate is invalid and/or unenforceable. In patent litigation in the U.S., defendant counterclaims alleging invalidity and/or unenforceability are commonplace. Grounds for a validity challenge could be an alleged failure to meet any of several statutory requirements, including lack of novelty, obviousness, or non-enablement. Grounds for an unenforceability assertion could be an allegation that someone connected with prosecution of the patent withheld relevant information from the USPTO, or made a misleading statement, during prosecution. The outcome following legal assertions of invalidity and unenforceability is unpredictable.

Interference proceedings or derivation proceedings now available under the Leahy-Smith Act provoked by third parties or brought by us or declared or instituted by the USPTO may be necessary to determine the priority of inventions with respect to our patents or patent applications or those of our licensors. An unfavorable outcome could require us to cease using the related technology or to attempt to license rights to it from the prevailing party. Our business could be harmed if the prevailing party does not offer us a license on commercially reasonable terms. In addition, the validity of our patents could be challenged in the USPTO by one of the new post grant proceedings (i.e., inter partes review or post grant review) now available under the Leahy-Smith Act. Our defense of litigation, interference proceedings, or post grant proceedings under the Leahy-Smith Act may fail and, even if successful, may result in substantial costs and distract our management and other employees.

We may in the future also be subject to claims that former employees, collaborators, or other third parties have an interest in our patents as an inventor or co-inventor. In addition, we may have ownership disputes arise from conflicting obligations of consultants or others who are involved in developing our product candidates. Litigation may be necessary to defend against these and other claims challenging inventorship or ownership. If we fail to successfully defend against such litigation or claims, in addition to paying monetary damages, we may lose valuable intellectual property rights, such as exclusive ownership of, or right to use, valuable intellectual property.

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Even if we are successful in defending against such litigation and claims, such proceedings could result in substantial costs and distract our management and other employees. Because of the substantial amount of discovery required in connection with intellectual property litigation, there is a risk that some of our confidential information could be compromised by disclosure during litigation. There could also be public announcements of the results of hearings, motions, or other interim proceedings or developments related to such litigation or claims. If securities analysts or investors perceive these results to be negative, it could have a material adverse effect on the price of our common stock.

We may be subject to claims that our employees, consultants, or independent contractors have wrongfully used or disclosed confidential information of third parties or that our employees have wrongfully used or disclosed alleged trade secrets of their former employers.

We employ certain individuals who were previously employed at universities or other biotechnology or pharmaceutical companies, including our competitors or potential competitors. Our efforts to vet our employees, consultants, and independent contractors and prevent their use of the proprietary information or know-how of others in their work for us may not be successful, and we may in the future be subject to claims that our employees, consultants, or independent contractors have wrongfully used or disclosed confidential information of third parties. If we fail in defending any such claims, in addition to paying monetary damages, we may lose valuable intellectual property rights or personnel, which could adversely impact our business. Even if we are successful in defending against such claims, litigation could result in substantial costs and distract management and other employees.

Changes in U.S. patent law could diminish the value of patents in general, thereby impairing our ability to protect our products.

As is the case with other biotechnology and pharmaceutical companies, our success is heavily dependent on intellectual property, particularly patents. Obtaining and enforcing patents in the biotechnology and pharmaceutical industries involves both technological and legal complexity. Therefore, obtaining and enforcing such patents is costly, time consuming, and inherently uncertain. In addition, the U.S. has recently enacted and is currently implementing wide-ranging patent reform legislation. Recent U.S. Supreme Court rulings have narrowed the scope of patent protection available in certain circumstances and weakened the rights of patent owners in certain situations. For example, in Association for Molecular Pathology v. Myriad Genetics, Inc., the Supreme Court ruled that a “naturally occurring DNA segment is a product of nature and not patent eligible merely because it has been isolated,” invalidating Myriad Genetics’ patents on the BRCA1 and BRCA2 genes. Certain claims of our licensed U.S. patents covering DTX301 and DTX401 relate to isolated AAV8 vectors, capsid proteins, or nucleic acids. To the extent that such claims are deemed to be directed to natural products, or to lack an inventive concept above and beyond an isolated natural product, a court may decide the claims are invalid under Myriad. Additionally, there have been recent proposals for additional changes to the patent laws of the U.S. and other countries that, if adopted, could impact our ability to obtain patent protection for our proprietary technology or our ability to enforce our proprietary technology. Depending on future actions by the U.S. Congress, the U.S. courts, the USPTO and the relevant law-making bodies in other countries, the laws and regulations governing patents could change in unpredictable ways that would weaken our ability to obtain new patents or to enforce our existing patents and patents that we might obtain in the future.

We may not be able to protect our intellectual property rights throughout the world.

Filing, prosecuting, and defending patents on our products or product candidates in all countries throughout the world would be prohibitively expensive, and our intellectual property rights in some countries outside the U.S. can be less extensive than those in the U.S. In addition, the laws of some foreign countries do not protect intellectual property rights to the same extent as federal and state laws in the U.S. Further, licensing partners such as KKC and Regeneron may not prosecute patents in certain jurisdictions in which we may obtain commercial rights, thereby precluding the possibility of later obtaining patent protection in these countries. Consequently, we may not be able to prevent third parties from practicing our inventions in all countries outside the U.S., or from selling or importing products made using our inventions in and into the U.S. or other jurisdictions. Competitors may use our technologies in jurisdictions where we have not obtained patent protection to develop their own products and may also export infringing products to territories where we have patent protection, but enforcement is not as strong as that in the U.S. These products may compete with our products, and our patents or other intellectual property rights may not be effective or sufficient to prevent them from competing.

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Many companies have encountered significant problems in protecting and defending intellectual property rights in foreign jurisdictions. The legal systems of certain countries, particularly certain developing countries, do not favor the enforcement of patents, trade secrets, and other intellectual property protection, particularly those relating to biotechnology products, which could make it difficult for us to stop the infringement of our patents or marketing of competing products in violation of our proprietary rights generally. Proceedings to enforce our patent rights in foreign jurisdictions, whether or not successful, could result in substantial costs and divert our efforts and attention from other aspects of our business, could put our patents at risk of being invalidated or interpreted narrowly, could put our patent applications at risk of not issuing, and could provoke third parties to assert claims against us. We may not prevail in any lawsuits that we initiate and the damages or other remedies awarded, if any, may not be commercially meaningful. Accordingly, our efforts to enforce our intellectual property rights around the world may be inadequate to obtain a significant commercial advantage from the intellectual property that we develop or license.

Risks Related to Our Business Operations

Actual or threatened public health epidemics or outbreaks, including the ongoing COVID-19 pandemic, have and could again materially and adversely impact our business and operating results.

A public health epidemic or outbreak, and the public and governmental efforts to mitigate the spread of such disease, could materially and adversely impact the commercialization of our products, development and regulatory approval of our product candidates and our clinical trial operations and significantly disrupt our business operations as well as those of our third party suppliers, CRO and collaboration partners that we rely on. In March 2020, the World Health Organization declared the novel coronavirus strain COVID-19 a pandemic.

Our clinical trial activities, including the initiation and completion of such activities and the timing thereof, have been and are expected to continue to be significantly delayed or disrupted by COVID-19. For instance, the pandemic has impacted enrollment of patients in certain of our clinical trials for our product candidates as patients have been more reluctant to conduct in-person visits at the sites due to concerns over COVID-19. Changes in local regulations in response to COVID-19 have also required us to change the way our clinical trials are conducted and certain data from our clinical trials were delayed as a result. Further, healthcare resources have been and may continue to be diverted away from the conduct of clinical trials, such as the diversion of hospitals serving as our clinical trial sites, in response to the COVID-19 pandemic. We have also had difficulties in recruiting clinical site investigators and clinical staff for our studies, and may continue to experience such difficulties. Any of these events, including if we are required to initiate new or additional sites in response to such events, could require us to incur substantial increased expenses, delay the development and commercialization of our product candidates, delay the timing of anticipated data releases, and impact our operating results.

The COVID-19 pandemic has also impacted the timing of review of our submissions and may continue to do so in the future. The pandemic has also significantly impacted our commercialization efforts for our products. Illness from the more contagious omicron variant impacted the availability of certain of our field and sales medical teams and also resulted in staffing shortages at offices, clinics and hospitals, making it difficult to maintain consistent contact with our current patients or identify new patients for our commercialized products and product candidates. Further, certain of our patients may experience interruptions in insurance coverage due to job loss or change in employment status due to the economic impact from the pandemic, which would limit patient access to our products. Effects from government budgetary constraints, either in the U.S. or internationally, due to the economic impact of the pandemic, such as changes to state coverage rules under Medicaid programs in the U.S., could also impact continued insurance coverage and reimbursement for our products. Any of these events could impact our ability to commercialize our products and adversely affect our operating results and revenue.

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We have experienced delays in delivery of ancillary clinical trial materials due to government-imposed mandates and other restrictions from COVID-19 and may in the future experience delays or interruptions in supply of drug product or raw materials, or incur increased costs or expenses. For instance, the Presidential Executive Order invoking the Defense Production Act of 1950 has caused certain of our third party manufacturers or suppliers to prioritize and allocate more resources and capacity to supply materials to other companies engaged in the study or manufacture of treatments or vaccinations for COVID-19, which has resulted in delays or shortages in supply of such materials to us. Any of these events could adversely impact our clinical trial activities and our ability to meet commercial demand for our product and product candidates and result in loss of revenue. In response to these events, we continue to seek and secure alternative sources of supply of drug product or raw materials in an attempt to avoid future potential delays in supply of product, which may result in additional expenses. We have also experienced interruptions or delays in sourcing certain equipment, materials and resources, and increased costs for certain raw materials, related to construction of our gene therapy manufacturing facility as a result of COVID-19, which could delay the anticipated timing for completion of the plant or result in significant additional expenses.

We have opened our offices in the U.S. and there is the risk that employees may transmit or contract COVID-19 when they return to work onsite despite the safety protocols we have implemented. If members of our management and other key personnel in critical functions across our organization are unable to perform their duties or have limited availability due to illness from COVID-19, we may not be able to execute on our business strategy and/or our operations may be negatively impacted. Further, as our offices reopen, we have offered a significant percentage of our employees flexibility in the amount of time they work in the office. Our new office model, our vaccination policy or other workforce actions taken in response to the COVID-19 pandemic, may not meet the expectations of our workforce, which could adversely impact our ability to attract and retain certain employees.

The COVID-19 pandemic has already impacted our operations and those of our third-party partners. The magnitude and extent to which the outbreak may impact or continue to impact our business operations, clinical trial activities, product candidate approvals, supply chain and commercialization of our products and product candidates will continue to remain highly dependent on future developments, which are very uncertain and cannot be predicted with confidence, such as the duration of the outbreak, the scope and magnitude of any resurgence in the outbreak due to virus mutations, such as the omicron or other new variants or other factors, the timing and efficacy of treatments and vaccines against virus mutations, the public acceptance of vaccines, the duration of, or implementation of additional, restrictions to contain the outbreak and the effectiveness of other actions taken in the U.S. and other countries to contain and address the pandemic. This pandemic also amplifies many of the other risks described throughout the “Risk Factors” section of this Quarterly Report on Form 10-Q.

We have no experience as a company developing or operating a manufacturing facility and may experience unexpected costs or delays or ultimately be unsuccessful in developing a facility.

During the fourth quarter 2020, we completed our purchase of land located in the Town of Bedford, Massachusetts for construction of our gene therapy manufacturing facility and began construction of the base building for the facility, which is currently expected to be completed in 2023. We do not have experience as a company, however, in developing a manufacturing facility and we may experience unexpected costs or delays or ultimately be unsuccessful in developing the facility or capability. We are dependent on key partners for delivery of power, electricity and other utilities to our manufacturing facility and we cannot assure that such services will be provided at the facility without interruptions, delays or unexpected costs. Further, as described in the risk factor above entitled, “Actual or threatened public health epidemics or outbreaks, including the ongoing COVID-19 pandemic, have and could again materially and adversely impact our business and operating results,” the COVID-19 pandemic has adversely impacted delivery of raw materials, and increased costs for certain materials, for construction of our facility. As we expand our commercial footprint to multiple geographies, we may establish multiple manufacturing facilities, which may lead to regulatory delays or prove costly. Even if we are successful, we cannot assure that such additional capacity will be required or that our investment will be recouped. Further, our manufacturing capabilities could be affected by cost-overruns, unexpected delays, equipment failures, lack of capacity, labor shortages, natural disasters, power failures, program failures, actual or threatened public health emergencies, and numerous other factors that could prevent us from realizing the intended benefits of our manufacturing strategy.

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Our future success depends in part on our ability to retain our Founder, President, and Chief Executive Officer and to attract, retain, and motivate other qualified personnel.

We are dependent on Emil D. Kakkis, M.D., Ph.D., our Founder, President, and Chief Executive Officer, the loss of whose services may adversely impact the achievement of our objectives. Dr. Kakkis could leave our employment at any time, as he is an “at will” employee. Recruiting and retaining other qualified employees, consultants, and advisors for our business, including scientific and technical personnel, will also be critical to our success. There is currently a shortage of skilled personnel in our industry, which is likely to continue. As a result, competition for skilled personnel is intense and the turnover rate can be high. Our investments and efforts in human capital management may not attract and retain personnel on acceptable terms given the competition among numerous pharmaceutical and biotechnology companies for individuals with similar skill sets. In addition, failure to succeed in preclinical or clinical studies may make it more challenging to recruit and retain qualified personnel. The inability to recruit and retain qualified personnel, or the loss of the services of Dr. Kakkis, may impede the progress of our research, development, and commercialization objectives.

If we fail to obtain or maintain orphan drug exclusivity for our products, our competitors may sell products to treat the same conditions and our revenue will be reduced.

Our business strategy focuses on the development of drugs that are eligible for FDA and EU orphan drug designation. In the U.S., orphan drug designation entitles a party to financial incentives such as opportunities for grant funding towards clinical study costs, tax advantages, and user-fee waivers. In addition, if a product receives the first FDA approval for the indication for which it has orphan designation, the product is entitled to orphan drug exclusivity, which means the FDA may not approve any other application to market the same drug for the same indication for a period of seven years, except in limited circumstances, such as a showing of clinical superiority over the product with orphan exclusivity or where the manufacturer is unable to assure sufficient product quantity. In the EU, orphan drug designation entitles a party to financial incentives such as reduction of fees or fee waivers and ten years of market exclusivity following drug or biological product approval. This period may be reduced to six years if the orphan drug designation criteria are no longer met, including where it is shown that the product is sufficiently profitable not to justify maintenance of market exclusivity.

Because the extent and scope of patent protection for our products may in some cases be limited, orphan drug designation is especially important for our products for which orphan drug designation may be available. For eligible drugs, we plan to rely on the exclusivity period under the Orphan Drug Act to maintain a competitive position. If we do not obtain orphan drug exclusivity for our drug products and biologic products that do not have broad patent protection, our competitors may then sell the same drug to treat the same condition sooner than if we had obtained orphan drug exclusivity, and our revenue will be reduced.

Even though we have orphan drug designation for Dojolvi for the treatment of fatty acid oxidation disorders in the U.S. and for various subtypes of LC-FAOD in Europe, as well as for Crysvita, Mepsevii, DTX301, DTX401 and UX701 in the U.S. and Europe, we may not be the first to obtain marketing approval for any particular orphan indication due to the uncertainties associated with developing pharmaceutical products. Further, even if we obtain orphan drug exclusivity for a product, that exclusivity may not effectively protect the product from competition because different drugs with different active moieties can be approved for the same condition or the same drug can be approved for a different indication unless there are other exclusivities such as new chemical entity exclusivity preventing such approval. Even after an orphan drug is approved, the FDA or EMA can subsequently approve the same drug with the same active moiety for the same condition if the FDA or EMA concludes that the later drug is safer, more effective, or makes a major contribution to patient care. Orphan drug designation neither shortens the development time or regulatory review time of a drug nor gives the drug any advantage in the regulatory review or approval process.

Our operating results would be adversely impacted if our intangible assets become impaired.

As a result of the accounting for our acquisition of Dimension Therapeutics, Inc. (Dimension) in November 2017, we have recorded on our Consolidated Balance Sheet intangible assets for in-process research and development (IPR&D) related to DTX301 and DTX401. We have also recorded contract-based intangible assets related to our license from third parties for certain assets related to Dojolvi following FDA approval of the product, in addition to the intangible asset related to our license from Regeneron for Evkeeza. We test the intangible assets for impairment annually during the fourth quarter and more frequently if events or changes in circumstances indicate that it is more likely than not that the asset is impaired. If the associated research and development effort is abandoned, the related assets will be written-off and we will record a noncash impairment loss on our Condensed Consolidated Statement of Operations. We have not recorded any impairments related to our intangible assets through the end of March 31, 2022.

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We may not be successful in our efforts to identify, license, discover, develop, or commercialize additional product candidates.

The success of our business depends upon our ability to identify, license, discover, develop, or commercialize additional product candidates in addition to the continued clinical testing, potential approval, and commercialization of our existing product candidates. Research programs to identify and develop new product candidates, such as those under our collaboration with Arcturus, require substantial technical, financial, and human resources. We may focus our efforts and resources on potential programs or product candidates that ultimately prove to be unsuccessful. Our research programs or licensing efforts may fail to yield additional product candidates for clinical development and commercialization for a number of reasons, including but not limited to the following:

•our research or business development methodology or search criteria and process may be unsuccessful in identifying potential product candidates;

•we may not be able or willing to assemble sufficient technical, financial or human resources to acquire or discover additional product candidates;

•we may face competition in obtaining and/or developing additional product candidates;

•our product candidates may not succeed in research, discovery, preclinical or clinical testing;

•our potential product candidates may be shown to have harmful side effects or may have other characteristics that may make the products unmarketable or unlikely to receive marketing approval;

•competitors may develop alternatives that render our product candidates obsolete or less attractive;

•product candidates we develop may be covered by third parties’ patents or other exclusive rights;

•the market for a product candidate may change during our program so that such a product may become unreasonable to continue to develop;

•a product candidate may not be capable of being produced in commercial quantities at an acceptable cost or at all; and

•a product candidate may not be accepted as safe and effective by regulatory authorities, patients, the medical community, or payors.

If any of these events occur, we may be forced to abandon our development efforts for a program or programs, or we may not be able to identify, license, discover, develop, or commercialize additional product candidates, which would have a material adverse effect on our business and could potentially cause us to cease operations.

We may expend our limited resources to pursue a particular product, product candidate or indication and fail to capitalize on products, product candidates or indications that may be more profitable or for which there is a greater likelihood of success.

Because we have limited financial and managerial resources, we focus our sales, marketing and research programs on certain products, product candidates or for specific indications. As a result, we may forego or delay pursuit of opportunities with other products or product candidates or other indications that later prove to have greater commercial potential. Our resource allocation decisions may cause us to fail to capitalize on viable commercial products or profitable market opportunities. Our spending on current and future research and development programs and product candidates may not yield any commercially viable products. If we do not accurately evaluate the commercial potential or target market for a particular product or product candidate, we may relinquish valuable rights through collaboration, licensing, or other royalty arrangements in cases in which it would have been advantageous for us to retain sole development and commercialization rights or we may allocate internal resources to a product candidate in a therapeutic area in which it would have been more advantageous to enter into a partnering arrangement.

Changes to healthcare and FDA laws, regulations, and policies may have a material adverse effect on our business and results of operations.

As described under “Item 1. Business - Government Regulation” in our Annual Report and in the Risk Factor above entitled “ – The insurance coverage and reimbursement status of newly approved products is uncertain” there have been and continue to be a number of legislative initiatives to contain healthcare costs and to modify the regulation of drug and biologic products. We expect that additional state and federal healthcare reform measures and regulations will be adopted in the future, including proposals to reduce the exclusivity protections provided to already approved biological products and to provide biosimilar and interchangeable biologic products an easier path to approval. Any of these measures and regulations could limit the amounts that federal and state governments will pay for healthcare products and services, result in reduced demand for our product candidates or additional pricing pressures and affect our product development, testing, marketing approvals and post-market activities.

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Failure to comply with laws and regulations could harm our business and our reputation.

Our business is subject to regulation by various federal, state, local and foreign governmental agencies, including agencies responsible for monitoring and enforcing employment and labor laws, workplace safety, and tax laws and regulations. In certain jurisdictions, these regulatory requirements may be more stringent than those in the U.S., and in other circumstances these requirements may be more stringent in the U.S.

In particular, our operations are directly, and indirectly through our customers, subject to various federal and state fraud and abuse laws, including, without limitation, the federal Anti-Kickback Statute, the federal False Claims Act, and physician sunshine laws and regulations and patient privacy regulations, including the EU General Data Protection Regulation and the California Consumer Privacy Act (CCPA), as described in “Item 1. Business – Government Regulation” of our Annual Report. Because of the breadth of these laws and the narrowness of the statutory exceptions and safe harbors available, it is possible that some of our business activities could be subject to challenge under one or more of such laws. For instance, one of our programs has been the subject of review by applicable governmental authorities of compliance with various fraud and abuse laws; we cannot assure that such program, or our other operations or programs, will not be challenged from time to time by such authorities for violation of such laws. Further, as we and our employees increasingly use social media tools as a means of communication with the public, there is a risk that the use of social media by us or our employees to communicate about our products or business may cause to be found in violation of applicable laws, despite our attempts to monitor such social media communications through company policies and guidelines. In addition, our employees may knowingly or inadvertently make use of social media in ways that may not comply with our company policies or other legal or contractual requirements, which may give rise to liability, lead to the loss of trade secrets or other intellectual property, or result in public exposure of personal information of our employees, clinical trial patients, customers, and others. If our operations are found to be in violation of any of the laws described above or any other governmental regulations that apply to us, we may be subject to penalties, including civil and criminal penalties, damages, fines, exclusion from participation in government health care programs, such as Medicare and Medicaid, imprisonment, disgorgement of profits, and the curtailment or restructuring of our operations. If any governmental sanctions, fines or penalties are imposed, or if we do not prevail in any possible civil or criminal litigation, our business, operating results, financial condition and our reputation could be harmed. In addition, responding to any action will likely result in a significant diversion of management’s attention and resources and an increase in professional fees.

Our research and development activities, including our process and analytical development activities in our quality control laboratory, and our and our third-party manufacturers’ and suppliers’ activities involve the controlled storage, use, and disposal of hazardous materials, including the components of our product candidates, such as viruses, and other hazardous compounds, which subjects us to laws and regulations governing such activities. In some cases, these hazardous materials and various wastes resulting from their use are stored at our or our manufacturers’ facilities pending their use and disposal. We cannot eliminate the risk of contamination, which could cause an interruption of our commercialization efforts, research and development efforts, and business operations or environmental damage that could result in costly clean-up and liabilities under applicable laws and regulations governing the use, storage, handling, and disposal of these materials and specified waste products. We cannot guarantee that the safety procedures utilized by us and our third-party manufacturers for handling and disposing of these materials comply with the standards prescribed by these laws and regulations, or eliminate the risk of accidental contamination or injury from these materials. In such an event, we may be held liable for any resulting damages—and such liability could exceed our resources—and state or federal or other applicable authorities may curtail our use of certain materials and/or interrupt our business operations. Furthermore, environmental laws and regulations are complex, change frequently, and have tended to become more stringent. We cannot predict the impact of such changes and cannot be certain of our future compliance. We do not currently carry biological or hazardous waste insurance coverage.

International expansion of our business exposes us to business, regulatory, political, operational, financial, and economic risks associated with doing business outside of the U.S.

Our business strategy includes international expansion. We currently conduct clinical studies and regulatory activities and we also commercialize products outside of the U.S. Doing business internationally involves a number of risks, including but not limited to:

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•multiple, conflicting, and changing laws and regulations such as privacy and data regulations, transparency regulations, tax laws, export and import restrictions, employment laws, regulatory requirements, and other governmental approvals, permits, and licenses;

•introduction of new health authority requirements and/or changes in health authority expectations;

•supply chain disruptions, changes to regulatory processes and other adverse effects resulting from the United Kingdom’s withdrawal from the EU, commonly referred to as Brexit;

•failure by us to obtain and maintain regulatory approvals for the use of our products in various countries;

•additional potentially relevant third-party patent rights;

•complexities and difficulties in obtaining protection for, and enforcing, our intellectual property;

•difficulties in staffing and managing foreign operations;

•complexities associated with managing multiple payor reimbursement regimes, government payors, or patient self-pay systems;

•limits on our ability to penetrate international markets;

•financial risks, such as longer payment cycles, difficulty collecting accounts receivable, the impact of local and regional financial crises on demand and payment for our products, and exposure to foreign currency exchange rate fluctuations;

•natural disasters and political and economic instability, including wars, terrorism, political unrest, results of certain elections and votes, actual or threatened public health emergencies and outbreak of disease (including for example, the COVID-19 pandemic), boycotts, adoption or expansion of government trade restrictions, and other business restrictions;

•certain expenses including, among others, expenses for travel, translation, and insurance;

•regulatory and compliance risks that relate to maintaining accurate information and control over commercial operations and activities that may fall within the purview of the U.S. Foreign Corrupt Practices Act, or FCPA, its books and records provisions, or its anti-bribery provisions, including those under the U.K. Bribery Act and similar foreign laws and regulations; and

•regulatory and compliance risks relating to doing business with any entity that is subject to sanctions administered by the Office of Foreign Assets Control of the U.S. Department of the Treasury.

Any of these factors could significantly harm our future international expansion and operations and, consequently, our results of operations.

Risks generally associated with the expansion of our enterprise resource planning (ERP) system may adversely affect our business and results of operations or the effectiveness of our internal controls over financial reporting.

We are in the process of expanding our company-wide ERP system to upgrade certain existing business, operational, and financial processes related to our gene therapy manufacturing facility, which we currently expect to be completed in 2023. The ERP expansion is a complex and time-consuming project. Our results of operations could be adversely affected if we experience time delays or cost overruns during the ERP expansion process, or if the ERP system or associated process changes do not give rise to the benefits that we expect. This project has required and may continue to require investment of capital and human resources, the re-engineering of processes of our business, and the attention of many employees who would otherwise be focused on other aspects of our business. Any deficiencies in the design and implementation of the expanded ERP system could result in potentially much higher costs than we had incurred and could adversely affect our ability to develop and launch solutions, provide services, fulfill contractual obligations, file reports with the SEC in a timely manner, operate our business or otherwise affect our controls environment. Any of these consequences could have an adverse effect on our results of operations and financial condition.

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Our business and operations may be materially adversely affected in the event of computer system failures or security breaches.

Cybersecurity incidents, including phishing attacks and attempts to misappropriate or compromise confidential or proprietary information or sabotage enterprise IT systems are becoming increasingly frequent and more sophisticated. The information and data processed and stored in our technology systems, and those of our strategic partners, CROs, contract manufacturers, suppliers, distributors or other third parties for which we depend to operate our business, may be vulnerable to loss, damage, denial-of-service, unauthorized access or misappropriation. Data security breaches can occur as a result of malware, hacking, business email compromise, ransomware attacks, phishing or other cyberattacks directed by third parties. We, and certain of the third parties for which we depend on to operate our business, have experienced cybersecurity incidents, including third party unauthorized access to and misappropriation of financial information. Further, risks of unauthorized access and cyber-attacks have increased as most of our personnel, and the personnel of many third-parties with which we do business, have adopted remote working arrangements as a result of the COVID-19 pandemic. Improper or inadvertent employee behavior, including data privacy breaches by employees, contractors and others with permitted access to our systems, pose a risk that sensitive data may be exposed to unauthorized persons or to the public. A system failure or security breach that interrupts our operations or the operations at one of our third-party vendors or partners could result in intellectual property and other proprietary or confidential information being lost or stolen or a material disruption of our drug development programs and commercial operations. For example, the loss of clinical trial data from ongoing or planned clinical trials could result in delays in our regulatory approval efforts and significantly increase our costs to recover or reproduce the data. To the extent that any disruption or security breach results in a loss of or damage to our data or applications, loss of trade secrets or inappropriate disclosure of confidential or proprietary information, including protected health information or personal identifiable information of employees or former employees, access to our clinical data, or disruption of the manufacturing process, we could incur liability and the further development of our drug candidates could be delayed. Further, we could incur significant costs to investigate and mitigate such cybersecurity incidents. A security breach that results in the unauthorized access, use or disclosure of personal identifiable information also requires us to notify individuals, governmental authorities, credit reporting agencies, or other parties, as applicable, pursuant to privacy and security laws and regulations or other obligations. Such a security breach could harm our reputation, erode confidence in our information security measures, and lead to regulatory scrutiny and result in penalties, fines, indemnification claims, litigation and potential civil or criminal liability.

We or the third parties upon whom we depend may be adversely affected by earthquakes or other natural disasters and our business continuity and disaster recovery plans may not adequately protect us from a serious disaster.

Our corporate headquarters and one of our laboratories are located in the San Francisco Bay Area, and our collaboration partner for Crysvita, KKC, is located in Japan, which have both in the past experienced severe earthquakes and other natural disasters. We do not carry earthquake insurance. Earthquakes or other natural disasters could severely disrupt our operations or those of our collaborators, and have a material adverse effect on our business, results of operations, financial condition, and prospects. We have also experienced power outages as a result of wildfires in the San Francisco Bay Area which are likely to continue to occur in the future. If a natural disaster, power outage, or other event occurred that prevented us from using all or a significant portion of our headquarters, that damaged critical infrastructure (such as the manufacturing facilities of our third-party contract manufacturers) or that otherwise disrupted operations, it may be difficult or, in certain cases, impossible for us to continue our business for a substantial period of time. The disaster recovery and business continuity plans we have in place currently are limited and are may be inadequate in the event of a serious disaster or similar event. We may incur substantial expenses as a result of the limited nature of our disaster recovery and business continuity plans, which, particularly when taken together with our lack of earthquake insurance, could have a material adverse effect on our business.

We may acquire companies or products or engage in strategic transactions, which could divert our management’s attention and cause us to incur various costs and expenses, or result in fluctuations with respect to the value of such investment, which could impact our operating results.

We may acquire or invest in businesses or products that we believe could complement or expand our business or otherwise offer growth opportunities. For example, we acquired Dimension in November 2017 and during the third quarter 2019, we entered into an agreement with GeneTx to collaborate on the development of a product for the treatment of Angelman Syndrome which included an exclusive option to acquire GeneTx. The pursuit of potential acquisitions or investments may divert the attention of management and may cause us to incur various costs and expenses in identifying, investigating, and pursuing them, whether or not they are consummated. We may not be able to identify desirable acquisitions or investments or be successful in completing or realizing anticipated benefits from such transactions. In addition, we may receive inquiries relating to potential strategic transactions, including collaborations, licenses, and acquisitions. Such potential transactions may divert the attention of management and may cause us to incur various costs and expenses in investigating and evaluating such transactions, whether or not they are consummated.

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The value of our investments in other companies or businesses may also fluctuate significantly and impact our operating results quarter to quarter or year to year. For instance, in June 2019, we purchased 2,400,000 shares of common stock of Arcturus and in May 2020, we exercised our option to purchase an additional 600,000 shares of Arcturus’ common stock pursuant to the terms of our equity purchase agreement with Arcturus; we have subsequently sold an aggregate of 2,500,000 shares. We also purchased 7,825,797 shares of common stock of Solid in October 2020. We have elected to apply the fair value option to account for our equity investments in Arcturus and Solid. As a result, increases or decreases in the stock price of Arcturus and Solid common stock will result in accompanying changes in the fair value of our investments, and cause substantial volatility in, our operating results for the reporting period. As the fair value of our investments in Arcturus and Solid is dependent on the stock price of Arcturus and Solid, which has recently seen wide fluctuations, the value of our investments and the impact on our operating results may similarly fluctuate significantly from quarter to quarter and year to year such that period-to-period comparisons may not be a good indication of the future value of the investments and our future operating results.

Risks Related to Ownership of Our Common Stock

The market price of our common stock may be highly volatile.

The market price of our common stock has been, and is likely to continue to be, volatile, including for reasons unrelated to changes in our business. Our stock price could be subject to wide fluctuations in response to a variety of factors, including but not limited to the following:

•adverse results or delays in preclinical or clinical studies;

•any inability to obtain additional funding;

•any delay in filing an IND, NDA, BLA, MAA, or other regulatory submission for any of our product candidates and any adverse development or perceived adverse development with respect to the applicable regulatory agency’s review of that IND, NDA, BLA, MAA, or other regulatory submission;

•the perception of limited market sizes or pricing for our products and product candidates;

•decisions by our collaboration partners with respect to the indications for our products and product candidates in countries where they have the right to commercialize the products and product candidates;

•decisions by our collaboration partners regarding market access and pricing in countries where they have the right to commercialize our products and product candidates;

•failure to successfully develop and commercialize our products and product candidates;

•the level of revenue we receive from our commercialized products or from named patient sales;

•post-marketing safety issues;

•failure to maintain our existing strategic collaborations or enter into new collaborations;

•failure by us or our licensors and strategic collaboration partners to prosecute, maintain, or enforce our intellectual property rights;

•changes in laws or regulations applicable to our products;

•any inability to obtain adequate product supply for our products and product candidates or the inability to do so at acceptable prices;

•adverse regulatory decisions;

•introduction of new products, services, or technologies by our competitors;

•changes in or failure to meet or exceed financial projections or other guidance we may provide to the public;

•changes in or failure to meet or exceed the financial projections or other expectations of the investment community;

•the perception of the pharmaceutical industry or our company by the public, legislatures, regulators, and the investment community;

•the perception of the pharmaceutical industry’s approach to drug pricing;

•announcements of significant acquisitions, strategic partnerships, joint ventures, or capital commitments by us, our strategic collaboration partners, or our competitors;

•the integration and performance of any businesses we have acquired or may acquire;

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•disputes or other developments relating to proprietary rights, including patents, litigation matters, and our ability to obtain patent protection for our technologies;

•additions or departures of key scientific or management personnel;

•significant investigations, regulatory proceedings or lawsuits, including patent or stockholder litigation;

•securities or industry analysts’ reports regarding our stock, or their failure to issue such reports;

•changes in the market valuations of similar companies;

•general market or macroeconomic conditions, including the impact from the COVID-19 pandemic;

•sales of our common stock by us or our stockholders in the future; and

•trading volume of our common stock.

In addition, biotechnology and biopharmaceutical companies in particular have experienced extreme price and volume fluctuations that have often been unrelated or disproportionate to the operating performance of these companies. Broad market and industry factors may negatively affect the market price of our common stock, regardless of our actual operating performance.

Future sales and issuances of our common stock or rights to purchase common stock, including pursuant to our equity incentive plans, could result in additional dilution of the percentage ownership of our stockholders and could cause our stock price to fall.

We will need additional capital in the future to continue our planned operations. To the extent we raise additional capital by issuing equity securities, our stockholders may experience substantial dilution. We may sell common stock, convertible securities, or other equity securities in one or more transactions at prices and in a manner we determine from time to time. If we sell common stock, convertible securities, or other equity securities in more than one transaction, investors may be materially diluted by subsequent sales. These sales may also result in material dilution to our existing stockholders, and new investors could gain rights superior to our existing stockholders.

Pursuant to our 2014 Incentive Plan, or the 2014 Plan, our management is authorized to grant stock options and other equity-based awards to our employees, directors, and consultants. At March 31, 2022, 2,008,628 shares were available for future grants under the 2014 Plan. Through January 1, 2024, the number of shares available for future grant under the 2014 Plan will automatically increase on January 1 of each year by the lesser of 2,500,000 shares or 4% of all shares of our capital stock outstanding as of December 31 of the prior calendar year, subject to the ability of our compensation committee to take action to reduce the size of the increase in any given year.

Pursuant to our 2014 Employee Stock Purchase Plan, or 2014 ESPP, eligible employees can acquire shares of our common stock at a discount to the prevailing market price. At March 31, 2022, 4,698,895 shares were available for issuance under the 2014 ESPP. Through January 1, 2024, the number of shares available for issuance under the 2014 ESPP will automatically increase on January 1 of each year by the lesser of 1,200,000 shares or 1% of all shares of our capital stock outstanding as of December 31 of the prior calendar year, subject to the ability of our compensation committee to take action to reduce the size of the increase in any given year.

In February 2021, our board of directors adopted the Employment Inducement Plan (the Inducement Plan) with a maximum of 500,000 shares available for grant under the plan. At March 31, 2022, 436,063 shares were available for issuance under the Inducement Plan. If our board of directors elects to increase the number of shares available for future grant under the 2014 Plan, the 2014 ESPP, or the Inducement Plan, our stockholders may experience additional dilution, which could cause our stock price to fall.

We do not intend to pay dividends on our common stock so any returns will be limited to the value of our stock.

We have never declared or paid any cash dividends on our common stock. We currently intend to retain all available funds and any future earnings, if any, for the development, operation, and expansion of our business and do not anticipate declaring or paying any cash dividends for the foreseeable future. Any return to stockholders will therefore be limited to the appreciation of their stock.

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Provisions in our amended and restated certificate of incorporation and by-laws, as well as provisions of Delaware law, could make it more difficult for a third-party to acquire us or increase the cost of acquiring us, even if doing so would benefit our stockholders, or remove our current management.

Our amended and restated certificate of incorporation, amended and restated by-laws, and Delaware law contain provisions that may have the effect of delaying or preventing a change in control of us or changes in our management. Our amended and restated certificate of incorporation and by-laws include provisions that:

•authorize “blank check” preferred stock, which could be issued by our board of directors without stockholder approval and may contain voting, liquidation, dividend, and other rights superior to our common stock;

•create a classified board of directors whose members serve staggered three-year terms;

•specify that special meetings of our stockholders can be called only by our board of directors or the chairperson of our board of directors;

•prohibit stockholder action by written consent;

•establish an advance notice procedure for stockholder approvals to be brought before an annual meeting of our stockholders, including proposed nominations of persons for election to our board of directors;

•provide that our directors may be removed only for cause;

•provide that vacancies on our board of directors may be filled only by a resolution adopted by the board of directors;

•expressly authorize our board of directors to modify, alter or repeal our amended and restated by-laws; and

•require holders of 75% of our outstanding common stock to amend specified provisions of our amended and restated certificate of incorporation and amended and restated by-laws.

These provisions, alone or together, could delay, deter, or prevent hostile takeovers and changes in control or changes in our management.

In addition, because we are incorporated in Delaware, we are governed by the provisions of Section 203 of the Delaware General Corporation Law, which limits the ability of stockholders owning in excess of 15% of our outstanding voting stock to merge or combine with us. Further, no stockholder is permitted to cumulate votes at any election of directors because this right is not included in our amended and restated certificate of incorporation.

Any provision of our amended and restated certificate of incorporation or amended and restated by-laws or Delaware law that has the effect of delaying or deterring a change in control could limit the opportunity for our stockholders to receive a premium for their shares of our common stock, and could also affect the price that some investors are willing to pay for our common stock.

Our amended and restated certificate of incorporation provides that the Court of Chancery of the State of Delaware is the sole and exclusive forum for substantially all disputes between us and our stockholders, which could limit our stockholders’ ability to obtain a favorable judicial forum for disputes with us or our directors, officers or employees.

Our amended and restated certificate of incorporation provides that the Court of Chancery of the State of Delaware is the sole and exclusive forum for (1) any derivative action or proceeding brought on our behalf, (2) any action asserting a claim of breach of fiduciary duty owed by any of our directors, officers, or other employees to us or to our stockholders, (3) any action asserting a claim against us arising under the Delaware General Corporation Law or under our amended and restated certificate of incorporation or bylaws, or (4) any action against us asserting a claim governed by the internal affairs doctrine. The choice of forum provision may limit a stockholder’s ability to bring a claim in a judicial forum that it finds favorable for disputes with us or our directors, officers, or other employees, which may discourage such lawsuits against us and our directors, officers, and other employees. Alternatively, if a court were to find the choice of forum provision contained in our amended and restated certificate of incorporation to be inapplicable or unenforceable in an action, we may incur additional costs associated with resolving such action in other jurisdictions, which could harm our business, operating results and financial condition.

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General Risk Factors

If we are unable to maintain effective internal control over financial reporting, investors may lose confidence in the accuracy and completeness of our financial reports and the market price of our stock may decrease.

The Sarbanes-Oxley Act requires, among other things, that we maintain effective internal controls for financial reporting and disclosure controls and procedures. In particular, we are required to perform system and process evaluation and testing of our internal controls over financial reporting to allow management to report on the effectiveness of our internal controls over financial reporting, as required by Section 404(a) of the Sarbanes-Oxley Act. Section 404(b) of the Sarbanes-Oxley Act also requires our independent auditors to attest to, and report on, this management assessment. Ensuring that we have adequate internal controls in place so that we can produce accurate financial statements on a timely basis is a costly and time-consuming effort that will need to be evaluated frequently. If we are not able to comply with the requirements of Section 404 or if we or our independent registered public accounting firm are unable to attest to the effectiveness of our internal control over financial reporting, investors may lose confidence in the accuracy and completeness of our financial reports, the market price of our stock could decline and we could be subject to sanctions or investigations by Nasdaq, the SEC, or other regulatory authorities, which would require additional financial and management resources.

We may incur additional tax liabilities related to our operations.

We have a multinational tax structure and are subject to income tax in the U.S. and various foreign jurisdictions. Our effective tax rate is influenced by many factors including changes in our operating structure, changes in the mix of our earnings among countries, our allocation of profits and losses among our subsidiaries, our intercompany transfer pricing agreements and rules relating to transfer pricing, the availability of U.S. research and development tax credits, and future changes in tax laws and regulations in the U.S. and foreign countries. Significant judgment is required in determining our tax liabilities including management’s judgment for uncertain tax positions. The Internal Revenue Service, other domestic taxing authorities, or foreign taxing authorities may disagree with our interpretation of tax laws as applied to our operations. Our reported effective tax rate and after-tax cash flows may be materially and adversely affected by tax assessments in excess of amounts accrued for our financial statements. This could materially increase our future effective tax rate thereby reducing net income and adversely impacting our results of operations for future periods.

Our ability to use our net operating loss carryforwards and certain other tax attributes may be limited.

We have incurred substantial losses during our history. To the extent that we continue to generate taxable losses, unused taxable losses will, subject to certain limitations, carry forward to offset future taxable income, if any, until such unused losses expire. Under Sections 382 and 383 of the Internal Revenue Code of 1986, as amended, or the IRC, if a corporation undergoes an “ownership change,” generally defined as a greater than 50% change (by value) in its equity ownership over a three-year period, the corporation’s ability to use its pre-change net operating loss carryforwards, or NOL carryforwards, and other pre-change tax attributes (such as research tax credits) to offset its post-change income may be limited. An analysis to determine limitations upon our NOL carryforwards and other pre-change tax attributes for ownership changes that have occurred previously has been performed, resulting in a permanent decrease of federal and state NOL carryforwards in the amount of $7.2 million and a permanent decrease in federal research tax credit carryforwards in the amount of $0.2 million. As a result of these decreases and others that may occur as a result of future ownership changes, our ability to use our pre-change NOL carryforwards and other tax attribute carryforwards to offset U.S. federal taxable income and tax liabilities is limited and may become subject to even greater limitations, which could potentially accelerate or permanently increase future federal tax liabilities for us. In addition, there may be periods during which the use of state income tax NOL carryforwards and other state tax attribute carryforwards (such as state research tax credits) are suspended or otherwise limited, which could potentially accelerate or permanently increase future state tax liabilities for us.

Litigation may substantially increase our costs and harm our business.

We have been, and may in the future become, party to lawsuits including, without limitation, actions and proceedings in the ordinary course of business relating to our directors, officers, stockholders, intellectual property, and employment matters and policies, which will cause us to incur legal fees and other costs related thereto, including potential expenses for the reimbursement of legal fees of officers and directors under indemnification obligations. The expense of defending against such litigation may be significant and there can be no assurance that we will be successful in any defense. Further, the amount of time that may be required to resolve such lawsuits is unpredictable, and these actions may divert management’s attention from the day-to-day operations of our business, which could adversely affect our business, results of operations, and cash flows. Litigation is subject to inherent uncertainties, and an adverse result in such matters that may arise from time to time could have a material adverse effect on our business, results of operations, and financial condition.

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Item 2. Unregistered Sales of Equity Securities and Use of Proceeds

None.

Item 3. Defaults Upon Senior Securities

None.

Item 4. Mine Safety Disclosures

Not applicable.

Item 5. Other Information

None.

Item 6. Exhibits

		Incorporated by Reference
Exhibit Number	Exhibit Description	Form	Date	Number	Furnished or Filed Herewith
3.1	Amended and Restated Certificate of Incorporation	8-K	2/5/2014	3.1
3.2	Amended and Restated Bylaws	8-K	2/5/2014	3.2
4.1	Form of Common Stock Certificate	S-1	11/8/2013	4.2
4.2	Form of Indenture	S-3ASR	2/12/2021	4.2
10.1#*	Form of Performance Stock Unit Agreement (2022)				X
31.1	Certification of Principal Executive Officer Required Under Rule 13a-14(a) or Rule 15d-14(a) of the Exchange Act				X
31.2	Certification of Principal Financial Officer Required Under Rule 13a-14(a) or Rule 15d-14(a) of the Exchange Act				X
32.1**	Certification of Principal Executive Officer and Principal Financial Officer Required Under Rule 13a-14(b) or Rule 15d-14(b) of the Exchange Act and 18 U.S.C. 1350				X
101.INS	XBRL Instance Document, formatted in Inline XBRL				X
101.SCH	Inline XBRL Taxonomy Extension Schema Document				X
101.CAL	Inline XBRL Taxonomy Extension Calculation Linkbase Document				X
101.DEF	Inline XBRL Taxonomy Extension Definition Linkbase Document				X
101.LAB	Inline XBRL Taxonomy Extension Labels Linkbase Document				X
101.PRE	Inline XBRL Taxonomy Extension Presentation Linkbase Document				X
104	Cover Page Interactive Data File, formatted in Inline XBRL (included in Exhibit 101).

# Indicates management contract or compensatory plan.

* Certain confidential portions of this exhibit were omitted by means of marking such portions with asterisks because the identified confidential portions (i) are not material and (ii) would be competitively harmful if publicly disclosed.

** The certification attached as Exhibit 32.1 that accompanies this Quarterly Report is furnished to, and not deemed filed with, the SEC and is not to be incorporated by reference into any filing of the Registrant under the Securities Act or the Exchange Act, whether made before or after the date of this Form 10-Q, irrespective of any general incorporation language contained in such filing.

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SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.

	ULTRAGENYX PHARMACEUTICAL INC.
Date: May 5, 2022	By:	/s/ Emil D. Kakkis
		Emil D. Kakkis, M.D., Ph.D.
		President and Chief Executive Officer (Principal Executive Officer)
Date: May 5, 2022	By:	/s/ Mardi C. Dier
		Mardi C. Dier
		Executive Vice President and Chief Financial Officer (Principal Financial Officer)
Date: May 5, 2022	By:	/s/ Theodore A. Huizenga
		Theodore A. Huizenga
		Senior Vice President and Chief Accounting Officer (Principal Accounting Officer)

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EX-10.1

Exhibit 10.1

[***] = CERTAIN CONFIDENTIAL INFORMATION CONTAINED IN THIS DOCUMENT, MARKED BY BRACKETS, HAS BEEN OMITTED BECAUSE THE INFORMATION (I) IS NOT MATERIAL AND (II) WOULD BE COMPETITIVELY HARMFUL IF PUBLICLY DISCLOSED

Name: [●]

Target Number of Performance Stock Units subject to Award: [●]

Date of Grant: [●]

ULTRAGENYX PHARMACEUTICAL INC.

2014 INCENTIVE PLAN

PERFORMANCE STOCK UNIT AGREEMENT (2022)

This agreement (this “Agreement”) evidences an award (the “Award”) of performance stock units (the “Performance Stock Units”) granted by Ultragenyx Pharmaceutical Inc. (the “Company”) to the undersigned (the “Grantee”) pursuant to and subject to the terms of the Ultragenyx Pharmaceutical Inc. 2014 Incentive Plan (as amended from time to time, the “Plan”), which is incorporated herein by reference.

1.Grant of Performance Stock Units. The Company grants to the Grantee on the date set forth above (the “Date of Grant”) an award consisting of the right to receive on the terms provided herein and in the Plan, one share of Stock with respect to each Performance Stock Unit forming part of the Award, in each case, subject to adjustment pursuant to Section 7(b) of the Plan in respect of transactions occurring after the date hereof.

2.Meaning of Certain Terms. Except as otherwise defined herein, all capitalized terms used herein have the same meaning as in the Plan.

3.Vesting.

a.Unless earlier terminated, forfeited, relinquished or expired, and subject to the Grantee’s continued employment through the applicable vesting dates, 80% of the Performance Stock Units shall vest in accordance with Section 3(b) (the “Revenue PSUs”) and the remaining 20% of the Performance Stock Units shall vest in accordance with Section 3(c) (the “TSR PSUs”).

b.The Revenue PSUs shall vest as follows:

(i)If the Administrator certifies that the revenue performance metric set forth in Appendix A attached hereto (the “Revenue Vesting Metric”) has been achieved at at least the threshold level of performance during the period beginning on January 1, 2022 and ending on December 31, 2023 (the “Revenue Performance Period”),100% of the Earned Revenue PSUs (as determined pursuant to Appendix A) shall vest on the later of (x) the date on which the Administrator certified such achievement and (y) March 1, 2024 (such date, the “First Time-Based Vesting Date”).

Notwithstanding anything to the contrary in this Section 3(b), in the event that the Company fails to achieve the threshold level of performance under the Revenue Vesting Metric during the Revenue Performance Period, the

vesting of the Revenue PSUs shall immediately cease and all of the Revenue PSUs shall be immediately forfeited as of the last day of the Revenue Performance Period.

c.If the Administrator certifies that the relative total stockholder return performance metric set forth in Appendix B attached hereto (the “TSR Vesting Metric”) has been achieved at at least the threshold level of performance during the period beginning on January 1, 2022 and ending on December 31, 2024 (the “TSR Performance Period”), 100% of the Earned TSR PSUs (as determined pursuant to Appendix B) shall vest on the later of (x) the date on which the Administrator certified such achievement and (y) March 1, 2025.

d.Notwithstanding anything to the contrary in Section 3(b) or Section 3(c) above and subject to the conditions set forth below, if the Company consummates a Covered Transaction prior to the end of the Revenue Performance Period and/or TSR Performance Period, the Performance Stock Units granted hereby that have not otherwise vested or been terminated, forfeited, relinquished or expired prior to the Covered Transaction shall automatically become a number of time-vested restricted stock units (“Restricted Stock Units”) assuming the greater of (i) the target level of performance or (ii) (x) with respect to the Revenue Vesting Metric, the expected (as determined by the Administrator) level of performance and (y) with respect to the TSR Vesting Metric, the actual level of performance through the date of the Covered Transaction, which Restricted Stock Units shall vest on the first anniversary of the Covered Transaction, subject to Grantee’s continued employment through that date. If the Administrator certifies that the Revenue Vesting Metric has been achieved during the Revenue Performance Period and prior to the Covered Transaction, the applicable Time-Based Vesting Dates for those Earned Performance Stock Units shall not be affected by any Covered Transaction, and such Earned Performance Stock Units shall continue to vest based on their applicable Time-Based Vesting Dates.

4.Delivery of Stock. The Company shall deliver to the Grantee as soon as practicable upon the vesting of the Performance Stock Units (or, if applicable, Restricted Stock Units) or any portion thereof, but in all events no later than March 15th of the year following the year in which such units vest, one share of Stock with respect to each such vested unit, subject to the terms of the Plan and this Agreement.

5.Dividends; Other Rights. The Award shall not be interpreted to bestow upon the Grantee any equity interest or ownership in the Company or any Affiliate prior to the date on which the Company delivers shares of Stock to the Grantee (if any). The Grantee is not entitled to vote any shares of Stock by reason of the granting of this Award or to receive or be credited with any dividends declared and payable on any share of Stock prior to the date on which any such share is delivered to the Grantee hereunder. The Grantee shall have the rights of a shareholder only as to those shares of Stock, if any, that are actually delivered under this Award.

6.Forfeiture; Recovery of Compensation.

a.The Administrator may cancel, rescind, withhold or otherwise limit or restrict the Award at any time if the Grantee is not in compliance with all applicable provisions of this Agreement and the Plan.

b.By accepting the Award the Grantee expressly acknowledges and agrees that his or her rights, and those of any permitted transferee of the Award, under the Award to any Stock acquired under the Award or proceeds from the disposition thereof, are subject to Section 6(a)(5) of the Plan (including any successor provision). Nothing in the preceding sentence shall be construed as limiting the general application of Section 10 hereof.

7.Nontransferability. Neither the Award nor the Performance Stock Units (or, if applicable, Restricted Stock Units) may be transferred except as expressly permitted under Section 6(a)(3) of the Plan.

8.Certain Tax Matters.

a.The Grantee expressly acknowledges and agrees that the Grantee’s rights hereunder, including the right to be issued shares of Stock upon the vesting of the Performance Stock Units (or, if applicable,

2

Restricted Stock Units) (or any portion thereof), are subject to the Grantee’s promptly paying, or in respect of any later requirement of withholding being liable promptly to pay at such time as such withholdings are due, to the Company in cash (or by such other means as may be acceptable to the Administrator in its discretion) all taxes required to be withheld, if any (the “Tax Withholding Obligation”). No shares of Stock will be transferred pursuant to the vesting of the Performance Stock Units (or, if applicable, Restricted Stock Units) (or any portion thereof) unless and until the Grantee or the person then holding the Award has remitted to the Company an amount in cash sufficient to satisfy any federal, state, or local withholding tax requirements then due and has committed (and by accepting this Award the Grantee shall be deemed to have committed) to pay in cash all tax withholdings required at any later time in respect of the transfer of such shares, or has made other arrangements satisfactory to the Company with respect to such taxes. The Grantee also authorizes the Company and its subsidiaries to withhold such amount from any amounts otherwise owed to the Grantee, but nothing in this sentence shall be construed as relieving the Grantee of any liability for satisfying his or her obligations under the preceding provisions of this Section 8.

b.The Grantee expressly acknowledges that the Grantee’s acceptance of this Agreement constitutes the Grantee’s instruction and authorization to the Company and any brokerage firm determined acceptable to the Company for such purpose to sell on the Grantee’s behalf a whole number of shares from those shares of Stock issuable to the Grantee as the Company determines to be appropriate to generate cash proceeds sufficient to satisfy the applicable Tax Withholding Obligation, and to transfer the proceeds from the sale of such Stock from the Grantee’s securities account established with the brokerage service provider for the settlement of the Grantee’s vested Performance Stock Units (or, if applicable, Restricted Stock Units) to any account held in the name of the Company. Such shares will be sold on the date of vesting or as soon thereafter as practicable. Grantee will be responsible for all brokers’ fees and other costs of sale, which fees and costs may be deducted from the proceeds of the foregoing sale of Stock, and Grantee agrees to indemnify and hold the Company and any brokerage firm selling such Stock harmless from any losses, costs, damages, or expenses relating to any such sale. To the extent the proceeds of such sale exceed Grantee’s Tax Withholding Obligation, such excess cash will be deposited into the securities account established with the brokerage service provider for the settlement of Grantee’s vested Performance Stock Units (or, if applicable, Restricted Stock Units). Grantee acknowledges that the Company or its designee is under no obligation to arrange for such sale at any particular price, and that the proceeds of any such sale may not be sufficient to satisfy Grantee’s Tax Withholding Obligation. Accordingly, Grantee agrees to pay to the Company as soon as practicable, including through additional payroll withholding, any amount of the Tax Withholding Obligation that is not satisfied by the sale of shares described above. Unless otherwise authorized by the Administrator in its sole discretion, the sale of Stock will be the primary method used by the Company to satisfy the applicable Tax Withholding Obligation.

c.The Grantee expressly acknowledges that because this Award consists of an unfunded and unsecured promise by the Company to deliver Stock in the future, subject to the terms hereof, it is not possible to make a so-called “83(b) election” with respect to the Award.

9.Effect on Employment. Neither the grant of the Award, nor the issuance of Shares upon vesting of the Award, will give the Grantee any right to be retained in the employ or service of the Company or any of its Affiliates, affect the right of the Company or any of its Affiliates to discharge or discipline such Grantee at any time, or affect any right of such Grantee to terminate his or her Employment at any time.

10.Provisions of the Plan. This Agreement is subject in its entirety to the provisions of the Plan, which are incorporated herein by reference. A copy of the Plan as in effect on the Date of Grant has been furnished to the Grantee. By accepting the Award, the Grantee agrees to be bound by the terms of the Plan and this Agreement. In the event of any conflict between the terms of this Agreement and the Plan, the terms of the Plan shall control.

11.Acknowledgments. The Grantee acknowledges and agrees that (a) this Agreement may be executed in two or more counterparts, each of which shall be an original and all of which together shall constitute one and the same instrument, (b) this agreement may be executed and exchanged using facsimile, portable document format (PDF) or electronic signature, which, in each case, shall constitute an original signature for all purposes hereunder

3

and (c) such signature by the Company will be binding against the Company and will create a legally binding agreement when this Agreement is countersigned by the Grantee.

[The remainder of this page is intentionally left blank.]

4

IN WITNESS WHEREOF, the Company has caused this Agreement to be executed by its duly authorized officer.

ULTRAGENYX PHARMACEUTICAL INC.

By:

Name:

Title:

Dated:

Acknowledged and Agreed:

By:

[Grantee’s Name]

5

Appendix A

The performance metric applicable to the Revenue PSUs shall be GAAP revenue for the Company over the Revenue Performance Period, with the number of Earned Revenue PSUs equal to the number of Revenue PSUs subject to the Award multiplied by the applicable percentage set forth in the following table:

Level of Performance	Aggregate GAAP Revenue(1) for FY 2022 and FY 2023	Earned Revenue PSUs(2)
Threshold	$[***]	50%
Target	$[***]	100%
Maximum	$[***]	200%

(1) Target revenue assumes [***].

(2) For performance between threshold and target and between target and maximum, the percentage of the Revenue PSUs that become Earned Revenue PSUs will be determined on a straight-line interpolated basis.

6

Appendix B

The performance metric applicable to the TSR PSUs shall be the Company’s Total Stockholder Return (as defined below) relative to the Total Stockholder Return of the companies in the NASDAQ Biotechnology Index (NBI) (the “Peer Group”), with the number of Earned TSR PSUs equal to the number of TSR PSUs subject to the Award multiplied by the applicable percentage set forth in the following table:

Level of Performance	TSR Percentile(1)	Earned TSR PSUs(2)
Threshold	25th	25%
Target	50th	100%
Stretch	75th	150%
Maximum	90th	200%

(1) TSR Percentile is calculated based on the Company’s ranking within the Peer Group based on its Total Stockholder Return as compared to the Total Stockholder Return of each member of the Peer Group.

(2) For performance between threshold and target, between target and stretch and between stretch and maximum, the percentage of the TSR PSUs that become Earned TSR PSUs will be determined on a straight-line interpolated basis.

“Total Stockholder Return” of the Company and of each member of the Peer Group shall be determined pursuant to the following formula:

Total Stockholder Return = (Final Stock Price - Initial Stock Price) + Reinvested Dividends

Initial Stock Price

For purposes of this formula, (a) “Final Stock Price” shall be the relevant company’s average closing stock price for the two-month period preceding the last trading day of the TSR Performance Period, (b) “Initial Stock Price” shall be the relevant company’s average closing stock price for the two-month period preceding the first trading day of the Performance Period, and (c) “Reinvested Dividends” shall be the aggregate number of shares (including fractional shares) that could have been purchased during the TSR Performance Period had each cash dividend paid on a single share during that period been immediately reinvested in additional shares (or fractional shares) at the closing stock price on the applicable dividend payment date. Each of the foregoing amounts shall be equitably adjusted for stock splits, stock dividends, recapitalizations and other similar events affecting the shares in question without the issuer’s receipt of consideration.

EX-31.1

Exhibit 31.1

CERTIFICATION PURSUANT TO SECTION 302 OF THE SARBANES-OXLEY ACT OF 2002

I, Emil D. Kakkis, certify that:

1.I have reviewed this Quarterly Report on Form 10-Q of Ultragenyx Pharmaceutical Inc.;

2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3.Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

4.The registrant’s other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

a)Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

b)Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

c)Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

d)Disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during the registrant’s most recent fiscal quarter (the registrant’s fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

5.The registrant’s other certifying officer and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant’s auditors and the audit committee of registrant’s Board of Directors (or persons performing the equivalent functions):

a)All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize and report financial information; and

b)Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

Dated: May 5, 2022	/s/ Emil D Kakkis
	Emil D. Kakkis, M.D., Ph.D.
	President and Chief Executive Officer
	(Principal Executive Officer)

EX-31.2

Exhibit 31.2

CERTIFICATION PURSUANT TO SECTION 302 OF THE SARBANES-OXLEY ACT OF 2002

I, Mardi C. Dier, certify that:

1.I have reviewed this Quarterly Report on Form 10-Q of Ultragenyx Pharmaceutical Inc.;

2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3.Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations and cash flows of the registrant as of, and for, the periods presented in this report;

4.The registrant’s other certifying officer and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) and internal control over financial reporting (as defined in Exchange Act Rules 13a-15(f) and 15d-15(f)) for the registrant and have:

a)Designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

b)Designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

c)Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of the end of the period covered by this report based on such evaluation; and

d)Disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during the registrant’s most recent fiscal quarter (the registrant’s fourth fiscal quarter in the case of an annual report) that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

5.The registrant’s other certifying officer and I have disclosed, based on our most recent evaluation of internal control over financial reporting, to the registrant’s auditors and the audit committee of registrant’s Board of Directors (or persons performing the equivalent functions):

a)All significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize and report financial information; and

b)Any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

Dated: May 5, 2022	/s/ Mardi C. Dier
	Mardi C. Dier
	Executive Vice President and Chief Financial Officer
	(Principal Financial Officer)

EX-32.1

Exhibit 32.1

CERTIFICATION PURSUANT TO SECTION 906 OF

THE SARBANES-OXLEY ACT OF 2002 (18 U.S.C. SECTION 1350)

In connection with the accompanying Quarterly Report of Ultragenyx Pharmaceutical Inc. (the “Company”) on Form 10-Q for the quarter ended March 31, 2022 (the “Report”), I, Emil D. Kakkis, M.D., Ph.D., as President and Chief Executive Officer of the Company, and Mardi C. Dier, as Executive Vice President and Chief Financial Officer of the Company, certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that:

(1)The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

(2)The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

Dated: May 5, 2022	/s/ Emil D. Kakkis
	Emil D. Kakkis, M.D., Ph.D.
	President and Chief Executive Officer (Principal Executive Officer)
Dated: May 5, 2022	/s/ Mardi C. Dier
	Mardi C. Dier
	Executive Vice President and Chief Financial Officer (Principal Financial Officer)

XML

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2022	May 02, 2022
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2022
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q1
Trading Symbol	RARE
Entity Registrant Name	ULTRAGENYX PHARMACEUTICAL INC.
Entity Central Index Key	0001515673
Entity Current Reporting Status	Yes
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		69,930,191
Entity Shell Company	false
Entity File Number	001-36276
Entity Tax Identification Number	27-2546083
Entity Address, Address Line One	60 Leveroni Court
Entity Address, City or Town	Novato
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94949
City Area Code	415
Local Phone Number	483-8800
Entity Interactive Data Current	Yes
Title of 12(b) Security	Common Stock, $0.001 par value
Security Exchange Name	NASDAQ
Entity Incorporation, State or Country Code	DE
Document Quarterly Report	true
Document Transition Report	false

XML

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 153,988	$ 307,584
Marketable debt securities	444,333	432,612
Accounts receivable, net	28,369	28,432
Inventory	17,809	16,231
Prepaid expenses and other current assets	63,020	71,745
Total current assets	707,519	856,604
Property, plant, and equipment, net	177,073	141,247
Equity investments	25,596	34,925
Marketable debt securities	215,526	258,933
Right-of-use assets	32,699	34,936
Intangible assets, net	159,992	130,788
Goodwill	44,406	44,406
Other assets	21,218	20,558
Total assets	1,384,029	1,522,397
Current liabilities:
Accounts payable	23,685	17,138
Accrued liabilities	126,356	145,555
Contract liabilities	5,867	7,609
Lease liabilities	11,323	11,066
Total current liabilities	167,231	181,368
Lease liabilities	28,043	30,904
Contract liabilities	0	1,467
Deferred tax liabilities	33,306	33,306
Liability related to the sale of future royalties	355,633	351,786
Other liabilities	3,392	1,005
Total liabilities	587,605	599,836
Stockholders’ equity:
Preferred stock - 25,000,000 shares authorized; nil outstanding as of March 30, 2022 and December 31, 2021	0	0
Common stock - 250,000,000 shares authorized; 67,961,963 and 66,818,520 shares issued and outstanding as of March 31, 2021 and December 31, 2021, respectively	70	69
Additional paid-in capital	3,028,829	2,997,497
Accumulated other comprehensive loss	(6,554)	(1,404)
Accumulated deficit	(2,225,921)	(2,073,601)
Total stockholders’ equity	796,424	922,561
Total liabilities and stockholders’ equity	$ 1,384,029	$ 1,522,397

XML

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - shares	Mar. 31, 2022	Dec. 31, 2021
Statement of Financial Position [Abstract]
Preferred stock, shares authorized	25,000,000	25,000,000
Preferred stock, shares outstanding	0	0
Common stock, shares authorized	250,000,000	250,000,000
Common stock, shares issued	69,796,940	69,344,998
Common stock, shares outstanding	69,796,940	69,344,998

XML

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Revenues:
Total revenues	$ 79,935	$ 99,395
Operating expenses:
Cost of sales	6,100	5,188
Research and development	143,155	147,518
Selling, general and administrative	67,312	53,258
Total operating expenses	216,567	205,964
Loss from operations	(136,632)	(106,569)
Interest income	494	639
Change in fair value of equity investments	(9,329)	(20,619)
Non-cash interest expense on liability related to the sale of future royalties	(6,584)	(8,418)
Other income (expense)	289	(795)
Loss before income taxes	(151,762)	(135,762)
Provision for income taxes	(558)	(379)
Net loss	$ (152,320)	$ (136,141)
Net loss per share, basic and diluted	$ (2.19)	$ (2.03)
Weighted-average shares used in computing net loss per share, basic and diluted	69,516,668	67,102,342
Collaboration and License
Revenues:
Total revenues	$ 48,413	$ 79,010
Product Sales
Revenues:
Total revenues	26,684	16,513
Non-cash Collaboration Royalty Revenue
Revenues:
Total revenues	$ 4,838	$ 3,872

XML

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Statement of Comprehensive Income [Abstract]
Net loss	$ (152,320)	$ (136,141)
Other comprehensive income (loss):
Foreign currency translation adjustments	(60)	(285)
Unrealized loss on available-for-sale securities	(5,090)	(348)
Other comprehensive loss:	(5,150)	(633)
Total comprehensive loss	$ (157,470)	$ (136,774)

XML

CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Beginning balance at Dec. 31, 2020	$ 1,154,375	$ 67	$ 2,773,195	$ (689)	$ (1,619,576)
Beginning balance, shares at Dec. 31, 2020		66,818,520
Stock-based compensation	24,220		24,220
Issuance of common stock under equity plan awards, net of tax	12,761		12,761
Issuance of common stock under equity plan awards, net of tax, shares		620,957
Other comprehensive income (loss)	(633)			(633)
Net loss	(136,141)				(136,141)
Ending balance at Mar. 31, 2021	1,054,582	$ 67	2,810,176	56	(1,755,717)
Ending balance, shares at Mar. 31, 2021		67,439,477
Beginning balance at Dec. 31, 2021	$ 922,561	$ 69	2,997,497	1,404	(2,073,601)
Beginning balance, shares at Dec. 31, 2021	69,344,998	69,344,998
Issuance of common stock in connection with at-the-market offering, net of issuance costs, shares	1,050,372
Stock-based compensation	$ 29,578		29,578
Issuance of common stock under equity plan awards, net of tax	1,755	$ 1	1,754
Issuance of common stock under equity plan awards, net of tax, shares		451,942
Other comprehensive income (loss)	(5,150)			(5,150)
Net loss	(152,320)				(152,320)
Ending balance at Mar. 31, 2022	$ 796,424	$ 70	$ 3,028,829	$ (6,554)	$ (2,225,921)
Ending balance, shares at Mar. 31, 2022	69,796,940	69,796,940

XML

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating activities:
Net loss	$ (152,320)	$ (136,141)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	29,396	24,254
Amortization of premium on marketable debt securities, net	1,894	940
Depreciation and amortization	4,088	3,367
Change in fair value of equity investments	9,329	20,619
Non-cash collaboration royalty revenue	(4,838)	(3,872)
Non-cash interest expense on liability related to the sale of future royalties	6,584	8,418
Other	35	325
Changes in operating assets and liabilities:
Accounts receivable	33	(1,993)
Inventory	(1,475)	474
Prepaid expenses and other assets	9,126	(10,656)
Accounts payable, accrued, and other liabilities	(16,164)	(23,602)
Contract liabilities	(3,209)	(41,479)
Net cash used in operating activities	(117,521)	(159,346)
Investing activities:
Purchase of property, plant, and equipment	(32,184)	(16,414)
Purchase of marketable debt securities	(203,710)	(405,230)
Proceeds from sale of marketable debt securities	39,422	14,980
Proceeds from maturities of marketable debt securities	188,990	224,240
Purchase of mutual funds related to nonqualified deferred compensation plan	(2,458)
Payment for intangible asset	(30,000)
Other	2,578
Net cash used in investing activities	(37,362)	(182,424)
Financing activities:
Proceeds from the issuance of common stock equity plan awards, net	1,755	12,761
Other	(143)	(112)
Net cash provided by financing activities	1,612	12,649
Effect of exchange rate changes on cash	(108)	(771)
Net decrease in cash, cash equivalents and restricted cash	(153,379)	(329,892)
Cash, cash equivalents and restricted cash at beginning of period	309,585	726,294
Cash, cash equivalents and restricted cash at end of period	156,206	$ 396,402
Supplemental disclosures of non-cash information:
Acquired lease liabilities arising from obtaining right-of-use assets	132
Non-cash interest expense on liability related to the sale of future royalties capitalized into ending property, plant and equipment	$ 2,101

XML

Organization

3 Months Ended

Mar. 31, 2022

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Organization

1. Organization

Ultragenyx Pharmaceutical Inc. (the Company) is a biopharmaceutical company incorporated in Delaware.

The Company is focused on the identification, acquisition, development, and commercialization of novel products for the treatment of serious rare and ultra-rare genetic diseases. The Company operates as one reportable segment. The Company has four commercially approved products.

Crysvita® (burosumab) is approved in the United States (U.S.) by the U.S. Food and Drug Administration (FDA) and in Canada for the treatment of X-linked hypophosphatemia (XLH) in adult and pediatric patients one year of age and older, and is approved in the European Union (EU) and the United Kingdom, for the treatment of XLH with radiographic evidence of bone disease in children one year of age and older, adolescents, and adults. In Brazil, Colombia, and Mexico, Crysvita is approved for treatment of XLH in adult and pediatric patients one year of age and older. Crysvita is also approved in the U.S. by the FDA for the treatment of fibroblast growth factor 23 (FGF23)-related hypophosphatemia in tumor-induced osteomalacia (TIO), associated with phosphaturic mesenchymal tumors that cannot be curatively resected or localized in adults and pediatric patients 2 years of age and older.

Mepsevii® (vestronidase alfa) is approved by the FDA as the first medicine for the treatment of children and adults with mucopolysaccharidosis VII (MPS VII), also known as Sly syndrome. In the European Union and the United Kingdom, Mepsevii is approved under exceptional circumstances for patients of all ages for the treatment of non-neurological manifestations of MPS VII. In Brazil, Mepsevii is approved for the treatment of MPS VII for patients of all ages.

Dojolvi® (triheptanoin) is approved in the U.S., Canada, and Brazil for the treatment of pediatric and adult patients severely affected by long-chain fatty acid oxidation disorders (LC-FAOD).

On January 7, 2022, the Company announced a collaboration with Regeneron Pharmaceuticals (Regeneron) to commercialize Evkeeza® (evinacumab) outside of the U.S. Evkeeza is approved in the U.S. and the European Economic Area (EEA) for the treatment of homozygous familial hypercholesterolemia (HoFH).

In addition to the approved products, the Company has the following ongoing clinical development programs:

•DTX401 is an adeno-associated virus 8 (AAV8) gene therapy product candidate for the treatment of patients with glycogen storage disease type Ia (GSDIa);

•DTX301 is an AAV8 gene therapy product candidate in development for the treatment of patients with ornithine transcarbamylase (OTC) deficiency, the most common urea cycle disorder;

•UX143 (setrusumab), which is subject to the Company's collaboration agreement with Mereo BioPharma 3 (Mereo), is a fully human monoclonal antibody that inhibits sclerostin, a protein that acts on a key bone-signaling pathway and inhibits the activity of bone-forming cells for the treatment of patients with osteogenesis imperfect (OI);

•GTX-102 is an antisense oligonucleotide (ASO), which the Company is collaborating on the development with GeneTx Biotherapeutics LLC (GeneTx) for the treatment of Angelman syndrome, a debilitating and rare neurogenetic disorder caused by loss-of-function of the maternally inherited allele of the UBE3A gene;

•UX701 is an AAV type 9 gene therapy designed to deliver stable expression of a truncated version of the ATP7B copper transporter following a single intravenous infusion to improve copper distribution and excretion from the body and reverse pathological findings of Wilson liver disease; and

•UX053 is a messenger RNA (mRNA) product candidate designed for the treatment of patients with Glycogen Storage Disease Type III (GSDIII), a disease caused by a glycogen debranching enzyme (AGL) deficiency that results in glycogen accumulation in the liver and muscle.

The Company has sustained operating losses and expects such annual losses to continue over the next several years. The Company’s ultimate success depends on the outcome of its research and development and commercialization activities, for which it expects to incur additional losses in the future. Management recognizes that the Company will likely need to raise additional capital to fully implement its business plans. Through March 31, 2022, the Company has relied primarily on its sale of equity securities, its revenues from commercial products, its sale of future royalties, and strategic collaboration arrangements to finance its operations.

The Company will likely raise additional capital through the issuance of equity, borrowings, or strategic alliances with partner companies. However, if such financing is not available at adequate levels, the Company would need to reevaluate its operating plans.

XML

Summary of Significant Accounting Policies

3 Months Ended

Mar. 31, 2022

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

2. Summary of Significant Accounting Policies

Basis of Presentation

The accompanying unaudited Condensed Consolidated Financial Statements include the accounts of the Company and its wholly-owned subsidiaries and have been prepared in accordance with U.S. generally accepted accounting principles (GAAP) for interim financial information and in accordance with the instructions to Form 10-Q and Rule 10-01 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. The unaudited interim Condensed Consolidated Financial Statements have been prepared on the same basis as the annual financial statements. In the opinion of management, the accompanying unaudited Condensed Consolidated Financial Statements reflect all adjustments (consisting only of normal recurring adjustments) considered necessary for a fair presentation. These financial statements should be read in conjunction with the audited financial statements and notes thereto for the preceding fiscal year contained in the Company’s Annual Report on Form 10-K filed on February 15, 2022 (Annual Report) with the United States Securities and Exchange Commission (the SEC).

The results of operations for the three months ended March 31, 2022 are not necessarily indicative of the results to be expected for the year ending December 31, 2022. The Condensed Consolidated Balance Sheet as of December 31, 2021 has been derived from audited financial statements at that date, but does not include all of the information required by GAAP for complete financial statements.

Use of Estimates

The accompanying Condensed Consolidated Financial Statements have been prepared in accordance with GAAP. The preparation of the Condensed Consolidated Financial Statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent liabilities and the reported amounts of expenses in the Condensed Consolidated Financial Statements and the accompanying notes. On an ongoing basis, management evaluates its estimates, including those related to clinical trial accruals, fair value of assets and liabilities, income taxes, stock-based compensation, revenue recognition, and the liability related to the sale of future royalties. Management bases its estimates on historical experience and on various other market-specific and relevant assumptions that management believes to be reasonable under the circumstances. Actual results could differ from those estimates.

Cash, Cash Equivalents and Restricted Cash

Restricted cash primarily consists of money market accounts used as collateral for the Company’s obligations under its facility leases and the gene therapy building construction project. The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the Condensed Consolidated Balance Sheets that sum to the total of the same such amounts shown in the Condensed Consolidated Statement of Cash Flows (in thousands):

	March 31,
	2022		2021
Cash and cash equivalents	$	153,988	$	383,794
Restricted cash included in prepaid expenses and     other current assets		217		10,687
Restricted cash included in other assets		2,001		1,921
Total cash, cash equivalents, and restricted cash     shown in the statements of cash flows	$	156,206	$	396,402

Credit Losses

The Company is exposed to credit losses primarily through receivables from customers and collaborators and through its available-for-sale debt securities. For trade receivables and other instruments, the Company uses a forward-looking expected loss

model that generally results in the earlier recognition of allowances for losses. For available-for-sale debt securities with unrealized losses, the losses are recognized as allowances rather than as reductions in the amortized cost of the securities.

The Company’s expected loss allowance methodology for the receivables is developed using historical collection experience, current and future economic market conditions, a review of the current aging status and financial condition of the entities. Specific allowance amounts are established to record the appropriate allowance for customers that have a higher probability of default. Balances are written off when determined to be uncollectible. The Company’s expected loss allowance methodology for the debt securities is developed by reviewing the extent of the unrealized loss, the size, term, geographical location, and industry of the issuer, the issuers’ credit ratings and any changes in those ratings, as well as reviewing current and future economic market conditions and the issuers’ current status and financial condition. There were no material credit losses recorded for receivables and available-for-sale debt securities for the three months ended March 31, 2022 and 2021.

Revenue Recognition

Collaboration and license revenue

The Company has certain license and collaboration agreements that are within the scope of Accounting Standards Codification (ASC) 808, Collaborative Agreements, which provides guidance on the presentation and disclosure of collaborative arrangements. Generally, the classification of the transactions under the collaborative arrangements is determined based on the nature of contractual terms of the arrangement, along with the nature of the operations of the participants. The Company records its share of collaboration revenue, net of transfer pricing related to net sales in the period in which such sales occur, if the Company is considered as an agent in the arrangement. The Company is considered an agent when the collaboration partner controls the product before transfer to the customers and has the ability to direct the use of and obtain substantially all of the remaining benefits from the product. Funding received related to research and development services and commercialization costs is generally classified as a reduction of research and development expenses and selling, general and administrative expenses, respectively, in the Condensed Consolidated Statement of Operations, because the provision of such services for collaborative partners are not considered to be part of the Company’s ongoing major or central operations.

In order to record collaboration revenue, the Company utilizes certain information from its collaboration partners, including revenue from the sale of the product, associated reserves on revenue, and costs incurred for development and sales activities. For the periods covered in the financial statements presented, there have been no material changes to prior period estimates of revenues and expenses.

The Company sold the right to receive certain royalty payments from net sales of Crysvita to RPI Finance Trust (RPI), an affiliate of Royalty Pharma, as further described in Note 7. The Company records the royalty revenue from the net sales of Crysvita in the applicable European territories on a prospective basis as non-cash royalty revenue in the Condensed Consolidated Statements of Operations over the term of the arrangement.

The terms of the Company’s collaboration and license agreements may contain multiple performance obligations, which may include licenses and research and development activities. The Company evaluates these agreements under ASC 606, Revenue from Contracts with Customers (ASC 606), to determine the distinct performance obligations. The Company analogizes to ASC 606 for the accounting for distinct performance obligations for which there is a customer relationship. Prior to recognizing revenue, the Company makes estimates of the transaction price, including variable consideration that is subject to a constraint. Amounts of variable consideration are included in the transaction price to the extent that it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur and when the uncertainty associated with the variable consideration is subsequently resolved. Total consideration may include nonrefundable upfront license fees, payments for research and development activities, reimbursement of certain third-party costs, payments based upon the achievement of specified milestones, and royalty payments based on product sales derived from the collaboration.

If there are multiple distinct performance obligations, the Company allocates the transaction price to each distinct performance obligation based on its relative standalone selling price. The standalone selling price is generally determined based on the prices charged to customers or using expected cost-plus margin. The Company estimates the efforts needed to complete the performance obligations and recognizes revenue by measuring the progress towards complete satisfaction of the performance obligations using input measures.

Product sales

The Company sells its approved products through a limited number of distributors. Under ASC 606, revenue from product sales is recognized at the point in time when the delivery is made and when title and risk of loss transfers to these distributors. The Company also recognizes revenue from sales of certain products on a “named patient” basis, which are allowed in certain countries prior to the commercial approval of the product. Prior to recognizing revenue, the Company makes estimates of the transaction

price, including any variable consideration that is subject to a constraint. Amounts of variable consideration are included in the transaction price to the extent that it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur and when the uncertainty associated with the variable consideration is subsequently resolved. Product sales are recorded net of estimated government-mandated rebates and chargebacks, estimated product returns, and other deductions.

Provisions for returns and other adjustments are provided for in the period the related revenue is recorded, as estimated by management. These reserves are based on estimates of the amounts earned or to be claimed on the related sales and are reviewed periodically and adjusted as necessary. The Company’s estimates of government mandated rebates, chargebacks, estimated product returns, and other deductions depends on the identification of key customer contract terms and conditions, as well as estimates of sales volumes to different classes of payors. If actual results vary, the Company may need to adjust these estimates, which could have an effect on earnings in the period of the adjustment.

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Financial Instruments

3 Months Ended

Mar. 31, 2022

Fair Value Disclosures [Abstract]

Financial Instruments

3. Financial Instruments

Financial assets and liabilities are recorded at fair value. The carrying amount of certain financial instruments, including cash and cash equivalents, accounts receivable, accounts payable and accrued liabilities approximate fair value due to their relatively short maturities. Assets and liabilities recorded at fair value on a recurring basis in the balance sheets are categorized based upon the level of judgment associated with the inputs used to measure their fair values. Fair value is defined as the exchange price that would be received for an asset or an exit price that would be paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The authoritative guidance on fair value measurements establishes a three-tier fair value hierarchy for disclosure of fair value measurements as follows:

Level 1—Inputs are unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date;

Level 2—Inputs are observable, unadjusted quoted prices in active markets for similar assets or liabilities, unadjusted quoted prices for identical or similar assets or liabilities in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the related assets or liabilities; and

Level 3—Unobservable inputs that are significant to the measurement of the fair value of the assets or liabilities that are supported by little or no market data.

The Company determines the fair value of its equity investments in Arcturus Therapeutics Holdings Inc. (Arcturus) and Solid Biosciences Inc. (Solid) by using the quoted market prices, which are Level 1 fair value measurements.

The following tables set forth the fair value of the Company’s financial assets remeasured on a recurring basis based on the three-tier fair value hierarchy (in thousands):

	March 31, 2022
	Level 1		Level 2		Level 3		Total
Money market funds	$	113,600	$	—	$	—	$	113,600
Certificate of deposits and time deposits		—		27,101		—		27,101
Corporate bonds		—		384,474		—		384,474
Commercial paper		—		120,685		—		120,685
Asset-backed securities		—		12,875		—		12,875
U.S. Government Treasury and agency securities		7,172		106,344		—		113,516
Debt securities in government-sponsored entities		—		19,328		—		19,328
Investments in Arcturus and Solid common stock		22,871		—		—		22,871
Other		—		3,400		—		3,400
Total	$	143,643	$	674,207	$	—	$	817,850

	December 31, 2021
	Level 1		Level 2		Level 3		Total
Money market funds	$	266,765	$	—	$	—	$	266,765
Certificate of deposits and time deposits		—		16,000		—		16,000
Corporate bonds		—		349,691		—		349,691
Commercial paper		—		187,624		—		187,624
Asset-backed securities		—		41,245		—		41,245
U.S. Government Treasury and agency securities		—		87,435		—		87,435
Debt securities in government-sponsored entities		—		19,549		—		19,549
Investments in Arcturus and Solid common stock		32,200		—		—		32,200
Other		—		942		—		942
Total	$	298,965	$	702,486	$	—	$	1,001,451

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Balance Sheet Components

3 Months Ended

Mar. 31, 2022

Investments, Debt and Equity Securities [Abstract]

Balance Sheet Components

4. Balance Sheet Components

Cash Equivalents and Investments

The fair values of cash equivalents and investments classified as available-for-sale securities consisted of the following (in thousands):

	March 31, 2022
				Gross Unrealized
		Amortized Cost		Gains		Losses			Estimated Fair Value
Money market funds		$	113,600	$	—	$	—		$	113,600
Certificates of deposit and time deposits			27,101		—		—			27,101
Corporate bonds			389,619		1		(5,146	)		384,474
Commercial paper			120,686		—		(1	)		120,685
Asset-backed securities			12,924		—		(49	)		12,875
U.S. Government Treasury and agency securities			114,445		29		(958	)		113,516
Debt securities in government-sponsored entities			19,577		—		(249	)		19,328
Total		$	797,952	$	30	$	(6,403	)	$	791,579

	December 31, 2021
				Gross Unrealized
		Amortized Cost		Gains		Losses			Estimated Fair Value
Money market funds		$	266,765	$	—	$	—		$	266,765
Certificates of deposit and time deposits			16,000		—		—			16,000
Corporate bonds			350,667		3		(979	)		349,691
Commercial paper			187,624		—		—			187,624
Asset-backed securities			41,282		1		(38	)		41,245
U.S. Government Treasury and agency securities			87,642		1		(208	)		87,435
Debt securities in government-sponsored entities			19,612		—		(63	)		19,549
Total		$	969,592	$	5	$	(1,288	)	$	968,309

At March 31, 2022, the remaining contractual maturities of available-for-sale securities were less than three years. There have been no significant realized gains or losses on available-for-sale securities for the three months ended March 31, 2022 and 2021. The unrealized losses on the Company’s investments in marketable debt securities were caused by interest rate increases. The contractual terms of these investments do not permit the issuers to settle the securities at a price less than the par value.

Accordingly, it is expected that the securities would not be settled at a price less than the amortized cost basis of these investments. The Company does not intend to sell the investments and it is not more likely than not that the Company will be required to sell the investments before recovery of their amortized cost basis. All marketable securities with unrealized losses at March 31, 2022 have been in a loss position for less than twelve months.

Inventory

Inventory consists of the following (in thousands):

	March 31,		December 31,
	2022		2021
Work-in-process	$	11,989	$	10,504
Finished goods		5,820		5,727
Total inventory	$	17,809	$	16,231

Accrued Liabilities

Accrued liabilities consist of the following (in thousands):

	March 31,		December 31,
	2022		2021
Research, clinical study, and manufacturing expenses	$	40,092	$	40,880
Payroll and related expenses		41,638		62,591
Other		44,626		42,084
Total accrued liabilities	$	126,356	$	145,555

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Revenue

3 Months Ended

Mar. 31, 2022

Revenue from Contract with Customer [Abstract]

Revenue

5. Revenue

The following table disaggregates total revenues from customers (in thousands):

	Three Months Ended
	March 31,
	2022		2021
Collaboration and license revenue:
Crysvita collaboration revenue in profit-     share territory	$	45,164	$	36,260
Daiichi Sankyo		3,249		42,750
Total collaboration and license revenue		48,413		79,010
Product sales:
Crysvita		9,394		5,872
Mepsevii		4,861		3,607
Dojolvi		12,429		7,034
Total product sales		26,684		16,513
Crysvita non-cash collaboration royalty     revenue		4,838		3,872
Total revenues	$	79,935	$	99,395

The following table disaggregates total revenues based on geographic location (in thousands):

	Three Months Ended
	March 31,
	2022		2021
U.S. and Canada	$	61,917	$	87,742
Europe		8,227		5,637
Latin America		9,791		6,016
Total revenues	$	79,935	$	99,395

The following table presents changes in the contract liabilities (in thousands):

	Three Months Ended March 31,
	2022			2021
Balance of contract liabilities at beginning of period	$	(9,076	)	$	(66,568	)
Additions		(40	)		(1,271	)
Deductions		3,249			42,750
Balance of contract liabilities at end of period	$	(5,867	)	$	(25,089	)

See Note 6 for additional details on contract liabilities activities.

The Company’s largest accounts receivable balance accounted for 61% and 71% of the total accounts receivable balance as of March 31, 2022 and December 31, 2021, respectively, and was due from a collaboration partner.

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License and Research Agreements

3 Months Ended

Mar. 31, 2022

Research Grant Agreement [Abstract]

License and Research Agreements

6. License and Research Agreements

Kyowa Kirin Collaboration and License Agreement

In August 2013, the Company entered into a collaboration and license agreement with Kyowa Kirin Co., Ltd. (KKC or formerly Kyowa Hakko Kirin Co., Ltd. or KHK). Under the terms of this collaboration and license agreement, as amended, the Company and KKC collaborate on the development and commercialization of Crysvita in the field of orphan diseases in the U.S. and Canada, or the profit-share territory, and in the European Union, United Kingdom, and Switzerland, or the European territory, and the Company has the right to develop and commercialize such products in the field of orphan diseases in Mexico and Central and South America, or Latin America.

Development Activities

In the field of orphan diseases, and except for ongoing studies being conducted by KKC, the Company is the lead party for development activities in the profit-share territory and in the European territory until the applicable transition date. The Company shares the costs for development activities in the profit-share territory and the European territory conducted pursuant to the development plan before the applicable transition date equally with KKC. In April 2023, which is the transition date for the profit-share territory, KKC will become the lead party and be responsible for the costs of the development activities. However, the Company will continue to share the costs of the studies commenced prior to the applicable transition date equally with KKC.

The collaboration and license agreements are within the scope of ASC 808, which provides guidance on the presentation and disclosure of collaborative arrangements.

Collaboration revenue related to sales in profit-share territory

The Company and KKC share commercial responsibilities and profits in the profit-share territory until April 2023. Under the collaboration agreement, KKC manufactures and supplies Crysvita for commercial use in the profit-share territory and charges the Company the transfer price of 35% of net sales through December 31, 2022, and 30% thereafter. The remaining profit or loss after supply costs from commercializing products in the profit-share territory are shared between the Company and KKC on a 50/50 basis until April 2023. Thereafter, the Company will be entitled to receive a tiered double-digit revenue share in the mid-to-high 20% range.

As KKC is the principal in the sale transaction with the customer, the Company recognizes a pro-rata share of collaboration revenue, net of transfer pricing, in the period the sale occurs. The Company concluded that its portion of KKC’s sales in the profit-share territory is analogous to a royalty and therefore recorded its share as collaboration revenue, similar to a royalty.

Royalty revenue related to sales in European territory

KKC has the commercial responsibility for Crysvita in the European territory. In December 2019, the Company sold its right to receive royalty payments based on sales in the European territory to Royalty Pharma, effective January 1, 2020, as further described in Note 7. Prior to the Company’s sale of the royalty, the Company received a royalty of up to 10% on net sales in the European territory, which was recognized as the underlying sales occur. Beginning in 2020, the Company recorded the royalty revenue as non-cash royalty revenues.

The Company’s share of collaboration and royalty revenue related to Crysvita was as follows (in thousands):

	Three Months Ended March 31,
	2022		2021
Company's share of revenue in profit-     share territory	$	45,164	$	36,260
Non-cash royalty revenue in European     territory		4,838		3,872
Total	$	50,002	$	40,132

Product revenue related to sales in other territories

The Company is responsible for commercializing Crysvita in Latin America and Turkey. The Company is considered the principal in these territories as the Company controls the product before it is transferred to the customer. Accordingly, the Company records revenue on a gross basis related to the sale of Crysvita once the product is delivered and the risk and title of the product is transferred to the distributor. The Company recorded product sales of $9.4 million and $5.9 million for the three months ended March 31, 2022 and 2021, respectively, net of estimated product returns and other deductions. KKC has the option to assume responsibility for commercialization efforts in Turkey from the Company, after a certain minimum period.

Under the collaboration agreement, KKC manufactures and supplies Crysvita, which is purchased by the Company for sales in its territories and is based on 35% of the net sales through December 31, 2022 and 30% thereafter. The Company also pays to KKC a low single-digit royalty on net sales in Latin America.

Cost sharing payments

Under the collaboration agreement, KKC and the Company share certain development and commercialization costs. As a result, the Company was reimbursed for these costs and operating expenses were reduced as follows (in thousands):

	Three Months Ended March 31,
	2022		2021
Research and development	$	4,619	$	6,185
Selling, general and administrative		9,196		7,495
Total	$	13,815	$	13,680

Collaboration receivable and payable

The Company had accounts receivable from KKC in the amount of $17.4 million and $20.2 million from profit-share revenue and royalties and other receivables recorded in prepaid expenses and other current assets of $3.8 million and $16.0 million and accrued liabilities of $4.2 million and $2.3 million from commercial and development activity reimbursements, as of March 31, 2022 and December 31, 2021, respectively.

GeneTx

In August 2019, the Company entered into a Program Agreement and a Unitholder Option Agreement with GeneTx to collaborate on the development of GeneTx’s GTX-102, an ASO for the treatment of Angelman syndrome.

Pursuant to the terms of the Unitholder Option Agreement, the Company made an upfront payment of $20.0 million for an exclusive option to acquire GeneTx, which was exercisable any time prior to 30 days following FDA acceptance of the IND for GTX-102. Pursuant to the agreement, upon acceptance of the IND, which occurred in January 2020, the Company elected to extend the option period by paying an option extension payment of $25.0 million (option extension premium) during the quarter ended March 31, 2020, which was recorded as an in-process research and development expense. In April 2022, the parties entered into an amendment to the Unitholder Option Agreement (the “Amendment”) which provides the Company with an additional, earlier option to acquire GeneTx for a payment of $75.0 million based on the earlier of receipt of interim data in the Phase 1/2 study or a specified date (such option, the “Interim Option”). After such date, the Company has the right to acquire GeneTx for a payment of $125.0 million until the earlier of 30 months from the first dosing of a patient in the Phase 1/2 study (subject to extensions) or 90 days after results are available from that study. This exclusive option to acquire GeneTx can be extended under certain circumstances by one additional three month period, by paying an additional extension fee. Pursuant to the Amendment, in the event the Company acquires GeneTx by exercising the Interim Option, the Company will be required to make a milestone payment to GeneTx in an amount up to $30.0 million upon achievement of the earlier of a Phase 3 clinical study start and product approvals in Canada and the U.K.

During the exclusive option period, GeneTx is responsible for conducting the program based on the development plan agreed between the parties and, subject to the terms in the Program Agreement, has the decision-making authority on all matters in connection with the research, development, manufacturing and regulatory activities with respect to the Program. The Company will provide support, at its discretion, including strategic guidance and clinical expertise. The Company and GeneTx will collaborate on the management of the Phase 1/2 study in patients with Angelman syndrome. If the Company acquires GeneTx, the Company would then be responsible for all development and commercialization activities from the date of acquisition. The Company would also be required to make payments upon achievement of certain development and commercial milestones, as well as royalties, depending upon the success of the program.
 

Daiichi Sankyo

In March 2020, the Company executed a License and Technology Access Agreement (the License Agreement) with Daiichi Sankyo Co., Ltd. (Daiichi Sankyo). Pursuant to the License Agreement, the Company granted Daiichi Sankyo a non-exclusive license to intellectual property, including know-how and patent applications, with respect to its Pinnacle PCLTM producer cell line platform (Pinnacle PCL Platform), and HEK293 transient transfection manufacturing technology platforms for AAV-based gene therapy products.

Under the terms of the License Agreement, Daiichi Sankyo made an upfront payment of $125.0 million and an additional $25.0 million upon completion of the technology transfer of the Pinnacle PCL Platform and HEK293 platform. Daiichi Sankyo reimbursed the Company for all costs associated with the transfer of the manufacturing technology and will pay single-digit royalties on net sales of products manufactured in either system.

The Company also entered into a Stock Purchase Agreement (SPA) with Daiichi Sankyo, pursuant to which Daiichi Sankyo purchased 1,243,913 shares of the Company’s common stock in exchange for $75.0 million in cash during the first quarter of 2020. The fair market value of the common stock issued to Daiichi Sankyo was $55.3 million based on the stock price of $44.43 per share on the date of issuance, resulting in a $19.7 million premium on the SPA. Daiichi Sankyo is also subject to a three-year standstill and restrictions on sale of the shares (subject to customary exceptions or release).

In June 2020, the Company executed a subsequent license agreement (the Sublicense Agreement) with Daiichi Sankyo for transfer of certain technology in consideration for an upfront payment of $8.0 million and annual maintenance fees, milestone payments, and royalties on any net sales of products incorporating the licensed intellectual property.

The License Agreement, the Sublicense Agreement, and the SPA are being accounted for as one arrangement because they were entered into at or near the same time and negotiated in contemplation of one another. The Company evaluated the License Agreement and the Sublicense Agreement under ASC 606 and determined that the performance obligations under the agreements are (i) intellectual property with respect to its Pinnacle PCL Platform and HEK293 transient transfection manufacturing technology platform together with the initial technical assistance and technology transfer services, which was completed in the first quarter of 2022, and (ii) the transfer of any know-how and improvements after the completion of the initial technology transfer through the end of the three year technology transfer period ending March 2023.

As of March 31, 2022, the Company has determined that the total transaction price of the License Agreement was $183.3 million which was comprised of the $19.7 million premium from the SPA, the $125.0 million upfront payment, the $25.0 million in unconstrained milestone payments, $8.0 million from the Sublicense Agreement, and the $5.6 million estimated reimbursement amount for delivering the license and technology services. Total revenue recognized under the license agreement through March 31, 2022 was $177.5 million.

The Company allocated the total transaction price to the two performance obligations on a relative stand-alone selling price basis. Revenue allocated to the intellectual property and the technology transfer services was recognized over an initial period which was completed during the first quarter of 2022, measuring the progress toward complete satisfaction of the individual performance obligation using an input measure. Revenue for know-how and improvements after the completion of technology transfer is being recognized on a straight-line basis over the remaining technology transfer period, which ends in March 2023, as it is expected that Daiichi Sankyo will receive and consume the benefits consistently throughout the period. Royalties from commercial sales will be accounted for as revenue upon achievement of such sales, assuming all other revenue recognition criteria are met.

The Company recognized $3.2 million and $42.8 million for the three months ended March 31, 2022 and 2021, respectively, in revenue related to this arrangement. Accordingly, the Company had recorded $5.9 and $9.1 million of contract liabilities, net, as of March 31, 2022 and December 31, 2021, respectively. The Company recorded an accounts receivable related to the above agreements of nil and $0.1 million as of March 31, 2022 and December 31, 2021, respectively.

Mereo BioPharma 3 Limited

In December 2020, the Company entered into a License and Collaboration Agreement with Mereo BioPharma 3 Limited, or Mereo, to collaborate on the development of setrusumab. Under the terms of the agreement, the Company will lead future global development of setrusumab in both pediatric and adult patients with Osteogenesis Imperfecta, or OI. The Company was granted an exclusive license to develop and commercialize setrusumab in the U.S., Turkey, and the rest of the world, excluding the European Economic Area, United Kingdom, and Switzerland, or the Mereo territory, where Mereo retains commercial rights. Each party will be responsible for post-marketing commitments and commercial supply in their respective territories.

Upon the closing of the transaction in January 2021, the Company made a payment of $50.0 million to Mereo and will be required to make payments of up to $254.0 million upon the achievement of certain clinical, regulatory, and commercial milestones. The Company will pay for all global development costs as well as tiered double-digit percentage royalties to Mereo on net sales in the U.S., Turkey, and the rest of the world (excluding the Mereo Territory), and Mereo will pay the Company a fixed double-digit percentage royalty on net sales in the Mereo Territory.

Although Mereo is a variable interest entity, the Company is not the primary beneficiary as it does not have the power to direct the activities that would most significantly impact the economic performance of Mereo. Prior to the achievement of certain development milestones, all consideration paid to Mereo represents rights to potential future benefits associated with Mereo’s in-process research and development activities, which have not reached technological feasibility and have no alternative future use. Accordingly, for the three months ended March 31, 2021, the Company recorded the upfront payment of $50.0 million as in-process research and development expense.

Regeneron Pharmaceuticals, Inc.

In January 2022, the Company announced a collaboration with Regeneron Pharmaceuticals, Inc., or Regeneron, to commercialize Evkeeza for HoFH outside of the U.S. Evkeeza is approved in the U.S., where it is marketed by Regeneron and in the European Economic Area, or EEA, as a first-in-class therapy for use together with diet and other low-density lipoprotein-cholesterol- lowering therapies to treat adults and adolescents aged 12 years and older with HoFH. Pursuant to the terms of the agreement, the Company received the rights to develop, commercialize and distribute the product for HoFH in countries outside of the U.S. The Company will share in certain costs for global trials led by Regeneron and also have the right to opt into other potential indications. The Company may be obligated to pay up to $63.0 million in future milestone payments, contingent upon the achievement of certain regulatory and sales milestones.

The collaboration agreement is within the scope of ASC 808 which provides guidance on the presentation and disclosure of collaborative arrangements. As the Company would be the principal in future sale transactions with the customer, the Company will recognize product sales and cost of sales in the period the related sale occurs and the related revenue recognition criteria are met. Under the collaboration agreement, Regeneron will supply the product and will charge the Company a transfer price from the low 20% range up to 40% on net sales, which will be recognized as cost of sales in the Company's Statement of Operations.

Upon the closing of the transaction in January 2022, the Company paid Regeneron a $30.0 million upfront payment. As the upfront payment was related to the Company's usage of intellectual property related to Evkeeza for HoFH, the upfront payment was recorded on the Consolidated Balance Sheet as an intangible asset, which is being amortized over its useful life of 10.5 years.

The Company recorded costs of goods sold of $0.7 million for the three months ended March 31, 2022, related to the amortization of the intangible asset. Further, the Company reimbursed Regeneron for certain development costs of $0.6 million for the three months ended March 31, 2022. No sales of Evkeeza were recorded for the three months ended March 31, 2022.

Other Arrangements

The Company has also entered into several collaborations and/or licensing arrangements in prior periods. Except as disclosed above, there have not been material changes in these arrangements as disclosed in Note 7 to the Consolidated Financial Statements in the Annual Report.

Under the financial terms of these arrangements, the Company may be required to make payments upon achievement of developmental, regulatory, and commercial milestones, which could be significant. Future milestone payments, if any, will be reflected in the Condensed Consolidated Statements of Operations upon the occurrence of the contingent event. In addition, the Company may be required to pay royalties on future sales if products related to these arrangements are commercialized. The payment of these amounts, however, is contingent upon the occurrence of various future events, which have a high degree of uncertainty of occurrence.

As described in the Annual Report, in connection with the Company’s collaborations with Solid Biosciences, Inc. (Solid) and Arcturus Therapeutic Holding, Inc. (Arcturus), the Company holds certain equity interests in each entity. The changes in the fair value of the Company’s equity investments in the common stock of Solid and Arcturus were as follows (in thousands ):

 

	Common stock
As of December 31, 2020		154,756
Change in fair value		(42,713	)
Sale of shares		(79,843	)
December 31, 2021		32,200
Change in fair value		(9,329	)
March 31, 2022	$	22,871

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Liability Related to the Sale of Future Royalties

3 Months Ended

Mar. 31, 2022

Deferred Revenue Disclosure [Abstract]

Liability Related to the Sale of Future Royalties

7. Liability Related to the Sale of Future Royalties

In December 2019, the Company entered into a Royalty Purchase Agreement with RPI. Pursuant to the agreement, RPI paid $320.0 million to the Company in consideration for the right to receive royalty payments effective January 1, 2020, arising from the net sales of Crysvita in the European Union, the United Kingdom, and Switzerland under the terms of the Company’s Collaboration and License Agreement with KKC dated August 29, 2013, as amended. The agreement with RPI will automatically terminate, and the payment of royalties to RPI will cease, in the event aggregate royalty payments received by RPI are equal to or greater than $608.0 million prior to December 31, 2030, or in the event aggregate royalty payments received by RPI are less than $608.0 million prior to December 31, 2030, when aggregate royalty payments received by RPI are equal to $800.0 million.

Proceeds from the transaction were recorded as a liability (liability related to sale of future royalties on the Consolidated Balance Sheets). The Company amortizes $320.0 million, net of transaction cost of $5.8 million, using the effective interest method over the estimated life of the arrangement. In order to determine the amortization of the liability, the Company is required to estimate the total amount of future royalty payments to be received by the Company and paid to RPI, subject to the capped amount, over the life of the arrangement. The excess of future estimated royalty payments (subject to the capped amount), over the $314.2 million of net proceeds, is recorded as non-cash interest expense over the life of the arrangement. Consequently, the Company estimates an imputed interest on the unamortized portion of the liability and records interest expense relating to the transaction. The Company records the royalty revenue arising from the net sales of Crysvita in the applicable European territories as non-cash royalty revenue in the Consolidated Statements of Operations over the term of the arrangement.

The Company periodically assesses the expected royalty payments using a combination of historical results, internal projections and forecasts from external sources. To the extent such payments are greater or less than the Company’s initial estimates or the timing of such payments is materially different than its original estimates, the Company will prospectively adjust the amortization of the liability and the effective interest rate. The Company's effective annual interest rate was approximately 9.6% as of March 31, 2022.

There are a number of factors that could materially affect the amount and timing of royalty payments from KKC in the applicable European territories, most of which are not within the Company’s control. Such factors include, but are not limited to, the success of KKC’s sales and promotion of Crysvita, changing standards of care, delays or disruptions related to the COVID-19 pandemic, the introduction of competing products, pricing for reimbursement in various European territories, manufacturing or other delays, intellectual property matters, adverse events that result in governmental health authority imposed restrictions on the use of Crysvita, significant changes in foreign exchange rates as the royalty payments are made in U.S. dollars (USD) while significant portions of the underlying European sales of Crysvita are made in currencies other than USD, and other events or circumstances that could result in reduced royalty payments from European sales of Crysvita, all of which would result in a reduction of non-cash royalty revenue and the non-cash interest expense over the life of the arrangement. Conversely, if sales of Crysvita in Europe are more than expected, the non-cash royalty revenue and the non-cash interest expense recorded by the Company would be greater over the term of the arrangement.

The following table shows the activity within the liability account (in thousands):

	Liability related to the sale of future royalties
December 31, 2020	$	335,665
Non-cash collaboration royalty revenue		(17,951	)
Non-cash interest expense		34,072
December 31, 2021		351,786
Non-cash collaboration royalty revenue		(4,838	)
Non-cash interest expense		8,685
March 31, 2022	$	355,633

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Stock-Based Awards

3 Months Ended

Mar. 31, 2022

Share-based Payment Arrangement [Abstract]

Stock-Based Awards

8. Stock-Based Awards

The 2014 Incentive Plan (the 2014 Plan) provides for automatic annual increases in shares available for grant, beginning on January 1, 2015 through January 1, 2024. As of March 31, 2022, there were 2,008,628 shares reserved under the 2014 Plan for the future issuance of equity awards, 4,698,895 shares reserved for the 2014 Employee Stock Purchase Plan, and 436,063 shares reserved for the Employment Inducement Plan.

The table below sets forth the stock-based compensation expense for the periods presented (in thousands):

	Three Months Ended March 31,
	2022		2021
Cost of sales	$	175	$	379
Research and development		16,907		13,489
Selling, general and administrative		12,305		10,430
Total stock-based compensation expense	$	29,387	$	24,298

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Net Loss Per Share

3 Months Ended

Mar. 31, 2022

Earnings Per Share [Abstract]

Net Loss Per Share

9. Net Loss Per Share

Basic net loss per share has been computed by dividing the net loss by the weighted-average number of shares of common stock outstanding during the period. Diluted net loss per share is calculated by dividing net loss by the weighted-average number of shares of common stock and potential dilutive securities outstanding during the period.

The following weighted-average outstanding common stock equivalents were excluded from the computation of diluted net loss per share for the periods presented because including them would have been antidilutive:

	Three Months Ended March 31,
	2022		2021
Options to purchase common stock,     restricted stock units, and performance stock units		9,363,681		8,084,585
Employee stock purchase plan		23,276		33,636
		9,386,957		8,118,221

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Equity Transactions

3 Months Ended

Mar. 31, 2022

Equity [Abstract]

Equity Transactions

10. Equity Transactions

In May 2021, the Company entered into an Open Market Sale Agreement with Jefferies LLC, (Jefferies), pursuant to which the Company may offer and sell shares of the Company’s common stock having an aggregate offering proceeds up to $350.0 million, from time to time, in at-the-market (ATM) offerings through Jefferies. As of March 31, 2022, the Company has sold 1,050,372 shares under the arrangement resulting in net proceeds of approximately $78.9 million. No shares were sold under the arrangement for the three months ended March 31, 2022.

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Accumulated Other Comprehensive Loss

3 Months Ended

Mar. 31, 2022

Other Comprehensive Income (Loss), Net of Tax [Abstract]

Accumulated Other Comprehensive Loss

11. Accumulated Other Comprehensive Loss

Total accumulated other comprehensive loss consisted of the following (in thousands):

	March 31,			December 31,
	2022			2021
Foreign currency translation adjustments	$	(181	)	$	(121	)
Unrealized loss on available-for-sale securities		(6,373	)		(1,283	)
Total accumulated other comprehensive loss	$	(6,554	)	$	(1,404	)

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Summary of Significant Accounting Policies (Policies)

3 Months Ended

Jun. 30, 2022

Mar. 31, 2022

Accounting Policies [Abstract]

Basis of Presentation

Basis of Presentation

The accompanying unaudited Condensed Consolidated Financial Statements include the accounts of the Company and its wholly-owned subsidiaries and have been prepared in accordance with U.S. generally accepted accounting principles (GAAP) for interim financial information and in accordance with the instructions to Form 10-Q and Rule 10-01 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. The unaudited interim Condensed Consolidated Financial Statements have been prepared on the same basis as the annual financial statements. In the opinion of management, the accompanying unaudited Condensed Consolidated Financial Statements reflect all adjustments (consisting only of normal recurring adjustments) considered necessary for a fair presentation. These financial statements should be read in conjunction with the audited financial statements and notes thereto for the preceding fiscal year contained in the Company’s Annual Report on Form 10-K filed on February 15, 2022 (Annual Report) with the United States Securities and Exchange Commission (the SEC).

The results of operations for the three months ended March 31, 2022 are not necessarily indicative of the results to be expected for the year ending December 31, 2022. The Condensed Consolidated Balance Sheet as of December 31, 2021 has been derived from audited financial statements at that date, but does not include all of the information required by GAAP for complete financial statements.

Use of Estimates

Use of Estimates

The accompanying Condensed Consolidated Financial Statements have been prepared in accordance with GAAP. The preparation of the Condensed Consolidated Financial Statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent liabilities and the reported amounts of expenses in the Condensed Consolidated Financial Statements and the accompanying notes. On an ongoing basis, management evaluates its estimates, including those related to clinical trial accruals, fair value of assets and liabilities, income taxes, stock-based compensation, revenue recognition, and the liability related to the sale of future royalties. Management bases its estimates on historical experience and on various other market-specific and relevant assumptions that management believes to be reasonable under the circumstances. Actual results could differ from those estimates.

Cash, Cash Equivalents, and Restricted Cash

Cash, Cash Equivalents and Restricted Cash

Restricted cash primarily consists of money market accounts used as collateral for the Company’s obligations under its facility leases and the gene therapy building construction project. The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the Condensed Consolidated Balance Sheets that sum to the total of the same such amounts shown in the Condensed Consolidated Statement of Cash Flows (in thousands):

	March 31,
	2022		2021
Cash and cash equivalents	$	153,988	$	383,794
Restricted cash included in prepaid expenses and     other current assets		217		10,687
Restricted cash included in other assets		2,001		1,921
Total cash, cash equivalents, and restricted cash     shown in the statements of cash flows	$	156,206	$	396,402

Credit Losses

Credit Losses

The Company is exposed to credit losses primarily through receivables from customers and collaborators and through its available-for-sale debt securities. For trade receivables and other instruments, the Company uses a forward-looking expected loss

model that generally results in the earlier recognition of allowances for losses. For available-for-sale debt securities with unrealized losses, the losses are recognized as allowances rather than as reductions in the amortized cost of the securities.

The Company’s expected loss allowance methodology for the receivables is developed using historical collection experience, current and future economic market conditions, a review of the current aging status and financial condition of the entities. Specific allowance amounts are established to record the appropriate allowance for customers that have a higher probability of default. Balances are written off when determined to be uncollectible. The Company’s expected loss allowance methodology for the debt securities is developed by reviewing the extent of the unrealized loss, the size, term, geographical location, and industry of the issuer, the issuers’ credit ratings and any changes in those ratings, as well as reviewing current and future economic market conditions and the issuers’ current status and financial condition. There were no material credit losses recorded for receivables and available-for-sale debt securities for the three months ended March 31, 2022 and 2021.

Revenue Recognition

Revenue Recognition

Collaboration and license revenue

The Company has certain license and collaboration agreements that are within the scope of Accounting Standards Codification (ASC) 808, Collaborative Agreements, which provides guidance on the presentation and disclosure of collaborative arrangements. Generally, the classification of the transactions under the collaborative arrangements is determined based on the nature of contractual terms of the arrangement, along with the nature of the operations of the participants. The Company records its share of collaboration revenue, net of transfer pricing related to net sales in the period in which such sales occur, if the Company is considered as an agent in the arrangement. The Company is considered an agent when the collaboration partner controls the product before transfer to the customers and has the ability to direct the use of and obtain substantially all of the remaining benefits from the product. Funding received related to research and development services and commercialization costs is generally classified as a reduction of research and development expenses and selling, general and administrative expenses, respectively, in the Condensed Consolidated Statement of Operations, because the provision of such services for collaborative partners are not considered to be part of the Company’s ongoing major or central operations.

In order to record collaboration revenue, the Company utilizes certain information from its collaboration partners, including revenue from the sale of the product, associated reserves on revenue, and costs incurred for development and sales activities. For the periods covered in the financial statements presented, there have been no material changes to prior period estimates of revenues and expenses.

The Company sold the right to receive certain royalty payments from net sales of Crysvita to RPI Finance Trust (RPI), an affiliate of Royalty Pharma, as further described in Note 7. The Company records the royalty revenue from the net sales of Crysvita in the applicable European territories on a prospective basis as non-cash royalty revenue in the Condensed Consolidated Statements of Operations over the term of the arrangement.

The terms of the Company’s collaboration and license agreements may contain multiple performance obligations, which may include licenses and research and development activities. The Company evaluates these agreements under ASC 606, Revenue from Contracts with Customers (ASC 606), to determine the distinct performance obligations. The Company analogizes to ASC 606 for the accounting for distinct performance obligations for which there is a customer relationship. Prior to recognizing revenue, the Company makes estimates of the transaction price, including variable consideration that is subject to a constraint. Amounts of variable consideration are included in the transaction price to the extent that it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur and when the uncertainty associated with the variable consideration is subsequently resolved. Total consideration may include nonrefundable upfront license fees, payments for research and development activities, reimbursement of certain third-party costs, payments based upon the achievement of specified milestones, and royalty payments based on product sales derived from the collaboration.

If there are multiple distinct performance obligations, the Company allocates the transaction price to each distinct performance obligation based on its relative standalone selling price. The standalone selling price is generally determined based on the prices charged to customers or using expected cost-plus margin. The Company estimates the efforts needed to complete the performance obligations and recognizes revenue by measuring the progress towards complete satisfaction of the performance obligations using input measures.

Product sales

The Company sells its approved products through a limited number of distributors. Under ASC 606, revenue from product sales is recognized at the point in time when the delivery is made and when title and risk of loss transfers to these distributors. The Company also recognizes revenue from sales of certain products on a “named patient” basis, which are allowed in certain countries prior to the commercial approval of the product. Prior to recognizing revenue, the Company makes estimates of the transaction

price, including any variable consideration that is subject to a constraint. Amounts of variable consideration are included in the transaction price to the extent that it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur and when the uncertainty associated with the variable consideration is subsequently resolved. Product sales are recorded net of estimated government-mandated rebates and chargebacks, estimated product returns, and other deductions.

Provisions for returns and other adjustments are provided for in the period the related revenue is recorded, as estimated by management. These reserves are based on estimates of the amounts earned or to be claimed on the related sales and are reviewed periodically and adjusted as necessary. The Company’s estimates of government mandated rebates, chargebacks, estimated product returns, and other deductions depends on the identification of key customer contract terms and conditions, as well as estimates of sales volumes to different classes of payors. If actual results vary, the Company may need to adjust these estimates, which could have an effect on earnings in the period of the adjustment.

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Summary of Significant Accounting Policies (Tables)

3 Months Ended

Mar. 31, 2022

Accounting Policies [Abstract]

Summary of Reconciliation of Cash, Cash Equivalents and Restricted Cash

The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the Condensed Consolidated Balance Sheets that sum to the total of the same such amounts shown in the Condensed Consolidated Statement of Cash Flows (in thousands):

	March 31,
	2022		2021
Cash and cash equivalents	$	153,988	$	383,794
Restricted cash included in prepaid expenses and     other current assets		217		10,687
Restricted cash included in other assets		2,001		1,921
Total cash, cash equivalents, and restricted cash     shown in the statements of cash flows	$	156,206	$	396,402

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Financial Instruments (Tables)

3 Months Ended

Mar. 31, 2022

Fair Value Disclosures [Abstract]

Summary of Financial Assets Measured on Recurring Basis

The following tables set forth the fair value of the Company’s financial assets remeasured on a recurring basis based on the three-tier fair value hierarchy (in thousands):

	March 31, 2022
	Level 1		Level 2		Level 3		Total
Money market funds	$	113,600	$	—	$	—	$	113,600
Certificate of deposits and time deposits		—		27,101		—		27,101
Corporate bonds		—		384,474		—		384,474
Commercial paper		—		120,685		—		120,685
Asset-backed securities		—		12,875		—		12,875
U.S. Government Treasury and agency securities		7,172		106,344		—		113,516
Debt securities in government-sponsored entities		—		19,328		—		19,328
Investments in Arcturus and Solid common stock		22,871		—		—		22,871
Other		—		3,400		—		3,400
Total	$	143,643	$	674,207	$	—	$	817,850

	December 31, 2021
	Level 1		Level 2		Level 3		Total
Money market funds	$	266,765	$	—	$	—	$	266,765
Certificate of deposits and time deposits		—		16,000		—		16,000
Corporate bonds		—		349,691		—		349,691
Commercial paper		—		187,624		—		187,624
Asset-backed securities		—		41,245		—		41,245
U.S. Government Treasury and agency securities		—		87,435		—		87,435
Debt securities in government-sponsored entities		—		19,549		—		19,549
Investments in Arcturus and Solid common stock		32,200		—		—		32,200
Other		—		942		—		942
Total	$	298,965	$	702,486	$	—	$	1,001,451

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Balance Sheet Components (Tables)

3 Months Ended

Mar. 31, 2022

Investments, Debt and Equity Securities [Abstract]

Summary of Cash Equivalents and Investments Classified as Available For Sale Securities

The fair values of cash equivalents and investments classified as available-for-sale securities consisted of the following (in thousands):

	March 31, 2022
				Gross Unrealized
		Amortized Cost		Gains		Losses			Estimated Fair Value
Money market funds		$	113,600	$	—	$	—		$	113,600
Certificates of deposit and time deposits			27,101		—		—			27,101
Corporate bonds			389,619		1		(5,146	)		384,474
Commercial paper			120,686		—		(1	)		120,685
Asset-backed securities			12,924		—		(49	)		12,875
U.S. Government Treasury and agency securities			114,445		29		(958	)		113,516
Debt securities in government-sponsored entities			19,577		—		(249	)		19,328
Total		$	797,952	$	30	$	(6,403	)	$	791,579

	December 31, 2021
				Gross Unrealized
		Amortized Cost		Gains		Losses			Estimated Fair Value
Money market funds		$	266,765	$	—	$	—		$	266,765
Certificates of deposit and time deposits			16,000		—		—			16,000
Corporate bonds			350,667		3		(979	)		349,691
Commercial paper			187,624		—		—			187,624
Asset-backed securities			41,282		1		(38	)		41,245
U.S. Government Treasury and agency securities			87,642		1		(208	)		87,435
Debt securities in government-sponsored entities			19,612		—		(63	)		19,549
Total		$	969,592	$	5	$	(1,288	)	$	968,309

Summary of Inventory

Inventory consists of the following (in thousands):

	March 31,		December 31,
	2022		2021
Work-in-process	$	11,989	$	10,504
Finished goods		5,820		5,727
Total inventory	$	17,809	$	16,231

Accrued Liabilities

Accrued liabilities consist of the following (in thousands):

	March 31,		December 31,
	2022		2021
Research, clinical study, and manufacturing expenses	$	40,092	$	40,880
Payroll and related expenses		41,638		62,591
Other		44,626		42,084
Total accrued liabilities	$	126,356	$	145,555

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Revenue (Tables)

3 Months Ended

Mar. 31, 2022

Revenue from Contract with Customer [Abstract]

Summary of Disaggregation of Total Revenues

The following table disaggregates total revenues from customers (in thousands):

	Three Months Ended
	March 31,
	2022		2021
Collaboration and license revenue:
Crysvita collaboration revenue in profit-     share territory	$	45,164	$	36,260
Daiichi Sankyo		3,249		42,750
Total collaboration and license revenue		48,413		79,010
Product sales:
Crysvita		9,394		5,872
Mepsevii		4,861		3,607
Dojolvi		12,429		7,034
Total product sales		26,684		16,513
Crysvita non-cash collaboration royalty     revenue		4,838		3,872
Total revenues	$	79,935	$	99,395

The following table disaggregates total revenues based on geographic location (in thousands):

	Three Months Ended
	March 31,
	2022		2021
U.S. and Canada	$	61,917	$	87,742
Europe		8,227		5,637
Latin America		9,791		6,016
Total revenues	$	79,935	$	99,395

Summary of Changes in Contract Liabilities

The following table presents changes in the contract liabilities (in thousands):

	Three Months Ended March 31,
	2022			2021
Balance of contract liabilities at beginning of period	$	(9,076	)	$	(66,568	)
Additions		(40	)		(1,271	)
Deductions		3,249			42,750
Balance of contract liabilities at end of period	$	(5,867	)	$	(25,089	)

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License and Research Agreements (Tables)

3 Months Ended

Mar. 31, 2022

Share of Collaboration and Royalty Revenue Related to Crysvita

The Company’s share of collaboration and royalty revenue related to Crysvita was as follows (in thousands):

	Three Months Ended March 31,
	2022		2021
Company's share of revenue in profit-     share territory	$	45,164	$	36,260
Non-cash royalty revenue in European     territory		4,838		3,872
Total	$	50,002	$	40,132

Schedule of Cost Sharing Payments

Under the collaboration agreement, KKC and the Company share certain development and commercialization costs. As a result, the Company was reimbursed for these costs and operating expenses were reduced as follows (in thousands):

	Three Months Ended March 31,
	2022		2021
Research and development	$	4,619	$	6,185
Selling, general and administrative		9,196		7,495
Total	$	13,815	$	13,680

Solid and Arcturus

Schedule of Changes in Fair Value of Equity Investment

The changes in the fair value of the Company’s equity investments in the common stock of Solid and Arcturus were as follows (in thousands ):

	Common stock
As of December 31, 2020		154,756
Change in fair value		(42,713	)
Sale of shares		(79,843	)
December 31, 2021		32,200
Change in fair value		(9,329	)
March 31, 2022	$	22,871

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Liability Related to the Sale of Future Royalties (Tables)

3 Months Ended

Mar. 31, 2022

Deferred Revenue Disclosure [Abstract]

Schedule of Activity Within Liability Related to Sale of Future Royalties

The following table shows the activity within the liability account (in thousands):

	Liability related to the sale of future royalties
December 31, 2020	$	335,665
Non-cash collaboration royalty revenue		(17,951	)
Non-cash interest expense		34,072
December 31, 2021		351,786
Non-cash collaboration royalty revenue		(4,838	)
Non-cash interest expense		8,685
March 31, 2022	$	355,633

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Stock-Based Awards (Tables)

3 Months Ended

Mar. 31, 2022

Share-based Payment Arrangement [Abstract]

Summary of Stock-Based Compensation Expense

The table below sets forth the stock-based compensation expense for the periods presented (in thousands):

	Three Months Ended March 31,
	2022		2021
Cost of sales	$	175	$	379
Research and development		16,907		13,489
Selling, general and administrative		12,305		10,430
Total stock-based compensation expense	$	29,387	$	24,298

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Net Loss Per Share (Tables)

3 Months Ended

Mar. 31, 2022

Earnings Per Share [Abstract]

Outstanding Shares of Common Stock Equivalents Excluded from Computation of Diluted Net Loss per Share

The following weighted-average outstanding common stock equivalents were excluded from the computation of diluted net loss per share for the periods presented because including them would have been antidilutive:

	Three Months Ended March 31,
	2022		2021
Options to purchase common stock,     restricted stock units, and performance stock units		9,363,681		8,084,585
Employee stock purchase plan		23,276		33,636
		9,386,957		8,118,221

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Accumulated Other Comprehensive Loss (Tables)

3 Months Ended

Mar. 31, 2022

Other Comprehensive Income (Loss), Net of Tax [Abstract]

Schedule of Total Accumulated Other Comprehensive Loss

Total accumulated other comprehensive loss consisted of the following (in thousands):

	March 31,			December 31,
	2022			2021
Foreign currency translation adjustments	$	(181	)	$	(121	)
Unrealized loss on available-for-sale securities		(6,373	)		(1,283	)
Total accumulated other comprehensive loss	$	(6,554	)	$	(1,404	)

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Organization - Additional Information (Details)	3 Months Ended
	Mar. 31, 2022 Segment
United States of America
Organization And Nature Of Business [Line Items]
Number of reportable segments	1

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Summary of Significant Accounting Policies - Summary of Reconciliation of Cash, Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 2020
Accounting Policies [Abstract]
Cash and cash equivalents	$ 153,988	$ 307,584	$ 383,794
Restricted cash included in prepaid expenses and other current assets	$ 217		$ 10,687
Restricted Cash and Cash Equivalents, Current, Asset, Statement of Financial Position [Extensible List]	Prepaid expenses and other current assets		Prepaid expenses and other current assets
Restricted cash included in other assets	$ 2,001		$ 1,921
Restricted Cash and Cash Equivalents, Noncurrent, Asset, Statement of Financial Position [Extensible List]	us-gaap:OtherNoncurrentAssetsMember		us-gaap:OtherNoncurrentAssetsMember
Total cash, cash equivalents, and restricted cash shown in the statements of cash flows	$ 156,206	$ 309,585	$ 396,402	$ 726,294

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Financial Instruments - Summary of Financial Assets Measured on Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value	$ 817,850	$ 1,001,451
Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value	143,643	298,965
Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value	674,207	702,486
Money Market Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value	113,600	266,765
Money Market Funds | Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value	113,600	266,765
Asset-backed Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value	12,875	41,245
Asset-backed Securities | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value	12,875	41,245
Certificate of Deposits and Time Deposits
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value	27,101	16,000
Certificate of Deposits and Time Deposits | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value	27,101	16,000
Corporate Bonds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value	384,474	349,691
Corporate Bonds | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value	384,474	349,691
Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value	120,685	187,624
Commercial Paper | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value	120,685	187,624
U.S. Government Treasury and Agency Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value	113,516	87,435
U.S. Government Treasury and Agency Securities | Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value	7,172
U.S. Government Treasury and Agency Securities | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value	106,344	87,435
Debt Securities in Government Sponsored Entities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value	19,328	19,549
Debt Securities in Government Sponsored Entities | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value	19,328	19,549
Investments in Arcturus and Solid Common Stock
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value	22,871	32,200
Investments in Arcturus and Solid Common Stock | Level 1
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value	22,871	32,200
Other
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value	3,400	942
Other | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total fair value	$ 3,400	$ 942

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Balance Sheet Components - Summary of Cash Equivalents and Investments Classified as Available For Sale Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	$ 797,952	$ 969,592
Gross Unrealized Gains	30	5
Gross Unrealized Losses	(6,403)	(1,288)
Estimated Fair Value	791,579	968,309
Money Market Funds
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	113,600	266,765
Estimated Fair Value	113,600	266,765
Asset-backed Securities
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	12,924	41,282
Gross Unrealized Gains		1
Gross Unrealized Losses	(49)	(38)
Estimated Fair Value	12,875	41,245
Certificate of Deposits and Time Deposits
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	27,101	16,000
Estimated Fair Value	27,101	16,000
Corporate Bonds
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	389,619	350,667
Gross Unrealized Gains	1	3
Gross Unrealized Losses	(5,146)	(979)
Estimated Fair Value	384,474	349,691
Commercial Paper
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	120,686	187,624
Gross Unrealized Losses	(1)
Estimated Fair Value	120,685	187,624
U.S. Government Treasury and Agency Securities
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	114,445	87,642
Gross Unrealized Gains	29	1
Gross Unrealized Losses	(958)	(208)
Estimated Fair Value	113,516	87,435
Debt Securities in Government Sponsored Entities
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	19,577	19,612
Gross Unrealized Losses	(249)	(63)
Estimated Fair Value	$ 19,328	$ 19,549

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Balance Sheet Components - Additional Information (Details)	3 Months Ended
	Mar. 31, 2022
Maximum
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale securities remaining contractual maturities	3 years

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Balance Sheet Components - Summary of Inventory (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Investments, Debt and Equity Securities [Abstract]
Work-in-process	$ 11,989	$ 10,504
Finished goods	5,820	5,727
Total inventory	$ 17,809	$ 16,231

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Balance Sheet Components - Accrued Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Payables and Accruals [Abstract]
Research, clinical study, and manufacturing expenses	$ 40,092	$ 40,880
Payroll and related expenses	41,638	62,591
Other	44,626	42,084
Total accrued liabilities	$ 126,356	$ 145,555

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Revenue - Summary of Disaggregation of Total Revenues from Customers (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Total revenues
Total revenues	$ 79,935	$ 99,395
Collaboration and License
Total revenues
Total revenues	48,413	79,010
Collaboration and License | Crysvita
Total revenues
Total revenues	45,164	36,260
Collaboration and License | Daiichi Sankyo
Total revenues
Total revenues	3,249	42,750
Product Sales
Total revenues
Total revenues	26,684	16,513
Product Sales | Crysvita
Total revenues
Total revenues	9,394	5,872
Product Sales | Mepsevii
Total revenues
Total revenues	4,861	3,607
Product Sales | Dojolvi
Total revenues
Total revenues	12,429	7,034
Non-cash Collaboration Royalty Revenue
Total revenues
Total revenues	4,838	3,872
Non-cash Collaboration Royalty Revenue | Crysvita
Total revenues
Total revenues	$ 4,838	$ 3,872

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Revenue - Summary of Disaggregation of Total Revenues (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Disaggregation Of Revenue [Line Items]
Total revenues	$ 79,935	$ 99,395
U.S. and Canada [Member]
Disaggregation Of Revenue [Line Items]
Total revenues	61,917	87,742
Europe
Disaggregation Of Revenue [Line Items]
Total revenues	8,227	5,637
Latin America
Disaggregation Of Revenue [Line Items]
Total revenues	$ 9,791	$ 6,016

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Revenue - Summary of Changes in Contract Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Disaggregation of Revenue [Abstract]
Balance of contract liabilities at beginning of period	$ (9,076)	$ (66,568)
Additions	(40)	(1,271)
Deductions	3,249	42,750
Balance of contract liabilities at end of period	$ (5,867)	$ (25,089)

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Revenue - Additional Information (Details)	Mar. 31, 2022	Dec. 31, 2021
Disaggregation of Revenue [Abstract]
Percentage of gross accounts receivable balance	61.00%	71.00%

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License and Research Agreements - Additional Information (Details) - USD ($)		1 Months Ended					3 Months Ended			113 Months Ended
	Jan. 01, 2023	Apr. 30, 2022	Jan. 31, 2022	Jan. 31, 2021	Mar. 31, 2020	Aug. 31, 2019	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2022	Dec. 31, 2021	Sep. 30, 2021
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaboration and license revenue							$ 79,935,000	$ 99,395,000
Daiichi Sankyo
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Deferred revenue							5,900,000				$ 9,100,000
Revenue recognized							3,200,000	42,800,000
Receivable related to Daiichi Sankyo license agreement							$ 0				100,000
Regeneron Pharmaceuticals, Inc.
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront payments of collaboration			$ 30,000,000.0
Intangible assets, remaining amortization period							10 years 6 months
Eligible future milestone payments			$ 63,000,000.0
Costs of goods sold related to amortization of intangible asset							$ 700,000
Development costs							600,000
Sales							$ 0
Regeneron Pharmaceuticals, Inc. | Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Profit loss sharing percentage on net sales							40.00%
Regeneron Pharmaceuticals, Inc. | Minimum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Profit loss sharing percentage on net sales			20.00%
Product Sales
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaboration and license revenue							$ 26,684,000	16,513,000
License and Collaboration Agreement | Mereo
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront payment for in-process research and development expense								50,000,000.0
Payments made under agreement				$ 50,000,000.0
License and Collaboration Agreement | Maximum | Mereo
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Future contingent milestone payments				$ 254,000,000.0
Kyowa Kirin Collaboration | License Agreement | Prepaid Expenses and Other Current Assets
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
License agreement other receivables							3,800,000				16,000,000.0
Kyowa Kirin Collaboration | License Agreement | Product Sales
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaboration and license revenue							9,400,000	$ 5,900,000
Kyowa Kirin Collaboration | License Agreement | Profit Share Revenue
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
License agreement accounts receivable							17,400,000				20,200,000
Kyowa Kirin Collaboration | License Agreement | Commercial and Development Activity Reimbursements
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
License agreement accrued liabilities							$ 4,200,000				$ 2,300,000
Kyowa Kirin Collaboration | License Agreement | Scenario Forecast
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Profit loss sharing percentage on net sales	30.00%									35.00%
Kyowa Kirin Collaboration | License Agreement | Profit Share Territory
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Remaining profit or loss share percentage on commercializing products							50.00%
Tiered double-digit revenue share percentage entitled to receive							20.00%
Kyowa Kirin Collaboration | License Agreement | Royalty Revenue in European Territory
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Percentage of royalty on net sales receives							10.00%
Program Agreement and Unitholder Option Agreement | GeneTx Biotherapeutics LLC
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Additional milestone payments						$ 30,000,000.0
Upfront payment for exclusive option to acquisition						20,000,000.0
Business acquisition option exercise period, description							the Company made an upfront payment of $20.0 million for an exclusive option to acquire GeneTx, which was exercisable any time prior to 30 days following FDA acceptance of the IND for GTX-102.
Option extension Premium						25,000,000.0
Business acquisition, consideration transferred						$ 125,000,000.0
Exercise of option extension, right to acquire condition							the Company has the right to acquire GeneTx for a payment of $125.0 million until the earlier of 30 months from the first dosing of a patient in the Phase 1/2 study (subject to extensions) or 90 days after results are available from that study.
Program Agreement and Unitholder Option Agreement | Subsequent Event | GeneTx Biotherapeutics LLC
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Acquisition cost		$ 75,000,000.0
License and Technology Access Agreement | Daiichi Sankyo
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront payment received							$ 125,000,000.0
Deferred revenue							25,000,000.0
Premium from stock purchase agreement							19,700,000
Transaction price of license agreement							183,300,000
Estimated reimbursement of delivering license and technology services							5,600,000
License and Technology Access Agreement | PCL and HEK293 Platform | Daiichi Sankyo
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Deferred revenue												$ 25,000,000.0
License and Technology Access Agreement | License Agreement | Daiichi Sankyo
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue recognized							177,500,000
Stock Purchase Agreement | Daiichi Sankyo
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Issuance of common stock in connection with license agreement, net of issuance costs, shares									1,243,913
Proceeds from issuance of common stock in connection with license agreement									$ 75,000,000.0
Issuance of common stock in connection with license agreement, net of issuance costs					$ 55,300,000
Stock price					$ 44.43				$ 44.43
Premium from stock purchase agreement					$ 19,700,000
Sublicense Agreement | Daiichi Sankyo
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront payment received							$ 8,000,000.0

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License and Research Agreements - Share of Collaboration and Royalty Revenue Related to Crysvita (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Disaggregation Of Revenue [Line Items]
Collaboration and license revenue	$ 79,935	$ 99,395
Collaboration and Royalty | Kyowa Kirin Collaboration | Profit Share Territory
Disaggregation Of Revenue [Line Items]
Collaboration and license revenue	45,164	36,260
Collaboration and Royalty | Kyowa Kirin Collaboration | Royalty Revenue in European Territory
Disaggregation Of Revenue [Line Items]
Collaboration and license revenue	4,838	3,872
Non-cash Collaboration Royalty Revenue
Disaggregation Of Revenue [Line Items]
Collaboration and license revenue	4,838	3,872
Non-cash Collaboration Royalty Revenue | Kyowa Kirin Collaboration | Royalty Revenue in European Territory
Disaggregation Of Revenue [Line Items]
Collaboration and license revenue	$ 50,002	$ 40,132

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License and Research Agreements - Schedule of Cost Sharing Payments (Details) - Kyowa Kirin Collaboration - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Cost Sharing Payments [Line Items]
Research and development	$ 4,619	$ 6,185
Selling, general and administrative	9,196	7,495
Total	$ 13,815	$ 13,680

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License and Research Agreements - Schedule of Changes in Fair Value of Equity Investment (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Common stock, Beginning balance	$ 1,001,451
Common stock, Ending balance	817,850	$ 1,001,451
Solid and Arcturus | Common Stock
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Common stock, Beginning balance	32,200	154,756
Common stock, Change in fair value	(9,329)	(42,713)
Common stock, Sale of shares		(79,843)
Common stock, Ending balance	$ 22,871	$ 32,200

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Liability Related to the Sale of Future Royalties - Additional Information (Details) - Royalty Purchase Agreement - RPI Finance Trust (RPI) - USD ($) $ in Millions	1 Months Ended	3 Months Ended
	Dec. 31, 2019	Mar. 31, 2022
Liability Related To Sale Of Future Royalties [Line Items]
Proceeds from sale of future royalties	$ 320.0
Royalty payment termination description		The agreement with RPI will automatically terminate, and the payment of royalties to RPI will cease, in the event aggregate royalty payments received by RPI are equal to or greater than $608.0 million prior to December 31, 2030, or in the event aggregate royalty payments received by RPI are less than $608.0 million prior to December 31, 2030, when aggregate royalty payments received by RPI are equal to $800.0 million
Royalties transaction costs net	5.8
Proceeds from the sale of future royalties, net	314.2
Effective annual interest rate		9.60%
Minimum
Liability Related To Sale Of Future Royalties [Line Items]
Royalty agreement termination threshold amount	608.0
Maximum
Liability Related To Sale Of Future Royalties [Line Items]
Royalty agreement termination threshold amount	$ 800.0

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Liability Related to the Sale of Future Royalties - Schedule of Activity Within Liability Related to Sale of Future Royalties (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Deferred Revenue Disclosure [Abstract]
Liability related to the sale of future royalties at beginning of year	$ 351,786	$ 335,665	$ 335,665
Non-cash collaboration royalty revenue	(4,838)	$ (3,872)	(17,951)
Non-cash interest expense	8,685		34,072
Liability related to the sale of future royalties at end of year	$ 355,633		$ 351,786

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Stock-Based Awards - Additional Information (Details)	3 Months Ended
	Mar. 31, 2022 shares
2014 Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share reserved for future issuance	2,008,628
Automatic increases in shares available for grant effective date	Jan. 01, 2015
Shares available for grant, ending date	Jan. 01, 2024
2014 Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share reserved for future issuance	4,698,895
Employment Inducement Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share reserved for future issuance	436,063

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Stock-Based Awards - Summary of Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 29,387	$ 24,298
Cost of sales
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	175	379
Research and development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	16,907	13,489
Selling, general and administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 12,305	$ 10,430

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Net Loss Per Share - Outstanding Shares of Common Stock Equivalents Excluded from Computation of Diluted Net Loss per Share (Details) - shares	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Common stock equivalents excluded from computation of diluted net loss per share	9,386,957	8,118,221
Options to Purchase Common Stock, RSUs, and PSUs
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Common stock equivalents excluded from computation of diluted net loss per share	9,363,681	8,084,585
Employee Stock Purchase Plan
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Common stock equivalents excluded from computation of diluted net loss per share	23,276	33,636

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Equity Transactions - Additional Information (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended
	May 31, 2021	Mar. 31, 2022
Stockholders Equity [Line Items]
Stock sold in at-the-market offering		1,050,372
Net proceeds from at-the-market offering		$ 78.9
Open Market Sale
Stockholders Equity [Line Items]
Common stock shares sold		0
Option to sell common stock aggregate offering price	$ 350.0

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Accumulated Other Comprehensive Income - Schedule of Total Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Foreign currency translation adjustments	$ (181)	$ (121)
Unrealized loss on available-for-sale securities	(6,373)	(1,283)
Total accumulated other comprehensive loss	$ (6,554)	$ (1,404)