10-Q

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 10-Q

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

For the quarterly period ended March 31, 2021

or

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

Commission File Number: 001-35921

______________________________________________________

Mirati Therapeutics, Inc.

(Exact Name of Registrant as Specified in Its Charter)

______________________________________________________

Delaware			46-2693615
(State of Incorporation)			(I.R.S. Employer Identification No.)
3545 Cray Court,	San Diego,	California	92121
(Address of Principal Executive Offices)			(Zip Code)

(858) 332-3410

(Registrant’s Telephone Number, Including Area Code)

______________________________________________________

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, par value $0.001 per share	MRTX	The Nasdaq Stock Market LLC

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 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 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, or a smaller reporting company. See the definitions of “large accelerated filer”, “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Securities Exchange Act of 1934.

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 financing 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 April 29, 2021, there were 51,439,928 total shares of common stock outstanding.

MIRATI THERAPEUTICS, INC.

FORM 10-Q

TABLE OF CONTENTS

PART I. FINANCIAL INFORMATION		1
Item 1.	Condensed Consolidated Financial Statements (Unaudited)	1
	Condensed Consolidated Balance Sheets as of March 31, 2021 and December 31, 2020	1
	Condensed Consolidated Statements of Operations and Comprehensive Loss for the Three Months Ended March 31, 2021 and 2020	2
	Condensed Consolidated Statements of Changes in Shareholders' Equity for the Three Months Ended March 31, 2021 and 2020	3
	Condensed Consolidated Statements of Cash Flows for the Three Months Ended March 31, 2021 and 2020	4
	Notes to Condensed Consolidated Financial Statements	5
Item 2.	Management’s Discussion and Analysis of Financial Condition and Results of Operations	15
Item 3.	Quantitative and Qualitative Disclosures about Market Risk	22
Item 4.	Controls and Procedures	22
PART II. OTHER INFORMATION		23
Item 1.	Legal Proceedings	23
Item 1A.	Risk Factors	23
Item 6.	Exhibits	48
SIGNATURES		50

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PART I. FINANCIAL INFORMATION

ITEM 1. Financial Statements

MIRATI THERAPEUTICS, INC.

CONDENSED CONSOLIDATED BALANCE SHEETS

(In thousands, except for share and per share amounts)

	March 31, 2021		December 31, 2020
	(Unaudited)
ASSETS
Current assets
Cash and cash equivalents	$	329,503	$	885,562
Short-term investments	957,660		504,544
Other current assets	16,347		13,537
Total current assets	1,303,510		1,403,643
Property and equipment, net	9,061		7,809
Long-term investment	11,676		15,629
Right-of-use asset	39,278		39,890
Other long-term assets	17,307		9,157
Total assets	$	1,380,832	$	1,476,128
LIABILITIES AND SHAREHOLDERS’ EQUITY
Current liabilities
Accounts payable	$	19,602	$	18,117
Accrued liabilities	57,503		53,355
Total current liabilities	77,105		71,472
Lease liability	43,175		41,905
Other liabilities	1,139		1,962
Total liabilities	121,419		115,339
Commitments and contingencies (see Note 9)
Shareholders’ equity
Preferred stock, $0.001 par value; 10,000,000 shares authorized; none issued and outstanding at both March 31, 2021 and December 31, 2020	—		—
Common stock, $0.001 par value; 100,000,000 shares authorized; 51,375,786 and 50,439,069 issued and outstanding at March 31, 2021 and December 31, 2020, respectively	51		50
Additional paid-in capital	2,515,824		2,481,218
Accumulated other comprehensive income	9,456		9,759
Accumulated deficit	(1,265,918)		(1,130,238)
Total shareholders’ equity	1,259,413		1,360,789
Total liabilities and shareholders’ equity	$	1,380,832	$	1,476,128

See accompanying notes

1

MIRATI THERAPEUTICS, INC.

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS

(Unaudited, in thousands, except for share and per share amounts)

	Three months ended March 31,
	2021		2020
Revenue
License and collaboration revenues	$	—	$	267
Total revenue	—		267
Expenses
Research and development	104,071		71,708
General and administrative	28,350		18,046
Total operating expenses	132,421		89,754
Loss from operations	(132,421)		(89,487)
Other (expense) income, net	(3,259)		2,832
Net loss	$	(135,680)	$	(86,655)
Unrealized loss on available-for-sale investments	(303)		(182)
Comprehensive loss	$	(135,983)	$	(86,837)
Basic and diluted net loss per share	$	(2.67)	$	(2.02)
Weighted average common shares outstanding, basic and diluted	50,779,364		42,886,691

See accompanying notes

2

MIRATI THERAPEUTICS, INC.

CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY

(Unaudited, in thousands, except share data)

Three Months Ended March 31, 2021
	Common Stock			Additional paid-in capital		Accumulated other comprehensive income		Accumulated deficit		Total shareholders' equity
	Shares	Amount
Balance at December 31, 2020	50,439,069	$	50	$	2,481,218	$	9,759	$	(1,130,238)	$	1,360,789
Net loss for the period	—	—		—		—		(135,680)		(135,680)
Share-based compensation expense	—	—		24,722		—		—		24,722
Issuance of common stock under equity incentive plans	312,903	—		9,885		—		—		9,885
Net exercise of warrants	623,814	1		(1)		—		—		—
Unrealized loss on investments	—	—		—		(303)		—		(303)
Balance at March 31, 2021	51,375,786	$	51	$	2,515,824	$	9,456	$	(1,265,918)	$	1,259,413

Three Months Ended March 31, 2020
	Common Stock			Additional paid-in capital		Accumulated other comprehensive income		Accumulated deficit		Total shareholders' equity
	Shares	Amount
Balance at December 31, 2019	39,517,329	$	40	$	1,144,667	$	9,889	$	(772,301)	$	382,295
Net loss for the period	—	—		—		—		(86,655)		(86,655)
Issuance of common stock, net of issuance costs	3,538,462	4		323,973		—		—		323,977
Share-based compensation expense	—	—		21,567		—		—		21,567
Issuance of common stock under equity incentive plans	496,521	—		15,183		—		—		15,183
Proceeds from disgorgement of shareholders' short-swing profits	—	—		41		—		—		41
Unrealized loss on investments	—	—		—		(182)		—		(182)
Balance at March 31, 2020	43,552,312	$	44	$	1,505,431	$	9,707	$	(858,956)	$	656,226

See accompanying notes

3

MIRATI THERAPEUTICS, INC.

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS

(Unaudited, in thousands)

	Three months ended March 31,
	2021		2020
Operating activities:
Net loss	$	(135,680)	$	(86,655)
Non-cash adjustments reconciling net loss to operating cash flows:
Change in fair value of long-term investment	3,953		—
Depreciation of property and equipment	294		126
Amortization of premium and accretion of discounts on investments	1,001		(520)
Share-based compensation expense	24,722		21,567
Changes in operating assets and liabilities:
Other current assets	(2,810)		(100)
Other long-term assets	(8,149)		(519)
Right-of-use asset	612		188
Lease liability	1,270		(198)
Accounts payable, accrued liabilities, and other liabilities	4,371		7,107
Cash flows used in operating activities	(110,416)		(59,004)
Investing activities:
Purchases of short-term investments	(621,661)		(230,384)
Sales and maturities of short-term investments	167,240		108,381
Purchases of property and equipment	(1,107)		(224)
Cash flows used in investing activities	(455,528)		(122,227)
Financing activities:
Proceeds from issuance of common stock, net of issuance costs	—		323,977
Proceeds from issuance of common stock under equity incentive plans	9,885		15,183
Proceeds from disgorgement of shareholders' short-swing profits	—		41
Cash flows provided by financing activities	9,885		339,201
(Decrease) increase in cash, cash equivalents and restricted cash	(556,059)		157,970
Cash, cash equivalents and restricted cash, beginning of period	886,182		46,856
Cash, cash equivalents and restricted cash, end of period	$	330,123	$	204,826
Reconciliation of cash, cash equivalents and restricted cash, end of period:
Cash and cash equivalents	$	329,503	$	204,505
Restricted cash included in other long-term assets	620		321
Total cash, cash equivalents and restricted cash	$	330,123	$	204,826
Supplemental disclosures of non-cash investing activities:
Purchases of property and equipment included within accounts payable and accrued liabilities	$	439	$	408

See accompanying notes

4

MIRATI THERAPEUTICS, INC.

Notes to Condensed Consolidated Financial Statements

March 31, 2021

(Unaudited)

1. Description of Business

Mirati Therapeutics, Inc. ("Mirati" or the "Company") is a clinical-stage oncology company developing product candidates to address the genetic and immunological promoters of cancer. The Company was incorporated under the laws of the State of Delaware on April 29, 2013 as Mirati Therapeutics, Inc. and is located in San Diego, California. The Company has a wholly owned subsidiary in Canada, MethylGene, Inc. ("MethylGene"), and operates in one business segment, primarily in the United States. The Company's common stock has been listed on the Nasdaq Global Select Market since June 5, 2018 and was previously listed on the Nasdaq Capital Market since July 15, 2013, under the ticker symbol "MRTX."

2. Summary of Significant Accounting Policies

Basis of Presentation

The unaudited condensed consolidated financial statements contained in this Quarterly Report on Form 10-Q have been prepared in accordance with the rules and regulations of the Securities and Exchange Commission ("SEC") and, therefore, certain information and disclosures normally included in annual financial statements prepared in accordance with accounting principles generally accepted in the United States of America ("U.S. GAAP") have been omitted.

In the opinion of management, the information reflects all adjustments necessary to make the results of operations for the interim periods a fair statement of such operations. All such adjustments are of a normal recurring nature. Interim results are not necessarily indicative of results for the full year. The condensed consolidated balance sheet at December 31, 2020 has been derived from the audited consolidated financial statements at that date, but does not include all information and footnotes required by U.S. GAAP for complete financial statements. These unaudited condensed consolidated financial statements should be read in conjunction with the audited financial statements included in the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2020.

Use of Estimates

The preparation of the Company's unaudited condensed consolidated financial statements requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenue and expenses during the reporting period.

Reported amounts and footnote disclosures reflect the overall economic conditions that are most likely to occur and anticipated measures management intends to take. Actual results could differ materially from those estimates. Estimates and assumptions are reviewed quarterly. Any revisions to accounting estimates are recognized in the period in which the estimates are revised and in any future periods affected.

Cash, Cash Equivalents and Short-term Investments

Cash and cash equivalents consist of cash and highly liquid securities with original maturities at the date of acquisition of ninety days or less. Investments with an original maturity of more than ninety days are considered short-term investments and have been classified by management as available-for-sale. These investments are classified as current assets, even though the stated maturity date may be one year or more beyond the current balance sheet date, which reflects management’s intention to use the proceeds from sales of these securities to fund its operations, as necessary. Such investments are carried at fair value, and the unrealized gains and losses are reported as a component of accumulated other comprehensive income in shareholders’ equity until realized. Realized gains and losses from the sale of available-for-sale securities, if any, are determined on a specific identification basis.    

Concentration of Credit Risk

The Company invests its excess cash in accordance with its investment policy. The Company's investments are comprised primarily of commercial paper and debt instruments of financial institutions, corporations, U.S. government-sponsored agencies and the U.S. Treasury. The Company mitigates credit risk by maintaining a diversified portfolio and

5

limiting the amount of investment exposure as to institution, maturity and investment type. Financial instruments that potentially subject the Company to significant credit risk consist principally of cash equivalents and short-term investments.

Revenue Recognition

The Company recognizes revenue in connection with certain collaboration and license agreements in accordance with the guidance of Revenue From Contracts With Customers, Accounting Standards Codification ("ASC") Topic 606 ("Topic 606"). Under Topic 606, the Company recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration that the entity expects to receive in exchange for those goods or services.  To determine revenue recognition for arrangements the Company determines are within the scope of Topic 606, the Company performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the Company satisfies a performance obligation.  The Company only applies the five-step model to contracts when it is probable that the Company will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer.  At contract inception, once the contract is determined to be within the scope of Topic 606, the Company assesses the goods or services promised within each contract and determines those that are performance obligations, and assesses whether each promised good or service is distinct.  The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied.

Leases

The Company determines if an arrangement is a lease at inception. Lease right-of-use assets represent the Company's right to use an underlying asset for the lease term and lease liabilities represent the Company's obligation to make lease payments arising from the lease. For operating leases with an initial term greater than 12 months, the Company recognizes operating lease right-of-use assets and operating lease liabilities based on the present value of lease payments over the lease term at the commencement date. Operating lease right-of-use assets are comprised of the lease liability plus any lease payments made and excludes lease incentives. Lease terms include options to renew or terminate the lease when the Company is reasonably certain that the renewal option will be exercised or when it is reasonably certain that the termination option will not be exercised. For operating leases, if the interest rate used to determine the present value of future lease payments it not readily determinable, the Company estimates its incremental borrowing rate as the discount rate for the lease. The incremental borrowing rate is estimated to approximate the interest rate on a collateralized basis with similar terms and payments, and in similar economic environments. Lease expense for lease payments is recognized on a straight-line basis over the lease term. The Company has elected the practical expedient to not separate lease and non-lease components.

Net Loss per Share

Basic net loss per common share is calculated by dividing net loss by the weighted-average number of common shares outstanding during the period, without consideration for common share equivalents as they are anti-dilutive. Diluted net loss per share is computed by dividing the net loss by the weighted-average number of common shares and common share equivalents outstanding for the period. Common share equivalents outstanding, determined using the treasury stock method, are comprised of shares that may be issued under the Company’s stock option and warrant agreements.

The following table presents the weighted-average number of common share equivalents, calculated using the treasury stock method, not included in the calculation of diluted net loss per share due to the anti-dilutive effect of the securities:

	Three months ended March 31,
	2021	2020
Common stock options	2,758,415	2,174,353
Common stock warrants	8,043,004	9,692,771
Total	10,801,419	11,867,124

6

Recently Adopted and Recently Issued Accounting Pronouncements

From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board ("FASB") or other standard setting bodies that are adopted by the Company as of the specified effective date. The Company has evaluated recently issued accounting pronouncements and does not believe any will have a material impact on the Company’s condensed consolidated financial statements or related financial statement disclosures.

3. Investments

The following tables summarize the Company's short-term investments (in thousands):

		As of March 31, 2021
	Maturity	Amortized cost		Gross unrealized gains		Gross unrealized losses		Estimated fair value
Corporate debt securities	2 years or less	$	182,895	$	45	$	(181)	$	182,759
Commercial paper	1 year or less	553,455		37		(19)		553,473
U.S. Agency bonds	2 years or less	133,484		48		—		133,532
U.S. Treasury bills	2 years or less	78,777		10		—		78,787
Sovereign debt securities	1 year or less	9,113		—		(4)		9,109
		$	957,724	$	140	$	(204)	$	957,660

		As of December 31, 2020
	Maturity	Amortized cost		Gross unrealized gains		Gross unrealized losses		Estimated fair value
Corporate debt securities	2 years or less	$	130,814	$	160	$	(4)	$	130,970
Commercial paper	1 year or less	240,725		58		(18)		240,765
U.S. Agency bonds	2 years or less	83,227		37		(1)		83,263
U.S. Treasury bills	2 years or less	49,539		10		(3)		49,546
		$	504,305	$	265	$	(26)	$	504,544

The Company has classified all of its short-term investments as available-for-sale as the sale of such securities may be required prior to maturity to implement management strategies, and accordingly, carries these investments at fair value. As of March 31, 2021, and December 31, 2020, aggregated gross unrealized losses of available-for-sale investments were not material, and accordingly, no allowance for credit losses was recorded.

As of March 31, 2021 and December 31, 2020, the Company held 588,235 shares of ORIC Pharmaceuticals, Inc. ("ORIC") common stock subject to certain transfer restrictions. The shares held by the Company are measured at fair value at each reporting period based on the closing price of ORIC's common stock on the last trading day of each reporting period, adjusted for a discount for lack of marketability, with any unrealized gains and losses recorded in other (expense) income, net on the Company's condensed consolidated statements of operations and comprehensive loss. See Note 4 for further details.

4. Fair Value Measurements

The Company has certain financial assets and liabilities recorded at fair value which have been classified as Level 1, 2 or 3 within the fair value hierarchy as described in the accounting standards for fair value measurements.

The authoritative guidance for fair value measurements defines fair value as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or the most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Market participants are buyers and sellers in the principal market that are (i) independent, (ii) knowledgeable, (iii) able to transact, and (iv) willing to transact. The guidance prioritizes the inputs used in measuring fair value into the following hierarchy:

•Level 1- Quoted prices (unadjusted) in active markets for identical assets or liabilities;

7

•Level 2- Inputs other than quoted prices included within Level 1 that are either directly or indirectly observable; and

•Level 3- Unobservable inputs in which little or no market activity exists, therefore requiring an entity to develop its own assumptions about the assumptions that market participants would use in pricing.

The following tables summarize the assets measured at fair value on a recurring basis (in thousands):

	March 31, 2021
	Total		Level 1		Level 2		Level 3
Assets
Cash and cash equivalents:
Cash	$	34,614	$	34,614	$	—	$	—
Money market funds	294,889		294,889		—		—
Total cash and cash equivalents	329,503		329,503		—		—
Short-term investments:
U.S. Treasury bills	78,787		78,787		—		—
Corporate debt securities	182,759		—		182,759		—
Commercial paper	553,473		—		553,473		—
U.S. Agency bonds	133,532		—		133,532		—
Sovereign debt securities	9,109		—		9,109		—
Total short-term investments	957,660		78,787		878,873		—
Long-term investment:
ORIC Pharmaceuticals, Inc.	11,676		—		—		11,676
Total	$	1,298,839	$	408,290	$	878,873	$	11,676

	December 31, 2020
	Total		Level 1		Level 2		Level 3
Assets
Cash and cash equivalents:
Cash	$	20,398	$	20,398	$	—	$	—
Money market funds	865,164		865,164		—		—
Total cash and cash equivalents	885,562		885,562		—		—
Short-term investments:
U.S. Treasury bills	49,546		49,546		—		—
Corporate debt securities	130,970		—		130,970		—
Commercial paper	240,765		—		240,765		—
U.S. Agency bonds	83,263		—		83,263		—
Total short-term investments	504,544		49,546		454,998		—
Long-term investment:
ORIC Pharmaceuticals, Inc.	15,629		—		—		15,629
Total	$	1,405,735	$	935,108	$	454,998	$	15,629

8

The Company’s investments in Level 1 assets are valued based on publicly available quoted market prices for identical securities as of March 31, 2021 and December 31, 2020. The Company determines the fair value of Level 2 related securities with the aid of valuations provided by third parties using proprietary valuation models and analytical tools. These valuation models and analytical tools use market pricing or prices for similar instruments that are both objective and publicly available, including matrix pricing or reported trades, benchmark yields, broker/dealer quotes, issuer spreads, two-sided markets, benchmark securities, bids and/or offers. As of March 31, 2021, the Level 3 fair value measurement of the Company's long-term investment in ORIC Pharmaceuticals, Inc., which was acquired in 2020, utilizes a combination of the Asian Protective Put Option and Finnerty Put Option fair value techniques with unobservable inputs of 96.0% volatility and an expected term of 0.8 years to determine the discount for lack of marketability of 19.0%. There were no transfers between fair value measurement levels during the three months ended March 31, 2021 or the year ended December 31, 2020.

The following table presents the changes in estimated fair value of the Company's asset measured using significant unobservable inputs (Level 3) (in thousands):

	March 31, 2021
Balance - December 31, 2020	$	15,629
Change in fair value	(3,953)
Balance - March 31, 2021	$	11,676

5. Other Current Assets and Other Long-Term Assets

Other current assets consisted of the following (in thousands):

	March 31, 2021		December 31, 2020
Prepaid expenses	$	9,933	$	8,158
Deposits and other receivables	4,576		3,075
Interest receivable	1,838		2,304
	$	16,347	$	13,537

The other long-term assets balance of $17.3 million as of March 31, 2021 consisted of $16.7 million in deposits paid in conjunction with the Company's research and development activities, and $0.6 million for a letter of credit secured by restricted cash in connection with the lease of the Company's corporate headquarters. The other long-term assets balance of $9.2 million as of December 31, 2020 consisted of $8.6 million in deposits paid in conjunction with the Company's research and development activities, and $0.6 million for a letter of credit secured by restricted cash in connection with the lease of the Company's corporate headquarters.

6. Accrued Liabilities and Other Liabilities

Accrued liabilities consisted of the following (in thousands):

	March 31, 2021		December 31, 2020
Accrued clinical expense	24,355		19,221
Accrued manufacturing expense	15,779		13,019
Accrued development expense	4,537		5,439
Accrued compensation and benefits	7,689		13,964
Other accrued expenses	5,143		1,712
	$	57,503	$	53,355

The other liabilities balance of $1.1 million as of March 31, 2021, and $2.0 million as of December 31, 2020, consisted primarily of clinical trial-related liabilities.

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7. License and Collaboration Agreements

BeiGene Agreement

Terms of Agreement

On January 7, 2018, the Company and BeiGene Ltd, ("BeiGene") entered into a Collaboration and License Agreement (the “BeiGene Agreement”), pursuant to which the Company and BeiGene agreed to collaboratively develop sitravatinib in Asia (excluding Japan and certain other countries), Australia and New Zealand (the “Licensed Territory”). Under the BeiGene Agreement, the Company granted BeiGene an exclusive license to develop, manufacture and commercialize sitravatinib in the Licensed Territory, with the Company retaining exclusive rights for the development, manufacture and commercialization of sitravatinib outside the Licensed Territory.

As consideration for the rights granted to BeiGene under the BeiGene Agreement, BeiGene paid the Company a non-refundable, non-creditable up-front fee of $10.0 million. BeiGene is also required to make milestone payments to the Company of up to an aggregate of $123.0 million upon the first achievement of specified clinical, regulatory and sales milestones. The BeiGene Agreement additionally provides that BeiGene is obligated to pay to the Company royalties at tiered percentage rates ranging from mid-single digits to twenty percent on annual net sales of licensed products in the Licensed Territory, subject to reduction under specified circumstances. The BeiGene Agreement also provides that the Company will supply BeiGene with sitravatinib for use in BeiGene’s development activities in the Licensed Territory.

The BeiGene Agreement will terminate upon the expiration of the last royalty term for the licensed products, which is the latest of (i) the date of expiration of the last valid patent claim related to the licensed products under the BeiGene Agreement, (ii) 10 years after the first commercial sale of a licensed product and (iii) the expiration of any regulatory exclusivity as to a licensed product. BeiGene may terminate the BeiGene Agreement at any time by providing 60 days prior written notice to the Company. Either party may terminate the BeiGene Agreement upon a material breach by the other party that remains uncured following 60 days after the date of written notice of such breach or upon certain bankruptcy events. In addition, the Company may terminate the BeiGene Agreement upon written notice to BeiGene under specified circumstances if BeiGene challenges the licensed patent rights.

Revenue Recognition

The Company evaluated the BeiGene Agreement under Topic 606. At the time we entered into the BeiGene Agreement, the Company determined the transaction price was equal to the up-front fee of $10.0 million. The transaction price was allocated to the performance obligations on the basis of the relative stand-alone selling price estimated for each performance obligation. In estimating the stand-alone selling price for each performance obligation, the Company developed assumptions that require judgment and included forecasted revenues, expected development timelines, discount rates, probabilities of technical and regulatory success and costs for manufacturing clinical supplies. As such, of the up-front fee, the Company allocated $9.5 million to the license to the Company's intellectual property, bundled with the associated know-how, and $0.5 million to the initial obligation to supply sitravatinib for clinical development in the Licensed Territory.

Licenses of Intellectual Property.   The license to the Company’s intellectual property, bundled with the associated know-how, represents a distinct performance obligation. The license and associated know-how was transferred to BeiGene during the three months ended March 31, 2018, therefore during 2018 the Company recognized the full revenue amount of $9.5 million related to this performance obligation as license and collaboration revenues in its condensed consolidated statements of operations and comprehensive loss.

Manufacturing Supply Services.  The Company's initial obligation to supply sitravatinib for clinical development in the Licensed Territory represents a distinct performance obligation, and the initial obligation was satisfied in 2020, therefore this $0.5 million initial supply obligation has been fully recognized in license and collaboration revenues as of December 31, 2020. Although the initial performance obligation was satisfied, BeiGene may request additional sitravatinib in the future for clinical development in the Licensed Territory. The Company recognizes revenue when BeiGene obtains control of the goods, upon delivery, over the period of the obligation. No revenue related to this performance obligation was recognized for the three months ended March 31, 2021. The Company recognized $0.3 million as license and collaboration revenues for this performance obligation for the three months ended March 31, 2020, primarily consisting of cost-sharing payments due from BeiGene.

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Milestone Payments. The Company is entitled to development milestones under the BeiGene Agreement. The next clinical development milestone is for BeiGene initiating the first pivotal clinical trial in the Licensed Territory upon which the Company will be paid a $5.0 million milestone payment. The Company is also entitled to certain regulatory milestone payments which are paid upon receipt of regulatory approvals within the Licensed Territory. No milestone payments were earned during the three months ended March 31, 2021 or 2020. The Company evaluated whether the remaining milestones are considered probable of being reached and determined that their achievement is highly dependent on factors outside of the Company's control. Therefore, these payments have been fully constrained and are not included in the transaction price. At the end of each subsequent reporting period, the Company will re-evaluate the probability of achievement of each milestone and any related constraint, and if necessary, adjust its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect the reported amount of license and collaboration revenues in the period of adjustment.

Royalties.  As the license is deemed to be the predominant item to which sales-based royalties relate, the Company will recognize revenue when the related sales occur. No royalty revenue was recognized during the three months ended March 31, 2021 or 2020.

Pfizer Agreement

In October 2014, the Company entered into a drug discovery collaboration and option agreement with Array BioPharma, Inc. ("Array," acquired by Pfizer Inc. ("Pfizer") during 2019) whereby Array provided services to facilitate the discovery, optimization and development of small molecule compounds that bind and specifically inhibit KRAS G12C. In June 2017, the two parties entered into a second, separate discovery collaboration and option agreement whereby Array provided services to facilitate the discovery, optimization and development of small molecule compounds that bind and specifically inhibit KRAS G12D. Both agreements established an option mechanism which enabled the Company to elect an exclusive worldwide license under the technology for the development and commercialization of certain products based on such compounds.

Under the agreements, following the joint discovery periods which have concluded, the Company executed its options to retain exclusive worldwide licenses to develop, manufacture and commercialize inhibitors of KRAS G12C and KRAS G12D, including but not limited to, MRTX849 (adagrasib is the provisionally filed name for MRTX849) and MRTX1133. Under each agreement, Pfizer is entitled to potential development milestone payments of up to $9.3 million, and tiered sales milestone payments of up to $337.0 million based upon worldwide net sales, and tiered royalties in the high single digits to mid-teens on worldwide net sales of products arising from the collaborations. Under the agreements, the Company has incurred $4.5 million in development milestone payments from inception through March 31, 2021.

The royalty term for each agreement shall be payable on a country-by-country and product-by-product basis, and separately will terminate at the later of (i) the date of expiration of the last valid patent claim within the collaboration patent rights or the Pfizer background technology covering such product in the country in which such product is sold at the time of such sale, or (ii) 10 years after the first commercial sale of such product in such country. The Company may terminate each agreement at any time by providing 60 days prior written notice to Pfizer. Either party may terminate each agreement upon a material breach by the other party that remains uncured following 60 days after the date of written notice of such breach or upon certain bankruptcy events.

For the three months ended March 31, 2021, no expenses were incurred under these agreements with Pfizer. For the three months ended March 31, 2020, the Company incurred expenses of $4.5 million, consisting of a $3.0 million milestone payment for initiation of the first Phase 2 trial for MRTX849, and $1.5 million in research and development services.

ORIC Pharmaceuticals Agreement

Terms of Agreement

On August 3, 2020, the Company entered into a license agreement with ORIC Pharmaceuticals, Inc. ("ORIC") pursuant to which the Company granted to ORIC an exclusive, worldwide license to develop and commercialize the Company's allosteric polycomb repressive complex 2 ("PRC2") inhibitors for all indications (the "ORIC License Agreement"). In accordance with the terms of the ORIC License Agreement, in exchange for such license, ORIC issued 588,235 shares of its common stock (the "Shares") to the Company on August 3, 2020. The Shares were issued under a stock issuance agreement entered into between ORIC and the Company, dated August 3, 2020. During the eighteen-month period following the date of

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the stock issuance agreement, the Company is subject to certain transfer restrictions. ORIC is not obligated to pay the Company milestone payments or royalty payments under the ORIC License Agreement.

Unless terminated earlier, the ORIC License Agreement will continue in effect on a country-by-country and licensed product-by-licensed product basis until the later (a) the expiration of the last valid claim of a licensed patent covering such licensed product in such country or (b) ten years after the first commercial sale of such licensed product in such country. Following the expiration of the ORIC License Agreement, ORIC will retain its licenses under the intellectual property the Company licensed to ORIC on a royalty-free basis. The Company and ORIC may each terminate the ORIC License Agreement if the other party materially breaches the terms of such agreement, subject to specified notice and cure provisions, or enters into bankruptcy or insolvency proceedings. The Company may terminate the agreement if ORIC challenges any of the patent rights licensed to ORIC by the Company or if ORIC discontinues development of licensed products for a specified period of time. ORIC also has the right to terminate the ORIC License Agreement without cause by providing prior written notice to the Company.

Revenue Recognition

The Company accounted for the ORIC License Agreement under Topic 606 and identified the granting of an exclusive, worldwide license to develop and commercialize the Company's allosteric PRC2 inhibitors for all indications as a distinct performance obligation since ORIC can benefit from the license on its own by developing and commercializing the underlying product using its own resources.

In determining the transaction price, the Company received the Shares as non-cash consideration. The Company allocated the entire transaction price to the distinct performance obligation described above, and the license and related know-how was transferred to ORIC during the third quarter of 2020. Therefore, the Company recognized the entire transaction price during 2020 and classified the amount as license and collaboration revenues in its condensed consolidated statements of operations and comprehensive loss. There were no such revenues recorded during the three months ended March 31, 2021.

The Shares are carried at fair value and are recorded on the condensed consolidated balance sheet as a long-term investment. Any change in fair value is recorded within other (expense) income, net on the condensed consolidated statements of operations and comprehensive loss. The value of the long-term investment is determined by utilizing a Level 3 fair value measurement as further described in Note 4.

8. Warrants

As of March 31, 2021, the following warrants for common stock were issued and outstanding:

Issue date	Expiration date	Exercise price		Number of warrants outstanding
January 11, 2017	None	$	0.001	3,578,036
November 20, 2017	None	$	0.001	3,669,360
June 11, 2018	None	$	0.001	358,415
				7,605,811

During the three months ended March 31, 2021, 623,821 warrants for shares of the Company's common stock were exercised via cashless exercise, resulting in the issuance of 623,814 shares of common stock. No warrants were exercised during the three months ended March 31, 2020.

9. Commitments and Contingencies

On June 30, 2020, the Company entered into an amended and restated lease agreement (the "Amended and Restated Lease") for office and laboratory space located in San Diego, California, for the Company's new corporate headquarters. The Amended and Restated Lease supersedes in its entirety the original lease agreement for the Company's future corporate headquarters dated as of August 22, 2019. The Amended and Restated Lease has a lease term of 12 years ("Lease Term"), unless terminated earlier. The Lease Term has an initial abatement period, and the initial base rent payable will be approximately $0.6 million per month following the abatement period, which amount will increase by 3% per year over the Lease Term. The Company has also received incentives from the landlord for tenant improvements. During 2020, the

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underlying asset was available for use by the Company to construct tenant improvements and therefore, the Lease Term was considered to have commenced.

The Amended and Restated Lease is considered to be an operating lease, and the Amended and Restated Lease indicates the interest rate applicable to the lease is 12%, therefore the Company used a discount rate of 12% to calculate the value of its lease payments over the Lease Term. As of March 31, 2021, the condensed consolidated balance sheet includes an operating right-of-use asset of $39.3 million and an operating lease liability of $43.2 million. As of December 31, 2020, the consolidated balance sheet includes an operating right-of-use asset of $39.9 million and an operating lease liability of $41.9 million. For the three months ended March 31, 2021, the Company recorded $2.0 million in operating lease expense.

As of March 31, 2021, the approximate future minimum lease payments under the Amended and Restated Lease are as follows (in thousands):

	Operating Lease
2021 - remainder	$	—
2022	1,681
2023	7,844
2024	8,080
2025	8,322
Thereafter	68,257
Total operating lease payments(†)	94,184
Less: Amount representing interest	(51,009)
Total lease liability	$	43,175

____________________

†The Company has an early termination right 7 years into the lease term, in which the total contractual obligation would be reduced by $41.1 million.

On June 24, 2014, the Company entered into a lease agreement for completed office and laboratory space located in San Diego, California. The office space under the lease was the Company's corporate headquarters. The lease commenced in two phases (in July 2014 and March 2015) at a combined total initial monthly rent of $24,100 per month and was subject to a 3% annual rent increase following availability. In addition to such base monthly rent, the Company is obligated to pay certain customary amounts for its share of operating expenses and facility amenities. The original lease provided for expiration on January 31, 2018, and the Company entered into subsequent amendments to the original lease to extend the lease term to mid-2021. All other terms and covenants from the original lease agreement remain unchanged. For the three months ended March 31, 2020, the Company recorded $0.1 million in operating lease cost.

10. Shareholders' Equity

Sale of Common Stock    

In October 2020, the Company sold 4,585,706 shares of its common stock at a public offering price of $202.00 per share. After deducting underwriter discounts, commissions and estimated offering expenses, the Company received net proceeds from the transaction of $879.6 million.

In January 2020, the Company sold 3,538,462 shares of its common stock at a public offering price of $97.50 per share. After deducting underwriter discounts, commissions and offering expenses, the Company received net proceeds from the transaction of $324.0 million.

At the Market Facility

On July 2, 2020, the Company entered into a sales agreement pursuant to which the Company may, from time to time, sell shares of the Company's common stock, par value $0.001 per share, having an aggregate offering price of up to $200.0 million. As of March 31, 2021, the Company has not offered or sold any shares of common stock pursuant to this sales agreement.

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Share-based Compensation

Total share-based compensation expense by statement of operations and comprehensive loss classification is presented below (in thousands):

	Three months ended March 31,
	2021		2020
Research and development expense	$	14,534	$	11,848
General and administrative expense	10,188		9,719
	$	24,722	$	21,567

During the three months ended March 31, 2021, 312,903 shares of common stock were issued under the Company's equity incentive plans, generating net proceeds of $9.9 million. During the three months ended March 31, 2020, 496,521 shares of common stock were issued under the Company's equity incentive plans, generating net proceeds of $15.2 million.

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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 our unaudited financial statements and related notes included in this Quarterly Report on Form 1O-Q and the audited financial statements and notes thereto as of and for the year ended December 31, 2020 and the related Management’s Discussion and Analysis of Financial Condition and Results of Operations, both of which are contained in our Annual Report on Form 10-K filed by us with the Securities and Exchange Commission ("SEC").

This Quarterly Report on Form 10-Q may contain “forward-looking statements” within the meaning of Section 27A of the Securities Act of 1933, as amended, or the Securities Act, and Section 21E of the Securities Exchange Act of 1934, as amended, or the Exchange Act. Such forward-looking statements, which represent our intent, belief, or current expectations, involve risks and uncertainties. We use words such as “may,” “will,” “expect,” “anticipate,” “estimate,” “intend,” “plan,” “predict,” “potential,” “believe,” “should” and similar expressions to identify forward-looking statements, although not all forward-looking statements contain these identifying words. Such statements may include, but are not limited to, statements concerning projections about our accounting and finances, plans and objectives for the future, future operating and economic performance and other statements regarding future performance.  Although we believe the expectations reflected in these forward-looking statements are reasonable, such statements are inherently subject to risk and we can give no assurances that our expectations will prove to be correct. You should not place undue reliance on these forward-looking statements, which apply only as of the date of this Quarterly Report on Form 10-Q. As a result of many factors, including without limitation those set forth under “Risk Factors” under Item 1A of Part II below, and elsewhere in this Quarterly Report on Form 10-Q, our actual results may differ materially from those anticipated in these forward-looking statements. We undertake no obligation to update these forward-looking statements to reflect events or circumstances after the date of this report or to reflect actual outcomes.

References in the following discussion to "we," "our," "us," or "Mirati" refer to Mirati Therapeutics, Inc. and its subsidiaries. 

Overview

Mirati Therapeutics, Inc. is a clinical-stage oncology company developing novel therapeutics to address the genetic and immunological promoters of cancer. MRTX849 is an investigational, selective, specific, potent and orally available KRAS G12C inhibitor in clinical development as a monotherapy and in combination with other agents. Adagrasib is the provisionally filed nonproprietary name for MRTX849. MRTX1133 is an investigational, selective, specific and potent KRAS G12D inhibitor in preclinical development. Sitravatinib is an investigational spectrum-selective kinase inhibitor designed to potently inhibit receptor tyrosine kinases ("RTK"s) and enhance immune responses through the inhibition of immunosuppressive signaling. The Company also has additional preclinical programs of potentially first-in-class and best-in-class product candidates specifically designed to address mutations and tumors where few treatment options exist, including an internally discovered investigational synthetic lethal PRMT5 inhibitor to specifically target the PRMT5/methylthioadensoine (MTA) complex. We approach all of our programs with a singular focus: to translate our deep understanding of the molecular drivers of cancer into better therapies and better outcomes for patients.

KRAS Inhibitor Programs

The RAS family of genes is the most commonly mutated oncogene and mutations in this gene family occur in up to approximately 25% of all human cancers. Among the RAS family members, mutations most frequently occur in KRAS (approximately 85% of all RAS family mutations). Tumors characterized by KRAS mutations are commonly associated with poor prognosis and resistance to therapy. Nonclinical studies have demonstrated that cancer cells exhibiting KRAS mutations are highly dependent on KRAS function for cell growth and survival. Our KRAS inhibitor programs are focused on the discovery and development of small molecule compounds that target KRAS G12C and G12D. We are pursuing development of our KRAS G12C and KRAS G12D inhibitor programs in both single agent and rational combination approaches.

MRTX849, a selective KRAS G12C inhibitor

MRTX849, our lead KRAS G12C compound, is an investigational, selective, specific, potent and orally available KRAS G12C inhibitor. MRTX849 is designed to directly inhibit KRAS G12C mutations. KRAS G12C mutations are present in

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approximately 14% of non-small cell lung cancer (“NSCLC”) adenocarcinoma patients, 3-4% of colorectal cancer (“CRC”) patients, 2% of pancreatic cancer patients, as well as smaller percentages of several other difficult-to-treat cancers.

We received U.S. Food and Drug Administration (“FDA”) authorization of our investigational new drug application (“IND”) for MRTX849 in November 2018, and on January 15, 2019, we announced that we had dosed the first patient in the dose escalation phase of a Phase 1/2 clinical trial in patients with advanced solid tumors that harbor KRAS G12C mutations. Following single agent dose escalation, we have expanded into cohorts that include patients with NSCLC, CRC and those with other tumors that carry the KRAS G12C mutation. We have completed enrollment in a Phase 2 registration enabling cohort of MRTX849 as a monotherapy treatment for patients in at least 2nd line NSCLC. This trial also enables exploratory combination cohorts, including evaluating the combination of MRTX849 and a PD-1 inhibitor (pembrolizumab) in patients with NSCLC, the combination of MRTX849 and a pan-EGFR inhibitor (afatinib) in patients with advanced NSCLC, and the combination of MRTX849 and an anti-EGFR antibody (cetuximab) in patients with CRC. In 2020, we initiated a Phase 1/2 clinical trial evaluating the combination of MRTX849 and a SHP-2 inhibitor (TNO-155) in patients with advanced NSCLC and advanced CRC. In the fourth quarter of 2020, we initiated a Phase 2 clinical trial evaluating the combination of MRTX849 and a PD-1 inhibitor (pembrolizumab) in patients with NSCLC stratified by <1% Tumor Proportion Score ("TPS") score and ≥1% TPS score. In the first quarter of 2021, we initiated a Phase 3 clinical trial evaluating MRTX849 as a monotherapy randomized against docetaxel in patients in at least 2nd line NSCLC, and a Phase 3 clinical trial evaluating the combination of MRTX849 and an anti-EGFR antibody (cetuximab) in patients in 2nd line CRC.

On October 25, 2020, at the 32nd EORTC-NCI-AACR Symposium on Molecular Targets and Therapeutics (“ENA”), we announced preliminary results from ongoing clinical trials for MRTX849 at a dose of 600 mg twice daily ("BID") in monotherapy as of August 30, 2020 and combination trials as of October 25, 2020. In a pooled assessment of 110 patients harboring a KRAS G12C mutation in NSCLC, CRC and other solid tumors, monotherapy MRTX849 was generally well tolerated; 4.5% of treatment-related adverse events had led to discontinuation. Over 50 patients had been treated with MRTX849 in combination with either pembrolizumab in NSCLC, cetuximab in CRC and TNO-155 in NSCLC or CRC. In the preliminary results reported, each combination was generally well tolerated; the pembrolizumab and cetuximab combination cohorts cleared the dose limiting toxicity evaluation period at the full dose of each commercial agent and at a 600 mg BID dose of MRTX849, and the TNO-155 combination dose escalation and expansion cohorts were ongoing at a 600 mg BID dose of MRTX849.

Preliminary efficacy data was assessed as of August 30, 2020 in patients with advanced NSCLC treated with MRTX849 as a monotherapy at a 600 mg BID from a pooled Phase 1/1b cohort and Phase 2 registration-enabling cohort (n=51): 45% (23/51) of patients had a confirmed objective response rate (“ORR”), and 70% (16/23) of responders had a best tumor response of greater than 40%. Patients had a disease control rate (“DCR”) of 96% (49/51), with 3.6 months median duration of follow-up; 65% (33/51) of patients remained on treatment and 87% (20/23) of responders remained on treatment.

Preliminary efficacy data was assessed as of August 30, 2020 in heavily pretreated patients with advanced CRC treated with MRTX849 as a monotherapy at a 600 mg BID dose. Efficacy data from pooled Phase 1/1b and Phase 2 cohorts (n=18): 17% (3/18) of patients had a confirmed ORR with 2 of 3 responders remaining on treatment. 94% (17/18) of patients had a DCR, with 67% (12/18) of patients remaining on treatment and 55% (10/18) of patients had a duration of treatment of greater than 4 months.

Preliminary efficacy data was assessed as of August 30, 2020 in six patients with advanced solid tumors, other than NSCLC and CRC, treated with MRTX849 as a monotherapy at 600 mg BID dose from a Phase 1/1b cohort. One patient each with pancreatic, ovarian, endometrial and cholangiocarcinoma tumors were treated and had a confirmed partial response to therapy. Two appendiceal cancer patients had stable disease and all six eligible patients remained on treatment.

MRTX849 Development in Collaboration with Novartis Pharmaceuticals Corporation ("Novartis")

In July 2019, we announced a clinical collaboration agreement with Novartis to evaluate the combination of MRTX849 and Novartis’ investigational SHP2 inhibitor, TNO155, in patients with advanced solid tumors that harbor KRAS G12C mutations. Under the terms of the non-exclusive collaboration, we will sponsor the trial and we and Novartis will jointly oversee and share the costs of clinical development activities for the combined therapy. Novartis will provide TNO155 at no cost. This clinical trial is currently active.

MRTX849 Development in Collaboration with Boehringer Ingelheim International GmbH ("BII")

In September 2020, we announced a clinical collaboration agreement with BII to evaluate the combination of MRTX849 and BII's investigational SOS1 inhibitor, BI 1701963, in patients with advanced solid tumors that harbor KRAS

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G12C mutations. Under the terms of the non-exclusive collaboration, we will sponsor the trial and we and BII will jointly oversee and share the costs of clinical development activities for the combined therapy.

MRTX1133, a selective KRAS G12D inhibitor

MRTX1133, our lead KRAS G12D compound, has been identified as a clinical development candidate and is an investigational, selective, specific and potent inhibitor of KRAS G12D. KRAS G12D mutations have been detected in over 25 different types of cancer, including pancreatic, colon, lung and endometrial adenocarcinoma. The prevalence of cancers harboring KRAS G12D mutations exceeds the prevalence of KRAS G12C positive cancers by greater than two-fold and is an area of significant unmet medical need.

On October 25, 2020 we announced initial preclinical in vivo data from MRTX1133. Based on preclinical analyses, MRTX1133 has a projected human half-life of approximately 50 hours and exhibits a low propensity for drug interactions or off-target pharmacology. MRTX1133 demonstrated tumor regression in multiple in vivo tumor models, including pancreatic and colorectal cancers. MRTX1133 has a low predicted target plasma concentration, based on its potency and high unbound fraction, and our goal is to achieve near complete and sustained target inhibition and maximal anti-tumor activity. We continue to explore both oral and parenteral routes of administration in parallel to allow selection of the route that results in the optimal KRAS G12D inhibition as we plan for a Phase 1 clinical trial.

MRTX849 and MRTX1133 Discovery Collaboration with Pfizer Inc. ("Pfizer")

In October 2014, we entered into a drug discovery collaboration and option agreement with Array BioPharma, Inc. ("Array," acquired by Pfizer in July 2019) whereby Array provided services to facilitate the discovery, optimization and development of small molecule compounds that bind and specifically inhibit KRAS G12C. In June 2017, the two parties entered into a second, separate discovery collaboration and option agreement whereby Array provided services to facilitate the discovery, optimization and development of small molecule compounds that bind and specifically inhibit KRAS G12D. Both agreements established an option mechanism which enabled the Company to elect an exclusive worldwide license under the technology for the development and commercialization of certain products based on such compounds.

Under the agreements, following the joint discovery periods which have concluded, we executed our options to retain exclusive worldwide licenses to develop, manufacture and commercialize inhibitors of KRAS G12C and KRAS G12D, including but not limited to, MRTX849 and MRTX1133. Under each agreement, Pfizer is entitled to potential development milestone payments of up to $9.3 million, and tiered sales milestone payments of up to $337.0 million based upon worldwide net sales, and tiered royalties in the high single digits to mid-teens on worldwide net sales of products arising from the collaborations. Under the agreements, we have incurred $4.5 million in development milestone payments from inception through March 31, 2021.

Sitravatinib

Sitravatinib is a spectrum-selective kinase inhibitor designed to potently inhibit receptor tyrosine kinases (“RTK”s), including TAM family receptors (TYRO3, Axl, Mer), split family receptors (VEGFR2, KIT) and RET. Sitravatinib’s potent inhibition of TAM and split family RTKs may overcome resistance to checkpoint inhibitor therapy through targeted reversal of an immunosuppressive tumor microenvironment, enhancing antigen-specific T cell response and expanding dendritic cell-dependent antigen presentation. As an immuno-oncology agent, sitravatinib is being evaluated in combination with nivolumab (OPDIVO®), Bristol-Myers Squibb Company’s (“BMS”) anti-PD-1 checkpoint inhibitor, in patients with NSCLC who have experienced documented disease progression following treatment with a checkpoint inhibitor. Sitravatinib is also being developed in certain Asian territories in collaboration with BeiGene, Ltd. (“BeiGene”) which is evaluating sitravatinib in combination with tislelizumab, BeiGene’s anti-PD-1 checkpoint inhibitor, in a number of advanced solid tumors.

Sitravatinib in Combination with Nivolumab

There are over 100,000 2nd or 3rd line NSCLC patients in the United States and Europe, who have derived prior clinical benefit following treatment with a PD-(L)1 inhibitor, with approximately 70,000 of these patients being of the non-squamous histology. We are enrolling an ongoing Phase 3 clinical trial in 2nd line non-squamous NSCLC patients whose tumors have progressed on prior therapy with platinum-chemotherapy in combination with a checkpoint inhibitor or 3rd line non-squamous NSCLC patients who have received chemotherapy followed by a checkpoint inhibitor. The Phase 3 clinical trial is comparing the combination of sitravatinib plus nivolumab randomized to docetaxel. The statistical design of the Phase 3 clinical trial includes an interim analysis of overall survival that we believe, if positive, could support an NDA submission seeking full approval.

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In January 2019, we announced a clinical trial collaboration with BMS in connection with the aforementioned Phase 3 clinical trial. Under the terms of the collaboration, we are sponsoring and funding the clinical trial and BMS is providing nivolumab at no cost. We maintain global development and commercial rights to sitravatinib outside of certain Asian territories and Australia and New Zealand, where we have partnered with BeiGene, and we are free to develop the program in combination with other agents.

We also have several Phase 2 clinical trials in which we are evaluating sitravatinib in combination with nivolumab in patients with NSCLC, urothelial carcinoma or other cancers who have experienced documented disease progression following prior treatment with chemotherapy and/or a checkpoint inhibitor.

Sitravatinib Development in Collaboration with BeiGene

In January 2018, we entered into a Collaboration and License Agreement (the “BeiGene Agreement”) with BeiGene. Under the BeiGene Agreement, we granted BeiGene an exclusive license to develop, manufacture and commercialize sitravatinib in Asia (excluding Japan and certain and other countries), Australia and New Zealand (the "Licensed Territory"), and we retained exclusive rights for the development, manufacturing and commercialization of sitravatinib outside the Licensed Territory.

In November 2018, we dosed the first patient under the BeiGene Agreement to assess the safety and tolerability, pharmacokinetics and preliminary anti-tumor activity of sitravatinib in combination with BeiGene’s investigational anti-PD-1 antibody, tislelizumab, in patients with advanced solid tumors. BeiGene’s clinical trials will evaluate the combination of sitravatinib and tislelizumab in patients with solid tumors including NSCLC, renal cell carcinoma, hepatocellular cancer, gastric cancer and ovarian cancer.

Critical Accounting Policies and Significant Judgments and Estimates

Our discussion and analysis of financial condition and results of operations are based upon our consolidated financial statements, which have been prepared in accordance with U.S. generally accepted accounting principles. The preparation of these financial statements requires us to make significant estimates and judgments that affect the reported amounts of assets, liabilities, revenue and expenses and related disclosures. On an ongoing basis, our actual results may differ significantly from our estimates.

There have been no material changes to our critical accounting policies and estimates from the information provided in Item 7, Management’s Discussion and Analysis of Financial Condition and Results of Operations, included in our Annual Report on Form 10-K for the year ended December 31, 2020.

Results of Operations

Comparison of the Three Months Ended March 31, 2021 and 2020

The following table summarizes the significant items within our results of operations for the three months ended March 31, 2021 and 2020 (in thousands):

	Three months ended March 31,				Increase
	2021		2020		(Decrease)
License and collaboration revenues	$	—	$	267	$	(267)
Research and development expenses	$	104,071	$	71,708	$	32,363
General and administrative expenses	28,350		18,046		10,304
Other (expense) income, net	(3,259)		2,832		(6,091)

Revenues

License and collaboration revenues relate to the BeiGene Agreement under which BeiGene was granted an exclusive license to develop, manufacture and commercialize sitravatinib in the Licensed Territory. No license and collaboration revenues were earned for the three months ended March 31, 2021. License and collaboration revenues for the three months ended March 31, 2020 were $0.3 million, and relate to the manufacturing supply services agreement with BeiGene.

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Research and development expenses

Research and development expenses consist primarily of:

•salaries and related expenses for personnel, including expenses related to stock options or other share-based compensation granted to personnel in research and development functions;

•fees paid to external service providers such as Clinical Research Organizations ("CROs") and contract manufacturing organizations related to clinical trials, including contractual obligations for clinical development, clinical sites, manufacturing and scale-up, and formulation of clinical drug supplies;

•fees paid to contract services related to drug discovery efforts including chemistry and biology services;

•license fees paid in connection with our early discovery efforts; and

•costs for allocated facilities and depreciation of equipment.

We record research and development expenses as incurred.

Our research and development efforts during the three months ended March 31, 2021 and 2020 were focused primarily on our clinical development programs and our preclinical programs. The following table summarizes our research and development expenses, (in thousands):

	Three months ended March 31,				Increase
	2021		2020		(Decrease)
Third-party research and development expenses:
Clinical development programs:
MRTX849	43,407		30,598		12,809
Sitravatinib	15,577		15,610		(33)
Discontinued programs	189		497		(308)
Pre-clinical development programs:
MRTX1133	2,242		2,239		3
Preclinical and early discovery	6,153		1,361		4,792
Total third-party research and development expenses	67,568		50,305		17,263
Salaries and other employee related expense	15,043		7,242		7,801
Share-based compensation expense	14,534		11,848		2,686
Other research and development costs	6,926		2,313		4,613
Research and development expense	$	104,071	$	71,708	$	32,363

Research and development expenses for the three months ended March 31, 2021 were $104.1 million compared to $71.7 million for the three months ended March 31, 2020. The increase of $32.4 million primarily relates to increases in third-party research and development expense of $17.3 million, salaries and other employee related expense of $7.8 million, other research and development expense of $4.6 million, and share-based compensation expense of $2.7 million. The increase in third-party research and development expense primarily relates to an increase in expenses associated with development of MRTX849 of $12.8 million. The increase in expenses associated with MRTX849 relates to the ongoing Phase 2 and Phase 1/2 clinical trials, and the start-up of Phase 3 clinical trials. The costs are comprised largely of manufacturing expenses, CRO fees, and other clinical trial-related expenses. The increase in salaries and other employee related expense of $7.8 million is primarily due to an increase in the number of research and development employees employed during the three months ended March 31, 2021, compared to the same period in 2020. The increase in other research and development costs of $4.6 million is primarily due to increases in rent, software license and professional services expenses. The increase in share-based compensation of $2.7 million is due to an increase in the fair value of equity awards granted during the three months ended March 31, 2021, compared to the same period in 2020.

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At this time, due to the risks inherent in the clinical development process and product development programs we are unable to estimate with any certainty the costs we will incur in the continued development of MRTX849, sitravatinib and MRTX1133. The process of conducting clinical trials necessary to obtain regulatory approval and manufacturing scale-up to support expanded development and potential future commercialization is costly and time consuming. Any failure by us or delay in completing clinical trials, manufacturing scale up or in obtaining regulatory approvals could lead to increased research and development expense and, in turn, have a material adverse effect on our results of operations. We expect that our research and development expenses may increase if we are successful in advancing MRTX849, sitravatinib and MRTX1133 or any of our other preclinical programs, into more advanced stages of clinical development.

General and administrative expenses

General and administrative expenses consist primarily of salaries and related benefits, including share-based compensation, related to our executive, finance, legal, commercial and support functions. Other general and administrative expenses include professional fees for auditing, tax, consulting and patent-related services, rent and utilities and insurance.

General and administrative expenses for the three months ended March 31, 2021 and 2020 were $28.4 million and $18.0 million, respectively, representing an increase of $10.3 million. The increase in expense for the three months ended March 31, 2021 is primarily due to an increase in sponsorship agreements expense of $4.0 million, an increase in professional services expense of $2.5 million, an increase in salaries and other employee related expense of $1.9 million, an increase in insurance, rent and other facilities-related costs and other expense of $1.4 million, and an increase in share-based compensation expense of $0.5 million. The increase in professional service expense is primarily due to an increase in commercial costs during the three months ended March 31, 2021, compared to the same period in 2020. The increase in salaries and other employee related expense is primarily due to an increase in the number of general and administrative employees during the three months ended March 31, 2021 compared to the same period in 2020, and is largely driven by commercial readiness activities. The increase in share-based compensation expense is due to an increase in the fair value of equity awards granted during the three months ended March 31, 2021, compared to the same period in 2020.

Other (Expense) Income, Net

Other (expense) income, net for the three months ended March 31, 2021 was a net expense of $3.3 million, compared to a net income of $2.8 million for the same period in 2020. The decrease is primarily due to an unrealized loss of $4.0 million in the fair value on the long-term investment in ORIC Pharmaceuticals, Inc. which was acquired in 2020 in connection with the ORIC License Agreement, and a decrease of $2.2 million in interest income primarily due to the lower interest rates.

Liquidity and Capital Resources

As of March 31, 2021, we had $1.3 billion of cash, cash equivalents and short-term investments compared to $1.4 billion at December 31, 2020. During 2020, we completed public offerings of our common stock that generated total net proceeds of $1.2 billion: in October 2020, we completed a public offering of our common stock that generated net proceeds of approximately $879.6 million, and in January 2020, we completed a public offering of our common stock that generated net proceeds of $324.0 million. In July 2020, we entered into a sales agreement pursuant to which we may, from time to time, sell shares of our common stock having an aggregate offering price of up to $200.0 million; as of March 31, 2021, no shares have been sold in connection with this sales agreement. Based on our current and anticipated level of operations, we believe that our cash, cash equivalents and short-term investments will be sufficient to meet our anticipated obligations for at least one year from the date that this Quarterly Report on Form 10-Q is filed with the SEC.

To date, we have funded our operations primarily through the sale of our common stock, pre-funded warrants to purchase our common stock, and to a lesser extent through up-front payments, research funding and milestone payments under collaborative arrangements. Since inception, we have primarily devoted our resources to funding research and development programs, including discovery research, preclinical and clinical development activities. To fund future operations, we will likely need to raise additional capital. The amount and timing of future funding requirements will depend on many factors, including the timing and results of our ongoing development efforts, the potential expansion of our current development programs, potential new development programs and related general and administrative support. We anticipate that we will seek to fund our operations through public or private equity or debt financings or other sources, such as potential collaboration agreements. We cannot make assurances that anticipated additional financing will be available to us on favorable terms, or at all. Although we have previously been successful in obtaining financing through our equity securities offerings, there can be no assurance that we will be able to do so in the future. As a result of the COVID-19 pandemic and actions taken to slow its spread, the global credit and financial markets have experienced extreme volatility, including in liquidity and credit availability, declines in consumer confidence, declines in economic growth, increases in unemployment rates and uncertainty about

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economic stability. There can be no assurance that deterioration in credit and financial markets and confidence in economic conditions will not occur. If equity and credit markets deteriorate, it may make any necessary debt or equity financing more difficult to obtain, more costly and/or more dilutive.

Cash Flows for the Three Months Ended March 31, 2021 and 2020

The following table provides a summary of the net cash flow activity for each of the periods set forth below (in thousands):

	Three months ended March 31,
	2021		2020
Net cash used in operating activities	$	(110,416)	$	(59,004)
Net cash used in investing activities	(455,528)		(122,227)
Net cash provided by financing activities	9,885		339,201
(Decrease) increase in cash, cash equivalents and restricted cash	$	(556,059)	$	157,970

Net cash used in operating activities

Net cash used in operating activities for the three months ended March 31, 2021 was $110.4 million, compared to $59.0 million for the same period in 2020, an increase of $51.4 million. Cash used in operating activities during 2021 primarily related to our net loss of $135.7 million, adjusted for non-cash items such as share-based compensation of $24.7 million and net cash outflow from a change in our operating assets and liabilities of $4.7 million. Cash used in operating activities during 2020 primarily related to our net loss of $86.7 million, adjusted for non-cash items such as share-based compensation expense of $21.6 million and net cash inflow from a change in our operating assets and liabilities of $6.5 million.

Net cash used in investing activities

For the three months ended March 31, 2021 and March 31, 2020, investing activities used cash of $455.5 million and $122.2 million, respectively, due to purchases of short-term investments and property and equipment, offset by sales and maturities of short-term investments.

Net cash provided by financing activities

Net cash provided by financing activities for the three months ended March 31, 2021 was $9.9 million and consisted primarily of proceeds from the exercise of common stock options. Net cash provided by financing activities for the three months ended March 31, 2020 was $339.2 million and consisted primarily of proceeds received from the issuance of common stock from public offerings and the exercise of common stock options.

Off-Balance Sheet Arrangements

During the three months ended March 31, 2021, we did not have any off-balance sheet arrangements (as defined by applicable SEC regulations) that are reasonably likely to have a current or future material effect on our financial condition, results of operations, liquidity, capital expenditures or capital resources.

Contractual Obligations and Commitments

There were no material changes outside of the ordinary course of business to our specific contractual obligations during the three months ended March 31, 2021.

Recent Accounting Pronouncements

Occasionally, new accounting standards are issued or proposed by the Financial Accounting Standards Board, or other standard-setting bodies that we adopt by the effective date specified within the standard. Unless otherwise discussed, standards that do not require adoption until a future date are not expected to have a material impact on our financial statements upon adoption.

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ITEM 3.  Quantitative and Qualitative Disclosures about Market Risk

Interest Rate Risk

Some of our short-term investments have market risk in that a change in prevailing interest rates may cause the fair value of the principal amount of the investment to fluctuate. Financial instruments that potentially subject us to significant concentrations of credit risk consist primarily of cash, cash equivalents and short-term investments. We invest our excess cash primarily in commercial paper and debt instruments of financial institutions, corporations, U.S. government-sponsored agencies and the U.S. Treasury. We mitigate credit risk by maintaining a well-diversified portfolio and limiting the amount of investment exposure as to institution, maturity and investment type. We invest our excess cash in accordance with our investment policy.

Because of the short-term maturities of our cash equivalents and short-term investments, we do not believe that an increase in market rates would have any significant impact on the realized value of our investments. If a 10% change in interest rates were to have occurred on March 31, 2021, this change would not have had a material effect on the fair value of our investment portfolio as of that date.

Effects of Inflation

We do not believe that inflation and changing prices had a significant impact on our results of operations for any periods presented herein.

ITEM 4.  Controls and Procedures

Evaluation of Disclosure Controls and Procedures

As required by Rule 13a-15(b) and Rule 15d-15(b) of the Exchange Act, our management, including our principal executive officer and our principal financial officer, conducted an evaluation as of the end of the period covered by this Quarterly Report on Form 10-Q of the effectiveness of the design and operation of our disclosure controls and procedures (as defined in Exchange Act Rule 13a-15(e) and 15d-15(e)). Based on that evaluation, management has concluded that as of March 31, 2021, the Company’s disclosure controls and procedures were effective at the reasonable assurance level and we believe the condensed consolidated financial statements included in this Form 10-Q for the three months ended March 31, 2021 present, in all material respects, our financial position, results of operations, comprehensive loss and cash flows for the periods presented in conformity with U.S. generally accepted accounting principles.

Changes in Internal Control over Financial Reporting

As required by Rule 13a-15(d) and Rule 15d-15(d) of the Exchange Act, our management, including our principal executive officer and our principal financial officer, conducted an evaluation of the internal control over financial reporting to determine whether any changes occurred during the period covered by this Quarterly Report on Form 10-Q that have materially affected, or are reasonably likely to materially affect, our internal control over financial reporting. Based on that evaluation, our principal executive officer and principal financial officer concluded that there were no changes in our internal controls over financial reporting during the period covered by this Quarterly Report on Form 10-Q that materially affected, or were reasonably likely to materially affect, our internal control over financial reporting.

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PART II-OTHER INFORMATION

ITEM 1.    LEGAL PROCEEDINGS

None.

Item 1A.     Risk Factors

You should carefully consider the following information about the risks described below, together with the other information contained in this Quarterly Report and in our other public filings in evaluating our business. The risk factors set forth below with an asterisk (*) next to the title contain changes to the description of the risk factors associated with our business previously disclosed in Item 1A of our Annual Report on Form 10-K for the year ended December 31, 2020. Additional risks and uncertainties that we are unaware of may also become important factors that affect us. If any of the following risks actually occurs, our business, financial condition, results of operations and future growth prospects would likely be materially and adversely affected. In these circumstances, the market price of our common stock would likely decline.

Summary of Risk Factors

We face a number of risks and uncertainties related to our business and our securities, many of which are beyond our control. Some of our principal risks related to our business include the following:

•Risks Relating to our Business and Industry

◦Our research and development programs and product candidates are in development. As a result, we are unable to predict if or when we will successfully develop or commercialize our product candidates.

◦All of our product candidates are subject to extensive regulation, which can be costly and time consuming, cause delays or prevent approval of such product candidates for commercialization

◦The successful commercialization of our product candidates, if approved, will depend on achieving market acceptance and we may not be able to gain sufficient acceptance to generate significant revenue.

◦The COVID-19 pandemic could adversely impact our business including our ongoing and planned clinical trials and preclinical research.

◦We rely upon third-party contractors and service providers for the execution of some aspects of our development programs. Failure of these collaborators to provide services of a suitable quality and within acceptable timeframes may cause the delay or failure of our development programs.

◦Competition in our targeted market area is intense and this field is characterized by rapid technological change. Therefore, developments by competitors may substantially alter the predicted market or render our product candidates uncompetitive

◦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 product label, or result in significant negative consequences following marketing approval, if any.

◦We are subject to competition for our skilled personnel and may experience challenges in identifying and retaining key personnel that could impair our ability to conduct our operations effectively.

•Risks Related to our Financial Position Capital Requirements

◦We will require additional financing and may be unable to raise sufficient capital, which could lead us to delay, reduce or abandon development programs or commercialization.

•Risks Related to our Intellectual Property

◦We may not obtain adequate protection for our product candidates through patents and other intellectual property rights and as such, our competitive advantage in the marketplace may be compromised.

•Other factors set forth herein.

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Risks Relating to Our Business and Industry

Our research and development programs and product candidates are in development. As a result, we are unable to predict if or when we will successfully develop or commercialize our product candidates.

Our clinical-stage product candidates as well as our other pipeline assets will require significant further investment and regulatory approvals prior to commercialization. MRTX849 is in Phase 3 and Phase 1/2 clinical trials and MRTX1133 is in preclinical development. Sitravatinib is in a Phase 3 clinical trial, and Phase 1/2 clinical trials. Each of our product candidates will require the selection of suitable patients for our clinical trials and additional clinical development, management of clinical, preclinical and manufacturing activities, obtaining regulatory approval, obtaining manufacturing supply, building of a commercial organization, substantial investment and significant marketing efforts before we generate any revenues from product sales. 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, and we may never receive such regulatory approval for any of our product candidates. The treatment of cancer is a rapidly evolving field and will continue to evolve. By such time, if ever, as we may receive necessary regulatory approvals for our product candidates, the standard of care for the treatment of cancers may have evolved such that it would be necessary to modify our plans for full approval and commercial acceptance of our products may be limited by a change in the standard of care. In addition, some of our product development programs contemplate the development of companion diagnostics. Companion diagnostics are subject to regulation as medical devices and we or our collaborators may be required to obtain marketing approval for accompanying companion diagnostics before we may commercialize our product candidates.

Even if we obtain the required financing or establish a collaboration to enable us to conduct late-stage clinical development of our product candidates and pipeline assets, we cannot be certain that such clinical development would be successful, or that we will obtain regulatory approval or be able to successfully commercialize any of our product candidates and generate revenue. Success in preclinical testing and early clinical trials does not ensure that later clinical trials will be successful, and the clinical trial process may fail to demonstrate that our product candidates are safe and effective for their proposed uses. Any such failure could cause us to abandon further development of any one or more of our product candidates and may delay development of other product candidates. Product candidates in later stages of clinical trials may fail to show the desired safety and efficacy traits despite having progressed through preclinical studies and initial clinical trials. Any delay in, or termination of, our clinical trials will delay and possibly preclude the submission of any new drug applications ("NDAs") with the FDA and, ultimately, our ability to commercialize our product candidates and generate product revenue.

We have not previously submitted an NDA to the FDA, or similar drug approval filings to comparable foreign authorities, for any product candidate, and we cannot be certain that any of our product candidates will receive regulatory approval. Further, our product candidates may not receive regulatory approval even if they are successful in clinical trials. If we do not receive regulatory approvals for our product candidates, we may not be able to continue our operations. Even if we successfully obtain regulatory approvals to market one or more of our product candidates, our revenues will be dependent, in part, upon our or our collaborators' and future collaborators’ ability to obtain regulatory approval for the companion diagnostics to be used with our product candidates, if required, and upon the size of the markets in the territories for which we gain regulatory approval and have commercial rights. If the markets for patient subsets that we are targeting are not as significant as we estimate, we may not generate significant revenues from sales of such products, if approved.

Further, even if any product candidate we develop was to receive marketing approval or be commercialized for use in combination with other existing therapies, we would continue to bear the risks that the FDA or similar foreign regulatory authorities could revoke approval of the therapy used in combination with our product candidate or that safety, efficacy, manufacturing or supply issues could arise with these existing therapies.

All of our product candidates are subject to extensive regulation, which can be costly and time consuming, cause delays or prevent approval of such product candidates for commercialization.

The clinical development of product candidates is subject to extensive regulation by the FDA in the United States and by comparable regulatory authorities in foreign markets. Product development is a very lengthy and expensive process, and its outcome is inherently uncertain. The product development timeline can vary significantly based upon the product candidate’s novelty and complexity. Regulations are subject to change and regulatory agencies have significant discretion in the approval process.

Numerous statutes and regulations govern human testing and the manufacture and sale of human therapeutic products in the United States, Europe and other countries and regions where we intend to market our products. Such legislation and regulation bears upon, among other things, the approval of trial protocols and human testing, the approval of manufacturing

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facilities, safety of the product candidates, testing procedures and controlled research, review and approval of manufacturing, preclinical and clinical data prior to marketing approval including adherence to good manufacturing practices ("GMP") during production and storage as well as regulation of marketing activities including advertising and labeling.

In order to obtain regulatory approval for the commercial sale of any of our product candidates, we must demonstrate through preclinical studies and clinical trials that the potential product is safe and effective for use in humans for each target indication. The failure to adequately demonstrate the safety and efficacy of a product under development could delay or prevent regulatory approval of our product candidates.

No assurance can be given that current regulations relating to regulatory approval will not change or become more stringent in the United States or foreign markets. Regulatory agencies may also require that additional trials be run in order to provide additional information regarding the safety or efficacy of any drug candidates for which we seek regulatory approval. Moreover, any regulatory approval of a drug which is eventually obtained may entail limitations on the indicated uses for which that drug may be marketed. Furthermore, product approvals may be withdrawn or limited in some way if problems occur following initial marketing or if compliance with regulatory standards is not maintained. Regulatory agencies could become more risk averse to any side effects or set higher standards of safety and efficacy prior to reviewing or approving a product. This could result in a product not being approved. Any of the foregoing scenarios could materially harm the commercial prospects for our product candidates.

The successful commercialization of our product candidates, if approved, will depend on achieving market acceptance and we may not be able to gain sufficient acceptance to generate significant revenue.

Even if our product candidates are successfully developed and receive regulatory approval, they may not gain market acceptance among physicians, patients, healthcare payors such as private insurers or governments and other funding parties and the medical community. The degree of market acceptance for any of our products will depend on a number of factors, including:

•demonstration of the clinical efficacy and safety of our products;

•the prevalence and severity of any adverse side effects;

•limitations or warnings contained in the product’s approved labeling;

•cost-effectiveness and availability of acceptable pricing;

•competitive product profile versus alternative treatment methods and the superiority of alternative treatment or therapeutics;

•the effectiveness of marketing and distribution methods and support for the products; and

•the availability of coverage and adequate reimbursement from third-party payors to the extent that our products receive regulatory approval.

Disease indications may be small subsets of a disease that could be parsed into smaller and smaller indications as different subsets of diseases are defined. This increasingly fine characterization of diseases could have negative consequences; including creating an approved indication that is so small as not to have a viable market for us. If future technology allows characterization of a disease in a way that is different from the characterization used for large pivotal studies, it may make those studies invalid or reduce their usefulness, and may require repeating all or a portion of the studies. Future technology may supply better prognostic ability which could reduce the portion of patients projected to need a new therapy. Even after being cleared by regulatory authorities, a product may later be shown to be unsafe or not to have its purported effect, thereby preventing its widespread use or requiring withdrawal from the market.

We may not be successful in establishing development and commercialization collaborations which could adversely affect, and potentially prohibit, our ability to develop our product candidates.

Developing pharmaceutical products, conducting clinical trials, obtaining regulatory approval, establishing manufacturing capabilities and marketing approved products is expensive, and therefore we may seek to enter into additional collaborations with companies that have more resources and experience in order to continue to develop and commercialize our product candidates. We also may be required due to financial or scientific constraints to enter into additional collaboration

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agreements to research and/or to develop and commercialize our product candidates. The establishment and realization of such collaborations may not be possible or may be problematic. There can be no assurance that we will be able to establish such additional collaborations on favorable terms, if at all, or that our current or future collaborative arrangements will be successful or maintained for any specific product candidate or indication. If we are unable to reach successful agreements with suitable collaboration partners for the ongoing development and commercialization of our product candidates, we may face increased costs, we may be forced to limit the scope and number of our product candidates we can commercially develop or the territories in which we commercialize such product candidates, and we may be unable to commercialize products or programs for which a suitable collaboration partner cannot be found. If we fail to achieve successful collaborations, our operating results and financial condition will be materially and adversely affected.

In addition, the terms of any collaboration agreements may place restrictions on our activities with respect to other products, including by limiting our ability to grant licenses or develop products with other third parties, or in different indications, diseases or geographical locations, or may place additional obligations on us with respect to development or commercialization of our product candidates. If we fail to comply with or breach any provision of a collaboration agreement, a collaborator may have the right to terminate, in whole or in part, such agreement or to seek damages.

Some of our collaboration agreements, including the BeiGene Agreement, are complex and involve sharing or division of ownership of certain data, know-how and intellectual property rights among the various parties. Accordingly, our collaborators could interpret certain provisions differently than we or our other collaborators which could lead to unexpected or inadvertent disputes with collaborators. In addition, these agreements might make additional collaborations, partnering or mergers and acquisitions difficult.

There is no assurance that a collaborator who is acquired by a third party would not attempt to change certain contract provisions that could negatively affect our collaboration. The acquiring company may also not accept the terms or assignment of our contracts and may seek to terminate the agreements. Any one of our collaborators could breach covenants, restrictions and/or sub-license agreement provisions leading us into disputes and potential breaches of our agreements with other partners.

We have no experience in clinical or commercial manufacturing and depend on others for the production of our product candidates at suitable levels of quality and quantity. Any problems or delays in the manufacture of our products would have a negative impact on our ability to successfully execute our development and commercialization strategies.

We do not currently have nor do we plan to acquire the infrastructure or capability internally to manufacture our clinical drug supplies for use in the conduct of our clinical trials, and we lack the resources and the capability to manufacture any of our product candidates on a clinical or commercial scale. We rely on collaborators and/or third parties for development, scale-up, formulation, optimization, management of clinical trial and commercial scale manufacturing and commercialization. There are no assurances we can scale-up, formulate or manufacture any product candidate in sufficient quantities with acceptable specifications for the conduct of our clinical trials or for the regulatory agencies to grant approval of such product candidate. We have not yet commercialized any products and have no commercial manufacturing experience. To be successful, our products must be properly formulated, scalable, stable and safely manufactured in clinical trial and commercial quantities in compliance with GMP and other regulatory requirements and at acceptable costs. Should any of our suppliers or our collaborators be unable to supply or be delayed in supplying us with sufficient supplies, no assurance can be given that we will be able to find alternative means of supply in a short period of time. Should such parties’ operations suffer a material adverse effect, the manufacturing of our products would also be adversely affected. Furthermore, key raw materials could become scarce or unavailable. There may be a limited number of third parties who can manufacture our products. We may not be able to meet specifications previously established for product candidates during scale-up and manufacturing.

Our reliance on third parties to manufacture our product candidates will expose us and our partners to risks including the following, any of which could delay or prevent the commercialization of our products, result in higher costs, or deprive us of potential product revenue:

•Contract manufacturers can encounter difficulties in achieving the scale-up, optimization, formulation, or volume production of a compound as well as maintaining quality control with appropriate quality assurance. They may also experience shortages of qualified personnel. Contract manufacturers are required to undergo a satisfactory GMP inspection prior to regulatory approval and are obliged to operate in accordance with FDA, International Council for Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use ("ICH"), European and other nationally mandated GMP regulations and/or guidelines governing manufacturing processes, stability testing, record keeping and quality standards. A failure of these contract manufacturers to follow GMP and to document their adherence to such practices or failure of an inspection by a regulatory agency may lead to significant delays in the availability of our product candidate materials for clinical study, leading to delays in our trials.

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•For each of our current product candidates we will initially rely on a limited number of contract manufacturers. Changing these or identifying future manufacturers may be difficult. Changing manufacturers requires re-validation of the manufacturing processes and procedures in accordance with FDA, ICH, European and other mandated GMP regulations and/or guidelines. Such re-validation may be costly and time-consuming. It may be difficult or impossible for us to quickly find replacement manufacturers on acceptable terms.

•Our contract manufacturers may not perform as agreed or may not remain in the contract manufacturing business for the time required to produce, store and distribute our products successfully.

We will not be able to successfully commercialize our product candidates without establishing sales and marketing capabilities internally or through collaborators.

We have begun to build our internal sales and marketing capabilities in the U.S., but we may not be able to find suitable sales and marketing staff and collaborators for all of our product candidates. We have no prior experience in the marketing, sale and distribution of pharmaceutical products and there are significant risks involved in building and managing a sales organization, including our ability to hire, retain and incentivize qualified individuals, generate sufficient sales leads, provide adequate training to sales and marketing personnel, and effectively manage a geographically dispersed sales and marketing team. Any collaborators may not be adequate or successful or could terminate or materially reduce the effort they direct to our products. The development of a marketing and sales capability will require significant expenditures, management resources and time. The cost of establishing such a sales force may exceed any potential product revenue, or our marketing and sales efforts may be unsuccessful. If we are unable to develop an internal marketing and sales capability in a timely fashion, or at all, or if we are unable to enter into a marketing and sales arrangement with a third party on acceptable terms, we may be unable to effectively market and sell approved products, if any, which would prevent us from being able to generate revenue and attain profitability. Further, we may not develop an internal marketing and sales capability if we are unable to successfully develop and seek regulatory approval for our product candidates.

The COVID-19 pandemic could adversely impact our business including our ongoing and planned clinical trials and preclinical research.

Our business could be materially adversely affected by the effects of health epidemics. For example, since December 2019, a novel strain of coronavirus, SARS-CoV-2, causing a disease referred to as COVID-19, has spread worldwide. In March 2020, the World Health Organization declared the COVID-19 outbreak a pandemic and the U.S. government-imposed travel restrictions on travel between the U.S., Europe and certain other countries. In addition, the Governor of the State of California issued a number of stay at home orders and health directives. As a result of such orders, we implemented work-from-home policies for most of our employees and generally suspended business-related travel. Out of an abundance of caution and to protect the health and welfare of our employees, we continue to maintain work-from-home policies for most of our employees. The effects of these work-from-home and travel policies have thus far had a limited impact on our business.

Our business could be materially adversely affected by health epidemics in regions where we or our partners have concentrations of clinical trial sites or other business operations, and could cause significant disruption in the operations of third-party manufacturers and contract research organizations upon whom we rely.

Quarantines, shelter-in-place, executive and similar government orders, or the perception that such orders, shutdowns or other restrictions on the conduct of business operations could occur, could impact personnel at third-party manufacturing facilities in the U.S. and other countries, or the availability or cost of materials, which would disrupt our supply chain. We have experienced impacts to our clinical trial operations due to the COVID-19 pandemic. Some examples of these impacts include:

•we have experienced impact on clinical site initiation and patient enrollment due to restrictions imposed as a result of the COVID-19 pandemic;

•some patients have not been able to comply with clinical trial protocols as quarantines have impeded patient movement and interrupted healthcare services;

•we have experienced some impact on our ability to recruit and retain patients and principal investigators and site staff who, as healthcare providers, may have heightened exposure to COVID-19; and

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•we have experienced some delays in necessary interactions with regulators, ethics committees and other important agencies and contractors due to limitations in employee resources or forced furlough of government or contractor personnel.

The global COVID-19 pandemic continues to rapidly evolve. While we have not yet experienced material adverse effects to our business as a result of the COVID-19 pandemic, the ultimate impact of the COVID-19 pandemic or a similar health epidemic is highly uncertain and could have negative impact our business, financial condition and operating results.

Changes in funding for the FDA, the SEC and other government agencies, or shutdowns, travel restrictions or furloughs related to the COVID-19 pandemic, could hinder their ability to hire and retain key leadership and other personnel, prevent new products and services from being developed or commercialized in a timely manner or otherwise prevent those agencies from performing normal functions on which the operation of our business may rely, which could negatively impact our business.

The ability of the FDA to review and approve new products can be affected by a variety of factors, including government budget and funding levels, travel restrictions, ability to hire and retain key personnel and accept payment of user fees, and statutory, regulatory, and policy changes. Average review times at the agency have fluctuated in recent years as a result. The impact of COVID-19 travel restrictions could result in the backlog of the FDA's ability to conduct pre-approval inspections, causing further delay in the approval of our products. In addition, government funding of the SEC and other government agencies on which our operations may rely, including those that fund research and development activities, is subject to the political process, which is inherently fluid and unpredictable.

Disruptions at the FDA and other agencies may also slow the time necessary for new drugs to be reviewed and/or approved by necessary government agencies, which would adversely affect our business. For example, over the last several years, including most recently beginning on December 22, 2018, the U.S. government has shut down several times and certain regulatory agencies, such as the FDA and the SEC, have had to furlough critical FDA, SEC and other government employees and stop critical activities. If a prolonged government shutdown occurs, it could significantly impact the ability of the FDA to timely review and process our regulatory submissions, which could have a material adverse effect on our business. Further, future government shutdowns could impact our ability to access the public markets and obtain necessary capital in order to properly capitalize and continue our operations.

We rely upon third-party contractors and service providers for the execution of some aspects of our development programs. Failure of these collaborators to provide services of a suitable quality and within acceptable timeframes may cause the delay or failure of our development programs.

We outsource certain functions, tests and services to CROs, medical institutions and collaborators and outsource manufacturing to collaborators and/or contract manufacturers, and we rely on third parties for quality assurance, clinical monitoring, clinical data management and regulatory expertise. In particular, we rely on CROs to run our clinical trials on our behalf and contract manufacturers to manufacture our product candidates. There is no assurance that such individuals or organizations will be able to provide the functions, tests, drug supply or services as agreed upon or to acceptable quality standards, and we could suffer significant delays in the development of our products or processes. In particular, certain third party service providers may be unable to comply with their contractual obligations to us due to disruptions caused by the COVID-19 pandemic, including reduced operations or headcount reductions, or otherwise, and in certain cases we may have limited recourse if the non-compliance is due to factors outside of the service provider’s control.

In some cases, there may be only one or few providers of such services, including manufacturing services. In addition, the cost of such services could increase significantly over time. We rely on third parties as mentioned above to enroll qualified patients and conduct, supervise and monitor our clinical trials. Our reliance on these third parties and collaborators for clinical development activities reduces our control over these activities, but does not relieve us of our regulatory responsibilities, including ensuring that our clinical trials are conducted in accordance with good clinical practices ("GCP") regulations and the investigational plan and protocols contained in the regulatory agency applications. In addition, these third parties may not complete activities on schedule or may not manufacture compounds under GMP conditions. Preclinical studies may not be performed or completed in accordance with good laboratory practices, regulatory requirements or our trial design. If we or our CROs fail to comply with GCP regulations, the clinical data generated in our clinical trials may be deemed unreliable and the FDA, the EMA or comparable foreign regulatory authorities may require us to perform additional clinical trials before approving any marketing applications. If these third parties or collaborators do not successfully carry out their contractual duties or meet expected deadlines, obtaining regulatory approval for manufacturing and commercialization of our product candidates may be delayed or prevented. We rely substantially on third-party data managers for our clinical trial data. There is no assurance that these third parties will not make errors in the design, management or retention of our data or data systems.

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There is no assurance that these third parties will pass FDA or regulatory audits, which could delay or prohibit regulatory approval.

Our CROs may also have relationships with other commercial entities, including our competitors, for whom they may also be conducting clinical trials or other product development activities, which could harm our competitive position. If any of our relationships with these third-party CROs terminate, we may not be able to enter into arrangements with alternative CROs or to do so on commercially reasonable terms. Further, switching or adding additional CROs involves additional cost and requires management time and attention. In addition, there is a natural transition period when a new CRO commences work. As a result, delays may occur, which could materially impact our ability to meet our desired clinical development timelines. Though we carefully manage our relationships with our CROs, there can be no assurance that we will not encounter 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 prospects.

Competition in our targeted market area is intense and this field is characterized by rapid technological change. Therefore, developments by competitors may substantially alter the predicted market or render our product candidates uncompetitive.

We are aware of three companies who currently have competing clinical-stage direct KRAS G12C inhibitor programs: Amgen, Inc., F. Hoffman-LaRoche Ltd., and Novartis AG.

There are several immune checkpoint inhibitors currently approved for use as single agents to treat multiple tumor types, including NSCLC. To augment the efficacy of these agents, combination studies are being conducted with a variety of potentially synergistic mechanisms, including inhibitors of CTLA-4, LAG3, and CSF-1R. Most of these combination studies are being conducted in patients who are naïve to immune checkpoint inhibitor therapy. Direct mechanistic competitors to sitravatinib in combination with checkpoint inhibitors in NSCLC patients who failed previous immune checkpoint inhibitor therapy include CABOMETYX® (Exelixis, Inc.) and LENVIMA® (Eisai Co., Ltd.), both anti-VEGF agents that also inhibit other receptor tyrosine kinases. Additional potential competitors whose agents are being evaluated in combination with checkpoint inhibitors in NSCLC patients who failed previous immune checkpoint inhibitor therapy include Corvus Pharmaceuticals, Inc. (Adenosine A2Ar inhibitor), BMS (GITR inhibitor and LAG3 inhibitor) and Syndax, Inc. (HDAC inhibitor).

In addition to companies that have kinase inhibitors addressing our targets of interest, our competition also includes hundreds of private and publicly traded companies that operate in the area of oncology but have therapeutics with different mechanisms of action. The oncology market in general is highly competitive with over 1,000 molecules currently in clinical development. Other important competitors, in addition to those mentioned above, are small and large biotechnology companies, specialty and regional pharmaceutical companies and multinational pharmaceutical companies, including but not limited to AbbVie Inc., Astellas Pharma Inc., AstraZeneca plc, Bayer-Schering Pharmaceutical, Boehringer Ingelheim AG, Eli Lilly and Company, Gilead Sciences, Inc., GlaxoSmithKline plc, Johnson & Johnson, Merck & Co., Inc., and Takeda Pharmaceutical Co.

Developments by others may render our products or technologies non-competitive or obsolete or we may not be able to keep pace with technological developments. Our competitors may have developed or may be developing technologies which may be the basis for competitive products. Some of these products may prove to be more effective and less costly than the products developed or being developed by us. Our competitors may obtain regulatory approval for their products more rapidly than we do which may change the standard of care in the indications we are targeting, rendering our technology or products non-competitive or obsolete. For example, with the recent approval of immunotherapy agents for the treatment of NSCLC and other cancers, the standard of care for the treatment of cancer is evolving and will continue to evolve which could require us to change the design and timelines for our registration trails and may limit the commercial acceptance of our products in the future. Others may develop treatments or cures superior to any therapy we are developing or will develop. Moreover, alternate, less toxic forms of medical treatment may be developed which may be competitive with our products.

Many of the organizations which could be considered to be our competitors have substantially more financial and technical resources, more extensive discovery research, preclinical research and development capabilities and greater manufacturing, marketing, distribution, production and human resources than we do. Many of our current or potential competitors have more experience than we do in research, preclinical testing and clinical trials, drug commercialization, manufacturing and marketing, and in obtaining domestic and foreign regulatory approvals. In addition, failure, unacceptable toxicity, lack of sales or disappointing sales or other issues regarding competitors’ products or processes could have a material adverse effect on our product candidates, including our clinical candidates or our lead compounds. Established pharmaceutical companies may invest heavily to accelerate discovery and development of novel compounds or to in-license novel compounds that could make our product candidates less competitive. In addition, any new product that competes with an approved product

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must demonstrate compelling advantages in efficacy, convenience, tolerability and safety in order to overcome price competition and brand recognition and to be commercially successful. Accordingly, our competitors may succeed in obtaining patent protection, receiving FDA, EMA or other regulatory approval or discovering, developing and commercializing medicines before we do, which would have a material adverse impact on our business.

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 product 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 trials and could result in a more restrictive label or the delay or denial of regulatory approval by the FDA or other comparable foreign authorities. Results of our trials could reveal a high and unacceptable severity and prevalence of side effects. In such an event, our trials could be suspended or terminated and the FDA or comparable foreign regulatory authorities could order us to cease further development of or deny approval of our product candidates for any or all targeted indications. Treatment-related side effects could affect patient recruitment or the ability of enrolled patients to complete the trial, or result in potential product liability claims. Any of these occurrences may harm our business, financial condition and prospects significantly.

Additionally, if one or more of our product candidates receives marketing approval, and we or others later identify undesirable side effects caused by such products, a number of potentially significant negative consequences could result, including:

•regulatory authorities may withdraw approvals of such product;

•regulatory authorities may require additional warnings on the product label;

•we may be required to create a medication guide outlining the risks of such side effects for distribution to patients;

•we could be sued and held liable for harm caused to patients; and

•our reputation may suffer.

Any of these events could prevent us from achieving or maintaining market acceptance of any product candidate, if approved, and could significantly harm our business, results of operations and prospects.

We are subject to competition for our skilled personnel and may experience challenges in identifying and retaining key personnel that could impair our ability to conduct our operations effectively.

Our future success depends on our ability to retain our executive officers and to attract, retain and motivate qualified personnel. If we are not successful in attracting and retaining highly qualified personnel, we may not be able to successfully implement our business strategy. Although we have not experienced problems attracting and retaining highly qualified personnel in the recent past, our industry has experienced a high rate of turnover of management personnel in recent years. Our ability to compete in the highly competitive biotechnology and pharmaceuticals industries depends upon our ability to attract and retain highly qualified managerial, scientific and medical personnel. We are highly dependent on our management, scientific and medical personnel, whose services are critical to the successful implementation of our product candidate acquisition, development and regulatory strategies, as well as the management of our financial operations. We are not aware of any present intention of any of these personnel to leave our Company. In order to induce valuable employees to continue their employment with us, we have provided equity awards that vest over time. The value to employees of equity awards that vest over time is significantly affected by movements in our stock price that are beyond our control, and may at any time be insufficient to counteract more lucrative offers from other companies.

Despite our efforts to retain valuable employees, members of our management, scientific and development teams may terminate their employment with us at any time, with or without notice. The loss of the services of any of our executive officers or other key employees and our inability to find suitable replacements could harm our business, financial condition and prospects. Our success also depends on our ability to continue to attract, retain and motivate highly skilled junior, mid-level and senior managers as well as junior, mid-level and senior scientific and medical personnel.

We may also experience growth in the number of our employees and the scope of our operations, especially in clinical development. This growth will place a significant strain on our management, operations and financial resources and we may

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have difficulty managing this future potential growth. No assurance can be provided that we will be able to attract new employees to assist in our growth. Many of the other pharmaceutical companies that we compete against for qualified personnel have greater financial and other resources, different risk profiles and a longer history in the industry than we do. We also may employ consultants or part-time and contract employees. There can be no assurance that these individuals are retainable. While we have been able to attract and retain skilled and experienced personnel and consultants in the past, no assurance can be given that we will be able to do so in the future.

We may attempt to obtain FDA approval of MRTX849, sitravatinib or other product candidates through the use of the accelerated approval pathway. If we are unable to obtain such approval, we may be required to await the completion of planned or ongoing clinical trials or conduct additional clinical trials, which could increase the expense of obtaining, and delay the receipt of, necessary approval. Even if we receive accelerated approval from the FDA, if our confirmatory trials do not verify clinical benefit, or if we do not comply with rigorous post-marketing requirements, the FDA may seek to withdraw accelerated approval.

We may in the future seek an accelerated approval for our one or more of our product candidates. Under the accelerated approval program, the FDA may grant accelerated approval to a product candidate designed to treat a serious or life-threatening condition that provides meaningful therapeutic benefit over available therapies upon a determination that the product candidate has an effect on a surrogate endpoint or intermediate clinical endpoint that is reasonably likely to predict clinical benefit. The FDA considers a clinical benefit to be a positive therapeutic effect that is clinically meaningful in the context of a given disease, such as irreversible morbidity or mortality. For the purposes of accelerated approval, a surrogate endpoint is a marker, such as a laboratory measurement, radiographic image, physical sign, or other measure that is thought to predict clinical benefit, but is not itself a measure of clinical benefit. An intermediate clinical endpoint is a clinical endpoint that can be measured earlier than an effect on irreversible morbidity or mortality that is reasonably likely to predict an effect on irreversible morbidity or mortality or other clinical benefit. The accelerated approval pathway may be used in cases in which the advantage of a new drug over available therapy may not be a direct therapeutic advantage, but is a clinically important improvement from a patient and public health perspective. If granted, accelerated approval is usually contingent on the sponsor’s agreement to conduct, in a diligent manner, additional post-approval confirmatory studies to verify and describe the drug’s clinical benefit. If such post-approval studies fail to confirm the drug’s clinical benefit, the FDA may withdraw its approval of the drug.

Prior to seeking accelerated approval for any of our product candidates, we intend to seek feedback from the FDA and will otherwise evaluate our ability to seek and receive accelerated approval. There can be no assurance that after our evaluation of the feedback and other factors we will decide to pursue or submit an NDA for accelerated approval. If we decide to submit an application for accelerated approval for our product candidates, there can be no assurance that such submission or application will be accepted or that review or approval will be granted on a timely basis, or at all. A failure to obtain accelerated approval would result in a longer time period to commercialization of such product candidate, could increase the cost of development of such product candidate and could harm our competitive position in the marketplace.

If we or third parties are unable to successfully develop companion diagnostics for our product candidates, or experience significant delays in doing so, we may not achieve marketing approval or realize the full commercial potential of such product candidates.

A key part of our development strategy for our product candidates is to identify subsets of patients with specific types of tumors that express specific genetic markers. Identification of these patients will require the use and development of companion diagnostics. The FDA generally will either require approval or clearance of the diagnostic at the same time the FDA approves the therapeutic product, or as a post-marketing commitment at the time of the therapeutic product's approval. We do not have experience or capabilities in developing or commercializing diagnostics and plan to rely in large part on third parties to perform these functions.

Companion diagnostics are subject to regulation by the FDA and comparable foreign regulatory authorities as medical devices and will likely require separate regulatory approval prior to commercialization. If we or third parties are unable to successfully develop companion diagnostics for our product candidates, or experience delays in doing so:

•the development of these product candidates may be delayed because it may be difficult to identify patients for enrollment in our clinical trials in a timely manner;

•these product candidates may not receive marketing approval if their safe and effective use depends on a companion diagnostic; and

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•we may not realize the full commercial potential of these product candidates that receive marketing approval if, among other reasons, we are unable to appropriately identify patients or types of tumors with the specific genetic alterations targeted by these product candidates.

Even if our product candidates and any associated companion diagnostics are approved for marketing, the need for companion diagnostics may slow or limit adoption of our product candidates. Although we believe genetic testing is becoming more prevalent in the diagnosis and treatment of cancer, our product candidates may be perceived negatively compared to alternative treatments that do not require the use of companion diagnostics, either due to the additional cost of the companion diagnostic or the need to complete additional procedures to identify genetic markers prior to administering our product candidates.

If any of these events were to occur, our business and growth prospects would be harmed, possibly materially.

Interim, topline and preliminary data from our clinical trials may change as more patient data become available, and are subject to audit and verification procedures that could result in material changes in the final data.

From time to time, we may publicly disclose preliminary, interim or topline data from our preclinical studies and clinical trials, which is based on a preliminary analysis of then-available data, and the results and related findings and conclusions are subject to change as patient enrollment and treatment continues and more patient data become available. Adverse differences between previous preliminary or interim data and future interim or final data could significantly harm our business prospects. We may also announce topline data following the completion of a preclinical study or clinical trial, which may be subject to change following a more comprehensive review of the data related to the particular study or trial. We also make assumptions, estimations, calculations and conclusions as part of our analyses of data, and we may not have received or had the opportunity to fully and carefully evaluate all data. As a result, the interim, topline or preliminary results that we report may differ from future results of the same studies, or different conclusions or considerations may qualify such results, once additional data have been received and fully evaluated. Preliminary, interim, or topline data also remain subject to audit and verification procedures that may result in the final data being materially different from the data we previously published. As a result, preliminary, interim, and topline data should be viewed with caution until the final data are available.

Further, others, including regulatory agencies, may not accept or agree with our assumptions, estimates, calculations, conclusions or analyses or may interpret or weigh the importance of data differently, which could impact the value of the particular program, the approvability or commercialization of the particular product candidate or product and our company in general. In addition, the information we choose to publicly disclose regarding a particular study or clinical trial is based on what is typically extensive information, and you or others may not agree with what we determine to be material or otherwise appropriate information to include in our disclosure.

The timelines of our clinical trials may be impacted by numerous factors and any delays may adversely affect our ability to execute our current business strategy.

Clinical testing is expensive, difficult to design and implement, can take many years to complete, and is uncertain as to outcome. We may experience delays in clinical trials at any stage of development and testing of our product candidates. Our planned clinical trials may not begin on time, have an effective design, enroll a sufficient number of subjects, or be completed on schedule, if at all.

Events which may result in a delay or unsuccessful completion of clinical trials include:

•inability to raise funding necessary to initiate or continue a trial;

•delays in obtaining regulatory approval to commence a trial;

•delays in reaching agreement with the FDA on final trial design;

•imposition of a clinical hold following an inspection of our clinical trial operations or trial sites by the FDA or other regulatory authorities;

•delays in reaching agreement on acceptable terms with prospective CROs and clinical trial sites;

•delays in obtaining required institutional review board approval at each site;

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•delays in having subjects complete participation in a trial or return for post-treatment follow-up;

•delays caused by subjects dropping out of a trial due to side effects or otherwise;

•clinical sites dropping out of a trial to the detriment of enrollment;

•time required to add new clinical sites; and

•delays by our contract manufacturers to produce and deliver a sufficient supply of clinical trial materials.

Furthermore, enrollment may depend on the availability of suitable companion diagnostics to identify genetic markers we are targeting and the capability and willingness of clinical sites to conduct genetic screening of potential patients.

If initiation or completion of any of our clinical trials for our product candidates are delayed for any of the above reasons or for other reasons, our development costs may increase, our approval process could be delayed, any periods after commercial launch and before expiration of patent protection may be reduced and our competitors may have more time to bring products to market before we do. Any of these events could impair the commercial potential of our product candidates and could have a material adverse effect on our business.

If we experience delays or difficulties in the enrollment of patients in clinical trials, those clinical trials could take longer than expected to complete and our receipt of necessary regulatory approvals could be delayed or prevented.

We may not be able to initiate or complete clinical trials for our product candidates if we are unable to locate and enroll a sufficient number of eligible patients to participate in these trials. In particular, because we are focused on patients with specific genetic alterations in some of our trials, our pool of suitable patients may be smaller and more selective and our ability to enroll a sufficient number of suitable patients may be limited or take longer than anticipated. In addition, some of our competitors have ongoing clinical trials for product candidates that treat the same indications, including NSCLC, where we are studying sitravatinib in combination with checkpoint inhibitors, or target the same genetic alterations as our product candidates. Therefore, patients who would otherwise be eligible for our clinical trials may instead enroll in clinical trials of our competitors’ product candidates.

Patient enrollment for any of our clinical trials may also be affected by other factors, including without limitation:

•the severity of the disease under investigation

•the frequency of the genetic alteration we are seeking to target in the applicable trial, and the ability to effectively identify such alteration;

•the willingness of clinical sites and principal investigators to subject candidate patients to genetic screening;

•the eligibility criteria for the study in question;

•the perceived risks and benefits of the product candidate under study;

•the availability, effectiveness and safety of other treatment options;

•the patient referral practices of physicians;

•the ability to monitor patients adequately during and after treatment; and

•the proximity and availability of a sufficient number of clinical trial sites that are willing to comply with the requirements of our clinical protocols.

For example, due to the targeted indications and patient populations we intend to focus on for development of our product candidates, the number of study sites and patient populations available to us may be limited, and therefore enrollment of suitable patients to participate in clinical trials for these product candidates may take longer than would be the case if we were pursuing broader indications or patient populations.

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We are and continue to be subject to stringent government regulations concerning the clinical testing of our products. We will also continue to be subject to government regulation of any product that receives regulatory approval.

Numerous statutes and regulations govern human testing and the manufacture and sale of human therapeutic products in the United States and other countries where we intend to market our products. Such legislation and regulation bears upon, among other things, the approval of trial protocols and human testing, the approval of manufacturing facilities, testing procedures and controlled research, the review and approval of manufacturing, preclinical and clinical data prior to marketing approval, including adherence to GMP during production and storage, and marketing activities including advertising and labeling.

Clinical trials may be delayed or suspended at any time by us or by the FDA or other similar regulatory authorities if it is determined at any time that patients may be or are being exposed to unacceptable health risks, including the risk of death, or if compounds are not manufactured under acceptable GMP conditions or with acceptable quality. Current regulations relating to regulatory approval may change or become more stringent. The agencies may also require additional trials be run in order to provide additional information regarding the safety, efficacy or equivalency of any product candidate for which we seek regulatory approval.

Moreover, any regulatory approval of a drug which is eventually obtained may entail limitations on the indicated uses for which that drug may be marketed or on the conditions of approval, or contain requirements for potentially costly post-marketing testing, including Phase 4 clinical trials, and surveillance to monitor the safety and efficacy of the product candidate. These requirements include submissions of safety and other post-marketing information and reports, registration, as well as continued compliance with GMPs and GCPs for any clinical trials that we conduct post-approval. In addition, if the FDA or a comparable foreign regulatory authority approves any of our product candidates, the manufacturing processes, labeling, packaging, distribution, adverse event reporting, storage, advertising, promotion and recordkeeping for the product will be subject to extensive and ongoing regulatory requirements. For example, prescription drugs may be promoted only for the approved indications in accordance with the approved label. The FDA and other agencies actively enforce the laws and regulations prohibiting the promotion of off-label uses, and a company that is found to have improperly promoted off-label uses may be subject to significant liability. However, physicians may, in their independent medical judgment, prescribe legally available products for off-label uses. The FDA does not regulate the behavior of physicians in their choice of treatments, but the FDA does restrict manufacturer’s communications on the subject of off-label use of their products. Furthermore, product approvals may be withdrawn or limited in some way if problems occur following initial marketing or if compliance with regulatory standards is not maintained. Similar restrictions are imposed in foreign markets. Regulatory agencies could become more risk averse to any side effects or set higher standards of safety and efficacy prior to reviewing or approving a product. This could result in a product not being approved.

If we, or any future marketing collaborators or contract manufacturers, fail to comply with applicable regulatory requirements, we may be subject to sanctions including fines, product recalls or seizures and related publicity requirements, injunctions, total or partial suspension of production, civil penalties, suspension or withdrawals of previously granted regulatory approvals, warning or untitled letters, refusal to approve pending applications for marketing approval of new products or of supplements to approved applications, import or export bans or restrictions, and criminal prosecution and penalties. Any of these penalties could delay or prevent the promotion, marketing or sale of our products and product candidates.

The FDA’s policies, and policies of comparable foreign regulatory authorities, may change and additional government regulations may be enacted that could prevent, limit or delay regulatory approval of our product candidates. If we are slow or unable to adapt to changes in existing requirements or to adopt new requirements or policies, or if we are not able to maintain regulatory compliance, we may lose any marketing approval that we may have obtained, which would adversely affect our business, prospects and ability to achieve or sustain profitability.

The failure to maintain the BeiGene Agreement or the failure of BeiGene to perform its obligations under the BeiGene Agreement, could negatively impact our business.

Pursuant to the terms of the BeiGene Agreement, we granted to BeiGene an exclusive license to develop, manufacture and commercialize sitravatinib in the Licensed Territory. Consequently, our ability to generate any revenues from sitravatinib in the Licensed Territory depends on our ability to maintain our collaboration with BeiGene. We have limited control over the amount and timing of resources that BeiGene will dedicate to these efforts.

We are subject to a number of other risks associated with our dependence on the BeiGene Agreement with respect to sitravatinib in the Licensed Territory, including:

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•BeiGene may not comply with applicable regulatory guidelines with respect to developing, manufacturing or commercializing sitravatinib, which could adversely impact sales or future development of sitravatinib in the Licensed Territory or elsewhere;

•There may be disputes between us and BeiGene, including disagreements regarding the BeiGene Agreement; and

•BeiGene may not properly defend our intellectual property rights, or may use our proprietary information in such a way as to invite litigation that could jeopardize or invalidate our intellectual property rights or expose us to potential litigation.

The BeiGene Agreement is also subject to early termination, including through BeiGene’s right to terminate without cause upon advance notice to us. If the agreement is terminated early, we may not be able to find another collaborator for the further development and commercialization of sitravatinib in the Licensed Territory on acceptable terms, or at all, and we may be unable to pursue continued development and commercialization of sitravatinib in the Licensed Territory on our own.

*If we fail to obtain coverage and adequate reimbursement for our products, or our products used in combination therapies, our revenue-generating ability will be diminished and there is no assurance that the anticipated market for our products will be sustained.

We believe that there will be many different applications for products successfully derived from our technologies and that the anticipated market for products under development will continue to expand. However, due to competition from existing or new products and the yet-to-be established commercial viability of our products, no assurance can be given that these beliefs will prove to be correct. Physicians, patients, formularies, payors or the medical community in general may not accept or utilize any products that we or our collaborative partners may develop. Other drugs may be approved during our clinical testing which could change the accepted treatments for the disease targeted and make our product candidates obsolete.

Our and our collaborators’ ability to commercialize our products successfully will depend, in part, on the extent to which coverage and adequate reimbursement for such products and related treatments will be available from governmental health payor programs at the federal and state levels, including Medicare and Medicaid, private health insurers, managed care plans and other organizations. No assurance can be given that third-party payor coverage and adequate reimbursement will be available that will allow us to maintain price levels sufficient for the realization of an appropriate return on our investment in product development.

Coverage and adequate reimbursement from governmental healthcare programs, such as Medicare and Medicaid, and private health insurers, managed care plans and other organizations is critical to new product acceptance. There is no uniform coverage and reimbursement policy among third-party payors in the United States; however, private third-party payors often follow Medicare coverage policy and payment limitations in setting their own reimbursement rates. Additionally, coverage decisions may depend upon clinical and economic standards that disfavor new drug products when more established or lower cost therapeutic alternatives are already available or subsequently become available. Even if we obtain coverage for our product candidates, the resulting reimbursement payment rates might not be adequate or may require co-payments that patients find unacceptably high. Patients are unlikely to use our product candidates unless coverage is provided and reimbursement is adequate to cover a significant portion of the cost of our product candidates.

Additionally, we or our collaborators may develop companion diagnostic tests for use with our product candidates. We or our collaborators will be required to obtain coverage and reimbursement for these tests separate and apart from the coverage and reimbursement we seek for our product candidates, once approved. While we have not yet developed any companion diagnostic test for use with our product candidates, if we do, there is significant uncertainty regarding our ability to obtain coverage and adequate reimbursement for the same reasons applicable to our product candidates.

In the United States and in many other countries, pricing and/or profitability of some or all prescription pharmaceuticals and biopharmaceuticals are subject to varying degrees of government control. In the United States, there has recently been increased government enforcement and government and payor scrutiny relating to drug pricing and price increases. For example, there have been several recent U.S. Congressional inquiries and proposed and enacted federal and state legislation designed to, among other things, bring more transparency to drug pricing, review the relationship between pricing and manufacturer patient programs, and reform government program reimbursement methodologies for drugs. At the federal level, the Trump administration used several means to propose implementing drug pricing reform, including through federal budget proposals, executive orders and policy initiatives. For example, on July 24, 2020 and September 13, 2020, President Trump signed several executive orders aimed at lowering drug prices. As a result, the FDA released a final rule on September 24, 2020, effective November 30, 2020, providing guidance for states to build and submit importation plans for drugs from

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Canada. Further, on November 20, 2020, the U.S. Department of Health and Human Services (“HHS”) finalized a regulation removing safe harbor protection for price reductions from pharmaceutical manufacturers to plan sponsors under Part D, either directly or through pharmacy benefit managers, unless the price reduction is required by law. The implementation of the rule has been delayed by the Biden administration from January 1, 2022 to January 1, 2023 in response to ongoing litigation. The rule also creates a new safe harbor for price reductions reflected at the point-of-sale, as well as a new safe harbor for certain fixed fee arrangements between pharmacy benefit managers and manufacturers, the implementation of which have also been delayed until January 1, 2023. On November 20, 2020, Centers for Medicare & Medicaid Services (“CMS”) issued an interim final rule implementing President Trump’s Most Favored Nation executive order, which would tie Medicare Part B payments for certain physician-administered drugs to the lowest price paid in other economically advanced countries, effective January 1, 2021. On December 28, 2020, the United States District Court in Northern California issued a nationwide preliminary injunction against implementation of the interim final rule. It is unclear whether the Biden administration will work to reverse these measures or pursue similar policy initiatives. At the state level, legislatures have increasingly passed legislation and implemented regulations designed to control pharmaceutical and biological product pricing, including price or patient reimbursement constraints, discounts, restrictions on certain product access and marketing cost disclosure and transparency measures, and, in some cases, designed to encourage importation from other countries and bulk purchasing. These changes may adversely impact the prices we or our future collaborators may charge for our products candidates, if commercialized.

Outside of the United States, the successful commercialization of our products will depend largely on obtaining and maintaining government coverage, because in many countries, patients are unlikely to use prescription drugs that are not covered by their government healthcare programs. Negotiating coverage and reimbursement with governmental authorities can delay commercialization by 12 months or more. Coverage and reimbursement policies may adversely affect our ability to sell our products on a profitable basis. In many international markets, governments control the prices of prescription pharmaceuticals, including through the implementation of reference pricing, price cuts, rebates, revenue-related taxes and profit control, and we expect prices of prescription pharmaceuticals to decline over the life of the product or as volumes increase.

Healthcare reform and controls on healthcare spending may limit the price we charge for any products and the amounts thereof that we can sell. In particular, in the United States, the federal government and private insurers have changed, and have considered ways to change, the manner in which healthcare services are provided. In March 2010, the Patient Protection and Affordable Care Act, as amended by the Health Care and Education Reconciliation Act (collectively, "ACA") became law in the United States. With respect to pharmaceutical products, the ACA, among other things, expanded and increased industry rebates for drugs covered by Medicaid and made changes to the coverage requirements under Medicare Part D, Medicare’s prescription drug benefits program. Some of the provisions of the ACA have yet to be fully implemented, and there have been executive, judicial and Congressional challenges to certain aspects of the ACA. On December 14, 2018, a Texas U.S. District Court Judge ruled that the ACA is unconstitutional in its entirety because the “individual mandate” was repealed by Congress as part of legislation enacted in 2017, informally titled the Tax Cuts and Jobs Act (the “Tax Act”). Additionally, on December 18, 2019, the U.S. Court of Appeals for the 5th Circuit upheld the District Court ruling that the individual mandate was unconstitutional and remanded the case back to the District Court to determine whether the remaining provisions of the ACA are invalid as well. The United States Supreme Court is currently reviewing this case, although it is unclear when a decision will be made. Further, although the United States Supreme Court has not yet ruled on the constitutionality of the ACA, on January 28, 2021, President Biden issued an executive order to initiate a special enrollment period from February 15, 2021 through May 15, 2021 for purposes of obtaining health insurance coverage through the ACA marketplace. The executive order also instructs certain governmental agencies to review and reconsider their existing policies and rules that limit access to healthcare, including among others, reexamining Medicaid demonstration projects and waiver programs that include work requirements, and policies that create unnecessary barriers to obtaining access to health insurance coverage through Medicaid or the ACA. It is unclear how the Supreme Court ruling, other such litigation, and the healthcare reform measures of the Biden administration will impact the ACA and our business

In addition, other legislative changes have been proposed and adopted since the ACA was enacted. In August 2011, the Budget Control Act of 2011, among other things, created measures for spending reductions by Congress. A Joint Select Committee on Deficit Reduction, tasked with recommending a targeted deficit reduction of at least $1.2 trillion for the years 2013 through 2021, was unable to reach required goals, thereby triggering the legislation’s automatic reduction to several government programs. These changes include aggregate reductions to Medicare payments to providers of up to 2% per fiscal year, which went into effect on April 1, 2013 and, as amended by subsequent legislation including the Bipartisan Budget Act of 2018, will stay in effect through 2030, except for a temporary suspension from May 1, 2020 through March 31, 2021 due to the COVID-19 pandemic, unless additional Congressional action is taken. Legislation is currently pending in Congress that would further extend the suspension through December 31, 2021. In January 2013, President Obama signed into law the American Taxpayer Relief Act of 2012, which, among other things, further reduced Medicare payments to several types of providers and increased the statute of limitations period for the government to recover overpayments to providers from three to five years. These laws may result in additional reductions in Medicare and other healthcare funding, which could have a material adverse effect on our customers and accordingly, our financial operations.

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We anticipate that the ACA, as well as alternative or replacement healthcare reform measures that may be adopted in the future, may result in more rigorous coverage criteria and additional downward pressure on the reimbursement we may receive for any approved product. It is possible that additional governmental action will be taken in response to the COVID-19 pandemic. Moreover, payment methodologies may be subject to changes in healthcare legislation and regulatory initiatives.

In addition, levels of reimbursement may be impacted by other current and future legislation, regulation or reimbursement policies of third-party payors in a manner that may harm the demand and reimbursement available for our products, including for companion diagnostics for our products, which in turn, could harm our future product pricing and sales. Any reduction in reimbursement from Medicare and other government programs may result in a similar reduction in payments from private payors. The implementation of cost containment measures or other healthcare reforms may prevent us from being able to generate revenue, attain profitability or commercialize our products.

Our potential future relationships with customers and third-party payors in the United States and elsewhere may be subject, directly or indirectly, to applicable anti-kickback, fraud and abuse, false claims, transparency, health information privacy and security and other healthcare laws and regulations, which could expose us to criminal sanctions, civil penalties, contractual damages, reputational harm, administrative burdens and diminished profits and future earnings.

As a clinical-stage company that could potentially become a commercial pharmaceutical company, even though we will not control referrals of healthcare services or bill directly to Medicare, Medicaid or other third-party payors, certain federal and state healthcare laws and regulations pertaining to fraud and abuse and patients’ rights will be applicable to our business. Our potential future arrangements with third-party payors and customers may expose us to broadly applicable fraud and abuse and other healthcare laws and regulations, including, without limitation, the federal Anti-Kickback Statute and the federal False Claims Act, which may constrain the business or financial arrangements and relationships through which we may sell, market and distribute any drugs for which we obtain marketing approval. In addition, we may be subject to transparency laws and patient privacy regulation by U.S. federal and state governments and by governments in foreign jurisdictions in which we conduct our business. The laws that may affect our ability to operate include:

•the federal Anti-Kickback Statute, which prohibits, among other things, persons from knowingly and willfully soliciting, offering, receiving or providing remuneration, directly or indirectly, in cash or in kind, to induce or reward, or in return for, either the referral of an individual for, or the purchase, order, lease, furnishing, prescribing or recommendation of, any good or service, for which payment may be made under federal and state healthcare programs, such as Medicare and Medicaid. The term “remuneration” has been broadly interpreted to include anything of value. The ACA, among other things, amended the intent requirement of the federal Anti‑Kickback Statute such that a person or entity no longer needs to have actual knowledge of the statute or specific intent to violate, in order to commit a violation;

•federal civil and criminal false claims laws, including the federal False Claims Act which can be enforced by private individuals on behalf of the government through civil whistleblower or qui tam actions, and civil monetary penalty laws prohibit individuals or entities for knowingly presenting, or causing to be presented, to the federal government, including the Medicare and Medicaid programs, claims for payment that are false or fraudulent or making a false statement to avoid, decrease or conceal an obligation to pay money to the federal government. Entities can be held liable under these laws if they are deemed to “cause” the submission of false or fraudulent claims by, for example, providing inaccurate billing or coding information to customers, promoting a product off‑label, or for providing medically unnecessary services or items. In addition, a claim including items or services resulting from a violation of the federal Anti-Kickback Statute constitutes a false or fraudulent claim for purposes of the federal False Claims Act;

•the federal Health Insurance Portability and Accountability Act of 1996 ("HIPAA"), which imposes criminal and civil liability for knowingly and willfully executing, or attempting to execute, a scheme to defraud any healthcare benefit program, including third-party payors, knowingly and willfully embezzling or stealing from a healthcare benefit program, willfully obstructing a criminal investigation of a healthcare offense, and knowingly and willfully falsifying, concealing or covering up a material fact or making any materially false, fictitious or fraudulent statements in connection with the delivery of or payment for healthcare benefits, items or services;

•HIPAA, as amended by the Health Information Technology for Economic and Clinical Health Act of 2009 ("HITECH"), and their respective implementing regulations, which impose obligations on certain healthcare providers, health plans, and healthcare clearinghouses, known as covered entities, as well as individuals and entities that create, receive, maintain or transmit individually identifiable health information for or on behalf of a covered entity, known as business associates, as well as their covered subcontractors, with respect to safeguarding the privacy, security and

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transmission of individually identifiable health information. HITECH also created new tiers of civil monetary penalties, amended HIPAA to make civil and criminal penalties directly applicable to business associates, and gave state attorneys general new authority to file civil actions for damages or injunctions in U.S. federal courts to enforce the federal HIPAA laws and seek attorneys' fees and costs associated with pursuing federal civil actions;

•the California Consumer Privacy Act (“CCPA”), which creates new individual privacy rights for California consumers (as defined in the law) and places increased privacy and security obligations on entities handling certain personal data of consumers or households. The CCPA requires covered companies to provide new disclosure to consumers about such companies’ data collection, use and sharing practices, provide such consumers new ways to opt-out of certain sales or transfers of personal information, and provide consumers with additional causes of action.

•the federal Open Payments program, which requires manufacturers of drugs, devices, biologics and medical supplies for which payment is available under Medicare, Medicaid or the Children’s Health Insurance Program, with specific exceptions, to report annually to CMS information related to “payments or other transfers of value” made to physicians, which is defined to include doctors, dentists, optometrists, podiatrists and chiropractors, and teaching hospitals and ownership and investment interests held by such healthcare professionals and their immediate family members. Beginning in 2022, applicable manufacturers also will be required to report such information regarding payments and transfers of value provided during the previous year to physician assistants, nurse practitioners, clinical nurse specialists, anesthesiologist assistants, certified nurse anesthetists and certified nurse-midwives; and

•analogous state and foreign laws and regulations, such as state anti-kickback and false claims laws, which may apply to sales or marketing arrangements and claims involving healthcare items or services reimbursed by non-governmental third-party payors, including private insurers; state and foreign laws that require pharmaceutical companies to comply with the pharmaceutical industry’s voluntary compliance guidelines and the relevant compliance guidance promulgated by the federal government or otherwise restrict payments that may be made to healthcare providers; state and foreign laws that require drug manufacturers to report information related to payments and other transfers of value to physicians and other healthcare providers, marketing expenditures, or drug pricing; state and local laws that require the registration of pharmaceutical sales representatives; and state and foreign laws governing the privacy and security of health information in certain circumstances, many of which differ from each other in significant ways and often are not preempted by HIPAA, thus complicating compliance efforts.

Because of the breadth of these laws and the narrowness of available statutory exceptions and regulatory safe harbors, it is possible that some of our business activities could be subject to challenge under one or more of such laws. To the extent that any of our product candidates is ultimately sold in countries other than the United States, we may be subject to similar laws and regulations in those countries. If we or 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 significant civil, criminal and administrative penalties, damages, fines, imprisonment, disgorgement, additional reporting obligations and oversight if we become subject to a corporate integrity agreement or other agreement to resolve allegations of non-compliance with these laws, exclusion from participation in government healthcare programs, and the curtailment or restructuring of our operations, any of which could have a material adverse effect on our business. If any of the physicians or other healthcare providers or entities with whom we expect to do business, including any of our collaborators, is found not to be in compliance with applicable laws, they may be subject to significant criminal, civil or administrative sanctions, including exclusion from participation in government healthcare programs, which could also materially affect our business.

We may become subject to the risk of product liability claims.

We face an inherent risk of product liability as a result of the clinical testing of our product candidates and will face an even greater risk if we commercialize any products. Human therapeutic products involve the risk of product liability claims and associated adverse publicity. Currently, the principal risks we face relate to patients in our clinical trials, who may suffer unintended consequences. Claims might be made by patients, healthcare providers, pharmaceutical companies or others. For example, we may be sued if any product we develop allegedly causes injury or is found to be otherwise unsuitable during product testing, manufacturing, marketing or sale. Any such product liability claims may include allegations of defects in manufacturing, defects in design, a failure to warn of dangers inherent in the product, negligence, strict liability and a breach of warranties. Claims could also be asserted under state consumer protection laws. If we cannot successfully defend ourselves against product liability claims, we may incur substantial liabilities or be required to limit commercialization of our product candidates, if approved. Even successful defense would require significant financial and management resources. Regardless of the merits or eventual outcome, liability claims may result in:

•decreased demand for our product candidates;

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•injury to our reputation;

•withdrawal of clinical trial participants;

•initiation of investigations by regulators;

•costs to defend the related litigation;

•a diversion of management’s time and our resources;

•substantial monetary awards to trial participants or patients;

•product recalls, withdrawals or labeling, marketing or promotional restrictions;

•loss of revenue from product sales; and

•the inability to commercialize any of our product candidates, if approved.

We may not have or be able to obtain or maintain sufficient and affordable insurance coverage, and without sufficient coverage any claim brought against us could have a materially adverse effect on our business, financial condition or results of operations. We run clinical trials through investigators that could be negligent through no fault of our own and which could affect patients, cause potential liability claims against us and result in delayed or stopped clinical trials. We are required in many cases by contractual obligations to indemnify collaborators, partners, third-party contractors, clinical investigators and institutions. These indemnifications could result in a material impact due to product liability claims against us and/or these groups. We currently carry $10 million in product liability insurance, which we believe is appropriate for our clinical trials. Although we maintain such insurance, any claim that may be brought against us could result in a court judgment or settlement in an amount that is not covered, in whole or in part, by our insurance or that is in excess of the limits of our insurance coverage. Our insurance policies also have various exclusions, and we may be subject to a product liability claim for which we have no coverage. We will have to pay any amounts awarded by a court or negotiated in a settlement that exceed our coverage limitations or that are not covered by our insurance, and we may not have, or be able to obtain, sufficient capital to pay such amounts.

Our business involves the controlled use of hazardous materials and as such we are subject to environmental and occupational safety laws. Continued compliance with these laws may incur substantial costs and failure to maintain compliance could result in liability for damages that may exceed our resources.

Our preclinical research, manufacturing and development processes involve the controlled use of hazardous and radioactive materials. We are subject to federal, local and foreign laws and regulations governing the use, manufacture, storage, handling and disposal of such materials and certain waste products. Our operations involve the use of hazardous and flammable materials, including chemicals and biological materials. Our operations also produce hazardous waste products. The risk of accidental contamination or injury from these materials cannot be completely eliminated. In the event of such an accident, we could be held liable for any damages that result, and any such liability could exceed our resources. We may not be adequately insured against this type of liability. We may be required to incur significant costs to comply with environmental laws and regulations in the future, and our operations, business or assets may be materially adversely affected by current or future environmental laws or regulations.

We may have to dedicate resources to the settlement of litigation.

Securities legislation in the United States, Canada and other countries makes it relatively easy for shareholders to sue. This could lead to frivolous lawsuits which could take substantial time, money, resources and attention or force us to settle such claims rather than seek adequate judicial remedy or dismissal of such claims.

If we are required to defend patent infringement actions brought by third parties, or if we sue to protect our own patent rights or otherwise to protect our proprietary information and to prevent its disclosure, or if we are involved in other litigation, whether as a plaintiff or defendant, we may be required to pay substantial litigation costs and managerial attention may be diverted from business operations even if the outcome is in our favor. If we are required to defend our patents or trademarks against infringement by third parties, we may be required to pay substantial litigation costs and managerial attention and financial resources may be diverted from our research and development operations even if the outcome is in our favor.

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We are dependent on information technology systems and may be vulnerable to disruption, damage, theft of our intellectual property and financial obligation as a result of system failures, system security risks, data protection breaches and cyber-attacks, any of which could disrupt our internal operations, product development, or information technology systems, and could lead to theft of our intellectual property, reduced revenue, increased expenses, damage to our reputation or decline of our stock price.

We are dependent upon our own or third-party information technology systems, infrastructure and data, to operate our business. Despite the implementation of security measures, any of the internal computer systems belonging to us, our collaborators or our third-party service providers are vulnerable to damage from computer viruses, unauthorized access (including by foreign private parties and state actors), natural disasters, terrorism, war and telecommunication and electrical failure. Cyber-attacks are increasing in their frequency, sophistication and intensity, and the prevalent use of mobile devices that access confidential information increases the risk of data security breaches. Any system failure, accident or security breach that causes interruptions in our own, in collaborators’ or in third-party service vendors’ operations could result in a material disruption of our drug discovery and development programs or theft of our intellectual property.

We devote considerable internal and external resources to implementing security measures to protect our systems, customers, and users, but these security measures cannot provide absolute security. Potential breaches of our security measures and the accidental loss, inadvertent disclosure, or unapproved dissemination of proprietary information, intellectual property, or sensitive or confidential data about us, our employees, or our customers or users (including the potential loss or disclosure of such information or data as a result of employee error or other employee actions or inactions, hacking, fraud, social engineering, or other forms of deception) could expose us, our customers, or the individuals affected to a risk of loss or misuse of this information, result in litigation and potential liability for us, damage our brand and reputation, or otherwise materially adversely affect our business, results of operations, and financial condition. The effects of a security breach or privacy violation could be further amplified during the current COVID-19 pandemic. In addition, the cost and operational consequences of implementing further data protection measures could be significant and theft of our intellectual property or proprietary business information could require substantial expenditures to remedy. Further, we cannot be certain that (a) our liability insurance will be sufficient in type or amount to cover us against claims related to security breaches, cyberattacks and other related breaches; (b) such coverage will cover any indemnification claims against us relating to any incident, will continue to be available to us on economically reasonable terms, or at all; or (c) any insurer will not deny coverage as to any future claim. The successful assertion of one or more large claims against us that exceed available insurance coverage, or the occurrence of changes in our insurance policies, including premium increases or the imposition of large deductible or co-insurance requirements, could adversely affect our reputation, business, financial condition and results of operations.

In addition, we rely upon third-party contractors and service providers for the hosting, support and/or maintenance of some aspects of our computer hardware, computer software and telecommunications systems. Failure of those contractors and service providers to provide systems and services of a suitable quality and within acceptable timeframes may cause the delay or failure of our development programs, or loss of confidential or proprietary information. To the extent that any disruption or security breach results in a loss or damage to our data or applications, or inappropriate disclosure of confidential or proprietary information, we may incur liability, our drug discovery and development programs may be adversely affected and the further development of our product candidates may be delayed. Furthermore, such disruptions or security breaches could harm our reputation, compel us to comply with federal and/or state breach notification laws and foreign law equivalents, subject us to mandatory corrective action, require us to verify the correctness of database contents and otherwise subject us to litigation or other liability under laws and regulations that protect personal data, any of which could disrupt our business and/or result in increased costs.

Risks Relating to Our Financial Position and Capital Requirements

*We will require additional financing and may be unable to raise sufficient capital, which could lead us to delay, reduce or abandon development programs or commercialization.

Our operations have consumed substantial amounts of cash since inception. Our research and development expenses were $104.1 million and $71.7 million for the three months ended March 31, 2021 and 2020, respectively. Our net loss for the three months ended March 31, 2021 and 2020 were $135.7 million and $86.7 million, respectively. As of March 31, 2021, we had an accumulated deficit of $1.3 billion. We may require substantial additional capital to pursue additional clinical development for our lead clinical programs, including conducting late-stage clinical trials, manufacturing clinical supplies and developing other assets in our pipeline, and, if we are successful, to commercialize any of our current product candidates. If the U.S. Food and Drug Administration ("FDA") or any foreign regulatory agency, such as the European Medicines Agency ("EMA") requires that we perform studies or trials in addition to those that we currently anticipate with respect to the

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development of our product candidates, or repeat studies or trials, or if our clinical trials are otherwise delayed or disrupted due to the COVID-19 pandemic or otherwise, our expenses would further increase beyond what we currently expect. We may not be able to adequately finance our development programs, which could limit our ability to move our programs forward in a timely and satisfactory manner or require us to abandon the programs, any of which would harm our business, financial condition and results of operations. Because successful development of our product candidates is uncertain, we are unable to accurately estimate the actual funds we will require to complete research and development and commercialize our product candidates.

If, at any point, we are unable to obtain funding from equity offerings or debt financings on a timely basis, we may be required to (1) seek additional collaborators for one or more of our product candidates at an earlier stage than otherwise would be desirable or on terms that are less favorable than might otherwise be available; (2) relinquish or license on unfavorable terms our rights to technologies or product candidates that we otherwise would seek to develop or commercialize ourselves; or (3) significantly curtail one or more of our research or development programs or cease operations altogether.

We may not generate revenue from sales of products. If any of our product candidates fail in clinical trials or do not gain regulatory approval, or if any of our product candidates, if approved, fail to achieve market acceptance, we may never become profitable. If one or more of our product candidates is approved for commercial sale and we retain commercial rights, we anticipate incurring significant costs associated with commercializing any such approved product candidate. Therefore, even if we are able to generate revenue from the sale of any approved product, we may never become profitable. Even if we achieve profitability in the future, we may not be able to sustain profitability in subsequent periods. Our ability to generate future revenue from product sales depends heavily on our success in:

•completing development and clinical trial programs for our product candidates;

•maintaining existing collaboration and licensing agreements and entering into additional ones;

•seeking and obtaining marketing approvals for any product candidates that successfully complete clinical trials;

•establishing and maintaining supply and manufacturing relationships with third parties;

•successfully commercializing any product candidates for which marketing approval is obtained; and

•successfully establishing a sales force and marketing and distribution infrastructure.

We are a clinical-stage company with no approved products and no product revenue. Consequently, we expect that our financial and operating results will vary significantly from period to period.

We are a clinical-stage company that has incurred losses since its inception and expect to continue to incur substantial losses in the foreseeable future. Biopharmaceutical product development is a highly speculative undertaking and involves a substantial degree of uncertainty.

Our actual financial condition and operating results have varied significantly in the past and are expected to continue to fluctuate significantly from quarter-to-quarter or year-to-year due to a variety of factors, many of which are beyond our control. Factors relating to our business that may contribute to these fluctuations include:

•the success of our clinical trials through all phases of clinical development;

•delays in the commencement, enrollment and timing of clinical trials;

•delays due to force majeure;

•our ability to secure and maintain collaborations, licensing or other arrangements for the future development and/or commercialization of our product candidates, as well as the terms of those arrangements;

•our ability to obtain, as well as the timeliness of obtaining, additional funding to develop our product candidates;

•the results of clinical trials or marketing applications for product candidates that may compete with our product candidates;

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•competition from existing products or new products that may receive marketing approval;

•potential side effects of our product candidates that could delay or prevent approval or cause an approved drug to be taken off the market;

•any delays in regulatory review and approval of our clinical development plans or product candidates;

•our ability to identify and develop additional product candidates;

•the ability of patients or healthcare providers to obtain coverage or sufficient reimbursement for our products;

•our ability, and the ability of third parties such as Clinical Research Organizations ("CROs") to adhere to clinical study and other regulatory requirements;

•the ability of third-party manufacturers to manufacture our product candidates and key ingredients needed to conduct clinical trials and, if approved, successfully commercialize our products;

•the costs to us, and our ability as well as the ability of any third-party collaborators, to obtain, maintain and protect our intellectual property rights;

•costs related to and outcomes of potential intellectual property litigation;

•our ability to adequately support future growth;

•our ability to attract and retain key personnel to manage our business effectively; and

•our ability to build our finance infrastructure and, to the extent required, improve our accounting systems and controls.

Accordingly, the likelihood of our success must be evaluated in light of many potential challenges and variables associated with a clinical-stage company, many of which are outside of our control, and past operating or financial results should not be relied on as an indication of future results. Fluctuations in our operating and financial results could cause our share price to decline. It is possible that in some future periods, our operating results will be above or below the expectations of securities analysts or investors, which could also cause our share price to decline.

Raising additional funds through debt or equity financing will be dilutive and raising funds through licensing agreements may be dilutive, restrict operations or relinquish proprietary rights.

To the extent that additional capital is raised through the sale of equity or convertible debt securities, the issuance of those securities could result in substantial dilution for our current shareholders and the terms may include liquidation or other preferences that adversely affect the rights of our current shareholders. Existing shareholders may not agree with our financing plans or the terms of such financings. In addition, the COVID-19 pandemic continues to rapidly evolve and may result in a significant disruption of global financial markets. Our ability to raise additional capital may be adversely impacted by potential worsening global economic conditions and the recent disruptions to, and volatility in, the credit and financial markets in the U.S. and worldwide resulting from the pandemic. If the disruption persists and deepens, we could experience an inability to access additional capital, which could in the future negatively affect our capacity to fund research and development programs, including discovery research, preclinical and clinical development activities. Moreover, the incurrence of debt financing could result in a substantial portion of our operating cash flow being dedicated to the payment of principal and interest on such indebtedness and could impose restrictions on our operations. In addition, if we raise additional funds through future collaboration and licensing arrangements, it may be necessary to relinquish potentially valuable rights to our products or proprietary technologies, or to grant licenses on terms that are not favorable to us. Additional funding may not be available to us on acceptable terms, or at all.

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

Our U.S. federal net operating loss ("NOL"), carryforwards generated in tax years beginning before January 1, 2018, are only permitted to be carried forward for 20 years under applicable U.S. tax law. Under the Tax Act, as modified by the Coronavirus Aid, Relief, and Economic Security Act (the "CARES Act"), our federal NOLs generated in tax years beginning after December 31, 2017, may be carried forward indefinitely, but the deductibility of such federal NOLs in tax years beginning after December 31, 2020, is limited to 80% of taxable income. It is uncertain if and to what extent various states will conform to

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the Tax Act or the CARES Act. In addition, under Sections 382 and 383 of the Code, and corresponding provisions of state law, if a corporation undergoes an “ownership change,” which is 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 NOL carryforwards and other pre-change U.S. tax attributes (such as research tax credits) to offset its post-change income or taxes may be limited. We believe we have experienced at least one ownership change based on past financing transactions and we may experience ownership changes in the future as a result of subsequent shifts in our stock ownership.

As a result, our NOL carryforwards generated in tax years beginning before January 1, 2018 may expire prior to being used, and the deductibility of our NOL carryforwards generated in tax years beginning after December 31, 2017, in taxable years beginning after December 31, 2020, will be subject to a percentage limitation.  In addition, we believe that we have in the past undergone, and in the future it is possible we may undergo, additional ownership changes that could limit our ability to use all of our pre-change NOLs and other pre-change tax attributes (such as research tax credits) to offset our post-change income or taxes. Similar provisions of state tax law may also apply to limit our use of accumulated state tax attributes. In addition, at the state level, there may be periods during which the use of NOLs or other tax attributes is suspended or otherwise limited, including a California franchise tax law limiting the usability of California state NOLs and certain tax credits to offset taxable income in taxable years beginning on or after January 1, 2020 and before January 1, 2023, which could accelerate or permanently increase state taxes owed. As a result, we may be unable to use all or a material portion of our NOLs and other tax attributes, which could adversely affect our future cash flows.

Risks Relating to Our Intellectual Property

We may not obtain adequate protection for our product candidates through patents and other intellectual property rights and as such, our competitive advantage in the marketplace may be compromised.

Our success depends to a significant degree upon on our ability to develop, secure and maintain our intellectual property rights to our proprietary products and to operate without infringing on the proprietary rights of others or having third parties circumvent the rights that we own or license. We have filed and are actively pursuing patent applications in the United States, Japan, Europe and other major markets via the Patent Cooperation Treaty or directly in countries of interest. However, we may not receive issued patents on any of our pending patent applications in these countries and we may not be able to obtain, maintain or enforce our patents and other intellectual property rights which could impact our ability to compete effectively. We cannot be certain that the U.S. Patent and Trademark Office, courts in the United States or the patent offices and courts in foreign countries will consider the claims in our patents and applications covering any of our products in development as patentable. In addition, the scope of any of our issued patents may not be sufficiently broad to provide us with a competitive advantage. Furthermore, other parties may successfully challenge, invalidate or circumvent our issued patents or patents licensed to us so that our patent rights do not create an effective competitive barrier. Our method-of-use patents protect the use of a product only for the specified method. This type of patent does not prevent a competitor from making and marketing a product that is identical to our product for an indication that is outside the scope of the patented method. Moreover, even if competitors do not actively promote their product for our targeted indications, physicians may prescribe these products off-label. Although off-label prescriptions may infringe or contribute to the infringement of method-of-use patents, the practice is common and such infringement is difficult to prevent, including through legal action. Further, if the patent applications we hold or in-license with respect to our programs, product candidates and companion diagnostic fail to issue, if their breadth or strength of protection is threatened, or if they fail to provide meaningful exclusivity for our product candidates, it could dissuade companies from collaborating with us to develop product candidates, and threaten our ability to commercialize future products.

We may file applications for trademark registrations in connection with our product candidates in various jurisdictions, including the United States. No assurance can be given that any of our trademark applications will be registered in the United States or elsewhere, or that the use of any registered or unregistered trademarks will confer a competitive advantage in the marketplace. Furthermore, even if we are successful in our trademark registrations, the FDA and regulatory authorities in other countries have their own process for drug nomenclature and their own views concerning appropriate proprietary names. The loss, abandonment, or cancellation of any of our trademarks or trademark applications could negatively affect the success of the product candidates to which they relate.

Moreover, some of our know-how and technology which is not patented or not patentable may constitute trade secrets. Therefore, we require our consultants, advisors and collaborators to enter into confidentiality agreements and our employees to enter into invention and non-disclosure agreements. However, no assurance can be given that such agreements will provide for a meaningful protection of our trade secrets, know-how or other proprietary information in the event of any unauthorized use or disclosure of information. Furthermore, we cannot provide assurance that any of our employees, consultants, contract personnel or collaborators, either accidentally or through willful misconduct, will not cause serious negative impact to our programs and/

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or our strategy. All of our employees have signed confidentiality agreements, but there can be no assurance that they will not inadvertently or through their misconduct give trade secrets away.

Third-party patents or intellectual property infringement claims may result in a reduction in the scope of our patent protection and competitive exclusivity with respect to our product candidates. Patent litigation, including defense against third-party intellectual property claims, may result in us incurring substantial costs.

Our patents may be challenged by third parties from time to time, and we will have to defend our intellectual property rights. If we are involved in an intellectual property dispute, we may need to litigate to defend our rights or assert them against others. Disputes can involve arbitration, litigation or proceedings declared by the United States Patent and Trademark office or the International Trade Commission or foreign patent authorities. These disputes can result in the successful invalidation of our patents or reduction in scope so that our patent rights do not create an effective competitive barrier. Even if resolved in our favor, litigation or other legal proceedings relating to intellectual property claims may cause us to incur significant expenses and could distract our technical and management personnel from their normal responsibilities. In addition, there could be public announcements of the results of hearings, motions or other interim proceedings or developments and if securities analysts or investors perceive these results to be negative, it could have a substantial adverse effect on the price of our common stock.

It is possible that third parties will circumvent our patents by means of alternate designs or processes or file applications or be granted patents that would block or hamper our efforts. Further, a third party may claim that our products or technology infringe its patents or other intellectual property rights, as such we may have to discontinue or alter our products and processes, pay license fees or cease certain activities. We may not be able to obtain a license to needed intellectual property on favorable terms, if at all. There are many patents issued or applied for in the biotechnology industry, and we may not be aware of patents or patent applications held by others that relate to our business. This is especially true since patent applications in the U.S. are filed confidentially for the first 18 months. Moreover, the validity and breadth of biotechnology patents involve complex legal and factual questions for which important legal issues remain.

Maintaining our patents and applications requires timely payment of fees and other associated costs in the countries of filing, and we could inadvertently abandon a patent or patent application (or trademark or trademark application) due to non-payment of fees, or as a result of a failure to comply with filing deadlines or other requirements of the prosecution process, resulting in the loss of protection of certain intellectual property rights in a certain country. Alternatively, we, our collaborators or our patent counsel may take action resulting in a patent or patent application becoming abandoned which may not be able to be reinstated, or if reinstated, may suffer patent term adjustments. Any of these outcomes could hurt our ability to gain full patent protection for our products. Registered trademarks and/or applications for trademark registrations in the United States that belong to us are subject to similar risks as described above for patents and patent applications.

Third parties may seek to obtain approval of a generic version of approved products. Defense against entry of a generic product may result in us incurring substantial costs and ultimate failure to prevail against approval of a generic product could result in a substantial loss of market share and profits.

Even if we are successful in obtaining regulatory approval to sell any of our product candidates in one or more countries, we cannot be certain that our patents and other intellectual property rights will ultimately prevent approval during the patent term of generic products developed and commercialized by third parties. A generic manufacturer may seek approval of a generic version of any of our products in the United States by filing an Abbreviated New Drug Application ("ANDA"), with the FDA asserting that our patents are invalid and/or unenforceable to maintain market exclusivity for any of our products, if approved. We cannot predict if, or when, one or more generic manufacturers may attempt to seek regulatory approval for a generic version of any of our products, if approved. There is no assurance that we will ultimately be successful in a court of law to prevent entry of a generic version of any of our products during the applicable patent term and we may incur substantial costs defending our patents and intellectual property rights. An inability to stop a generic manufacturer from selling a generic version of our products could result in a substantial loss of market share and profits or even preclude the ability to continue to commercialize any of our products, if approved.

Risks Related to Our Shares of Common Stock

*Our principal shareholders control the majority of our shares, and their actions may significantly influence matters submitted to our shareholders for approval and our share price.

Based on the information available to us as of March 31, 2021, our shareholders and their affiliates who owned more than 5% of our outstanding common stock collectively owned 48% of our outstanding common stock. Boxer Capital, LLC ("Boxer Capital") and its affiliates collectively own 10% of our outstanding common stock. In addition, in conjunction with certain financing transactions, we granted Boxer Capital the right to nominate a member of our Board of Directors and the right

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to appoint an observer on our Board of Directors. In addition, we granted Baker Brothers Advisors, LLC ("Baker Brothers") the right to appoint an observer on our Board of Directors. Collectively Baker Brothers and Boxer Capital may have significant influence over matters submitted to our shareholders for approval, including the election and removal of directors and the approval of any merger, consolidation, or sale of all or substantially all of our assets. Furthermore, if Baker Brothers, Boxer Capital or any other of our major shareholders determine to exit from the industry or from their holdings in us, for whatever reason, the impact on our share price could be detrimental over a prolonged period of time.

Our bylaws, as amended (our “Bylaws”) provide that the Court of Chancery of the State of Delaware is the exclusive forum for certain disputes between us and our shareholders, which could limit our shareholders’ ability to obtain a favorable judicial forum for disputes with us or our directors, officers or employees.

Our Bylaws provide that the Court of Chancery of the State of Delaware will be the sole and exclusive forum for the following types of actions or proceedings under Delaware statutory or common law: (i) any derivative action or proceeding brought on our behalf, (ii) any action asserting a claim of breach of a fiduciary duty owed by any of our directors or officers to our company or our shareholders, (iii) any action asserting a claim against our company arising pursuant to any provision of the Delaware General Corporation Law or our amended and restated certificate of incorporation or Bylaws, or (iv) any action asserting a claim against our company governed by the internal affairs doctrine. This choice of forum provision does not apply to suits brought to enforce a duty or liability created by the Securities Act of 1933, as amended, or the Exchange Act, or any other claim for which the federal courts have exclusive jurisdiction.  

This choice of forum provision may limit a shareholder’s ability to bring certain claims in a judicial forum that it finds favorable for disputes with us or any of our directors, officers, other employees or shareholders, which may discourage lawsuits with respect to such claims, although our shareholders will not be deemed to have waived our compliance with federal securities laws and the rules and regulations thereunder. If a court were to find this choice of forum provision to be inapplicable or unenforceable in an action, we may incur additional costs associated with resolving such action in other jurisdictions, which could adversely affect our business and financial condition.

Because we do not anticipate paying any cash dividends on our common stock in the foreseeable future, capital appreciation, if any, would be our shareholders’ only source of gain.

We have never declared or paid any cash dividends on our common shares, and we currently expect that earnings, if any, and cash flow will primarily be retained and used in our operations, including servicing any debt obligations we may have now or in the future. Accordingly, although we do not anticipate paying any dividends in the foreseeable future, we may not be able to generate sufficient cash flow in order to allow us to pay future dividends on, or make any distributions with respect to our common stock. As a result, capital appreciation, if any, of our common stock would be our shareholders’ sole source of gain on their investment in our common stock for the foreseeable future.

General Risks

As a public company in the United States, we incur significant legal and financial compliance costs and we are subject to the Sarbanes-Oxley Act. We can provide no assurance that we will, at all times, in the future be able to report that our internal controls over financial reporting are effective.

Companies that file reports with the Securities and Exchange Commission ("SEC"), including us, are subject to the requirements of Section 404 of the Sarbanes-Oxley Act of 2002. Section 404 requires management to establish and maintain a system of internal control over financial reporting, and annual reports on Form 10-K filed under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), must contain a report from management assessing the effectiveness of a company’s internal control over financial reporting. Ensuring that we have adequate internal financial and accounting controls and procedures in place to produce accurate financial statements on a timely basis remains a costly and time-consuming effort that needs to be re-evaluated frequently. Failure on our part to have effective internal financial and accounting controls would cause our financial reporting to be unreliable, could have a material adverse effect on our business, operating results, and financial condition, and could cause our stock price to decline as a result.

If we cannot conclude that we have effective internal control over our financial reporting, or if our independent registered public accounting firm is unable to provide an unqualified opinion regarding the effectiveness of our internal control over financial reporting, investors could lose confidence in the reliability of our financial statements. Failure to comply with reporting requirements could also subject us to sanctions and/or investigations by the SEC, The Nasdaq Global Select Market or other regulatory authorities.

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Furthermore, shareholder activism, the current political environment and the current high level of government intervention and regulatory reform may lead to substantial new regulations and disclosure obligations, which may lead to additional compliance costs and impact the manner in which we operate our business in ways we cannot currently anticipate. Our management and other personnel will need to devote a substantial amount of time to these compliance initiatives. Moreover, any new regulations or disclosure obligations may increase our legal and financial compliance costs and will make some activities more time-consuming and costly.

Our share price is volatile and may be influenced by numerous factors that are beyond our control.

A low share price and low market valuation may make it difficult to raise sufficient additional cash due to the significant dilution to current shareholders. Market prices for shares of biotechnology and biopharmaceutical companies such as ours are often volatile. Factors such as clinical and regulatory developments regarding our products or processes, developments regarding potential or future third-party collaborators, announcements of technological innovations, new commercial products, patents, the development of proprietary rights by us or by others or any litigation relating to these rights, regulatory actions, general conditions in the biotechnology and pharmaceutical industries, failure to meet analysts’ expectations, publications, financial results or public concern over the safety of biopharmaceutical and biotechnological products, economic conditions in the United States and other countries, terrorism and other factors could have a significant effect on the share price for our shares of common stock. Any setback or delay in the clinical development of our programs could result in a significant decrease in our share price. In recent years the stock of other biotechnology and biopharmaceutical companies has experienced extreme price fluctuations that have been unrelated to the operating performance of the affected companies. There can be no assurance that the market price of our shares of common stock will not experience significant fluctuations in the future, including fluctuations that are unrelated to our performance. These fluctuations may result due to macroeconomic and world events, national or local events, general perception of the biotechnology industry or to a lack of liquidity. In addition, other biotechnology companies' or our competitors’ programs could have positive or negative results that impact their stock prices and their results or experience stock price fluctuations that could have a positive or negative impact on our stock price, regardless whether such impact is direct or not.

Shareholders may not agree with our business, scientific, clinical and financial strategy, including additional dilutive financings, and may decide to sell their shares or vote against such proposals. Such actions could materially impact our stock price. In addition, portfolio managers of funds or large investors can change or change their view on us and decide to sell our shares. These actions could have a material impact on our stock price. In order to complete a financing, or for other business reasons, we may elect to consolidate our shares of common stock. Investors may not agree with these actions and may sell our shares. We may have little or no ability to impact or alter such decisions.

Changes in tax laws or regulations that are applied adversely to us or our future potential customers may have a material adverse effect on our business, cash flow, financial condition or results of operations.

New income, sales, use or other tax laws, statutes, rules, regulations or ordinances could be enacted at any time, which could adversely affect our business operations and financial performance. Further, existing tax laws, statutes, rules, regulations or ordinances could be interpreted, changed, modified or applied adversely to us. For example, the Tax Act enacted many significant changes to the U.S. tax laws. Future guidance from the Internal Revenue Service and other tax authorities with respect to the Tax Act may affect us, and certain aspects of the Tax Act could be repealed or modified in future legislation. For example, the CARES Act modified certain provisions of the Tax Act. In addition, it is uncertain if and to what extent various states will conform to the Tax Act, CARES Act or any newly enacted federal tax legislation. Changes in corporate tax rates, the realization of net deferred tax assets relating to our operations, the taxation of foreign earnings, and the deductibility of expenses under the Tax Act or future reform legislation could have a material impact on the value of our deferred tax assets, could result in significant one-time charges, and could increase our future U.S. tax expense.

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 shareholders and could cause our stock price to fall.

We expect that significant additional capital will be needed in the future to continue our planned operations. To the extent we raise additional capital by issuing equity securities, our shareholders 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 shareholders, and new investors could gain rights superior to our existing shareholders.

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Pursuant to our 2013 Equity Incentive Plan (the "2013 Plan"), and our 2013 Employee Stock Purchase Plan (the "ESPP"), our management is authorized to grant stock options, restricted stock units and other equity-based awards to our employees, directors and consultants, and to sell our common stock to our employees, respectively. Pursuant to the Inducement Plan, the Board of Directors is authorized to grant stock options, restricted stock units and other equity-based awards to new employees who satisfy the standards for inducement grants in accordance with the Nasdaq Stock Market LLC listing rules. Any increase in the number of shares outstanding as a result of the exercise of outstanding options, the vesting or settlement of outstanding stock awards, or the purchase of shares pursuant to the ESPP will cause our shareholders to experience additional dilution, which could cause our stock price to fall.

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ITEM 6. Exhibits

Exhibit number	Description of document
2.1	Arrangement Agreement, dated May 8, 2013, by and between MethylGene Inc. and the Company.(2)
3.1	Amended and Restated Certificate of Incorporation.(1)
3.2	Bylaws.(1)
3.3	Amendment to Bylaws.(3)
4.1	Form of Common Stock Certificate.(2)
4.2	Form of Warrant to Purchase Common Stock.(4)
4.3	Form of Warrant to Purchase Common Stock.(5)
4.4	Form of Warrant to Purchase Common Stock.(6)
10.1	Second Amendment to Letter Agreement, effective December 31, 2020, by and between the Registrant and Dr. Charles M. Baum.
10.2	Second Amendment to Letter Agreement, effective December 31, 2020, by and between the Registrant and Dr. James Christensen.
31.1	Certification of the Principal Executive Officer pursuant to Rule 13a-14(a) or 15d-14(a) of the Securities Exchange Act of 1934.
31.2	Certification of the Principal Financial Officer pursuant to Rule 13a-14(a) or 15d-14(a) of the Securities Exchange Act of 1934.
32.1	Certifications Pursuant to U.S.C. Section 1350, As Adopted Pursuant to Section 906 of the Public Company Accounting Reform and Investor Protection Act of 2002.
101.INS	Inline XBRL Instance Document - the instance document does not appear in the Interactive Data File because its XBRL tags are embedded within the Inline XBRL document.
101.SCH	Inline XBRL Taxonomy Extension Schema Document.
101.CAL	Inline XBRL Taxonomy Extension Calculation Linkbase Document.
101.DEF	Inline XBRL Taxonomy Extension Definition Linkbase Document.
101.LAB	Inline XBRL Taxonomy Extension Label Linkbase Document.
101.PRE	Inline XBRL Taxonomy Extension Presentation Linkbase Document.
104	104 Cover Page Interactive Data File (formatted as Inline XBRL and contained in Exhibit 101).

_____________________________________________________

(1)    Incorporated by reference to Mirati Therapeutics, Inc.’s Registration Statement on Form 10-12B (No. 001-35921), filed with the Securities and Exchange Commission on May 10, 2013.

(2)    Incorporated by reference to Mirati Therapeutics, Inc.’s Amended Registration Statement on Form 10-12B/A (No. 001-35921), filed with the Securities and Exchange Commission on June 14, 2013.

(3)     Incorporated by reference to Mirati Therapeutics, Inc.'s Current Report on Form 8-K, filed with the Securities and Exchange Commission on June 16, 2016.

(4)    Incorporated by reference to Mirati Therapeutics, Inc.'s Current Report on Form 8-K, filed with the Securities and Exchange Commission on January 6, 2017.

(5)    Incorporated by reference to Mirati Therapeutics, Inc.'s Current Report on Form 8-K, filed with the Securities and Exchange Commission on November 16, 2017.

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(6)    Incorporated by reference to Mirati Therapeutics, Inc.'s Current Report on Form 8-K, filed with the Securities and Exchange Commission on June 7, 2018.

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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 hereunto duly authorized.

		MIRATI THERAPEUTICS, INC.
May 6, 2021	by:	/s/ Charles M. Baum
		Chief Executive Officer
		(Principal Executive Officer)
May 6, 2021	by:	/s/ Daniel R. Faga
		Executive Vice President and Chief Operating Officer
		(Principal Financial Officer)
May 6, 2021	by:	/s/ Vickie S. Reed
		Senior Vice President and Chief Accounting Officer
		(Principal Accounting Officer)

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EX-10.1

SECOND AMENDMENT TO LETTER AGREEMENT

This Second Amendment to Letter Agreement (the “Amendment”) is entered into by Mirati Therapeutics, Inc., a Delaware corporation (the “Company”), and Charles M. Baum, M.D. (“Employee”) and shall be effective as of December 31, 2020.

The purpose of this Amendment is to provide Employee with certain severance benefits as described herein. The severance benefits set forth in this Amendment replace and supersede the severance benefits set forth in that certain Amended and Restated Employment Agreement entered into as of December 19, 2016 (the “Employment Agreement”) as further described in Section 6 below.

In consideration of the mutual covenants and promises contained herein, the continuing employment of Employee by the Company and other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged by each of the Company and Employee, the Company and Employee agree as follows:

Section 1.    Termination; Severance Benefits.

1.1    Involuntary Termination. If you are subject to an Involuntary Termination that does not occur within the Change in Control Period, the Company shall pay to you the Accrued Amounts and in addition, you will be entitled to the benefits set forth in this Section 1.1 (the “Severance Benefits”), subject to your satisfaction of all the conditions described in Section 1.4 below.

(a)    Cash Severance.You will receive a cash payment equal to (i) twenty-four (24) months (the “Severance Period”) of your Base Salary at the rate in effect immediately prior to your Involuntary Termination (but without giving effect to any prior reduction to Base Salary by the Company which would give rise to your right to resign for Good Reason), plus (ii) two times any Annual Bonus determined by the Board to be payable for the immediately preceding calendar year that has not yet been paid as of the date of termination, and plus (iii) notwithstanding the requirement to be employed through the date the Annual Bonus is paid in order to earn such bonus, a prorated portion of your target Annual Bonus for the year in which the Involuntary Termination occurs irrespective of whether the performance goals applicable to such Annual Bonus have been established or satisfied (in each case calculated by reference to your Base Salary rate as in effect immediately prior to your Involuntary Termination, but without giving effect to any prior reduction in Base Salary by the Company which would give rise to your right to resign for Good Reason) subject to applicable payroll deductions and tax withholdings (the “Severance Payment”). The Severance Payment shall be paid to you in a lump sum on the first regular payroll date of the Company following the effective date of the Release.

(b)    Accelerated Vesting.The vesting and exercisability of all outstanding options, restricted stock unit awards, and other equity awards covering the Company’s common stock that are held by you as of immediately prior to the Involuntary Termination, to the extent

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such equity awards would otherwise have vested solely conditioned on your continued services with the Company, shall accelerate vesting in accordance with their applicable vesting schedules as if you had completed an additional number of months of service with the Company equal to the Severance Period as of the date of Involuntary Termination.

(c)     Payment of Continued Group Health Plan Benefits. If you are eligible for and timely elect continued group health plan coverage under the Consolidated Omnibus Budget Reconciliation Act of 1985 or any state law of similar effect (“COBRA”) following your Involuntary Termination, the Company will pay your COBRA group health insurance premiums for you and your eligible dependents directly to the insurer until the earliest of (A) the end of the period immediately following your Involuntary Termination that is equal to the Severance Period (the “COBRA Payment Period”), (B) the expiration of your eligibility for continuation coverage under COBRA, or (C) the date when you become eligible for substantially equivalent health insurance coverage in connection with new employment or self-employment.  For purposes of this Section, references to COBRA premiums shall not include any amounts payable by you under a Section 125 health care reimbursement plan under the Code.  Notwithstanding the foregoing, if at any time the Company determines, in its sole discretion, that it cannot pay the COBRA premiums without potentially incurring financial costs or penalties under applicable law (including, without limitation, Section 2716 of the Public Health Service Act), then regardless of whether you elect continued health coverage under COBRA, and in lieu of providing the COBRA premiums, the Company will instead pay you on the last day of each remaining month of the COBRA Payment Period, a fully taxable cash payment equal to the COBRA premiums for that month, subject to applicable tax withholdings (such amount, the “Special Severance Payment”), which payments shall continue until the earlier of expiration of the COBRA Payment Period or the date when you become eligible for substantially equivalent health insurance coverage in connection with new employment or self-employment.  On the first payroll date following the effectiveness of the Release, the Company will make the first payment to the insurer under this clause (and, in the case of the Special Severance Payment, such payment will be to you, in a lump sum) equal to the aggregate amount of payments that the Company would have paid through such date had such payments instead commenced on the date of your Involuntary Termination, with the balance of the payments paid thereafter on the schedule described above.  If you become eligible for coverage under another employer’s group health plan, you must immediately notify the Company of such event, and all payments and obligations under this subsection shall cease.

1.2    Involuntary Termination in Connection with a Change in Control. If your Involuntary Termination occurs during the Change in Control Period, then you shall be entitled to the Accrued Amounts and to the benefits set forth in this Section (the “Change in Control Severance Benefits”), subject to your satisfaction of all the conditions described in Section 1.4 below.

    (a)    Cash Severance. You will receive a cash payment equal to: (i) twenty-four (24) months (the “Severance Period”) of your Base Salary, plus (ii) two times your target Annual Bonus for the year in which the Involuntary Termination occurs (in each case calculated by reference to your Base Salary rate as in effect immediately prior to your Involuntary

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Termination, but without giving effect to any prior reduction in Base Salary by the Company which would give rise to your right to resign for Good Reason), subject to applicable payroll deductions and tax withholdings (the “Severance Payment”). The Severance Payment shall be paid to you in a lump sum on the first regular payroll date of the Company following the effective date of the Release.

(b)    Full Accelerated Vesting. Effective as of the later of your Involuntary Termination or the effective date of the Change in Control, the vesting and exercisability of all outstanding stock options, restricted stock unit awards and other equity awards covering the Company’s common stock that are held by you as of immediately prior to the Involuntary Termination shall accelerate vesting in full. For purposes of determining the number of shares that will accelerate vesting pursuant to this Section 1.2(b) with respect to any equity award subject to performance-based vesting for which the performance period has not ended and that has multiple vesting levels depending upon the level of performance, the portion of such award that shall accelerate vesting shall be calculated assuming that the applicable performance criteria were attained at the greater of (1) a 100% level or (2) the actual level of achievement of the applicable performance criteria as of the later of the Change in Control or Involuntary Termination, as applicable. Your equity awards shall remain outstanding following your Involuntary Termination if and to the extent necessary to give effect to this Section 1.2(b). For the avoidance of doubt, vesting acceleration under this subsection is conditioned upon the actual consummation of a Change in Control.

    (c)    Payment of Continued Group Health Plan Benefits. If you are eligible for and timely elect continued group health plan coverage under the Consolidated Omnibus Budget Reconciliation Act of 1985 or any state law of similar effect (“COBRA”) following your Involuntary Termination, the Company will pay your COBRA group health insurance premiums for you and your eligible dependents directly to the insurer until the earliest of (A) the end of the period immediately following your Involuntary Termination that is equal to the Severance Period (the “COBRA Payment Period”), (B) the expiration of your eligibility for continuation coverage under COBRA, or (C) the date when you become eligible for substantially equivalent health insurance coverage in connection with new employment or self-employment.  For purposes of this Section, references to COBRA premiums shall not include any amounts payable by you under a Section 125 health care reimbursement plan under the Code.  Notwithstanding the foregoing, if at any time the Company determines, in its sole discretion, that it cannot pay the COBRA premiums without potentially incurring financial costs or penalties under applicable law (including, without limitation, Section 2716 of the Public Health Service Act), then regardless of whether you elect continued health coverage under COBRA, and in lieu of providing the COBRA premiums, the Company will instead pay you on the last day of each remaining month of the COBRA Payment Period, a fully taxable cash payment equal to the COBRA premiums for that month, subject to applicable tax withholdings (such amount, the “Special Severance Payment”), which payments shall continue until the earlier of expiration of the COBRA Payment Period or the date when you become eligible for substantially equivalent health insurance coverage in connection with new employment or self-employment.  On the first payroll date following the effectiveness of the Release, the Company will make the first payment under this clause (and, in the case of the Special Severance Payment, such payment will be to you, in a

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lump sum) equal to the aggregate amount of payments that the Company would have paid through such date had such payments instead commenced on the date of your Involuntary Termination, with the balance of the payments paid thereafter on the schedule described above.  If you become eligible for coverage under another employer’s group health plan, you must immediately notify the Company of such event, and all payments and obligations under this subsection shall cease.

    For the avoidance of doubt, in no event shall you be entitled to benefits under both Section 1.1 and this Section 1.2. If you are eligible for benefits under both Section 1.1 and this Section 1.2, you shall receive the benefits set forth in this Section 1.2 and such benefits shall be reduced by any benefits previously provided to you under Section 1.1.

1.3    Termination for Cause; Resignation Without Good Reason; Death or Disability. If the Company terminates your employment for Cause, you resign your employment with the Company without Good Reason, or your employment terminates due to your death or disability or under any other circumstances not involving an Involuntary Termination, you shall only be entitled to the Accrued Amounts. You will not be eligible for, or entitled to any severance benefits, including (without limitation) the Severance Benefits in Section 1.1 and Change in Control Severance Benefits in Section 1.2.

1.4    Conditions to Receiving Severance Benefits and Change in Control Severance Benefits. Your receipt of the Severance Benefits in Section 1.1 and the Change in Control Severance Benefits in Section 1.2 of this Agreement will be conditioned upon and subject in all cases to:

(a) You executing, delivering to the Company and allowing to become effective, a waiver and release of claims in a form provided by the Company, which may be included by the Company in a separate separation agreement (the “Release”), within the applicable deadline set forth therein following your Involuntary Termination, and permitting the Release to become effective in accordance with its terms, which effective date of the Release may not be later than sixty (60) days following the date of your Involuntary Termination (such sixty (60) day deadline, the “Release Deadline”);

(b) Your compliance with your continuing obligations to the Company under this Agreement and the PIIA; and

(c) Your resignation from all offices, directorships and trusteeships then held by you at the Company or any affiliate of the Company, with such resignation to be effective upon your date of Involuntary Termination, unless otherwise requested by the Company.

2.    Definitions. The terms used in this Agreement shall have the following meanings:

2.1 “Accrued Amounts”means your Base Salary that is earned but unpaid as of your employment termination date, any unreimbursed business expenses payable to you and any accrued but unused personal time off or vacation benefits and any other payments or benefits

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otherwise earned and payable to you or otherwise as required by law to be paid or provided through your employment termination date.

2.2 “Cause” shall mean, for purposes of this Agreement, your (i) material breach of your obligations under this Agreement, the PIIA, or any code of ethics or business conduct policy adopted by the Company from time to time, or of any other material contract with the Company or statutory duty owed to the Company; (ii) neglect or failure to conscientiously and diligently carry out your functions and/or duties after you have received a written demand of performance from the Company which specifically set forth the factual basis for the Company’s belief that you have not substantially performed your functions and have failed to cure such non-performance to the Company’s satisfaction within ten (10) business days after receiving such notice; (iii) commission of any act that is reasonably likely to lead to a conviction of, or plea of nolo contendere to, a felony or any crime involving fraud, embezzlement or any other act of moral turpitude under the laws of the United States or of any jurisdiction applicable to you; or (iv) commission or attempted commission of, or participation (whether by affirmative act or omission) in, a fraud or act of dishonesty against the Company.

2.3 “Change in Control” has the meaning ascribed to such term in the Plan.

2.4 “Change in Control Period” means the period commencing three (3) months prior to a Change in Control and ending twenty-four (24) months following a Change in Control.

2.5 “Code” means the U.S. Internal Revenue Code of 1986 (as it has been and may be amended from time to time) and any regulations and guidance that has been promulgated or may be promulgated from time to time thereunder and any state law of similar effect.

2.6 “Good Reason” for you to resign your employment with the Company means the occurrence of any of the following events without your express written consent; provided, however, that any such resignation by you due to any of the following conditions shall only be deemed for Good Reason if: (1) you give the Company written notice of the intent to terminate for Good Reason within sixty (60) days following the first occurrence of the particular condition or conditions that you believe constitutes Good Reason, which notice shall describe such condition(s); provided, however, that failure to provide such notice shall not operate as a waiver of your right to resign employment for Good Reason based on the occurrence of a different condition or subsequent occurrence of the same condition; (2) the Company fails to remedy such condition(s) within thirty (30) days following receipt of the written notice (the “Cure Period”) of such condition(s) from you; and (3) you actually resign employment from all positions you then hold with the Company within the first thirty (30) days after expiration of the Cure Period:

(a) a material reduction in your authority, duties, status or responsibilities;

(b) a material reduction of your then current Base Salary, and regardless of whether implemented in a single reduction or a series of reductions, which the parties agree is a reduction of at least five percent (5%) of your Base Salary; notwithstanding the foregoing, such a material reduction of your Base Salary shall not constitute Good Reason if such material reduction was made under a salary reduction program that commenced at least three (3) months

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prior to a Change in Control and is applicable generally to the Company’s similarly situated leadership team members;

(c) a material reduction in the budget over which you retain authority;

(d) a material reduction in the authority, duties, or responsibilities of the CEO to whom you are required to report;

(e) any relocation of your principal place of employment to a place that increases your one-way commute by more than thirty-five (35) miles, provided, however, that required travel for Company business shall not constitute Good Reason; or

(f) the Company’s material breach of this Agreement.

2.7 “Involuntary Termination” means a termination of your employment with the Company pursuant to either (i) a termination initiated by the Company without Cause, (ii) your resignation for Good Reason or (iii) due to “Redundancy” which shall mean the elimination by the Board of your role or position in the Company, and provided in any case (i), (ii) or (iii) such termination constitutes a Separation from Service. An Involuntary Termination does not include any other termination of your employment, including a termination due to your death or disability.

2.8 “Plan” shall mean the Company’s 2013 Equity Incentive Plan, as amended from time to time, and any successor plan thereto.

2.9 “Separation from Service” means a “separation from service”, as defined under Treasury Regulation Section 1.409A-1(h).

3.    Section 409A. It is intended that all of the severance benefits and other payments payable under this Agreement satisfy, to the greatest extent possible, the exemptions from the application of Code Section 409A provided under Treasury Regulations Sections 1.409A1(b)(4), 1.409A1(b)(5) and 1.409A1(b)(9), and this Agreement will be construed to the greatest extent possible as consistent with those provisions, and to the extent no so exempt, this Agreement (and any definitions hereunder) will be construed in a manner that complies with Section 409A. For all purposes of Code Section 409A (including, without limitation, for purposes of Treasury Regulations Sections 1.409A2(b)(2)(i) and (iii)), your right to receive any installment payments under this Agreement (whether severance payments, reimbursements or otherwise) shall be treated as a right to receive a series of separate payments and, accordingly, each installment payment hereunder shall at all times be considered a separate and distinct payment. Notwithstanding any provision to the contrary in this Agreement, if you are deemed by the Company at the time of your Separation from Service to be a “specified employee” for purposes of Code Section 409A(a)(2)(B)(i), and if any of the payments upon Separation from Service set forth herein and/or under any other agreement with the Company are deemed to be “deferred compensation,” then to the extent delayed commencement of any portion of such payments is required in order to avoid a prohibited distribution under Code Section 409A(a)(2)(B)(i) and the related adverse taxation under Section 409A, such payments shall not

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be provided to you prior to the earliest of (i) the first date following expiration of the six-month period following the date of your Separation from Service with the Company, (ii) the date of your death or (iii) such earlier date as permitted under Section 409A without the imposition of adverse taxation. Upon the first business day following the expiration of such applicable Code Section 409A(a)(2)(B)(i) period, all payments deferred pursuant to this Paragraph shall be paid in a lump sum to you, and any remaining payments due shall be paid as otherwise provided herein or in the applicable agreement. No interest shall be due on any amounts so deferred. If the severance benefits are not covered by one or more exemptions from the application of Section 409A and the Release Deadline occurs in the calendar year following the calendar year of your Separation from Service, the Release will not be deemed effective any earlier than the Release Deadline for purposes of determining the timing of provision of any severance benefits.

4.    Section 280G.

If any payment or benefit you will or may receive from the Company or otherwise (a “280G Payment”) would (i) constitute a “parachute payment” within the meaning of Section 280G of the Code, and (ii) but for this sentence, be subject to the excise tax imposed by Section 4999 of the Code (the “Excise Tax”), then any such 280G Payment pursuant to this Amendment or otherwise (a “Payment”) shall be equal to the Reduced Amount. The “Reduced Amount” shall be either (x) the largest portion of the Payment that would result in no portion of the Payment (after reduction) being subject to the Excise Tax or (y) the largest portion, up to and including the total, of the Payment, whichever amount (i.e., the amount determined by clause (x) or by clause (y)), after taking into account all applicable federal, state and local employment taxes, income taxes, and the Excise Tax (all computed at the highest applicable marginal rate), results in your receipt, on an after-tax basis, of the greater economic benefit notwithstanding that all or some portion of the Payment may be subject to the Excise Tax. If a reduction in a Payment is required pursuant to the preceding sentence and the Reduced Amount is determined pursuant to clause (x) of the preceding sentence, the reduction shall occur in the manner (the “Reduction Method”) that results in the greatest economic benefit for you. If more than one method of reduction will result in the same economic benefit, the items so reduced will be reduced pro rata (the “Pro Rata Reduction Method”).

Notwithstanding the foregoing, if the Reduction Method or the Pro Rata Reduction Method would result in any portion of the Payment being subject to taxes pursuant to Section 409A that would not otherwise be subject to taxes pursuant to Section 409A, then the Reduction Method and/or the Pro Rata Reduction Method, as the case may be, shall be modified so as to avoid the imposition of taxes pursuant to Section 409A as follows: (A) as a first priority, the modification shall preserve to the greatest extent possible, the greatest economic benefit for you as determined on an after-tax basis; (B) as a second priority, Payments that are contingent on future events (e.g., being terminated without Cause), shall be reduced (or eliminated) before Payments that are not contingent on future events; and (C) as a third priority, Payments that are “deferred compensation” within the meaning of Section 409A shall be reduced (or eliminated) before Payments that are not deferred compensation within the meaning of Section 409A.

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Unless you and the Company agree on an alternative accounting firm, the accounting firm engaged by the Company for general tax compliance purposes as of the day prior to the effective date of the change in control transaction triggering the Payment shall perform the foregoing calculations. If the accounting firm so engaged by the Company is serving as accountant or auditor for the individual, entity or group effecting the change in control transaction, the Company shall appoint a nationally recognized accounting firm to make the determinations required hereunder. The Company shall bear all expenses with respect to the determinations by such accounting firm required to be made hereunder. The Company shall use commercially reasonable efforts to cause the accounting firm engaged to make the determinations hereunder to provide its calculations, together with detailed supporting documentation, to you and the Company within fifteen (15) calendar days after the date on which your right to a 280G Payment becomes reasonably likely to occur (if requested at that time by you or the Company) or such other reasonable time as requested by you or the Company.

If you receives a Payment for which the Reduced Amount was determined pursuant to clause (x) of the first paragraph of this Section and the Internal Revenue Service determines thereafter that some portion of the Payment is subject to the Excise Tax, you shall promptly return to the Company a sufficient amount of the Payment (after reduction pursuant to clause (x) of the first paragraph of this Section so that no portion of the remaining Payment is subject to the Excise Tax. For the avoidance of doubt, if the Reduced Amount was determined pursuant to clause (y) in the first paragraph of this Section, you shall have no obligation to return any portion of the Payment pursuant to the preceding sentence.

5.    Arbitration of All Disputes.

5.1    Agreement to Arbitrate. To ensure the timely and economical resolution of disputes that may arise between you and the Company, both you and the Company mutually agree that pursuant to the Federal Arbitration Act, 9 U.S.C. §1-16, and to the fullest extent permitted by applicable law, you will submit solely to final, binding and confidential arbitration any and all disputes, claims, or causes of action arising from or relating to: (i) the negotiation, execution, interpretation, performance, breach or enforcement of this Agreement; or (ii) your employment with the Company (including but not limited to all statutory claims); or (iii) the termination of your employment with the Company (including but not limited to all statutory claims). BY AGREEING TO THIS ARBITRATION PROCEDURE, BOTH YOU AND THE COMPANY WAIVE THE RIGHT TO RESOLVE ANY SUCH DISPUTES THROUGH A TRIAL BY JURY OR JUDGE.

5.2    Arbitrator Authority. The Arbitrator shall have the sole and exclusive authority to determine whether a dispute, claim or cause of action is subject to arbitration under this Section and to determine any procedural questions which grow out of such disputes, claims or causes of action and bear on their final disposition.

5.3    Individual Capacity Only. All claims, disputes, or causes of action under this Section, whether by you or the Company, must be brought solely in an individual capacity, and shall not be brought as a plaintiff (or claimant) or class member in any purported class or

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representative proceeding, nor joined or consolidated with the claims of any other person or entity. The Arbitrator may not consolidate the claims of more than one person or entity and may not preside over any form of representative or class proceeding. To the extent that the preceding sentences in this Section are found to violate applicable law or are otherwise found unenforceable, any claim(s) alleged or brought on behalf of a class shall proceed in a court of law rather than by arbitration.

5.4    Arbitration Process. Any arbitration proceeding under this Section shall be presided over by a single arbitrator and conducted by Judicial Arbitration and Mediation Services, Inc. (“JAMS”) in San Diego, California under the then applicable JAMS rules for the resolution of employment disputes (available upon request and also currently available at http://www.jamsadr.com/rules-employment-arbitration/). You and the Company both have the right to be represented by legal counsel at any arbitration proceeding, at each party’s own expense. The Arbitrator shall: (i) have the authority to compel adequate discovery for the resolution of the dispute; (ii) issue a written arbitration decision, to include the arbitrator’s essential findings and conclusions and a statement of the award; and (iii) be authorized to award any or all remedies that you or the Company would be entitled to seek in a court of law. The Company shall pay all JAMS arbitration fees in excess of the amount of court fees that would be required of you if the dispute were decided in a court of law.

5.5 Excluded Claims. This Section shall not apply to any action or claim that cannot be subject to mandatory arbitration as a matter of law, including, without limitation, claims brought pursuant to the California Private Attorneys General Act of 2004, as amended, the California Fair Employment and Housing Act, as amended, and the California Labor Code, as amended, to the extent such claims are not permitted by applicable law to be submitted to mandatory arbitration and are not preempted by the Federal Arbitration Act (collectively, the “Excluded Claims”). In the event you intend to bring multiple claims, including one of the Excluded Claims listed above, the Excluded Claims may be publicly filed with a court, while any other claims will remain subject to mandatory arbitration.

5.6 Injunctive Relief and Final Orders. Nothing in this Section is intended to prevent either you or the Company from obtaining injunctive relief in court to prevent irreparable harm pending the conclusion of any such arbitration. Any final award in any arbitration proceeding hereunder may be entered as a judgment in the federal and state courts of any competent jurisdiction and enforced accordingly.

6.    General Provisions. This Agreement, together with the PIIA, constitutes the entire agreement between you and the Company with regard to this subject matter and is the complete, final, and exclusive embodiment of the parties’ agreement with regard to this subject matter. This Agreement is entered into without reliance on any promise or representation, written or oral, other than those expressly contained herein, and it supersedes any other such promises, warranties or representations. It is entered into without reliance on any promise or representation other than those expressly contained herein, and it cannot be modified or amended except in a writing signed by a duly authorized officer of the Company. Whenever possible, each provision of this Agreement will be interpreted in such manner as to be effective and valid under

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applicable law, but if any provision of this Agreement is held to be invalid, illegal or unenforceable in any respect under any applicable law or rule in any jurisdiction, such invalidity, illegality or unenforceability will not affect any other provision or any other jurisdiction, but this Agreement will be reformed, construed and enforced in such jurisdiction to the extent possible in keeping with the intent of the parties. Any waiver of any breach of any provisions of this Agreement must be in writing to be effective, and it shall not thereby be deemed to have waived any preceding or succeeding breach of the same or any other provision of this Agreement. This Agreement is intended to bind and inure to the benefit of and be enforceable by you and the Company, and their respective successors, assigns, heirs, executors and administrators. The Company may freely assign this Agreement, without your prior written consent. You may not assign any of your duties hereunder and you may not assign any of your rights hereunder without the written consent of the Company. This Agreement shall become effective as of the Start Date and shall terminate upon your termination of employment with the Company. The obligations as forth under Sections 1 (Termination; Severance Benefits), 3(Section 409A), 4(Section 280G), 5(Arbitration of All Disputes); and 6 (General Provisions) will survive the termination of this Agreement. All questions concerning the construction, validity and interpretation of this Agreement will be governed by the laws of the State of California.

This Amendment may be executed in several counterparts, each of which shall be deemed an original, but all of which together shall constitute one and the same instrument.

IN WITNESS WHEREOF, Employee and the Company have executed this Amendment as of the day and year set forth above.

MIRATI THERAPEUTICS, INC.

By: /s/ Kristin Gustafson

Name: Kristin Gustafson

Title: CHRO

/s/ Charles M. Baum

Charles M. Baum, M.D.

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EX-10.2

SECOND AMENDMENT TO LETTER AGREEMENT

This Second Amendment to Letter Agreement (the “Amendment”) is entered into by Mirati Therapeutics, Inc., a Delaware corporation (the “Company”), and James Christensen, Ph.D. (“Employee”) and shall be effective as of December 31, 2020.

The purpose of this Amendment is to provide Employee with certain severance benefits as described herein. The severance benefits set forth in this Amendment replace and supersede the severance benefits set forth in that certain Letter Agreement entered into as of May 20, 2013 and as amended on December 19, 2016 (the “Employment Agreement”) as further described in Section 6 below.

In consideration of the mutual covenants and promises contained herein, the continuing employment of Employee by the Company and other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged by each of the Company and Employee, the Company and Employee agree as follows:

Section 1.    Termination; Severance Benefits.

1.1    Involuntary Termination. If you are subject to an Involuntary Termination that does not occur within the Change in Control Period, the Company shall pay to you the Accrued Amounts and in addition, you will be entitled to the benefits set forth in this Section 1.1 (the “Severance Benefits”), subject to your satisfaction of all the conditions described in Section 1.4 below.

(a)    Cash Severance.You will receive a cash payment equal to (i) eighteen (18) months (the “Severance Period”) of your Base Salary at the rate in effect immediately prior to your Involuntary Termination (but without giving effect to any prior reduction to Base Salary by the Company which would give rise to your right to resign for Good Reason), subject to applicable payroll deductions and tax withholdings (the “Severance Payment”). The Severance Payment shall be paid to you in a lump sum on the first regular payroll date of the Company following the effective date of the Release.

(b)    Accelerated Vesting.The vesting and exercisability of all outstanding options, restricted stock unit awards, and other equity awards covering the Company’s common stock that are held by you as of immediately prior to the Involuntary Termination, to the extent such equity awards would otherwise have vested solely conditioned on your continued services with the Company, shall accelerate vesting in accordance with their applicable vesting schedules as if you had completed an additional number of months of service with the Company equal to the Severance Period as of the date of Involuntary Termination.

(c)     Payment of Continued Group Health Plan Benefits. If you are eligible for and timely elect continued group health plan coverage under the Consolidated Omnibus Budget Reconciliation Act of 1985 or any state law of similar effect (“COBRA”) following your Involuntary Termination, the Company will pay your COBRA group health insurance premiums

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for you and your eligible dependents directly to the insurer until the earliest of (A) the end of the period immediately following your Involuntary Termination that is equal to the Severance Period (the “COBRA Payment Period”), (B) the expiration of your eligibility for continuation coverage under COBRA, or (C) the date when you become eligible for substantially equivalent health insurance coverage in connection with new employment or self-employment.  For purposes of this Section, references to COBRA premiums shall not include any amounts payable by you under a Section 125 health care reimbursement plan under the Code.  Notwithstanding the foregoing, if at any time the Company determines, in its sole discretion, that it cannot pay the COBRA premiums without potentially incurring financial costs or penalties under applicable law (including, without limitation, Section 2716 of the Public Health Service Act), then regardless of whether you elect continued health coverage under COBRA, and in lieu of providing the COBRA premiums, the Company will instead pay you on the last day of each remaining month of the COBRA Payment Period, a fully taxable cash payment equal to the COBRA premiums for that month, subject to applicable tax withholdings (such amount, the “Special Severance Payment”), which payments shall continue until the earlier of expiration of the COBRA Payment Period or the date when you become eligible for substantially equivalent health insurance coverage in connection with new employment or self-employment.  On the first payroll date following the effectiveness of the Release, the Company will make the first payment to the insurer under this clause (and, in the case of the Special Severance Payment, such payment will be to you, in a lump sum) equal to the aggregate amount of payments that the Company would have paid through such date had such payments instead commenced on the date of your Involuntary Termination, with the balance of the payments paid thereafter on the schedule described above.  If you become eligible for coverage under another employer’s group health plan, you must immediately notify the Company of such event, and all payments and obligations under this subsection shall cease.

1.2    Involuntary Termination in Connection with a Change in Control. If your Involuntary Termination occurs during the Change in Control Period, then you shall be entitled to the Accrued Amounts and to the benefits set forth in this Section (the “Change in Control Severance Benefits”), subject to your satisfaction of all the conditions described in Section 1.4 below.

    (a)    Cash Severance. You will receive a cash payment equal to: (i) eighteen (18) months (the “Severance Period”) of your Base Salary, plus (ii) your target Annual Bonus for the year in which the Involuntary Termination occurs (in each case calculated by reference to your Base Salary rate as in effect immediately prior to your Involuntary Termination, but without giving effect to any prior reduction in Base Salary by the Company which would give rise to your right to resign for Good Reason), subject to applicable payroll deductions and tax withholdings (the “Severance Payment”). The Severance Payment shall be paid to you in a lump sum on the first regular payroll date of the Company following the effective date of the Release.

(b)    Full Accelerated Vesting. Effective as of the later of your Involuntary Termination or the effective date of the Change in Control, the vesting and exercisability of all outstanding stock options, restricted stock unit awards and other equity awards covering the

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Company’s common stock that are held by you as of immediately prior to the Involuntary Termination shall accelerate vesting in full. For purposes of determining the number of shares that will accelerate vesting pursuant to this Section 1.2(b) with respect to any equity award subject to performance-based vesting for which the performance period has not ended and that has multiple vesting levels depending upon the level of performance, the portion of such award that shall accelerate vesting shall be calculated assuming that the applicable performance criteria were attained at the greater of (1) a 100% level or (2) the actual level of achievement of the applicable performance criteria as of the later of the Change in Control or Involuntary Termination, as applicable. Your equity awards shall remain outstanding following your Involuntary Termination if and to the extent necessary to give effect to this Section 1.2(b). For the avoidance of doubt, vesting acceleration under this subsection is conditioned upon the actual consummation of a Change in Control.

    (c)    Payment of Continued Group Health Plan Benefits. If you are eligible for and timely elect continued group health plan coverage under the Consolidated Omnibus Budget Reconciliation Act of 1985 or any state law of similar effect (“COBRA”) following your Involuntary Termination, the Company will pay your COBRA group health insurance premiums for you and your eligible dependents directly to the insurer until the earliest of (A) the end of the period immediately following your Involuntary Termination that is equal to the Severance Period (the “COBRA Payment Period”), (B) the expiration of your eligibility for continuation coverage under COBRA, or (C) the date when you become eligible for substantially equivalent health insurance coverage in connection with new employment or self-employment.  For purposes of this Section, references to COBRA premiums shall not include any amounts payable by you under a Section 125 health care reimbursement plan under the Code.  Notwithstanding the foregoing, if at any time the Company determines, in its sole discretion, that it cannot pay the COBRA premiums without potentially incurring financial costs or penalties under applicable law (including, without limitation, Section 2716 of the Public Health Service Act), then regardless of whether you elect continued health coverage under COBRA, and in lieu of providing the COBRA premiums, the Company will instead pay you on the last day of each remaining month of the COBRA Payment Period, a fully taxable cash payment equal to the COBRA premiums for that month, subject to applicable tax withholdings (such amount, the “Special Severance Payment”), which payments shall continue until the earlier of expiration of the COBRA Payment Period or the date when you become eligible for substantially equivalent health insurance coverage in connection with new employment or self-employment.  On the first payroll date following the effectiveness of the Release, the Company will make the first payment under this clause (and, in the case of the Special Severance Payment, such payment will be to you, in a lump sum) equal to the aggregate amount of payments that the Company would have paid through such date had such payments instead commenced on the date of your Involuntary Termination, with the balance of the payments paid thereafter on the schedule described above.  If you become eligible for coverage under another employer’s group health plan, you must immediately notify the Company of such event, and all payments and obligations under this subsection shall cease.

    For the avoidance of doubt, in no event shall you be entitled to benefits under both Section 1.1 and this Section 1.2. If you are eligible for benefits under both Section 1.1 and

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this Section 1.2, you shall receive the benefits set forth in this Section 1.2 and such benefits shall be reduced by any benefits previously provided to you under Section 1.1.

1.3    Termination for Cause; Resignation Without Good Reason; Death or Disability. If the Company terminates your employment for Cause, you resign your employment with the Company without Good Reason, or your employment terminates due to your death or disability or under any other circumstances not involving an Involuntary Termination, you shall only be entitled to the Accrued Amounts. You will not be eligible for, or entitled to any severance benefits, including (without limitation) the Severance Benefits in Section 1.1 and Change in Control Severance Benefits in Section 1.2.

1.4    Conditions to Receiving Severance Benefits and Change in Control Severance Benefits. Your receipt of the Severance Benefits in Section 1.1 and the Change in Control Severance Benefits in Section 1.2 of this Agreement will be conditioned upon and subject in all cases to:

(a) You executing, delivering to the Company and allowing to become effective, a waiver and release of claims in a form provided by the Company, which may be included by the Company in a separate separation agreement (the “Release”), within the applicable deadline set forth therein following your Involuntary Termination, and permitting the Release to become effective in accordance with its terms, which effective date of the Release may not be later than sixty (60) days following the date of your Involuntary Termination (such sixty (60) day deadline, the “Release Deadline”);

(b) Your compliance with your continuing obligations to the Company under this Agreement and the PIIA; and

(c) Your resignation from all offices, directorships and trusteeships then held by you at the Company or any affiliate of the Company, with such resignation to be effective upon your date of Involuntary Termination, unless otherwise requested by the Company.

2.    Definitions. The terms used in this Agreement shall have the following meanings:

2.1 “Accrued Amounts”means your Base Salary that is earned but unpaid as of your employment termination date, any unreimbursed business expenses payable to you and any accrued but unused personal time off or vacation benefits and any other payments or benefits otherwise earned and payable to you or otherwise as required by law to be paid or provided through your employment termination date.

2.2 “Cause” shall mean, for purposes of this Agreement, your (i) material breach of your obligations under this Agreement, the PIIA, or any code of ethics or business conduct policy adopted by the Company from time to time, or of any other material contract with the Company or statutory duty owed to the Company; (ii) neglect or failure to conscientiously and diligently carry out your functions and/or duties after you have received a written demand of performance from the Company which specifically set forth the factual basis for the Company’s belief that you have not substantially performed your functions and have failed to cure such non-

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performance to the Company’s satisfaction within ten (10) business days after receiving such notice; (iii) commission of any act that is reasonably likely to lead to a conviction of, or plea of nolo contendere to, a felony or any crime involving fraud, embezzlement or any other act of moral turpitude under the laws of the United States or of any jurisdiction applicable to you; or (iv) commission or attempted commission of, or participation (whether by affirmative act or omission) in, a fraud or act of dishonesty against the Company.

2.3 “Change in Control” has the meaning ascribed to such term in the Plan.

2.4 “Change in Control Period” means the period commencing three (3) months prior to a Change in Control and ending twenty-four (24) months following a Change in Control.

2.5 “Code” means the U.S. Internal Revenue Code of 1986 (as it has been and may be amended from time to time) and any regulations and guidance that has been promulgated or may be promulgated from time to time thereunder and any state law of similar effect.

2.6 “Good Reason” for you to resign your employment with the Company means the occurrence of any of the following events without your express written consent; provided, however, that any such resignation by you due to any of the following conditions shall only be deemed for Good Reason if: (1) you give the Company written notice of the intent to terminate for Good Reason within sixty (60) days following the first occurrence of the particular condition or conditions that you believe constitutes Good Reason, which notice shall describe such condition(s); provided, however, that failure to provide such notice shall not operate as a waiver of your right to resign employment for Good Reason based on the occurrence of a different condition or subsequent occurrence of the same condition; (2) the Company fails to remedy such condition(s) within thirty (30) days following receipt of the written notice (the “Cure Period”) of such condition(s) from you; and (3) you actually resign employment from all positions you then hold with the Company within the first thirty (30) days after expiration of the Cure Period:

(a) a material reduction in your authority, duties, status or responsibilities;

(b) a material reduction of your then current Base Salary, and regardless of whether implemented in a single reduction or a series of reductions, which the parties agree is a reduction of at least five percent (5%) of your Base Salary; notwithstanding the foregoing, such a material reduction of your Base Salary shall not constitute Good Reason if such material reduction was made under a salary reduction program that commenced at least three (3) months prior to a Change in Control and is applicable generally to the Company’s similarly situated leadership team members;

(c) a material reduction in the budget over which you retain authority;

(d) a material reduction in the authority, duties, or responsibilities of the CEO to whom you are required to report;

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(e) any relocation of your principal place of employment to a place that increases your one-way commute by more than thirty-five (35) miles, provided, however, that required travel for Company business shall not constitute Good Reason; or

(f) the Company’s material breach of this Agreement.

2.7 “Involuntary Termination” means a termination of your employment with the Company pursuant to either (i) a termination initiated by the Company without Cause, (ii) your resignation for Good Reason or (iii) due to “Redundancy” which shall mean the elimination by the Board of your role or position in the Company, and provided in any case (i), (ii) or (iii) such termination constitutes a Separation from Service. An Involuntary Termination does not include any other termination of your employment, including a termination due to your death or disability.

2.8 “Plan” shall mean the Company’s 2013 Equity Incentive Plan, as amended from time to time, and any successor plan thereto.

2.9 “Separation from Service” means a “separation from service”, as defined under Treasury Regulation Section 1.409A-1(h).

3.    Section 409A. It is intended that all of the severance benefits and other payments payable under this Agreement satisfy, to the greatest extent possible, the exemptions from the application of Code Section 409A provided under Treasury Regulations Sections 1.409A1(b)(4), 1.409A1(b)(5) and 1.409A1(b)(9), and this Agreement will be construed to the greatest extent possible as consistent with those provisions, and to the extent no so exempt, this Agreement (and any definitions hereunder) will be construed in a manner that complies with Section 409A. For all purposes of Code Section 409A (including, without limitation, for purposes of Treasury Regulations Sections 1.409A2(b)(2)(i) and (iii)), your right to receive any installment payments under this Agreement (whether severance payments, reimbursements or otherwise) shall be treated as a right to receive a series of separate payments and, accordingly, each installment payment hereunder shall at all times be considered a separate and distinct payment. Notwithstanding any provision to the contrary in this Agreement, if you are deemed by the Company at the time of your Separation from Service to be a “specified employee” for purposes of Code Section 409A(a)(2)(B)(i), and if any of the payments upon Separation from Service set forth herein and/or under any other agreement with the Company are deemed to be “deferred compensation,” then to the extent delayed commencement of any portion of such payments is required in order to avoid a prohibited distribution under Code Section 409A(a)(2)(B)(i) and the related adverse taxation under Section 409A, such payments shall not be provided to you prior to the earliest of (i) the first date following expiration of the six-month period following the date of your Separation from Service with the Company, (ii) the date of your death or (iii) such earlier date as permitted under Section 409A without the imposition of adverse taxation. Upon the first business day following the expiration of such applicable Code Section 409A(a)(2)(B)(i) period, all payments deferred pursuant to this Paragraph shall be paid in a lump sum to you, and any remaining payments due shall be paid as otherwise provided herein or in the applicable agreement. No interest shall be due on any amounts so deferred. If the severance benefits are not covered by one or more exemptions from the application of Section

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409A and the Release Deadline occurs in the calendar year following the calendar year of your Separation from Service, the Release will not be deemed effective any earlier than the Release Deadline for purposes of determining the timing of provision of any severance benefits.

4.    Section 280G.

If any payment or benefit you will or may receive from the Company or otherwise (a “280G Payment”) would (i) constitute a “parachute payment” within the meaning of Section 280G of the Code, and (ii) but for this sentence, be subject to the excise tax imposed by Section 4999 of the Code (the “Excise Tax”), then any such 280G Payment pursuant to this Amendment or otherwise (a “Payment”) shall be equal to the Reduced Amount. The “Reduced Amount” shall be either (x) the largest portion of the Payment that would result in no portion of the Payment (after reduction) being subject to the Excise Tax or (y) the largest portion, up to and including the total, of the Payment, whichever amount (i.e., the amount determined by clause (x) or by clause (y)), after taking into account all applicable federal, state and local employment taxes, income taxes, and the Excise Tax (all computed at the highest applicable marginal rate), results in your receipt, on an after-tax basis, of the greater economic benefit notwithstanding that all or some portion of the Payment may be subject to the Excise Tax. If a reduction in a Payment is required pursuant to the preceding sentence and the Reduced Amount is determined pursuant to clause (x) of the preceding sentence, the reduction shall occur in the manner (the “Reduction Method”) that results in the greatest economic benefit for you. If more than one method of reduction will result in the same economic benefit, the items so reduced will be reduced pro rata (the “Pro Rata Reduction Method”).

Notwithstanding the foregoing, if the Reduction Method or the Pro Rata Reduction Method would result in any portion of the Payment being subject to taxes pursuant to Section 409A that would not otherwise be subject to taxes pursuant to Section 409A, then the Reduction Method and/or the Pro Rata Reduction Method, as the case may be, shall be modified so as to avoid the imposition of taxes pursuant to Section 409A as follows: (A) as a first priority, the modification shall preserve to the greatest extent possible, the greatest economic benefit for you as determined on an after-tax basis; (B) as a second priority, Payments that are contingent on future events (e.g., being terminated without Cause), shall be reduced (or eliminated) before Payments that are not contingent on future events; and (C) as a third priority, Payments that are “deferred compensation” within the meaning of Section 409A shall be reduced (or eliminated) before Payments that are not deferred compensation within the meaning of Section 409A.

Unless you and the Company agree on an alternative accounting firm, the accounting firm engaged by the Company for general tax compliance purposes as of the day prior to the effective date of the change in control transaction triggering the Payment shall perform the foregoing calculations. If the accounting firm so engaged by the Company is serving as accountant or auditor for the individual, entity or group effecting the change in control transaction, the Company shall appoint a nationally recognized accounting firm to make the determinations required hereunder. The Company shall bear all expenses with respect to the determinations by such accounting firm required to be made hereunder. The Company shall use commercially reasonable efforts to cause the accounting firm engaged to make the determinations hereunder to

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provide its calculations, together with detailed supporting documentation, to you and the Company within fifteen (15) calendar days after the date on which your right to a 280G Payment becomes reasonably likely to occur (if requested at that time by you or the Company) or such other reasonable time as requested by you or the Company.

If you receives a Payment for which the Reduced Amount was determined pursuant to clause (x) of the first paragraph of this Section and the Internal Revenue Service determines thereafter that some portion of the Payment is subject to the Excise Tax, you shall promptly return to the Company a sufficient amount of the Payment (after reduction pursuant to clause (x) of the first paragraph of this Section so that no portion of the remaining Payment is subject to the Excise Tax. For the avoidance of doubt, if the Reduced Amount was determined pursuant to clause (y) in the first paragraph of this Section, you shall have no obligation to return any portion of the Payment pursuant to the preceding sentence.

5.    Arbitration of All Disputes.

5.1    Agreement to Arbitrate. To ensure the timely and economical resolution of disputes that may arise between you and the Company, both you and the Company mutually agree that pursuant to the Federal Arbitration Act, 9 U.S.C. §1-16, and to the fullest extent permitted by applicable law, you will submit solely to final, binding and confidential arbitration any and all disputes, claims, or causes of action arising from or relating to: (i) the negotiation, execution, interpretation, performance, breach or enforcement of this Agreement; or (ii) your employment with the Company (including but not limited to all statutory claims); or (iii) the termination of your employment with the Company (including but not limited to all statutory claims). BY AGREEING TO THIS ARBITRATION PROCEDURE, BOTH YOU AND THE COMPANY WAIVE THE RIGHT TO RESOLVE ANY SUCH DISPUTES THROUGH A TRIAL BY JURY OR JUDGE.

5.2    Arbitrator Authority. The Arbitrator shall have the sole and exclusive authority to determine whether a dispute, claim or cause of action is subject to arbitration under this Section and to determine any procedural questions which grow out of such disputes, claims or causes of action and bear on their final disposition.

5.3    Individual Capacity Only. All claims, disputes, or causes of action under this Section, whether by you or the Company, must be brought solely in an individual capacity, and shall not be brought as a plaintiff (or claimant) or class member in any purported class or representative proceeding, nor joined or consolidated with the claims of any other person or entity. The Arbitrator may not consolidate the claims of more than one person or entity and may not preside over any form of representative or class proceeding. To the extent that the preceding sentences in this Section are found to violate applicable law or are otherwise found unenforceable, any claim(s) alleged or brought on behalf of a class shall proceed in a court of law rather than by arbitration.

5.4    Arbitration Process. Any arbitration proceeding under this Section shall be presided over by a single arbitrator and conducted by Judicial Arbitration and Mediation

8

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Services, Inc. (“JAMS”) in San Diego, California under the then applicable JAMS rules for the resolution of employment disputes (available upon request and also currently available at http://www.jamsadr.com/rules-employment-arbitration/). You and the Company both have the right to be represented by legal counsel at any arbitration proceeding, at each party’s own expense. The Arbitrator shall: (i) have the authority to compel adequate discovery for the resolution of the dispute; (ii) issue a written arbitration decision, to include the arbitrator’s essential findings and conclusions and a statement of the award; and (iii) be authorized to award any or all remedies that you or the Company would be entitled to seek in a court of law. The Company shall pay all JAMS arbitration fees in excess of the amount of court fees that would be required of you if the dispute were decided in a court of law.

5.5 Excluded Claims. This Section shall not apply to any action or claim that cannot be subject to mandatory arbitration as a matter of law, including, without limitation, claims brought pursuant to the California Private Attorneys General Act of 2004, as amended, the California Fair Employment and Housing Act, as amended, and the California Labor Code, as amended, to the extent such claims are not permitted by applicable law to be submitted to mandatory arbitration and are not preempted by the Federal Arbitration Act (collectively, the “Excluded Claims”). In the event you intend to bring multiple claims, including one of the Excluded Claims listed above, the Excluded Claims may be publicly filed with a court, while any other claims will remain subject to mandatory arbitration.

5.6 Injunctive Relief and Final Orders. Nothing in this Section is intended to prevent either you or the Company from obtaining injunctive relief in court to prevent irreparable harm pending the conclusion of any such arbitration. Any final award in any arbitration proceeding hereunder may be entered as a judgment in the federal and state courts of any competent jurisdiction and enforced accordingly.

6.    General Provisions. This Agreement, together with the PIIA, constitutes the entire agreement between you and the Company with regard to this subject matter and is the complete, final, and exclusive embodiment of the parties’ agreement with regard to this subject matter. This Agreement is entered into without reliance on any promise or representation, written or oral, other than those expressly contained herein, and it supersedes any other such promises, warranties or representations. It is entered into without reliance on any promise or representation other than those expressly contained herein, and it cannot be modified or amended except in a writing signed by a duly authorized officer of the Company. Whenever possible, each provision of this Agreement will be interpreted in such manner as to be effective and valid under applicable law, but if any provision of this Agreement is held to be invalid, illegal or unenforceable in any respect under any applicable law or rule in any jurisdiction, such invalidity, illegality or unenforceability will not affect any other provision or any other jurisdiction, but this Agreement will be reformed, construed and enforced in such jurisdiction to the extent possible in keeping with the intent of the parties. Any waiver of any breach of any provisions of this Agreement must be in writing to be effective, and it shall not thereby be deemed to have waived any preceding or succeeding breach of the same or any other provision of this Agreement. This Agreement is intended to bind and inure to the benefit of and be enforceable by you and the Company, and their respective successors, assigns, heirs, executors and administrators. The

9

137797675 v2

Company may freely assign this Agreement, without your prior written consent. You may not assign any of your duties hereunder and you may not assign any of your rights hereunder without the written consent of the Company. This Agreement shall become effective as of the Start Date and shall terminate upon your termination of employment with the Company. The obligations as forth under Sections 1 (Termination; Severance Benefits), 3(Section 409A), 4(Section 280G), 5(Arbitration of All Disputes); and 6 (General Provisions) will survive the termination of this Agreement. All questions concerning the construction, validity and interpretation of this Agreement will be governed by the laws of the State of California.

This Amendment may be executed in several counterparts, each of which shall be deemed an original, but all of which together shall constitute one and the same instrument.

IN WITNESS WHEREOF, Employee and the Company have executed this Amendment as of the day and year set forth above.

MIRATI THERAPEUTICS, INC.

By: /s/ Kristin Gustafson

Name: Kristin Gustafson

Title: CHRO

/s/ James Christensen

JAMES CHRISTENSEN, PH.D.

10

137797675 v2

EX-31.1

Exhibit 31.1

CERTIFICATION

I, Charles M. Baum, certify that:

1. I have reviewed this Quarterly Report on Form 10-Q of Mirati Therapeutics, 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 the 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 the registrant’s board of directors (or person 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.

Date:	May 6, 2021	/s/ Charles M. Baum
		Charles M. Baum
		President and Chief Executive Officer
		(Principal Executive Officer)

EX-31.2

Exhibit 31.2

CERTIFICATION

I, Daniel R. Faga, certify that:

1. I have reviewed this Quarterly Report on Form 10-Q of Mirati Therapeutics, 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 the 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 the registrant’s board of directors (or person 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.

Date:	May 6, 2021	/s/ Daniel R. Faga
		Daniel R. Faga
		Executive Vice President and Chief Operating Officer
		(Principal Financial Officer)

EX-32.1

Exhibit 32.1

CERTIFICATION

Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002

(Subsections (a) and (b) of Section 1350, Chapter 63 of Title 18, United States Code)

In connection with the Quarterly Report on Form 10-Q of Mirati Therapeutics, Inc. (the “Company”) for the period ended March 31, 2021, as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I, Charles M. Baum, the President and Chief Executive Officer, and I, Daniel R. Faga, the Executive Vice President and Chief Operating Officer, certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that to my knowledge:

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

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

 Date: May 6, 2021

/s/ Charles M. Baum	/s/ Daniel R. Faga
Charles M. Baum	Daniel R. Faga
President and Chief Executive Officer (Principal Executive Officer)	Executive Vice President and Chief Operating Officer (Principal Financial Officer)

The foregoing certification is being furnished solely to accompany the Report pursuant to 18 U.S.C. § 1350, and is not being filed for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, and is not to be incorporated by reference into any filing of the Company, whether made before or after the date hereof, regardless of any general incorporation language in such filing. A signed original of this written statement required by Section 906 has been provided to the Company and will be retained by the Company and furnished to the Securities and Exchange Commission or its staff upon request.

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Cover Page - shares	3 Months Ended
	Mar. 31, 2021	Apr. 29, 2021
Cover [Abstract]
Entity Central Index Key	0001576263
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q1
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2021
Document Transition Report	false
Entity File Number	001-35921
Entity Registrant Name	Mirati Therapeutics, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	46-2693615
Entity Address, Address Line One	3545 Cray Court,
Entity Address, City or Town	San Diego,
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	(Zip Code)
City Area Code	858
Local Phone Number	332-3410
Title of 12(b) Security	Common Stock, par value $0.001 per share
Trading Symbol	MRTX
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		51,439,928

XML

Description of Business	3 Months Ended
	Mar. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	Description of BusinessMirati Therapeutics, Inc. ("Mirati" or the "Company") is a clinical-stage oncology company developing product candidates to address the genetic and immunological promoters of cancer. The Company was incorporated under the laws of the State of Delaware on April 29, 2013 as Mirati Therapeutics, Inc. and is located in San Diego, California. The Company has a wholly owned subsidiary in Canada, MethylGene, Inc. ("MethylGene"), and operates in one business segment, primarily in the United States. The Company's common stock has been listed on the Nasdaq Global Select Market since June 5, 2018 and was previously listed on the Nasdaq Capital Market since July 15, 2013, under the ticker symbol "MRTX."

XML

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Current assets
Cash and cash equivalents	$ 329,503	$ 885,562
Short-term investments	957,660	504,544
Other current assets	16,347	13,537
Total current assets	1,303,510	1,403,643
Property and equipment, net	9,061	7,809
Long-term investment	11,676	15,629
Right-of-use asset	39,278	39,890
Other long-term assets	17,307	9,157
Total assets	1,380,832	1,476,128
Accounts Payable	19,602	18,117
Current liabilities
Accrued Liabilities	57,503	53,355
Total current liabilities	77,105	71,472
Lease liability	43,175	41,905
Other liabilities	1,139	1,962
Total liabilities	121,419	115,339
Commitments and contingencies (see Note 9)
Shareholders’ equity
Preferred stock, $0.001 par value; 10,000,000 shares authorized; none issued and outstanding at both March 31, 2021 and December 31, 2020	0	0
Common stock, $0.001 par value; 100,000,000 shares authorized; 51,375,786 and 50,439,069 issued and outstanding at March 31, 2021 and December 31, 2020, respectively	51	50
Additional paid-in capital	2,515,824	2,481,218
Accumulated other comprehensive income	9,456	9,759
Accumulated deficit	(1,265,918)	(1,130,238)
Total shareholders’ equity	1,259,413	1,360,789
Total liabilities and shareholders’ equity	$ 1,380,832	$ 1,476,128

XML

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Mar. 31, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Preferred stock, par value (USD per share)	$ 0.001	$ 0.001
Preferred stock authorized (shares)	10,000,000	10,000,000
Preferred stock issued (shares)	0	0
Preferred stock outstanding (shares)	0	0
Common stock, par value (USD per share)	$ 0.001	$ 0.001
Common stock authorized (shares)	100,000,000	100,000,000
Common stock issued (shares)	51,375,786	50,439,069
Common stock outstanding (shares)	51,375,786	50,439,069

XML

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Revenue
License and collaboration revenues	$ 0	$ 267
Total revenue	0	267
Expenses
Research and development	104,071	71,708
General and administrative	28,350	18,046
Total operating expenses	132,421	89,754
Loss from operations	(132,421)	(89,487)
Other (expense) income, net	(3,259)	2,832
Net loss	(135,680)	(86,655)
Unrealized loss on available-for-sale investments	(303)	(182)
Comprehensive loss	$ (135,983)	$ (86,837)
Basic and diluted net loss per share (USD per share)	$ (2.67)	$ (2.02)
Weighted average number of shares used in computing net loss per share, basic and diluted (shares)	50,779,364	42,886,691

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CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional paid-in capital	Accumulated other comprehensive income	Accumulated deficit
Balance at beginning of period (shares) at Dec. 31, 2019		39,517,329
Balance at beginning of period at Dec. 31, 2019	$ 382,295	$ 40	$ 1,144,667	$ 9,889	$ (772,301)
Increase (Decrease) in Stockholders' Equity
Net loss	(86,655)				(86,655)
Issuance of common stock, net of issuance costs (shares)		3,538,462
Issuance of common stock, net of issuance costs	323,977	$ 4	323,973
Share-based compensation expense	21,567		21,567
Issuance of common stock under equity incentive plans (shares)		496,521
Issuance of common stock under equity incentive plans	15,183		15,183
Proceeds from disgorgement of shareholders' short-swing profits	41		41
Unrealized loss on investments	(182)			(182)
Balance at end of period (shares) at Mar. 31, 2020		43,552,312
Balance at end of period at Mar. 31, 2020	$ 656,226	$ 44	1,505,431	9,707	(858,956)
Balance at beginning of period (shares) at Dec. 31, 2020	50,439,069	50,439,069
Balance at beginning of period at Dec. 31, 2020	$ 1,360,789	$ 50	2,481,218	9,759	(1,130,238)
Increase (Decrease) in Stockholders' Equity
Net loss	(135,680)				(135,680)
Share-based compensation expense	24,722		24,722
Issuance of common stock under equity incentive plans (shares)		312,903
Issuance of common stock under equity incentive plans	$ 9,885		9,885
Net exercise of warrants (shares)	623,814	623,814
Net exercise of warrants	$ 0	$ 1	(1)
Unrealized loss on investments	$ (303)			(303)
Balance at end of period (shares) at Mar. 31, 2021	51,375,786	51,375,786
Balance at end of period at Mar. 31, 2021	$ 1,259,413	$ 51	$ 2,515,824	$ 9,456	$ (1,265,918)

XML

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Operating activities:
Net loss	$ (135,680)	$ (86,655)
Non-cash adjustments reconciling net loss to operating cash flows:
Change in fair value of long-term investment	3,953	0
Depreciation of property and equipment	294	126
Amortization of premium and accretion of discounts on investments	1,001	(520)
Share-based compensation expense	24,722	21,567
Changes in operating assets and liabilities:
Other current assets	(2,810)	(100)
Other long-term assets	(8,149)	(519)
Right-of-use asset	612	188
Lease liability	1,270	(198)
Accounts payable, accrued liabilities, and other liabilities	4,371	7,107
Cash flows used in operating activities	(110,416)	(59,004)
Investing activities:
Purchases of short-term investments	(621,661)	(230,384)
Sales and maturities of short-term investments	167,240	108,381
Purchases of property and equipment	(1,107)	(224)
Cash flows used in investing activities	(455,528)	(122,227)
Financing activities:
Proceeds from issuance of common stock, net of issuance costs	0	323,977
Proceeds from issuance of common stock under equity incentive plans	9,885	15,183
Proceeds from disgorgement of shareholders' short-swing profits	0	41
Cash flows provided by financing activities	9,885	339,201
(Decrease) increase in cash, cash equivalents and restricted cash	(556,059)	157,970
Cash, cash equivalents and restricted cash, beginning of period	886,182	46,856
Cash, cash equivalents and restricted cash, end of period	330,123	204,826
Reconciliation of cash, cash equivalents and restricted cash, end of period:
Total cash, cash equivalents and restricted cash	330,123	204,826
Supplemental disclosures of non-cash investing activities:
Purchases of property and equipment included within accounts payable and accrued liabilities	$ 439	$ 408

XML

Summary of Significant Accounting Policies

3 Months Ended

Mar. 31, 2021

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

Summary of Significant Accounting Policies

Basis of Presentation

The unaudited condensed consolidated financial statements contained in this Quarterly Report on Form 10-Q have been prepared in accordance with the rules and regulations of the Securities and Exchange Commission ("SEC") and, therefore, certain information and disclosures normally included in annual financial statements prepared in accordance with accounting principles generally accepted in the United States of America ("U.S. GAAP") have been omitted.

In the opinion of management, the information reflects all adjustments necessary to make the results of operations for the interim periods a fair statement of such operations. All such adjustments are of a normal recurring nature. Interim results are not necessarily indicative of results for the full year. The condensed consolidated balance sheet at December 31, 2020 has been derived from the audited consolidated financial statements at that date, but does not include all information and footnotes required by U.S. GAAP for complete financial statements. These unaudited condensed consolidated financial statements should be read in conjunction with the audited financial statements included in the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2020.

Use of Estimates

The preparation of the Company's unaudited condensed consolidated financial statements requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenue and expenses during the reporting period.

Reported amounts and footnote disclosures reflect the overall economic conditions that are most likely to occur and anticipated measures management intends to take. Actual results could differ materially from those estimates. Estimates and assumptions are reviewed quarterly. Any revisions to accounting estimates are recognized in the period in which the estimates are revised and in any future periods affected.

Cash, Cash Equivalents and Short-term Investments

Cash and cash equivalents consist of cash and highly liquid securities with original maturities at the date of acquisition of ninety days or less. Investments with an original maturity of more than ninety days are considered short-term investments and have been classified by management as available-for-sale. These investments are classified as current assets, even though the stated maturity date may be one year or more beyond the current balance sheet date, which reflects management’s intention to use the proceeds from sales of these securities to fund its operations, as necessary. Such investments are carried at fair value, and the unrealized gains and losses are reported as a component of accumulated other comprehensive income in shareholders’ equity until realized. Realized gains and losses from the sale of available-for-sale securities, if any, are determined on a specific identification basis.    

Concentration of Credit Risk

The Company invests its excess cash in accordance with its investment policy. The Company's investments are comprised primarily of commercial paper and debt instruments of financial institutions, corporations, U.S. government-sponsored agencies and the U.S. Treasury. The Company mitigates credit risk by maintaining a diversified portfolio and

limiting the amount of investment exposure as to institution, maturity and investment type. Financial instruments that potentially subject the Company to significant credit risk consist principally of cash equivalents and short-term investments.

Revenue Recognition

The Company recognizes revenue in connection with certain collaboration and license agreements in accordance with the guidance of Revenue From Contracts With Customers, Accounting Standards Codification ("ASC") Topic 606 ("Topic 606"). Under Topic 606, the Company recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration that the entity expects to receive in exchange for those goods or services.  To determine revenue recognition for arrangements the Company determines are within the scope of Topic 606, the Company performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the Company satisfies a performance obligation.  The Company only applies the five-step model to contracts when it is probable that the Company will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer.  At contract inception, once the contract is determined to be within the scope of Topic 606, the Company assesses the goods or services promised within each contract and determines those that are performance obligations, and assesses whether each promised good or service is distinct.  The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied.

Leases

The Company determines if an arrangement is a lease at inception. Lease right-of-use assets represent the Company's right to use an underlying asset for the lease term and lease liabilities represent the Company's obligation to make lease payments arising from the lease. For operating leases with an initial term greater than 12 months, the Company recognizes operating lease right-of-use assets and operating lease liabilities based on the present value of lease payments over the lease term at the commencement date. Operating lease right-of-use assets are comprised of the lease liability plus any lease payments made and excludes lease incentives. Lease terms include options to renew or terminate the lease when the Company is reasonably certain that the renewal option will be exercised or when it is reasonably certain that the termination option will not be exercised. For operating leases, if the interest rate used to determine the present value of future lease payments it not readily determinable, the Company estimates its incremental borrowing rate as the discount rate for the lease. The incremental borrowing rate is estimated to approximate the interest rate on a collateralized basis with similar terms and payments, and in similar economic environments. Lease expense for lease payments is recognized on a straight-line basis over the lease term. The Company has elected the practical expedient to not separate lease and non-lease components.

Net Loss per Share

Basic net loss per common share is calculated by dividing net loss by the weighted-average number of common shares outstanding during the period, without consideration for common share equivalents as they are anti-dilutive. Diluted net loss per share is computed by dividing the net loss by the weighted-average number of common shares and common share equivalents outstanding for the period. Common share equivalents outstanding, determined using the treasury stock method, are comprised of shares that may be issued under the Company’s stock option and warrant agreements.

The following table presents the weighted-average number of common share equivalents, calculated using the treasury stock method, not included in the calculation of diluted net loss per share due to the anti-dilutive effect of the securities:

	Three months ended March 31,
	2021	2020
Common stock options	2,758,415	2,174,353
Common stock warrants	8,043,004	9,692,771
Total	10,801,419	11,867,124

Recently Adopted and Recently Issued Accounting Pronouncements

From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board ("FASB") or other standard setting bodies that are adopted by the Company as of the specified effective date. The Company has evaluated recently issued accounting pronouncements and does not believe any will have a material impact on the Company’s condensed consolidated financial statements or related financial statement disclosures.

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Investments

3 Months Ended

Mar. 31, 2021

Investments, Debt and Equity Securities [Abstract]

Investments

Investments

The following tables summarize the Company's short-term investments (in thousands):

		As of March 31, 2021
	Maturity	Amortized cost		Gross unrealized gains		Gross unrealized losses		Estimated fair value
Corporate debt securities	2 years or less	$	182,895	$	45	$	(181)	$	182,759
Commercial paper	1 year or less	553,455		37		(19)		553,473
U.S. Agency bonds	2 years or less	133,484		48		—		133,532
U.S. Treasury bills	2 years or less	78,777		10		—		78,787
Sovereign debt securities	1 year or less	9,113		—		(4)		9,109
		$	957,724	$	140	$	(204)	$	957,660

		As of December 31, 2020
	Maturity	Amortized cost		Gross unrealized gains		Gross unrealized losses		Estimated fair value
Corporate debt securities	2 years or less	$	130,814	$	160	$	(4)	$	130,970
Commercial paper	1 year or less	240,725		58		(18)		240,765
U.S. Agency bonds	2 years or less	83,227		37		(1)		83,263
U.S. Treasury bills	2 years or less	49,539		10		(3)		49,546
		$	504,305	$	265	$	(26)	$	504,544

The Company has classified all of its short-term investments as available-for-sale as the sale of such securities may be required prior to maturity to implement management strategies, and accordingly, carries these investments at fair value. As of March 31, 2021, and December 31, 2020, aggregated gross unrealized losses of available-for-sale investments were not material, and accordingly, no allowance for credit losses was recorded.

As of March 31, 2021 and December 31, 2020, the Company held 588,235 shares of ORIC Pharmaceuticals, Inc. ("ORIC") common stock subject to certain transfer restrictions. The shares held by the Company are measured at fair value at each reporting period based on the closing price of ORIC's common stock on the last trading day of each reporting period, adjusted for a discount for lack of marketability, with any unrealized gains and losses recorded in other (expense) income, net on the Company's condensed consolidated statements of operations and comprehensive loss. See Note 4 for further details.

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Fair Value Measurements

3 Months Ended

Mar. 31, 2021

Fair Value Disclosures [Abstract]

Fair Value Measurements

Fair Value Measurements

The Company has certain financial assets and liabilities recorded at fair value which have been classified as Level 1, 2 or 3 within the fair value hierarchy as described in the accounting standards for fair value measurements.

The authoritative guidance for fair value measurements defines fair value as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or the most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Market participants are buyers and sellers in the principal market that are (i) independent, (ii) knowledgeable, (iii) able to transact, and (iv) willing to transact. The guidance prioritizes the inputs used in measuring fair value into the following hierarchy:

•Level 1- Quoted prices (unadjusted) in active markets for identical assets or liabilities;

•Level 2- Inputs other than quoted prices included within Level 1 that are either directly or indirectly observable; and

•Level 3- Unobservable inputs in which little or no market activity exists, therefore requiring an entity to develop its own assumptions about the assumptions that market participants would use in pricing.

The following tables summarize the assets measured at fair value on a recurring basis (in thousands):

	March 31, 2021
	Total		Level 1		Level 2		Level 3
Assets
Cash and cash equivalents:
Cash	$	34,614	$	34,614	$	—	$	—
Money market funds	294,889		294,889		—		—
Total cash and cash equivalents	329,503		329,503		—		—
Short-term investments:
U.S. Treasury bills	78,787		78,787		—		—
Corporate debt securities	182,759		—		182,759		—
Commercial paper	553,473		—		553,473		—
U.S. Agency bonds	133,532		—		133,532		—
Sovereign debt securities	9,109		—		9,109		—
Total short-term investments	957,660		78,787		878,873		—
Long-term investment:
ORIC Pharmaceuticals, Inc.	11,676		—		—		11,676
Total	$	1,298,839	$	408,290	$	878,873	$	11,676

	December 31, 2020
	Total		Level 1		Level 2		Level 3
Assets
Cash and cash equivalents:
Cash	$	20,398	$	20,398	$	—	$	—
Money market funds	865,164		865,164		—		—
Total cash and cash equivalents	885,562		885,562		—		—
Short-term investments:
U.S. Treasury bills	49,546		49,546		—		—
Corporate debt securities	130,970		—		130,970		—
Commercial paper	240,765		—		240,765		—
U.S. Agency bonds	83,263		—		83,263		—
Total short-term investments	504,544		49,546		454,998		—
Long-term investment:
ORIC Pharmaceuticals, Inc.	15,629		—		—		15,629
Total	$	1,405,735	$	935,108	$	454,998	$	15,629

The Company’s investments in Level 1 assets are valued based on publicly available quoted market prices for identical securities as of March 31, 2021 and December 31, 2020. The Company determines the fair value of Level 2 related securities with the aid of valuations provided by third parties using proprietary valuation models and analytical tools. These valuation models and analytical tools use market pricing or prices for similar instruments that are both objective and publicly available, including matrix pricing or reported trades, benchmark yields, broker/dealer quotes, issuer spreads, two-sided markets, benchmark securities, bids and/or offers. As of March 31, 2021, the Level 3 fair value measurement of the Company's long-term investment in ORIC Pharmaceuticals, Inc., which was acquired in 2020, utilizes a combination of the Asian Protective Put Option and Finnerty Put Option fair value techniques with unobservable inputs of 96.0% volatility and an expected term of 0.8 years to determine the discount for lack of marketability of 19.0%. There were no transfers between fair value measurement levels during the three months ended March 31, 2021 or the year ended December 31, 2020.

The following table presents the changes in estimated fair value of the Company's asset measured using significant unobservable inputs (Level 3) (in thousands):

	March 31, 2021
Balance - December 31, 2020	$	15,629
Change in fair value	(3,953)
Balance - March 31, 2021	$	11,676

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Other Current Assets and Other Long-Term Assets

3 Months Ended

Mar. 31, 2021

Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]

Other Current Assets and Other Long-Term Assets

Other Current Assets and Other Long-Term Assets

Other current assets consisted of the following (in thousands):

	March 31, 2021		December 31, 2020
Prepaid expenses	$	9,933	$	8,158
Deposits and other receivables	4,576		3,075
Interest receivable	1,838		2,304
	$	16,347	$	13,537

The other long-term assets balance of $17.3 million as of March 31, 2021 consisted of $16.7 million in deposits paid in conjunction with the Company's research and development activities, and $0.6 million for a letter of credit secured by restricted cash in connection with the lease of the Company's corporate headquarters. The other long-term assets balance of $9.2 million as of December 31, 2020 consisted of $8.6 million in deposits paid in conjunction with the Company's research and development activities, and $0.6 million for a letter of credit secured by restricted cash in connection with the lease of the Company's corporate headquarters.

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Accrued Liabilities and Other Liabilities

3 Months Ended

Mar. 31, 2021

Payables and Accruals [Abstract]

Accrued Liabilities and Other Liabilities

Accrued Liabilities and Other Liabilities

Accrued liabilities consisted of the following (in thousands):

	March 31, 2021		December 31, 2020
Accrued clinical expense	24,355		19,221
Accrued manufacturing expense	15,779		13,019
Accrued development expense	4,537		5,439
Accrued compensation and benefits	7,689		13,964
Other accrued expenses	5,143		1,712
	$	57,503	$	53,355

The other liabilities balance of $1.1 million as of March 31, 2021, and $2.0 million as of December 31, 2020, consisted primarily of clinical trial-related liabilities.

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License and Collaboration Agreements

3 Months Ended

Mar. 31, 2021

Research and Development [Abstract]

License and Collaboration Agreements

License and Collaboration Agreements

BeiGene Agreement

Terms of Agreement

On January 7, 2018, the Company and BeiGene Ltd, ("BeiGene") entered into a Collaboration and License Agreement (the “BeiGene Agreement”), pursuant to which the Company and BeiGene agreed to collaboratively develop sitravatinib in Asia (excluding Japan and certain other countries), Australia and New Zealand (the “Licensed Territory”). Under the BeiGene Agreement, the Company granted BeiGene an exclusive license to develop, manufacture and commercialize sitravatinib in the Licensed Territory, with the Company retaining exclusive rights for the development, manufacture and commercialization of sitravatinib outside the Licensed Territory.

As consideration for the rights granted to BeiGene under the BeiGene Agreement, BeiGene paid the Company a non-refundable, non-creditable up-front fee of $10.0 million. BeiGene is also required to make milestone payments to the Company of up to an aggregate of $123.0 million upon the first achievement of specified clinical, regulatory and sales milestones. The BeiGene Agreement additionally provides that BeiGene is obligated to pay to the Company royalties at tiered percentage rates ranging from mid-single digits to twenty percent on annual net sales of licensed products in the Licensed Territory, subject to reduction under specified circumstances. The BeiGene Agreement also provides that the Company will supply BeiGene with sitravatinib for use in BeiGene’s development activities in the Licensed Territory.

The BeiGene Agreement will terminate upon the expiration of the last royalty term for the licensed products, which is the latest of (i) the date of expiration of the last valid patent claim related to the licensed products under the BeiGene Agreement, (ii) 10 years after the first commercial sale of a licensed product and (iii) the expiration of any regulatory exclusivity as to a licensed product. BeiGene may terminate the BeiGene Agreement at any time by providing 60 days prior written notice to the Company. Either party may terminate the BeiGene Agreement upon a material breach by the other party that remains uncured following 60 days after the date of written notice of such breach or upon certain bankruptcy events. In addition, the Company may terminate the BeiGene Agreement upon written notice to BeiGene under specified circumstances if BeiGene challenges the licensed patent rights.

Revenue Recognition

The Company evaluated the BeiGene Agreement under Topic 606. At the time we entered into the BeiGene Agreement, the Company determined the transaction price was equal to the up-front fee of $10.0 million. The transaction price was allocated to the performance obligations on the basis of the relative stand-alone selling price estimated for each performance obligation. In estimating the stand-alone selling price for each performance obligation, the Company developed assumptions that require judgment and included forecasted revenues, expected development timelines, discount rates, probabilities of technical and regulatory success and costs for manufacturing clinical supplies. As such, of the up-front fee, the Company allocated $9.5 million to the license to the Company's intellectual property, bundled with the associated know-how, and $0.5 million to the initial obligation to supply sitravatinib for clinical development in the Licensed Territory.

Licenses of Intellectual Property.   The license to the Company’s intellectual property, bundled with the associated know-how, represents a distinct performance obligation. The license and associated know-how was transferred to BeiGene during the three months ended March 31, 2018, therefore during 2018 the Company recognized the full revenue amount of $9.5 million related to this performance obligation as license and collaboration revenues in its condensed consolidated statements of operations and comprehensive loss.

Manufacturing Supply Services.  The Company's initial obligation to supply sitravatinib for clinical development in the Licensed Territory represents a distinct performance obligation, and the initial obligation was satisfied in 2020, therefore this $0.5 million initial supply obligation has been fully recognized in license and collaboration revenues as of December 31, 2020. Although the initial performance obligation was satisfied, BeiGene may request additional sitravatinib in the future for clinical development in the Licensed Territory. The Company recognizes revenue when BeiGene obtains control of the goods, upon delivery, over the period of the obligation. No revenue related to this performance obligation was recognized for the three months ended March 31, 2021. The Company recognized $0.3 million as license and collaboration revenues for this performance obligation for the three months ended March 31, 2020, primarily consisting of cost-sharing payments due from BeiGene.

Milestone Payments. The Company is entitled to development milestones under the BeiGene Agreement. The next clinical development milestone is for BeiGene initiating the first pivotal clinical trial in the Licensed Territory upon which the Company will be paid a $5.0 million milestone payment. The Company is also entitled to certain regulatory milestone payments which are paid upon receipt of regulatory approvals within the Licensed Territory. No milestone payments were earned during the three months ended March 31, 2021 or 2020. The Company evaluated whether the remaining milestones are considered probable of being reached and determined that their achievement is highly dependent on factors outside of the Company's control. Therefore, these payments have been fully constrained and are not included in the transaction price. At the end of each subsequent reporting period, the Company will re-evaluate the probability of achievement of each milestone and any related constraint, and if necessary, adjust its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect the reported amount of license and collaboration revenues in the period of adjustment.

Royalties.  As the license is deemed to be the predominant item to which sales-based royalties relate, the Company will recognize revenue when the related sales occur. No royalty revenue was recognized during the three months ended March 31, 2021 or 2020.

Pfizer Agreement

In October 2014, the Company entered into a drug discovery collaboration and option agreement with Array BioPharma, Inc. ("Array," acquired by Pfizer Inc. ("Pfizer") during 2019) whereby Array provided services to facilitate the discovery, optimization and development of small molecule compounds that bind and specifically inhibit KRAS G12C. In June 2017, the two parties entered into a second, separate discovery collaboration and option agreement whereby Array provided services to facilitate the discovery, optimization and development of small molecule compounds that bind and specifically inhibit KRAS G12D. Both agreements established an option mechanism which enabled the Company to elect an exclusive worldwide license under the technology for the development and commercialization of certain products based on such compounds.

Under the agreements, following the joint discovery periods which have concluded, the Company executed its options to retain exclusive worldwide licenses to develop, manufacture and commercialize inhibitors of KRAS G12C and KRAS G12D, including but not limited to, MRTX849 (adagrasib is the provisionally filed name for MRTX849) and MRTX1133. Under each agreement, Pfizer is entitled to potential development milestone payments of up to $9.3 million, and tiered sales milestone payments of up to $337.0 million based upon worldwide net sales, and tiered royalties in the high single digits to mid-teens on worldwide net sales of products arising from the collaborations. Under the agreements, the Company has incurred $4.5 million in development milestone payments from inception through March 31, 2021.

The royalty term for each agreement shall be payable on a country-by-country and product-by-product basis, and separately will terminate at the later of (i) the date of expiration of the last valid patent claim within the collaboration patent rights or the Pfizer background technology covering such product in the country in which such product is sold at the time of such sale, or (ii) 10 years after the first commercial sale of such product in such country. The Company may terminate each agreement at any time by providing 60 days prior written notice to Pfizer. Either party may terminate each agreement upon a material breach by the other party that remains uncured following 60 days after the date of written notice of such breach or upon certain bankruptcy events.

For the three months ended March 31, 2021, no expenses were incurred under these agreements with Pfizer. For the three months ended March 31, 2020, the Company incurred expenses of $4.5 million, consisting of a $3.0 million milestone payment for initiation of the first Phase 2 trial for MRTX849, and $1.5 million in research and development services.

ORIC Pharmaceuticals Agreement

Terms of Agreement

On August 3, 2020, the Company entered into a license agreement with ORIC Pharmaceuticals, Inc. ("ORIC") pursuant to which the Company granted to ORIC an exclusive, worldwide license to develop and commercialize the Company's allosteric polycomb repressive complex 2 ("PRC2") inhibitors for all indications (the "ORIC License Agreement"). In accordance with the terms of the ORIC License Agreement, in exchange for such license, ORIC issued 588,235 shares of its common stock (the "Shares") to the Company on August 3, 2020. The Shares were issued under a stock issuance agreement entered into between ORIC and the Company, dated August 3, 2020. During the eighteen-month period following the date of

the stock issuance agreement, the Company is subject to certain transfer restrictions. ORIC is not obligated to pay the Company milestone payments or royalty payments under the ORIC License Agreement.

Unless terminated earlier, the ORIC License Agreement will continue in effect on a country-by-country and licensed product-by-licensed product basis until the later (a) the expiration of the last valid claim of a licensed patent covering such licensed product in such country or (b) ten years after the first commercial sale of such licensed product in such country. Following the expiration of the ORIC License Agreement, ORIC will retain its licenses under the intellectual property the Company licensed to ORIC on a royalty-free basis. The Company and ORIC may each terminate the ORIC License Agreement if the other party materially breaches the terms of such agreement, subject to specified notice and cure provisions, or enters into bankruptcy or insolvency proceedings. The Company may terminate the agreement if ORIC challenges any of the patent rights licensed to ORIC by the Company or if ORIC discontinues development of licensed products for a specified period of time. ORIC also has the right to terminate the ORIC License Agreement without cause by providing prior written notice to the Company.

Revenue Recognition

The Company accounted for the ORIC License Agreement under Topic 606 and identified the granting of an exclusive, worldwide license to develop and commercialize the Company's allosteric PRC2 inhibitors for all indications as a distinct performance obligation since ORIC can benefit from the license on its own by developing and commercializing the underlying product using its own resources.

In determining the transaction price, the Company received the Shares as non-cash consideration. The Company allocated the entire transaction price to the distinct performance obligation described above, and the license and related know-how was transferred to ORIC during the third quarter of 2020. Therefore, the Company recognized the entire transaction price during 2020 and classified the amount as license and collaboration revenues in its condensed consolidated statements of operations and comprehensive loss. There were no such revenues recorded during the three months ended March 31, 2021.

The Shares are carried at fair value and are recorded on the condensed consolidated balance sheet as a long-term investment. Any change in fair value is recorded within other (expense) income, net on the condensed consolidated statements of operations and comprehensive loss. The value of the long-term investment is determined by utilizing a Level 3 fair value measurement as further described in Note 4.

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Warrants

3 Months Ended

Mar. 31, 2021

Equity [Abstract]

Warrants

Warrants

As of March 31, 2021, the following warrants for common stock were issued and outstanding:

Issue date	Expiration date	Exercise price		Number of warrants outstanding
January 11, 2017	None	$	0.001	3,578,036
November 20, 2017	None	$	0.001	3,669,360
June 11, 2018	None	$	0.001	358,415
				7,605,811

During the three months ended March 31, 2021, 623,821 warrants for shares of the Company's common stock were exercised via cashless exercise, resulting in the issuance of 623,814 shares of common stock. No warrants were exercised during the three months ended March 31, 2020.

Shareholders' Equity

Sale of Common Stock    

In October 2020, the Company sold 4,585,706 shares of its common stock at a public offering price of $202.00 per share. After deducting underwriter discounts, commissions and estimated offering expenses, the Company received net proceeds from the transaction of $879.6 million.

In January 2020, the Company sold 3,538,462 shares of its common stock at a public offering price of $97.50 per share. After deducting underwriter discounts, commissions and offering expenses, the Company received net proceeds from the transaction of $324.0 million.

At the Market Facility

On July 2, 2020, the Company entered into a sales agreement pursuant to which the Company may, from time to time, sell shares of the Company's common stock, par value $0.001 per share, having an aggregate offering price of up to $200.0 million. As of March 31, 2021, the Company has not offered or sold any shares of common stock pursuant to this sales agreement.

Share-based Compensation

Total share-based compensation expense by statement of operations and comprehensive loss classification is presented below (in thousands):

	Three months ended March 31,
	2021		2020
Research and development expense	$	14,534	$	11,848
General and administrative expense	10,188		9,719
	$	24,722	$	21,567

During the three months ended March 31, 2021, 312,903 shares of common stock were issued under the Company's equity incentive plans, generating net proceeds of $9.9 million. During the three months ended March 31, 2020, 496,521 shares of common stock were issued under the Company's equity incentive plans, generating net proceeds of $15.2 million.

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Commitments and Contingencies

3 Months Ended

Mar. 31, 2021

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

Commitments and ContingenciesOn June 30, 2020, the Company entered into an amended and restated lease agreement (the "Amended and Restated Lease") for office and laboratory space located in San Diego, California, for the Company's new corporate headquarters. The Amended and Restated Lease supersedes in its entirety the original lease agreement for the Company's future corporate headquarters dated as of August 22, 2019. The Amended and Restated Lease has a lease term of 12 years ("Lease Term"), unless terminated earlier. The Lease Term has an initial abatement period, and the initial base rent payable will be approximately $0.6 million per month following the abatement period, which amount will increase by 3% per year over the Lease Term. The Company has also received incentives from the landlord for tenant improvements. During 2020, the

underlying asset was available for use by the Company to construct tenant improvements and therefore, the Lease Term was considered to have commenced.

The Amended and Restated Lease is considered to be an operating lease, and the Amended and Restated Lease indicates the interest rate applicable to the lease is 12%, therefore the Company used a discount rate of 12% to calculate the value of its lease payments over the Lease Term. As of March 31, 2021, the condensed consolidated balance sheet includes an operating right-of-use asset of $39.3 million and an operating lease liability of $43.2 million. As of December 31, 2020, the consolidated balance sheet includes an operating right-of-use asset of $39.9 million and an operating lease liability of $41.9 million. For the three months ended March 31, 2021, the Company recorded $2.0 million in operating lease expense.

As of March 31, 2021, the approximate future minimum lease payments under the Amended and Restated Lease are as follows (in thousands):

	Operating Lease
2021 - remainder	$	—
2022	1,681
2023	7,844
2024	8,080
2025	8,322
Thereafter	68,257
Total operating lease payments(†)	94,184
Less: Amount representing interest	(51,009)
Total lease liability	$	43,175

____________________

†The Company has an early termination right 7 years into the lease term, in which the total contractual obligation would be reduced by $41.1 million.

On June 24, 2014, the Company entered into a lease agreement for completed office and laboratory space located in San Diego, California. The office space under the lease was the Company's corporate headquarters. The lease commenced in two phases (in July 2014 and March 2015) at a combined total initial monthly rent of $24,100 per month and was subject to a 3% annual rent increase following availability. In addition to such base monthly rent, the Company is obligated to pay certain customary amounts for its share of operating expenses and facility amenities. The original lease provided for expiration on January 31, 2018, and the Company entered into subsequent amendments to the original lease to extend the lease term to mid-2021. All other terms and covenants from the original lease agreement remain unchanged. For the three months ended March 31, 2020, the Company recorded $0.1 million in operating lease cost.

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Shareholders' Equity

3 Months Ended

Mar. 31, 2021

Share-based Payment Arrangement [Abstract]

Shareholders' Equity

Warrants

As of March 31, 2021, the following warrants for common stock were issued and outstanding:

Issue date	Expiration date	Exercise price		Number of warrants outstanding
January 11, 2017	None	$	0.001	3,578,036
November 20, 2017	None	$	0.001	3,669,360
June 11, 2018	None	$	0.001	358,415
				7,605,811

During the three months ended March 31, 2021, 623,821 warrants for shares of the Company's common stock were exercised via cashless exercise, resulting in the issuance of 623,814 shares of common stock. No warrants were exercised during the three months ended March 31, 2020.

Shareholders' Equity

Sale of Common Stock    

In October 2020, the Company sold 4,585,706 shares of its common stock at a public offering price of $202.00 per share. After deducting underwriter discounts, commissions and estimated offering expenses, the Company received net proceeds from the transaction of $879.6 million.

In January 2020, the Company sold 3,538,462 shares of its common stock at a public offering price of $97.50 per share. After deducting underwriter discounts, commissions and offering expenses, the Company received net proceeds from the transaction of $324.0 million.

At the Market Facility

On July 2, 2020, the Company entered into a sales agreement pursuant to which the Company may, from time to time, sell shares of the Company's common stock, par value $0.001 per share, having an aggregate offering price of up to $200.0 million. As of March 31, 2021, the Company has not offered or sold any shares of common stock pursuant to this sales agreement.

Share-based Compensation

Total share-based compensation expense by statement of operations and comprehensive loss classification is presented below (in thousands):

	Three months ended March 31,
	2021		2020
Research and development expense	$	14,534	$	11,848
General and administrative expense	10,188		9,719
	$	24,722	$	21,567

During the three months ended March 31, 2021, 312,903 shares of common stock were issued under the Company's equity incentive plans, generating net proceeds of $9.9 million. During the three months ended March 31, 2020, 496,521 shares of common stock were issued under the Company's equity incentive plans, generating net proceeds of $15.2 million.

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Summary of Significant Accounting Policies (Policies)

3 Months Ended

Mar. 31, 2021

Accounting Policies [Abstract]

Basis of Presentation

Basis of Presentation

The unaudited condensed consolidated financial statements contained in this Quarterly Report on Form 10-Q have been prepared in accordance with the rules and regulations of the Securities and Exchange Commission ("SEC") and, therefore, certain information and disclosures normally included in annual financial statements prepared in accordance with accounting principles generally accepted in the United States of America ("U.S. GAAP") have been omitted.

In the opinion of management, the information reflects all adjustments necessary to make the results of operations for the interim periods a fair statement of such operations. All such adjustments are of a normal recurring nature. Interim results are not necessarily indicative of results for the full year. The condensed consolidated balance sheet at December 31, 2020 has been derived from the audited consolidated financial statements at that date, but does not include all information and footnotes required by U.S. GAAP for complete financial statements. These unaudited condensed consolidated financial statements should be read in conjunction with the audited financial statements included in the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2020.

Use of Estimates

Use of Estimates

The preparation of the Company's unaudited condensed consolidated financial statements requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenue and expenses during the reporting period.

Reported amounts and footnote disclosures reflect the overall economic conditions that are most likely to occur and anticipated measures management intends to take. Actual results could differ materially from those estimates. Estimates and assumptions are reviewed quarterly. Any revisions to accounting estimates are recognized in the period in which the estimates are revised and in any future periods affected.

Cash and Cash Equivalents

Cash and cash equivalents consist of cash and highly liquid securities with original maturities at the date of acquisition of ninety days or less.

Short-term Investments

Investments with an original maturity of more than ninety days are considered short-term investments and have been classified by management as available-for-sale. These investments are classified as current assets, even though the stated maturity date may be one year or more beyond the current balance sheet date, which reflects management’s intention to use the proceeds from sales of these securities to fund its operations, as necessary.

Concentration of Credit Risk

Concentration of Credit Risk

The Company invests its excess cash in accordance with its investment policy. The Company's investments are comprised primarily of commercial paper and debt instruments of financial institutions, corporations, U.S. government-sponsored agencies and the U.S. Treasury. The Company mitigates credit risk by maintaining a diversified portfolio and

limiting the amount of investment exposure as to institution, maturity and investment type. Financial instruments that potentially subject the Company to significant credit risk consist principally of cash equivalents and short-term investments.

Revenue Recognition

Revenue Recognition

The Company recognizes revenue in connection with certain collaboration and license agreements in accordance with the guidance of Revenue From Contracts With Customers, Accounting Standards Codification ("ASC") Topic 606 ("Topic 606"). Under Topic 606, the Company recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration that the entity expects to receive in exchange for those goods or services.  To determine revenue recognition for arrangements the Company determines are within the scope of Topic 606, the Company performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the Company satisfies a performance obligation.  The Company only applies the five-step model to contracts when it is probable that the Company will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer.  At contract inception, once the contract is determined to be within the scope of Topic 606, the Company assesses the goods or services promised within each contract and determines those that are performance obligations, and assesses whether each promised good or service is distinct.  The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied.

Leases

Leases

The Company determines if an arrangement is a lease at inception. Lease right-of-use assets represent the Company's right to use an underlying asset for the lease term and lease liabilities represent the Company's obligation to make lease payments arising from the lease. For operating leases with an initial term greater than 12 months, the Company recognizes operating lease right-of-use assets and operating lease liabilities based on the present value of lease payments over the lease term at the commencement date. Operating lease right-of-use assets are comprised of the lease liability plus any lease payments made and excludes lease incentives. Lease terms include options to renew or terminate the lease when the Company is reasonably certain that the renewal option will be exercised or when it is reasonably certain that the termination option will not be exercised. For operating leases, if the interest rate used to determine the present value of future lease payments it not readily determinable, the Company estimates its incremental borrowing rate as the discount rate for the lease. The incremental borrowing rate is estimated to approximate the interest rate on a collateralized basis with similar terms and payments, and in similar economic environments. Lease expense for lease payments is recognized on a straight-line basis over the lease term. The Company has elected the practical expedient to not separate lease and non-lease components.

Net Loss per Share

Net Loss per ShareBasic net loss per common share is calculated by dividing net loss by the weighted-average number of common shares outstanding during the period, without consideration for common share equivalents as they are anti-dilutive. Diluted net loss per share is computed by dividing the net loss by the weighted-average number of common shares and common share equivalents outstanding for the period. Common share equivalents outstanding, determined using the treasury stock method, are comprised of shares that may be issued under the Company’s stock option and warrant agreements.

Recently Adopted and Recently Issued Accounting Pronouncements

Recently Adopted and Recently Issued Accounting Pronouncements

From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board ("FASB") or other standard setting bodies that are adopted by the Company as of the specified effective date. The Company has evaluated recently issued accounting pronouncements and does not believe any will have a material impact on the Company’s condensed consolidated financial statements or related financial statement disclosures.

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Summary of Significant Accounting Policies (Tables)

3 Months Ended

Mar. 31, 2021

Accounting Policies [Abstract]

Schedule of Potentially Dilutive Securities not included in the Calculation of Diluted Net Loss per Share

The following table presents the weighted-average number of common share equivalents, calculated using the treasury stock method, not included in the calculation of diluted net loss per share due to the anti-dilutive effect of the securities:

	Three months ended March 31,
	2021	2020
Common stock options	2,758,415	2,174,353
Common stock warrants	8,043,004	9,692,771
Total	10,801,419	11,867,124

XML

Investments (Tables)

3 Months Ended

Mar. 31, 2021

Investments, Debt and Equity Securities [Abstract]

Schedule of Short-Term Investments

The following tables summarize the Company's short-term investments (in thousands):

		As of March 31, 2021
	Maturity	Amortized cost		Gross unrealized gains		Gross unrealized losses		Estimated fair value
Corporate debt securities	2 years or less	$	182,895	$	45	$	(181)	$	182,759
Commercial paper	1 year or less	553,455		37		(19)		553,473
U.S. Agency bonds	2 years or less	133,484		48		—		133,532
U.S. Treasury bills	2 years or less	78,777		10		—		78,787
Sovereign debt securities	1 year or less	9,113		—		(4)		9,109
		$	957,724	$	140	$	(204)	$	957,660

		As of December 31, 2020
	Maturity	Amortized cost		Gross unrealized gains		Gross unrealized losses		Estimated fair value
Corporate debt securities	2 years or less	$	130,814	$	160	$	(4)	$	130,970
Commercial paper	1 year or less	240,725		58		(18)		240,765
U.S. Agency bonds	2 years or less	83,227		37		(1)		83,263
U.S. Treasury bills	2 years or less	49,539		10		(3)		49,546
		$	504,305	$	265	$	(26)	$	504,544

XML

Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2021

Fair Value Disclosures [Abstract]

Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis

The following tables summarize the assets measured at fair value on a recurring basis (in thousands):

	March 31, 2021
	Total		Level 1		Level 2		Level 3
Assets
Cash and cash equivalents:
Cash	$	34,614	$	34,614	$	—	$	—
Money market funds	294,889		294,889		—		—
Total cash and cash equivalents	329,503		329,503		—		—
Short-term investments:
U.S. Treasury bills	78,787		78,787		—		—
Corporate debt securities	182,759		—		182,759		—
Commercial paper	553,473		—		553,473		—
U.S. Agency bonds	133,532		—		133,532		—
Sovereign debt securities	9,109		—		9,109		—
Total short-term investments	957,660		78,787		878,873		—
Long-term investment:
ORIC Pharmaceuticals, Inc.	11,676		—		—		11,676
Total	$	1,298,839	$	408,290	$	878,873	$	11,676

	December 31, 2020
	Total		Level 1		Level 2		Level 3
Assets
Cash and cash equivalents:
Cash	$	20,398	$	20,398	$	—	$	—
Money market funds	865,164		865,164		—		—
Total cash and cash equivalents	885,562		885,562		—		—
Short-term investments:
U.S. Treasury bills	49,546		49,546		—		—
Corporate debt securities	130,970		—		130,970		—
Commercial paper	240,765		—		240,765		—
U.S. Agency bonds	83,263		—		83,263		—
Total short-term investments	504,544		49,546		454,998		—
Long-term investment:
ORIC Pharmaceuticals, Inc.	15,629		—		—		15,629
Total	$	1,405,735	$	935,108	$	454,998	$	15,629

Schedule of Changes in Estimated Fair Value of Assets with Unobservable Inputs

The following table presents the changes in estimated fair value of the Company's asset measured using significant unobservable inputs (Level 3) (in thousands):

	March 31, 2021
Balance - December 31, 2020	$	15,629
Change in fair value	(3,953)
Balance - March 31, 2021	$	11,676

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Other Current Assets and Other Long-Term Assets (Tables)

3 Months Ended

Mar. 31, 2021

Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]

Schedule of Other Current Assets

Other current assets consisted of the following (in thousands):

	March 31, 2021		December 31, 2020
Prepaid expenses	$	9,933	$	8,158
Deposits and other receivables	4,576		3,075
Interest receivable	1,838		2,304
	$	16,347	$	13,537

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Accrued Liabilities and Other Liabilities (Tables)

3 Months Ended

Mar. 31, 2021

Payables and Accruals [Abstract]

Schedule of Accounts Payable and Accrued Liabilities

Accrued liabilities consisted of the following (in thousands):

	March 31, 2021		December 31, 2020
Accrued clinical expense	24,355		19,221
Accrued manufacturing expense	15,779		13,019
Accrued development expense	4,537		5,439
Accrued compensation and benefits	7,689		13,964
Other accrued expenses	5,143		1,712
	$	57,503	$	53,355

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Warrants (Tables)

3 Months Ended

Mar. 31, 2021

Equity [Abstract]

Schedule of Warrants Issued and Outstanding

As of March 31, 2021, the following warrants for common stock were issued and outstanding:

Issue date	Expiration date	Exercise price		Number of warrants outstanding
January 11, 2017	None	$	0.001	3,578,036
November 20, 2017	None	$	0.001	3,669,360
June 11, 2018	None	$	0.001	358,415
				7,605,811

XML

Commitment and Contingencies (Tables)

3 Months Ended

Mar. 31, 2021

Commitments and Contingencies Disclosure [Abstract]

Schedule of Future Minimum Lease Payments

As of March 31, 2021, the approximate future minimum lease payments under the Amended and Restated Lease are as follows (in thousands):

	Operating Lease
2021 - remainder	$	—
2022	1,681
2023	7,844
2024	8,080
2025	8,322
Thereafter	68,257
Total operating lease payments(†)	94,184
Less: Amount representing interest	(51,009)
Total lease liability	$	43,175

____________________

†The Company has an early termination right 7 years into the lease term, in which the total contractual obligation would be reduced by $41.1 million.

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Shareholders' Equity (Tables)

3 Months Ended

Mar. 31, 2021

Share-based Payment Arrangement [Abstract]

Schedule of Employee Service Share-based Compensation Allocation

Total share-based compensation expense by statement of operations and comprehensive loss classification is presented below (in thousands):

	Three months ended March 31,
	2021		2020
Research and development expense	$	14,534	$	11,848
General and administrative expense	10,188		9,719
	$	24,722	$	21,567

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Description of Business - Narrative (Details)	3 Months Ended
	Mar. 31, 2021 segment
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of operating segments	1

XML

Summary of Significant Accounting Policies - Narrative (Details)	3 Months Ended
	Mar. 31, 2021
Marketable Securities
Minimum original maturity period of marketable securities	90 days

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Summary of Significant Accounting Policies - Antidilutive Securities (Details) - shares	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities	10,801,419	11,867,124
Common stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities	2,758,415	2,174,353
Common stock warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities	8,043,004	9,692,771

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Investments - Summary (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Amortized cost	$ 957,724	$ 504,305
Gross unrealized gains	140	265
Gross unrealized losses	(204)	(26)
Estimated fair value	957,660	504,544
Corporate debt securities
Debt Securities, Available-for-sale [Line Items]
Amortized cost	182,895	130,814
Gross unrealized gains	45	160
Gross unrealized losses	(181)	(4)
Estimated fair value	$ 182,759	$ 130,970
Corporate debt securities | Maximum
Debt Securities, Available-for-sale [Line Items]
Maturity	2 years	2 years
Commercial paper
Debt Securities, Available-for-sale [Line Items]
Amortized cost	$ 553,455	$ 240,725
Gross unrealized gains	37	58
Gross unrealized losses	(19)	(18)
Estimated fair value	$ 553,473	$ 240,765
Commercial paper | Maximum
Debt Securities, Available-for-sale [Line Items]
Maturity	1 year	1 year
U.S. Agency bonds
Debt Securities, Available-for-sale [Line Items]
Amortized cost	$ 133,484	$ 83,227
Gross unrealized gains	48	37
Gross unrealized losses	0	(1)
Estimated fair value	$ 133,532	$ 83,263
U.S. Agency bonds | Maximum
Debt Securities, Available-for-sale [Line Items]
Maturity	2 years	2 years
U.S. Treasury bills
Debt Securities, Available-for-sale [Line Items]
Amortized cost	$ 78,777	$ 49,539
Gross unrealized gains	10	10
Gross unrealized losses	0	(3)
Estimated fair value	$ 78,787	$ 49,546
U.S. Treasury bills | Maximum
Debt Securities, Available-for-sale [Line Items]
Maturity	2 years	2 years
Sovereign debt securities
Debt Securities, Available-for-sale [Line Items]
Amortized cost	$ 9,113
Gross unrealized gains	0
Gross unrealized losses	(4)
Estimated fair value	$ 9,109
Sovereign debt securities | Maximum
Debt Securities, Available-for-sale [Line Items]
Maturity	1 year

XML

Investments - Narrative (Details) - USD ($)	Mar. 31, 2021	Dec. 31, 2020
Schedule of Investments [Line Items]
Allowance for credit losses on available-for-sale investments	$ 0	$ 0
ORIC
Schedule of Investments [Line Items]
Stock held in investment (shares)	588,235	588,235

XML

Fair Value Measurements - Summary (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash and cash equivalents	$ 329,503	$ 885,562
Investments	957,660	504,544
Total	1,298,839	1,405,735
U.S. Treasury bills
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	78,787	49,546
Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	182,759	130,970
Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	553,473	240,765
U.S. Agency bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	133,532	83,263
Sovereign debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	9,109
Long-term Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	11,676	15,629
Cash
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash and cash equivalents	34,614	20,398
Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash and cash equivalents	294,889	865,164
Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash and cash equivalents	329,503	885,562
Investments	78,787	49,546
Total	408,290	935,108
Level 1 | U.S. Treasury bills
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	78,787	49,546
Level 1 | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0	0
Level 1 | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0	0
Level 1 | U.S. Agency bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0	0
Level 1 | Sovereign debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0
Level 1 | Long-term Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0	0
Level 1 | Cash
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash and cash equivalents	34,614	20,398
Level 1 | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash and cash equivalents	294,889	865,164
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash and cash equivalents	0	0
Investments	878,873	454,998
Total	878,873	454,998
Level 2 | U.S. Treasury bills
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0	0
Level 2 | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	182,759	130,970
Level 2 | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	553,473	240,765
Level 2 | U.S. Agency bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	133,532	83,263
Level 2 | Sovereign debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	9,109
Level 2 | Long-term Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0	0
Level 2 | Cash
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash and cash equivalents	0	0
Level 2 | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash and cash equivalents	0	0
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash and cash equivalents	0	0
Investments	0	0
Total	11,676	15,629
Level 3 | U.S. Treasury bills
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0	0
Level 3 | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0	0
Level 3 | Commercial paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0	0
Level 3 | U.S. Agency bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0	0
Level 3 | Sovereign debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	0
Level 3 | Long-term Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	11,676	15,629
Level 3 | Cash
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash and cash equivalents	0	0
Level 3 | Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total cash and cash equivalents	$ 0	$ 0

XML

Fair Value Measurements - Narrative (Details)	Mar. 31, 2021
Volatility
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Measurement input of investment	0.960
Expected Term
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Measurement input of investment	0.8
Discount for Lack of Marketability
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Measurement input of investment	0.190

XML

Fair Value Measurements - Changes in Estimated Fair Value of Assets with Unobservable Inputs (Details) - Level 3 $ in Thousands	3 Months Ended
	Mar. 31, 2021 USD ($)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	$ 15,629
Change in fair value	(3,953)
Balance at end of period	$ 11,676

XML

Other Current Assets and Other Long-Term Assets - Summary (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepaid expenses	$ 9,933	$ 8,158
Deposits and other receivables	4,576	3,075
Interest receivable	1,838	2,304
Other current assets	$ 16,347	$ 13,537

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Other Current Assets and Other Long-Term Assets - Narrative (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Other long-term assets	$ 17,307	$ 9,157
Deposits paid for research and development	16,700	8,600
Security deposit for lease	$ 600	$ 600

XML

Accrued Liabilities and Other Liabilities - Summary (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Payables and Accruals [Abstract]
Accrued clinical expense	$ 24,355	$ 19,221
Accrued manufacturing expense	15,779	13,019
Accrued development expense	4,537	5,439
Accrued compensation and benefits	7,689	13,964
Other accrued expenses	5,143	1,712
Accrued liabilities	$ 57,503	$ 53,355

XML

Accrued Liabilities and Other Liabilities - Narrative (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Payables and Accruals [Abstract]
Other liabilities	$ 1,139	$ 1,962

XML

License and Collaboration Agreements - Narrative (Details) - USD ($)			1 Months Ended	3 Months Ended
	Aug. 03, 2020	Jan. 07, 2018	Oct. 31, 2014	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2018
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Expenses related to collaboration agreement				$ 104,071,000	$ 71,708,000
BeiGene Agreement
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Up-front fee received		$ 10,000,000.0
Revenue from performance obligation expected to be earned		$ 123,000,000.0
Termination of contract, period after first commercial sale of product		10 years
Period required for notice of termination of contract		60 days
BeiGene Agreement | Licenses of Intellectual Property
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenue from performance obligation earned						$ 9,500,000
BeiGene Agreement | Manufacturing Supply Services
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenue from performance obligation earned						$ 500,000
Payments received in advance				0	(300,000)
BeiGene Agreement | Milestone Payments
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenue from performance obligation expected to be earned				5,000,000.0
Milestone payments earned				0	0
BeiGene Agreement | Royalties
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Revenue				0	0
Pfizer Agreement
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Termination of contract, period after first commercial sale of product			10 years
Period required for notice of termination of contract			60 days
Expenses related to collaboration agreement				$ 0	4,500,000
Pfizer Agreement | Milestone Payments
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Expenses related to collaboration agreement					3,000,000.0
Pfizer Agreement | Research and Development Services
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Expenses related to collaboration agreement					$ 1,500,000
ORIC Pharmaceuticals Agreement
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Stock received as part of stock issuance and license agreements (shares)	588,235
License agreement, period of transfer restrictions	18 months
License agreement, period of agreement after first commercial sale	10 years

XML

Warrants - Summary (Details) - $ / shares	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Class of Warrant or Right [Line Items]
Number of warrants outstanding (shares)	7,605,811
Warrants exercised via cashless exercises (shares)	623,821	0
Common stock issued from exercise of warrants (shares)	623,814
January 11, 2017 Warrants
Class of Warrant or Right [Line Items]
Exercise price of warrants (USD per share)	$ 0.001
Number of warrants outstanding (shares)	3,578,036
November 20, 2017 Warrants
Class of Warrant or Right [Line Items]
Exercise price of warrants (USD per share)	$ 0.001
Number of warrants outstanding (shares)	3,669,360
June 11, 2018 Warrants
Class of Warrant or Right [Line Items]
Exercise price of warrants (USD per share)	$ 0.001
Number of warrants outstanding (shares)	358,415

XML

Commitments and Contingencies - Narrative (Details) - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Lessee, Lease, Description [Line Items]
Operating lease cost		$ 100,000
Right-of-use asset	$ 39,278,000		$ 39,890,000
Current Headquarters
Lessee, Lease, Description [Line Items]
Minimum monthly rental expense	$ 2,000,000.0
Discount rate (as a percent)	12.00%
Right-of-use asset	$ 39,300,000		39,900,000
Operating lease liability	43,175,000		$ 41,900,000
Building | Current Headquarters
Lessee, Lease, Description [Line Items]
Minimum monthly rental expense	$ 24,100
Annual rent increase (as a percent)	3.00%
Building | Future Headquarters
Lessee, Lease, Description [Line Items]
Lease term	12 years
Minimum monthly rental expense	$ 600,000
Annual rent increase (as a percent)	3.00%

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Commitments and Contingencies - Future Minimum Lease Payments (Details) - Current Headquarters - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Lessee, Lease, Description [Line Items]
2021 - remainder	$ 0
2022	1,681
2023	7,844
2024	8,080
2025	8,322
Thereafter	68,257
Total operating lease payments	94,184
Less: Amount representing interest	(51,009)
Total lease liability	$ 43,175	$ 41,900
Number of years into lease before termination can occur	7 years
Reduction of lease liability, amount	$ 41,100

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Shareholders' Equity - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended		3 Months Ended
	Oct. 31, 2020	Jan. 31, 2020	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Jul. 02, 2020
Share-based Payment Arrangement [Abstract]
Stock issued in transaction (shares)	4,585,706	3,538,462
Sale price of common stock (USD per share)	$ 202.00	$ 97.50
Proceeds from sale of stock	$ 879.6	$ 324.0
Common stock, par value (USD per share)			$ 0.001		$ 0.001	$ 0.001
Aggregate offering price						$ 200.0
Stock issued pursuant to stock option exercises (shares)			312,903	496,521
Proceeds from stock options exercised			$ 9.9	$ 15.2

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Shareholders' Equity - Summary (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated share-based compensation expense	$ 24,722	$ 21,567
Research and development expense
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated share-based compensation expense	14,534	11,848
General and administrative expense
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated share-based compensation expense	$ 10,188	$ 9,719

XML

Label	Element	Value
Restricted Cash	us-gaap_RestrictedCash	$ 321,000
Restricted Cash	us-gaap_RestrictedCash	620,000
Pfizer Discovery and Collaboration Agreement [Member] | Sales Milestone Payments [Member]
Research and Development Arrangement, Discovery and Collaboration Agreement, Compensation Expected to be Paid	mrtx_ResearchandDevelopmentArrangementDiscoveryandCollaborationAgreementCompensationExpectedtobePaid	337,000,000.0
Pfizer Discovery and Collaboration Agreement [Member] | Development Milestone Payments [Member]
Research and Development Arrangement, Discovery and Collaboration Agreement, Compensation Expected to be Paid	mrtx_ResearchandDevelopmentArrangementDiscoveryandCollaborationAgreementCompensationExpectedtobePaid	9,300,000
Research and Development Arrangement, Discovery and Collaboration Agreement, Milestone Payments Paid	mrtx_ResearchandDevelopmentArrangementDiscoveryandCollaborationAgreementMilestonePaymentsPaid	$ 4,500,000