arna-10q_20200930.htm

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. ☒ Yes ☐ No

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

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

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

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

The number of shares of common stock outstanding as of the close of business on November 4, 2020:

In this Quarterly Report on Form 10-Q, “Arena Pharmaceuticals,” “Arena,” “we,” “us” and “our” refer to Arena Pharmaceuticals, Inc., and our wholly owned subsidiaries on a consolidated basis, unless the context otherwise provides. “APD” is an abbreviation for Arena Pharmaceuticals Development.

Arena Pharmaceuticals ® and Arena ® are registered service marks of Arena. Any other brand names or trademarks appearing in this Quarterly Report on Form 10-Q are the property of their respective holders.

	September 30,			December 31,
	2020			2019

Assets
Current assets:
Cash and cash equivalents	$	460,145		$	243,274
Short-term investments, available-for-sale		707,719			496,291
Prepaid expenses and other current assets		34,383			20,369
Total current assets		1,202,247			759,934
Investments, available-for-sale		33,286			370,938
Land, property and equipment, net		22,913			25,128
Other non-current assets		17,097			18,123
Total assets	$	1,275,543		$	1,174,123
Liabilities and Stockholders' Equity
Current liabilities:
Accounts payable and other accrued liabilities	$	26,697		$	25,499
Accrued clinical and preclinical study fees		20,950			15,654
Current portion of lease financing obligations		4,249			3,814
Total current liabilities		51,896			44,967
Other long-term liabilities		11,352			12,078
Lease financing obligations, less current portion		42,368			45,613
Commitments and contingencies
Stockholders' equity:
Common stock		6			5
Additional paid-in capital		2,553,939			2,173,154
Accumulated other comprehensive income		1,552			1,303
Accumulated deficit		(1,385,570	)		(1,102,997	)
Total stockholders' equity		1,169,927			1,071,465
Total liabilities and stockholders' equity	$	1,275,543		$	1,174,123

See accompanying notes to unaudited condensed consolidated financial statements.

	Three Months Ended						Nine months ended
	September 30,						September 30,
	2020			2019			2020			2019
Revenues:
United Therapeutics revenue	$	—		$	—		$	—		$	800,000
Royalty revenue		—			811			262			2,725
Collaboration and other revenue		20			539			20			704
Total revenues		20			1,350			282			803,429
Operating Costs and Expenses:
Research and development		79,820			60,257			223,299			156,864
Selling, general and administrative		19,002			20,428			68,321			55,373
Transaction costs		—			—			—			14,573
Total operating costs and expenses		98,822			80,685			291,620			226,810
Income (loss) from operations		(98,802	)		(79,335	)		(291,338	)		576,619
Interest and Other Income (Expense):
Interest income		1,825			6,889			9,836			20,971
Interest expense		(1,120	)		(1,203	)		(3,427	)		(3,666	)
Other income		659			784			2,356			2,275
Total interest and other income (expense), net		1,364			6,470			8,765			19,580
Income (loss) before income taxes		(97,438	)		(72,865	)		(282,573	)		596,199
Income tax provision		—			—			—			(110,333	)
Net income (loss)	$	(97,438	)	$	(72,865	)	$	(282,573	)	$	485,866


Net income (loss) per share, basic:	$	(1.69	)	$	(1.46	)	$	(5.27	)	$	9.78
Net income (loss) per share, diluted:	$	(1.69	)	$	(1.46	)	$	(5.27	)	$	9.39

Shares used in calculating net income (loss) per share, basic:		57,779			49,864			53,608			49,667
Shares used in calculating net income (loss) per share, diluted:		57,779			49,864			53,608			51,763

Comprehensive Income (Loss):
Net income (loss)	$	(97,438	)	$	(72,865	)	$	(282,573	)	$	485,866
Foreign currency translation gain (loss)		52			(33	)		69			(45	)
Unrealized gain (loss) on available-for-sale investments		(1,151	)		168			180			1,642
Comprehensive income (loss)	$	(98,537	)	$	(72,730	)	$	(282,324	)	$	487,463

See accompanying notes to unaudited condensed consolidated financial statements.

	Common Stock				Additional Paid-In		Accumulated Other Comprehensive			Accumulated			Total Stockholders'
	Shares		Amount		Capital		Income (Loss)			Deficit			Equity


Balance at December 31, 2019		50,170,953	$	5	$	2,173,154	$	1,303		$	(1,102,997	)	$	1,071,465
Issuance of common stock upon exercise of options		125,761		—		3,191		—			—			3,191
Share-based compensation expense		—		—		15,214		—			—			15,214
Unrealized loss on available-for-sale investments		—		—		—		(1,164	)		—			(1,164	)
Translation loss		—		—		—		(14	)		—			(14	)
Net loss		—		—		—		—			(100,207	)		(100,207	)
Balance at March 31, 2020		50,296,714	$	5	$	2,191,559	$	125		$	(1,203,204	)	$	988,485
Issuance of common stock to underwriters, net		6,325,000		1		301,753		—			—			301,754
Issuance of common stock upon exercise of options		903,641		—		21,089		—			—			21,089
Issuance of common stock under employee stock purchase plan and upon vesting of restricted stock unit awards		49,523		—		1,475		—			—			1,475
Share-based compensation expense		—		—		12,236		—			—			12,236
Unrealized gain on available-for-sale investments		—		—		—		2,495			—			2,495
Translation gain		—		—		—		31			—			31
Net loss		—		—		—		—			(84,928	)		(84,928	)
Balance at June 30, 2020		57,574,878	$	6	$	2,528,112	$	2,651		$	(1,288,132	)	$	1,242,637
Issuance of common stock upon exercise of options		468,909		—		13,510		—			—			13,510
Share-based compensation expense		—		—		12,317		—			—			12,317
Unrealized loss on available-for-sale investments		—		—		—		(1,151	)		—			(1,151	)
Translation gain		—		—		—		52			—			52
Net loss		—		—		—		—			(97,438	)		(97,438	)
Balance at September 30, 2020		58,043,787	$	6	$	2,553,939	$	1,552		$	(1,385,570	)	$	1,169,927

See accompanying notes to unaudited condensed consolidated financial statements.

	Common Stock				Additional Paid-In		Accumulated Other Comprehensive			Accumulated			Total Stockholders'
	Shares		Amount		Capital		Income (Loss)			Deficit			Equity


Balance at December 31, 2018		49,422,991	$	5	$	2,106,960	$	(155	)	$	(1,500,552	)	$	606,258
Issuance of common stock upon exercise of options		125,655		—		3,364		—			—			3,364
Share-based compensation expense		—		—		13,024		—			—			13,024
Unrealized gain on available-for-sale investments		—		—		—		676			—			676
Translation loss		—		—		—		(19	)		—			(19	)
Net income		—		—		—		—			620,134			620,134
Balance at March 31, 2019		49,548,646	$	5	$	2,123,348	$	502		$	(880,418	)	$	1,243,437
Issuance of common stock upon exercise of options		229,565		—		4,722		—			—			4,722
Issuance of common stock upon vesting of restricted stock unit awards		24,362		—		—		—			—			—
Share-based compensation expense		—		—		13,428		—			—			13,428
Unrealized gain on available-for-sale investments		—		—		—		798			—			798
Translation gain		—		—		—		7			—			7
Net loss		—		—		—		—			(61,403	)		(61,403	)
Balance at June 30, 2019		49,802,573	$	5	$	2,141,498	$	1,307		$	(941,821	)	$	1,200,989
Issuance of common stock upon exercise of options		181,908		—		4,602		—			—			4,602
Share-based compensation expense		—		—		13,345		—			—			13,345
Unrealized gain on available-for-sale investments		—		—		—		168			—			168
Translation loss		—		—		—		(33	)		—			(33	)
Net loss		—		—		—		—			(72,865	)		(72,865	)
Balance at September 30, 2019		49,984,481	$	5	$	2,159,445	$	1,442		$	(1,014,686	)	$	1,146,206

See accompanying notes to unaudited condensed consolidated financial statements.

	Nine Months Ended
	September 30,
	2020			2019
Operating Activities:
Net income (loss)	$	(282,573	)	$	485,866
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization		2,899			2,349
Deferred income taxes		—			110,333
Share-based compensation		39,767			39,797
Amortization of prepaid financing costs		67			67
Amortization of original issue premiums (discounts), net, on available-for-sale investments		416			(5,000	)
Changes in operating assets and liabilities:
Accounts receivable		1,766			3,390
Prepaid expenses and other assets		(13,440	)		(10,771	)
Payables and accrued liabilities		5,254			5,205
Deferred rent		(867	)		(1,114	)
Net cash provided by (used in) operating activities		(246,711	)		630,122
Investing Activities:
Purchases of available-for-sale investments		(641,445	)		(1,248,644	)
Proceeds from sale and maturity of available-for-sale investments		767,434			619,441
Purchases of property and equipment		(684	)		(2,933	)
Net cash provided by (used in) investing activities - continuing operations		125,305			(632,136	)
Net cash provided by investing activities - discontinued operations		—			997
Net cash provided by (used in) investing activities		125,305			(631,139	)
Financing Activities:
Principal payments on lease financing obligations		(2,810	)		(2,416	)
Proceeds from issuance of common stock, net		341,019			12,688
Net cash provided by financing activities		338,209			10,272
Effect of exchange rate changes on cash		68			(45	)
Net increase in cash, cash equivalents and restricted cash		216,871			9,210
Cash, cash equivalents and restricted cash at beginning of period		243,500			161,900
Cash, cash equivalents and restricted cash at end of period	$	460,371		$	171,110

See accompanying notes to unaudited condensed consolidated financial statements.

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

This discussion and analysis should be read in conjunction with our financial statements and notes thereto included in this quarterly report on Form 10-Q, or Quarterly Report, and the audited consolidated financial statements and notes thereto included in our annual report on Form 10-K for the year ended December 31, 2019, or 2019 Annual Report, as filed with the Securities and Exchange Commission, or SEC. Operating results are not necessarily indicative of results that may occur in future periods.

This Quarterly Report includes forward-looking statements that involve a number of risks, uncertainties and assumptions. These forward-looking statements can generally be identified as such because the context of the statement will include words such as “may,” “will,” “intend,” “plan,” “believe,” “anticipate,” “expect,” “estimate,” “predict,” “potential,” “continue,” “likely,” or “opportunity,” the negative of these words or other similar words. Similarly, statements that describe our plans, strategies, intentions, expectations, objectives, goals or prospects and other statements that are not historical facts are also forward-looking statements. For such statements, we claim the protection of the Private Securities Litigation Reform Act of 1995. Readers of this Quarterly Report are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the time this Quarterly Report was filed with the SEC. These forward-looking statements are based largely on our expectations and projections about future events and future trends affecting our business, and are subject to risks and uncertainties that could cause actual results to differ materially from those anticipated in the forward-looking statements. These risks and uncertainties include, without limitation, the risk factors identified in our SEC reports, including this Quarterly Report. In addition, past financial or operating performance is not necessarily a reliable indicator of future performance, and you should not use our historical performance to anticipate results or future period trends. We can give no assurances that any of the events anticipated by the forward-looking statements will occur or, if any of them do, what impact they will have on our results of operations and financial condition. Except as required by law, we undertake no obligation to update publicly or revise our forward-looking statements.

We are a biopharmaceutical company focused on delivering novel, transformational medicines with optimized pharmacology and pharmacokinetics to patients globally. Our internally developed pipeline includes multiple potentially first- or best-in-class assets with broad clinical utility.

We continue to leverage our two decades of world-class G protein-coupled receptor, or GPCR, target discovery research to develop breakthrough drugs and ultimately deliver these to patients with large unmet needs. Our long-term pipeline prospects include an enhanced collaboration with Beacon Discovery across a broad range of immune-mediated inflammatory targets and compounds.

We also have license agreements or collaborations with various companies, including:

In November 2020, we announced topline results from our ADVISE Phase 2b trial evaluating etrasimod in atopic dermatitis, or AD, and our intention to advance etrasimod into a Phase 3 registrational program in AD. ADVISE was a Phase 2b multicenter, randomized, double-blinded, placebo-controlled trial to assess the safety and efficacy of once-daily etrasimod in participants with

moderate-to-severe atopic dermatitis. The ADVISE trial enrolled approximately 140 participants and was conducted in study sites across the United States, Canada and Australia. An open-label extension of the ADVISE trial is ongoing.

In November 2020, we also announced additional detail on our Phase 2b VOYAGE trial of etrasimod in EoE. VOYAGE is a Phase 2b randomized, double-blind, placebo-controlled trial, with a primary efficacy measurement at week 16 and a secondary efficacy analysis at week 24, to assess the safety and efficacy of 1 mg and 2 mg etrasimod in participants with EoE. Initiation of the study in 2020 is dependent upon the impact of COVID-19.

In November 2020, we also announced the completion of a first-in-human Phase 1 safety and tolerability trial of APD418 in AHF. The trial found APD418 was generally safe and well tolerated. The FDA has granted us Fast Track designation for development of APD418 in AHF. Phase 2 planning is ongoing.

In October 2020, we announced the launch and $56.0 million financing of Longboard Pharmaceuticals, Inc., or Longboard (formerly known as Arena Neuroscience, Inc.) which is expected to focus on developing novel central nervous system, or CNS, targeted assets discovered by our GPCR research engine. Proceeds from the financing will be used to support the development of LP352 (formerly referred to as AN352), a clinical stage program for treatment-resistant developmental and epileptic encephalopathies, or DEE, and preclinical programs relating to LP143 (formerly referred to as AN143) and LP659 (formerly referred to as AN659) for the potential treatment of microglial neuroinflammatory diseases. The financing was led by Farallon Capital Management, LLC, and included Cormorant Asset Management, HBM Healthcare Investments, Highside Capital Management and T. Rowe Price Associates, with $1.0 million participation from Arena. Longboard was previously a wholly owned subsidiary of Arena. Subsequent to the financing, our founder common stock and Series A preferred stock of Longboard comprised approximately 33.4% of the outstanding shares of capital stock of Longboard. We have licensed certain development and worldwide commercialization rights to Longboard and are entitled to receive royalties on potential sales of LP352, LP143 and LP659, in the future. As Longboard continues to progress, it may seek additional capital to fund its future operating needs and may pursue various financing alternatives, like issuing shares of its stock in private or public financings, issuing debt instruments, or securing lines of credit. Longboard may also consider entering into collaborations related to its pipeline to provide for additional operating cash.

In October 2020, we also announced that we completed full enrollment of our Phase 2b CAPTIVATE trial evaluating olorinab for the potential treatment of abdominal pain in IBS. CAPTIVATE is a Phase 2, multi-center, randomized, double-blind, placebo-controlled, 12-week trial to assess the safety and efficacy of olorinab administered three times daily in 273 participants. We expect to announce topline data for this trial in the first quarter of 2021.

In September 2020, we announced that the first participant has been dosed in ELEVATE UC 12, the second of two pivotal trials of 12 weeks and 52 weeks, respectively, that constitute our Phase 3 ELEVATE UC global registrational program to assess the safety and efficacy of once-daily etrasimod 2 mg in participants with moderately to severely active UC. The other pivotal trial in the ELEVATE UC program, ELEVATE UC 52, is expected to complete enrollment by the end of 2020, with the 52-week treatment period finishing by the end of 2021, and we expect topline data from this trial shortly thereafter. We continue to monitor the impact of the COVID-19 pandemic on trial enrollment for both ELEVATE UC 52 and ELEVATE UC 12.

In September 2020, we also announced that we plan to initiate a Phase 2 trial evaluating etrasimod for the potential treatment of moderately active UC. GLADIATOR UC is a Phase 2 multicenter, randomized, placebo-controlled 52-week trial to assess the safety and efficacy of once-daily etrasimod 2 mg in participants with moderately active UC. This trial is intended to evaluate etrasimod in a less severe patient population than ELEVATE UC, potentially broadening the patient population and demonstrating the potential use of a once a day oral therapy earlier in the treatment paradigm.

In September 2020, we also announced the addition of Sub-Study A to our Phase 2/3 CULTIVATE program evaluating etrasimod in CD. Sub-Study A is a Phase 2 multicenter, randomized 14-week trial, intended to provide supportive data for dose selection evaluating 2 mg and 3 mg etrasimod in subjects with moderate to severely active CD. The Phase 2/3 program also consists of a Phase 2b dose-ranging multicenter, randomized, double-blinded, placebo-controlled trial to assess the safety and efficacy of once-daily etrasimod in participants with moderate to severely active CD. The Phase 3 portion of the program will include two induction trials, with re-randomization of clinical responders into a single maintenance trial. The program is intended to provide an operationally seamless transition from Phase 2 to Phase 3. Our CULTIVATE Phase 2 dose-ranging trial of etrasimod in CD is ongoing and we are confirming options to help facilitate the availability of topline data for this trial in 2021. We have withdrawn previously announced overall program guidance for CULTIVATE based on the expected COVID-19 impact on trial execution, including site activation and participant enrollment.

In September 2020, we also announced that the first participant has been dosed in a Phase 2 trial evaluating etrasimod for the potential treatment of AA. This Phase 2 multicenter, randomized, placebo-controlled trial will assess the safety and efficacy of once-

daily etrasimod 2 mg in participants with moderate-to-severe AA. We expect to announce topline data for this trial in the second half of 2021.

In December 2019, an outbreak of a novel strain of coronavirus and associated coronavirus disease 2019, or COVID-19, was identified in Wuhan, China. In March 2020, the World Health Organization categorized COVID-19 as a pandemic, and it continues to spread throughout the United States and other countries across the world. To limit the spread of COVID-19, governments have taken various actions including the issuance of stay-at-home orders and social distancing guidelines, causing some businesses to suspend operations and a reduction in demand for many products from direct or ultimate customers. Accordingly, many businesses have adjusted, reduced or suspended operating activities. The impact of this pandemic has been and will likely continue to be extensive in many aspects of society, which has resulted in and will likely continue to result in significant disruptions to businesses and capital markets around the world. The extent to which the coronavirus impacts us will depend on future developments, which are highly uncertain and cannot be predicted, including new information which may emerge concerning the severity of the coronavirus and the actions to contain the coronavirus or treat its impact, among others. Beginning the week of March 16, 2020, substantially all of our workforce began working from home, either all or substantially all of the time. In addition, we have experienced delays in site initiation and participant enrollment and screening rates in certain of our clinical development programs as a result of the COVID-19 pandemic. The potential impact, if any, that these site-level delays could have on our development program timelines remains uncertain. The effects of the stay-at-home orders and our work-from-home policies may negatively impact productivity, disrupt our business and delay our development programs, and may delay our regulatory and commercialization timelines, the magnitude of which will depend, in part, on the length and severity of the restrictions and other limitations on our ability to conduct our business in the ordinary course. Our future research and development expenses and selling, general and administrative expenses may vary significantly based on developments related to the coronavirus outbreak and impact of it and COVID-19 on the costs and timing associated with the conduct of our clinical trials and other related business activities.

Revenues. We recognized revenues of $20,000 for the three months ended September 30, 2020, compared to revenues of $1.4 million for the three months ended September 30, 2019.

Absent any new collaborations, we do not expect to receive any milestone payments in 2020.

Revenues from milestones and royalties are difficult to predict, and our overall revenues will likely continue to vary from quarter to quarter and year to year. In the short term, we expect the amount of revenue we earn to fluctuate.

Research and development expenses, which account for the majority of our expenses, consist primarily of salaries and other personnel costs, clinical trial costs (including payments to contract research organizations, or CROs), preclinical study fees and facility costs. We expense research and development costs as they are incurred when these expenditures have no alternative future uses. We generally do not track our earlier-stage, internal research and development expenses by project; rather, we track such expenses by the type of cost incurred.

Research and development expenses increased by $19.5 million to $79.8 million for the three months ended September 30, 2020, from $60.3 million for the three months ended September 30, 2019. This increase was primarily due to increases of $16.3 million in external clinical and preclinical study fees and $4.7 million in salary and other personnel costs. The increase in salary and other personnel costs is primarily due to an increase in the number of research and development employees.

We expect to incur substantial research and development expenses in 2020 and for the aggregate amount in 2020 to be greater than the amount incurred in 2019. We expect our research and development costs to be higher primarily due to higher external clinical trial costs and increasing headcount in connection with advancing the etrasimod and olorinab programs. Our actual expenses may be higher or lower than anticipated due to various factors, including our progress and results. For example, patient enrollment in our Phase 3 clinical program for etrasimod is expected to be competitive and challenging, and could take longer than originally projected, which may result in our related external expenses being lower in 2020 than anticipated (but which might increase the overall costs for completing this multi-year program).

Included in the $54.4 million of total external clinical and preclinical study fees noted in the table above for the three months ended September 30, 2020, were the following:

Included in the $38.1 million of total external clinical and preclinical study fees noted in the table above for the three months ended September 30, 2019, were the following:

Selling, general and administrative expenses decreased by $1.4 million to $19.0 million for the three months ended September 30, 2020, from $20.4 million for the three months ended September 30, 2019. This decrease was primarily due to a decrease in legal, accounting and other professional fees of $2.5 million partially offset by an increase of $1.8 million in salary and other personnel costs. The increase in salary and other personnel costs is primarily due to an increase in the number of selling, general and administrative employees. We expect that our 2020 selling, general and administrative expenses will be higher than in 2019.

Interest and other income (expense), net. Interest and other income, net decreased by $5.1 million to $1.4 million for the three months ended September 30, 2020, from $6.5 million for the three months ended September 30, 2019. This decrease was primarily due to a decrease of $5.1 million in interest income from our available-for-sale investments activity.

Revenues. We recognized revenues of $0.3 million for the nine months ended September 30, 2020, compared to $803.4 million for the nine months ended September 30, 2019. This decrease resulted primarily from the revenue associated with the upfront payment of $800.0 million we received in January 2019 pursuant to an exclusive license agreement with United Therapeutics. In connection with the United Therapeutics transaction, during the first quarter of 2019, we incurred transaction expenses of $14.6 million, which are presented as transaction costs in our condensed consolidated statement of operations for the nine months ended September 30, 2019.

Research and development expenses increased by $66.4 million to $223.3 million for the nine months ended September 30, 2020, from $156.9 million for the nine months ended September 30, 2019. This increase was primarily due to increases of $53.4 million in external clinical and preclinical study fees and $15.0 million in salary and other personnel costs. The increase in salary and other personnel costs is primarily due to an increase in the number of research and development employees.

Included in the $147.2 million of total external clinical and preclinical study fees noted in the table above for the nine months ended September 30, 2020, were the following:

Included in the $93.8 million of total external clinical and preclinical study fees noted in the table above for the nine months ended September 30, 2019, were the following:

Selling, general and administrative expenses increased by $12.9 million to $68.3 million for the nine months ended September 30, 2020, from $55.4 million for the nine months ended September 30, 2019. This increase was primarily due to increases of $9.1 million in salary and other personnel costs, $1.6 million in facility and equipment costs and $1.0 million in non-cash share-based compensation expenses. The increases in compensation costs are primarily due to an increase in the number of selling, general and administrative employees.

Interest and other income (expense), net. Interest and other income, net decreased by $10.8 million to $8.8 million for the nine months ended September 30, 2020, from $19.6 million for the nine months ended September 30, 2019. This decrease was primarily due to a decrease of $11.1 million in interest income primarily from our available-for-sale investments activity.

Income tax provision. Income tax provision was $110.3 million for the nine months ended September 30, 2019, as a result of the treatment of the United Therapeutics Agreement income as a discrete item during the first quarter of 2019 and the utilization of the deferred tax assets that were recorded in the fourth quarter of 2018.

In general, developing drugs and obtaining marketing approval is a long, uncertain and expensive process, and our ability to execute on our plans and achieve our goals depends on numerous factors, many of which we do not control. To date, we have generated limited revenues. We expect to continue to incur substantial net losses for the foreseeable future as we advance our clinical development programs and support our collaborators.

We have accumulated a large deficit since inception that has primarily resulted from the significant research and development expenditures we have incurred in seeking to identify and develop compounds that could become marketed drugs. We expect to continue to incur substantial losses for at least the short term. To date, we have obtained cash and funded our operations primarily through the sale of common stock, the issuance of debt and related financial instruments, payments from collaborators and customers, and sale leaseback transactions.

We believe our cash resources are sufficient to allow us to continue operations for at least the next 12 months from the date this Quarterly Report is filed with the SEC.

At September 30, 2020, we had $1.2 billion in cash, cash equivalents and available-for-sale investments. Our potential sources of liquidity in the short term include (i) milestone and other payments from collaborators or licensees, (ii) entering into new collaboration, licensing or commercial agreements for one or more of our drug candidates or programs, (iii) the sale or lease of our facilities or other assets and (iv) sale of equity, issuance of debt or other transactions.

We will require substantial cash to achieve our objectives of discovering, developing and commercializing drugs, and this process typically takes many years and potentially several hundreds of millions of dollars for an individual drug. We may not have adequate available cash, or assets that could be readily turned into cash, to meet these objectives in the long term. We will need to obtain significant funds under our existing licensing or collaboration agreements, under new collaboration, licensing or other commercial agreements for one or more of our drug candidates and programs or patent portfolios, or from other potential sources of liquidity, which may include the sale of equity, including shares offered and sold under the Sales Agreement, issuance of debt or other transactions. Our ability to raise additional funds may be adversely impacted by potential worsening global economic conditions and potential disruptions to, and volatility in, the credit and financial markets in the United States and worldwide resulting from the ongoing COVID-19 pandemic. If we are not able to secure adequate additional funding when required, we may be forced to make reductions in spending, extend payment terms with our CROs and suppliers, liquidate assets where possible and/or suspend or curtail planned programs. Any of these actions could materially harm our business, results of operations and future prospects. To the extent we obtain additional funding through product collaborations, these arrangements would generally require us to relinquish rights to some of our product candidates or products, and we may not be able to enter into such agreements on acceptable terms, if at all.

In addition to potential payments from our current collaborators, as well as funds from public and private financial markets, potential sources of liquidity in the long term include (i) upfront, milestone, royalty and other payments from any future collaborators or licensees and (ii) revenues from sales of any drugs we obtain regulatory approval to commercialize on our own. The length of time that our current cash and cash equivalents and any available borrowings will sustain our operations will be based on, among other things, the rate of adoption and commercial success of any drugs we or our collaborators obtain regulatory approval to market, regulatory decisions affecting our and our collaborator’s drug candidates, prioritization decisions regarding funding for our programs, progress in our clinical and earlier-stage programs, the time and costs related to current and future clinical trials and nonclinical studies, our research, development, manufacturing and commercialization costs (including personnel costs), our progress in any programs under collaborations, costs associated with intellectual property, our capital expenditures, and costs associated with securing any in-licensing opportunities. Any significant shortfall in funding may result in us reducing our development and/or research activities, which, in turn, would affect our development pipeline and ability to obtain cash in the future.

We evaluate from time to time potential acquisitions, in-licensing and other opportunities. Any such transaction may impact our liquidity as well as affect our expenses if, for example, our operating expenses increase as a result of such acquisition or license or we use our cash to finance the acquisition or license.

Net cash used in operating activities was $246.7 million in the nine months ended September 30, 2020, compared to net cash provided by operating activities of $630.1 million in the nine months ended September 30, 2019. This change was primarily the result of an $800.0 million upfront payment from United Therapeutics received in the nine months ended September 30, 2019, an increase of $46.0 million in payments made for external clinical study fees, and an increase in cash expenditures of approximately $23.7 million for personnel costs resulting primarily from an increase in the number of employees.

Net cash provided by investing activities was $125.3 million in the nine months ended September 30, 2020, compared to net cash used in investing activities of $631.1 million in the nine months ended September 30, 2019. This change was primarily due to a net increase of $755.2 million in proceeds from sales and maturities of available-for-sale investments, net of purchases, and a decrease of $2.2 million in purchases of property and equipment.

Net cash of $338.2 million was provided by financing activities in the nine months ended September 30, 2020, as a result of $301.8 million in net proceeds from our June 2020 underwritten public offering of our common stock and $39.2 million in proceeds from stock option exercises and purchases under our employee stock purchase plan, partially offset by $2.8 million in payments on our lease financing obligations. Net cash of $10.3 million was provided by financing activities in the nine months ended September 30, 2019, as a result of $12.7 million in proceeds from stock option exercises, partially offset by $2.4 million in payments on our lease financing obligations.

The SEC defines critical accounting policies as those that are, in management’s view, important to the portrayal of our financial condition and results of operations and demanding of management’s judgment. Our discussion and analysis of financial condition and results of operations is based on our condensed consolidated financial statements, which have been prepared in accordance with US generally accepted accounting principles, or GAAP. The preparation of these financial statements requires us to make estimates and judgments that affect the reported amounts of assets, liabilities, revenues and expenses and related disclosures. We base our estimates on historical experience and on various assumptions that we believe are reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results may differ significantly from those estimates.

At each reporting date, we perform an evaluation of impairment of our available-for-sale investments to determine if any unrealized losses are the result of credit losses. Impairment is assessed at the individual security level. Factors considered in determining whether a loss resulted from a credit loss or other factors include the Company’s intent and ability to hold the investment until the recovery of its amortized cost basis, the extent to which the fair value is less than the amortized cost basis, the length of time and extent to which fair value has been less than the cost basis, the financial condition of the issuer, any historical failure of the issuer to make scheduled interest or principal payments, any changes to the rating of the security by a rating agency, any adverse legal or regulatory events affecting the issuer or issuer’s industry, and any significant deterioration in economic conditions. If a decline in the fair value below the amortized cost basis of available-for-sale securities is determined to be due to credit-related factors, we will record the losses in earnings through an allowance account. Unrealized gains and losses that are not credit-related are included in accumulated other comprehensive income (loss).

Our remaining critical accounting policies and management estimates are discussed in our Annual Report on Form 10-K for the fiscal year ended December 31, 2019.

There have been no material changes from the information we included in this section of our Annual Report on Form 10-K for the year ended December 31, 2019.

Based on an evaluation carried out as of the end of the period covered by this Quarterly Report, under the supervision and with the participation of our management, including our President and Chief Executive Officer and our Executive Vice President and Chief Financial Officer, of the effectiveness of our disclosure controls and procedures, our President and Chief Executive Officer and our Executive Vice President and Chief Financial Officer have concluded that, as of the end of such period, our disclosure controls and procedures (as defined in Rule 13a-15(e) under the Securities Exchange Act of 1934, as amended, or the Exchange Act) were effective at the reasonable assurance level. There were no changes to our internal control over financial reporting that occurred during the

quarter covered by this Quarterly Report that have materially affected, or are reasonably likely to materially affect, our internal control over financial reporting.

Below is a summary of the principal factors that make an investment in our stock speculative or risky. This summary does not address all of the risks that we face. Additional discussion of the risks summarized in this risk factor summary, and other risks that we face, can be found below under the heading “Risk Factors” and should be carefully considered, together with other information in this Quarterly Report on Form 10-Q and our other filings with the Securities and Exchange Commission, or SEC, before making investment decisions regarding our stock.

Investment in our stock involves a high degree of risk. You should consider carefully the risks described below, together with other information in this Quarterly Report on Form 10-Q and our other filings with the SEC, before making investment decisions regarding our stock. If any of the following events actually occur, our business, operating results, prospects or financial condition could be materially and adversely affected. This could cause the trading price of our common stock to decline and you may lose all or part of your investment. Moreover, the risks described below are not the only ones that we face. Additional risks not presently known to us or that we currently deem immaterial may also affect our business, operating results, prospects or financial condition.

The risk factors set forth below with an asterisk (*) before the title are new risk factors or ones containing substantive changes from the risk factors previously disclosed in Item 1A to Part I of our Annual Report on Form 10-K for the year ended December 31, 2019, as filed with the SEC.

* Drug development programs are expensive, time consuming, uncertain and susceptible to change, interruption, delay or termination.

Drug development programs are very expensive, time consuming and difficult to design and implement. Our drug candidates are in various stages of clinical and preclinical development and are prone to the risks of failure inherent in research and development. Clinical trials and preclinical studies are needed to demonstrate that drug candidates are safe and effective to the satisfaction of the FDA, and similar non-US regulatory authorities, and the FDA or other regulatory authority may require us to, or we or others may decide to, conduct additional research and development even after a drug is approved. The commencement or completion of our clinical trials or preclinical studies could be substantially delayed or prevented by several factors, including the following:

In addition, the FDA, other regulatory authorities, collaborators, or we may suspend, delay or terminate our development programs at any time for various reasons, including those listed above affecting the commencement or completion of trials and the following:

There is typically a high rate of attrition from the failure of drug candidates proceeding through clinical trials, and many companies have experienced significant setbacks in advanced development programs even after promising results in earlier studies or trials. We have experienced setbacks in our internal and partnered development programs and expect to experience additional setbacks from time to time in the future. In addition, even if the earlier-stage results of our development programs are favorable, these programs may take significantly longer than expected to complete or may not be completed at all. If we or our collaborators abandon or are delayed in our development efforts related to any drug or drug candidate, we may not be able to generate sufficient revenues to continue our operations at the current or planned level or be profitable, our reputation in the industry and in the investment community would likely be significantly damaged, additional funding may not be available to us or may not be available on terms we or others believe are favorable, and our stock price may decrease significantly.

We may not be successful in initiating, enrolling participants in, or completing our studies or trials or advancing our programs on our projected timetable, if at all. Any failure to initiate or delays in our studies, trials or development programs, or unfavorable results or decisions or negative perceptions regarding any of our programs, could cause our stock price to decline significantly. This is particularly the case with respect to our clinical programs.

* We will need to obtain additional funds or enter into collaboration agreements to execute on our corporate strategy, and we may not be able to do so at all or on terms you view as favorable; your ownership may be substantially diluted if we do obtain additional funds; you may not agree with the manner in which we allocate our available resources; and we may not be profitable.

It takes many years and potentially hundreds of millions of dollars to successfully develop a compound into a marketed drug. We have accumulated a large deficit that has primarily resulted from the significant expenditures we have made in research and development since our inception. We expect that our losses and operating expenses will continue to be substantial.

All of our internal programs are in the development stage, and we may not have adequate funds to develop all of our compounds into marketed drugs.

We may seek to obtain additional funding through the capital markets or other financing sources. Additional funding may not be available to us or may not be available on terms we or others believe are favorable, including due to negative impacts on the stock market and investor sentiment resulting from the COVID-19 pandemic. Our ability to obtain additional funding may depend on many factors, including those outside our control. Should we obtain additional funding, your ownership interest may be diluted or otherwise negatively impacted.

We have entered into, and may in the future seek to enter into, collaboration or other agreements with other entities to continue to develop and, if successful, commercialize one or more of our drug candidates. We may not be able to enter into any such agreements on terms that we or third parties, including investors or analysts, view as favorable, if at all. Our ability to enter into any such agreement for any of our programs or drug candidates depends on many factors, potentially including the outcomes of additional testing (including clinical trial results) or regulatory applications for marketing approval, and we do not control these outcomes.

We may allocate our resources in ways that do not improve our results of operations or enhance the value of our assets, and our stockholders and others may also not agree with the manner in which we choose to allocate our resources or obtain additional funding. We may also eliminate, scale back or delay some or all of our research and development programs, and any such reductions or failure to apply our resources effectively or to obtain additional funding could narrow, slow or otherwise adversely impact the development and commercialization of one or more of our drug candidates, which could reduce our opportunities for success and have a material adverse effect on our business, our prospects and the market price of our common stock.

In addition, we cannot assure you that we will be profitable or, if we are profitable for any particular time period, that we will be profitable in the future.

Our business may be negatively impacted based on the clinical trials and preclinical studies of, and decisions affecting, one or more of our drug candidates.

The results and timing of clinical trials and preclinical studies obtained by us or our collaborators or licensees, as well as related decisions by us, collaborators, licensees and regulators, can affect our stock price. Results of clinical trials and preclinical studies are uncertain and subject to different interpretations by regulatory agencies, us or others. The design of these trials and studies (which may change significantly and be more expensive than anticipated depending on results and regulatory decisions), as well as related analyses of such results, including adverse effects, may not be viewed favorably by us or third parties, including investors, analysts, current or potential collaborators, the academic and medical communities, and regulators, which could adversely impact the development and opportunities for regulatory approval of drug candidates and commercialization (and even result in withdrawal from the market) of approved drugs. The same may be true of decisions regarding the focus and prioritization of our research and development efforts. Stock prices of companies in our industry have declined significantly when such results and decisions were unfavorable or perceived negatively or when a drug candidate or product did not otherwise meet expectations.

* The development, approval or commercialization of any of our drug candidates could be negatively affected by circumstances related to other drug candidates or approved products.

Information on our drug candidates in clinical development is preliminary and incomplete, and for such drug candidates, particularly in the earlier stages of development, information on approved products in the same or related drug classes may indicate potential risks related to the development of our drug candidates. In particular, safety issues affecting other drugs or drug candidates may result in increased regulatory scrutiny of the safety of our drugs or drug candidates, may raise potential adverse publicity and may affect product sales or result in litigation.

For example, etrasimod is an orally available modulator of the S1P receptors. Other orally available modulators of the S1P receptors, such as Gilenya, have been associated with risks such as adverse cardiovascular effects, including lowering of the heart rate and heart blocks, infection, macular edema, respiratory effects, fetal risk, a rare brain infection, and elevations in liver enzymes. These adverse reactions and risks may be associated with S1P receptor modulation and could be found to be associated with the use of etrasimod. Such adverse reactions and risks, either actual or perceived, could negatively impact the development, approval or commercialization of etrasimod, or our ability to enter into a collaboration on acceptable terms.

Topline data may not accurately reflect the complete results of a particular study or trial.

We may publicly disclose topline or interim data from time to time, which are based on a preliminary analysis of then-available efficacy and safety data, and the results and related findings and conclusions are 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 others, including regulatory agencies, may not accept or agree with our assumptions, estimations, 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 drug candidate or drug and our company in general. In addition, the information we may publicly disclose regarding a particular study or clinical trial is based on what is typically extensive information, and you, regulators or others may not agree with what we determine is the material or otherwise appropriate information to include in our disclosure, and any information we determine not to disclose may ultimately be deemed significant with respect to future decisions, conclusions, views, activities or otherwise regarding a particular drug, drug candidate or our business.

Our hypothesis that selectively targeting receptors can lead to more efficacious or safer drugs may not be correct.

In general, we have designed and optimized the drug candidates that we or our collaborators and licensees are developing (including etrasimod, olorinab, APD418 and ralinepag) to selectively target certain receptors found on cells in humans. Our hypothesis is that selectivity may allow our drug candidates to address diseases more efficaciously or without some of the negative effects associated with less selective drugs. In certain cases, we believe early research and, if available, early clinical testing, provides preliminary support for our hypothesis. However, our hypothesis may not be correct, early research and early phase clinical testing may not be predictive of efficacy or safety in later trials, and our drug candidates may not be approved or, if approved, have the desired efficacy or safety profile.

It is generally our strategy to develop drug candidates that we believe will be first-in-class, best-in-class, or similar descriptions, or otherwise have broad clinical utility, optimized pharmacology or optimized pharmacokinetics. Some or all of our drug candidates may not achieve these goals. For example, failure to complete enrollment in clinical trials on schedule or at all could prevent a drug candidate from being first-in-class. Similarly, comparing data from different trials, or making predictions based on preclinical data, may not allow us to correctly determine whether our drug candidates are superior to competitive drugs or drug candidates in the same way that comparisons can be made from conducting trials in which our and a competitive drug is tested “head to head” in the same trial. The failure of our drugs or drug candidates to be first-in-class, best-in-class, or similar descriptions, or have broad clinical utility, optimized pharmacology, or optimized pharmacokinetics, or a lack of “head to head” data, could adversely affect development, regulatory approval, third-party payor support, or market adoption, which would have a material adverse impact on our business.

The results of preclinical studies and completed clinical trials are not necessarily predictive of future results, and our current drug candidates or any approved drugs may not be further developed or have favorable results in later studies or trials.

Preclinical studies and Phase 1 and Phase 2 clinical trials are not primarily designed to test the efficacy of a drug candidate, but rather to test safety, to study pharmacokinetics and pharmacodynamics, and to understand the drug candidate’s side effects at various doses and schedules. Favorable results in early studies or trials may not be confirmed in later studies or trials, including preclinical studies that continue or that are initiated after earlier clinical trials and large-scale clinical trials, and our drug candidates or drugs in subsequent trials or studies may fail to show desired safety and efficacy despite having progressed through earlier-stage trials. For example, we have announced positive topline Phase 2 results for etrasimod in participants with ulcerative colitis, but these results may not be confirmed in any subsequent Phase 3 study. By way of another example, the impact of etrasimod on heart rate that was observed in completed clinical trials may not be observed in subsequent trials, and it could be viewed negatively by the FDA or other regulatory agencies.

Unfavorable results from clinical trials or preclinical studies could result in delays, modifications or abandonment of ongoing or future clinical trials, or abandonment of a program. Clinical and preclinical results are frequently susceptible to varying interpretations that may delay, limit or prevent regulatory approvals or commercialization. Negative or inconclusive results or adverse medical events during such trials or studies could cause a clinical trial to be delayed, repeated or terminated; a program to be abandoned; or negatively impact a related marketed drug, which could have a material adverse effect on our business, financial condition and results of operations.

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

Undesirable side effects caused by our product candidates could cause us or regulatory authorities to interrupt, delay or halt clinical 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 these or other 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. The drug-related side effects could affect patient recruitment or the ability of enrolled participants 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:

For example, in February 2020 the FDA issued a drug safety communication announcing that it requested Eisai voluntarily withdraw lorcaserin (previously marketed in the United States as BELVIQ and BELVIQ XR) from the U.S. market based on the FDA’s analysis of data from a study completed by Eisai and a change in the FDA’s risk-benefit assessment of BELVIQ. Eisai agreed to voluntarily withdraw lorcaserin products from the U.S. market, as requested by the FDA, and from foreign markets. Following these events, lawsuits relating to lorcaserin against us and others have been filed in the United States and abroad.

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

Drug discovery and development is intensely competitive in the therapeutic areas on which we focus. If the number of our competitors increase or they develop treatments that are approved faster, marketed better, less expensive or demonstrated to be more effective or safer than our drugs or drug candidates, our commercial opportunities will be reduced or eliminated.

Many of the drugs we or our collaborators are attempting or may attempt to discover and develop may compete with existing therapies in the United States and other territories. In addition, many companies are pursuing the development of new drugs that target the same diseases and conditions that we target. For example, with regard to etrasimod, there are other drugs that have a similar mechanism of action that entered Phase 3 clinical development before etrasimod for the same indications that we are pursuing, such as ulcerative colitis.

Our competitors, particularly large pharmaceutical companies, may have substantially greater research, development and marketing and sales capabilities and greater financial, scientific and human resources than we do. Companies that complete clinical trials, obtain required regulatory agency approvals and commence commercial sale of their drugs before we do for the same indication may achieve a significant competitive advantage, including certain patent and marketing exclusivity rights. In addition, our competitors’ drugs may have fewer side effects, more desirable characteristics (such as efficacy, route of administration or frequency of dosing), or be viewed more favorably by patients, healthcare providers, healthcare payers, the medical community, the media or others than our drug candidates or drugs, if any, for the same indication. Our competitors may also market generic or other drugs that compete with our drugs at a lower price than our drugs, which may negatively impact our drug sales, if any. Any results from our research and development efforts, or from our joint efforts with our existing or any future collaborators, may not compete successfully with existing or newly discovered products or therapies.

Our revenues in the future will be substantially dependent on the success of our or our collaborators’ and licensees’ marketing of drugs we have discovered or developed. To the extent such drugs are not commercially successful, our business, financial condition and results of operations may be materially adversely affected, and the price of our common stock may decline.

We believe our revenues will be substantially dependent on the success of the drugs we or our collaborators and licensees successfully develop. We do not know whether or when such drug candidates will be approved by regulatory authorities for sale or commercialized. Even if approved and commercialization begins, we do not know if such commercialization will be successful or otherwise meet our, your, analysts’ or others’ expectations, and the market price of our common stock could decline significantly. For example, sales of lorcaserin to date have been less than we and others initially anticipated, and, in February 2020, Eisai (as well as its distributor in South Korea) determined to withdraw lorcaserin (previously marketed in the United States as BELVIQ and BELVIQ XR) from the market based on concerns raised by the FDA.

We cannot guarantee future product sales or achievement of milestones under our collaborations and license agreements. For example, our license agreement with United Therapeutics for ralinepag does not contain a covenant obligating United Therapeutics to use any particular efforts to develop or commercialize any product, and we may never receive any milestone or royalty payments under this license agreement. In addition, our collaboration and license agreements may be terminated in certain circumstances, which may result in us not receiving additional milestone or other payments under the terminated agreement.

The degree of market acceptance and commercial success of a drug will depend on a number of factors, including the following, as well as risks identified in other risk factors:

* Our drugs may not be commercially successful if not widely covered and adequately reimbursed by third-party payers, and we may depend on others to obtain and maintain third-party payer access; inadequate third-party coverage and reimbursement could make entering into agreements with pharmaceutical companies to collaborate or commercialize our drugs more difficult and diminish our revenues.

Our and our collaborators’ and licensee’s ability to successfully commercialize any of our drugs that have been or may be approved will depend, in part, on government regulation and the availability of coverage and adequate reimbursement from third-party payers, including private health insurers and government payers, such as the Medicaid and Medicare programs, increases in government-run, single-payer health insurance plans and compulsory licenses of drugs. We expect government and third-party payers will continue their efforts to contain healthcare costs by limiting coverage and reimbursement levels for new drugs. In addition, many countries outside of the U.S. have nationalized healthcare systems in which the government pays for all such products and services and must approve product pricing, and some U.S. politicians advocate for implementation of a comparable system in the United States. A government or third-party payer decision not to approve pricing, or provide adequate coverage and reimbursements, for our drugs, if any, could limit market acceptance of and demand for our drugs.

It is increasingly difficult to obtain coverage and adequate reimbursement levels from third-party payers, and significant uncertainty exists as to the coverage and reimbursement of newly approved prescription drug products. We or our collaborators also face competition in negotiating for coverage from pharmaceutical companies and others with competitive drugs or other treatment, and these competitors may have significantly more negotiating leverage or success with respect to individual payers than we or our collaborators may have.

Federal and state healthcare reform measures that have been or may be implemented in the future, may result in more rigorous coverage criteria, more limited coverage and downward pressure on the price that we may receive for any approved product, which could seriously decrease our future revenues. The Patient Protection and Affordable Care Act, as amended, or the ACA, which was enacted in 2010, is one such healthcare reform measure that has made a number of substantial changes in the way healthcare is financed by both governmental and private insurers. In the years since its enactment, there have been, and continue to be, significant developments in, and continued legislative, executive, and judicial activity around, attempts to repeal, replace, or modify the ACA. While Congress has not passed comprehensive repeal legislation, several bills affecting the implementation of certain taxes under the ACA have been signed into law. Legislation enacted in 2017, informally titled the Tax Cuts and Jobs Act of 2017, or TCJA, includes a provision repealing, effective January 1, 2019, the tax-based shared responsibility payment imposed by the ACA on certain individuals who fail to maintain qualifying health coverage for all or part of a year that is commonly referred to as the “individual mandate”. Additionally, the 2020 federal spending package permanently eliminated, effective January 1, 2020, the ACA-mandated “Cadillac” tax on high-cost employer-sponsored health coverage and medical device tax and, effective January 1, 2021, also eliminates the health insurer tax. Further, the Bipartisan Budget Act of 2018, or the BBA, among other things, amended the ACA, effective January 1, 2019, to increase from 50 percent to 70 percent the point-of-sale discount that is owed by pharmaceutical manufacturers who participate in Medicare Part D and to close the coverage gap in most Medicare drug plans, commonly referred to

as the “donut hole”. In December 2018, the United States Department of Health and Human Services’ Centers for Medicare & Medicaid Services, or CMS, published a new final rule permitting further collections and payments to and from certain ACA qualified health plans, or QHPs, and health insurance issuers under the ACA risk adjustment program in response to the outcome of federal district court litigation regarding the method CMS uses to determine this risk adjustment. On April 27, 2020, the United States Supreme Court reversed a Federal Circuit decision that previously upheld Congress’s denial of $12 billion in "risk corridor" funding. 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 the TCJA. On December 18, 2019, the U.S. Court of Appeals for the Fifth 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. On March 2, 2020, the United States Supreme Court granted the petitions for writs of certiorari to review this case, and has allotted one hour for oral arguments. It is unclear how this litigation and other efforts to repeal and replace the ACA will impact the ACA and our business and operations.

In addition, there has been heightened scrutiny in the United States and other countries of pharmaceutical pricing practices in light of the rising cost of prescription drugs and biologics. In the United States, such scrutiny has resulted in congressional inquiries and proposed and enacted federal and state legislation designed to, among other things, bring more transparency to product pricing, review the relationship between pricing and manufacturer patient programs, and reform government program reimbursement methodologies for drugs. Further, the Trump administration’s budget proposal for fiscal year 2021 includes a $135 billion allowance to support legislative proposals seeking to reduce drug prices, increase competition, lower out-of-pocket drug costs for patients, and increase patient access to lower-cost generic and biosimilar drugs. On March 10, 2020, the Trump administration sent “principles” for drug pricing to Congress, calling for legislation that would, among other things, cap Medicare Part D beneficiary out-of-pocket pharmacy expenses, provide an option to cap Medicare Part D beneficiary monthly out-of-pocket expenses, and place limits on pharmaceutical price increases. Moreover, the Trump administration previously released a “Blueprint” to lower drug prices and reduce out of pocket costs of drugs that contained proposals to increase drug manufacturer competition, increase the negotiating power of certain federal healthcare programs, incentivize manufacturers to lower the list price of their products, and reduce the out of pocket costs of drug products paid by consumers. The Department of Health and Human Services, or HHS, has solicited feedback on some of these measures and has implemented others under its existing authority. Additionally, on July 24, 2020, President Trump announced four executive orders related to prescription drug pricing that attempt to implement several of the Trump administration proposals, including (i) a policy that would tie certain Medicare Part B drug prices to international drug prices, or the “most favored nation price,” the details of which were released on September 13, 2020 and also expanded to cover certain Part D drugs; (ii) an order that directs HHS to finalize the Canadian drug importation proposed rule previously issued by HHS and makes other changes allowing for personal importation of drugs from Canada; (iii) an order that directs HHS to finalize the rulemaking process on modifying the Anti-Kickback Statute safe harbors for discounts for plans, pharmacies, and pharmaceutical benefit managers; (iv) a policy that reduces costs of insulin and epipens to patients of federally qualified health centers. The FDA also recently released a final rule, effective November 30, 2020, implementing a portion of the importation executive order providing guidance for states to build and submit importation plans for drugs from Canada. While some measures may require additional authorization to become effective, Congress and the Trump administration have each indicated that they will continue to seek new legislative and/or administrative measures to control drug costs. 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. It is possible that additional governmental action is taken in response to the COVID-19 pandemic. For example, the CARES Act suspended the 2% Medicare rate reduction sequester from May 1, 2020 through December 31, 2020, and extended the sequester by one year, through 2030. Further, on August 6, 2020, the Trump administration issued another executive order that instructs the federal government to develop a list of “essential” medicines and then buy them and other medical supplies from U.S. manufacturers instead of from companies around the world, including China. The order is meant to reduce regulatory barriers to domestic pharmaceutical manufacturing and catalyze manufacturing technologies needed to keep drug prices low and the production of drug products in the United States.

Any reduction in reimbursement from Medicare or other government programs may result in a similar reduction in payments from private payors. The implementation of additional cost containment measures or other healthcare reforms may also limit our commercial opportunities by reducing the amount a potential collaborator or licensee is willing to pay to license our programs or drug candidates in the future, which may prevent us from being able to establish and maintain collaborations and license agreements, generate revenue, attain profitability, or commercialize our products.

Forecasting potential sales for drugs will be difficult, and if our projections are inaccurate, our business may be harmed and our stock price may be adversely affected.

Our business planning requires us to forecast or make assumptions regarding demand and revenues for our drugs if they are approved despite numerous uncertainties. These uncertainties may be increased if we rely on our collaborators to conduct commercial activities and provide us with accurate and timely information. Actual results may deviate materially from projected results for various reasons, including the following, as well as risks identified in other risk factors:

Revenues from drug sales may be based in part on estimates, judgment and accounting policies, and incorrect estimates or regulators’ or others’ disagreement regarding such estimates or accounting policies may result in changes to guidance, projections or previously reported results. Expected and actual product sales and quarterly and other results may greatly fluctuate, and such fluctuations can adversely affect the market price of our common stock, perceptions of our ability to forecast demand and revenues, and our ability to maintain and fund our operations.

Our efforts will be seriously jeopardized if we are unable to attract and retain key and other employees.

Our success depends on the continued contributions of our principal management, development and scientific personnel, and the ability to hire and retain key and other personnel. We face competition for such personnel, and we believe that risks and uncertainties related to our business may impact our ability to hire and retain key and other personnel. If we do not recruit and retain effective management and other key employees, particularly our executive officers, our operations, our ability to generate or raise additional capital, and our business in general, may be adversely impacted. For example, to execute our clinical programs, our strategy is to maintain a sufficient and robust program management function with clinical expertise. We are in the process of modifying and building this function, and we may not be able to establish the function we believe necessary to support our clinical goals and meet our corporate objectives.

* We are expanding our organization and may experience difficulties in managing this growth, which could disrupt our operations.

Although we are currently limiting our recruiting and hiring activities to key positions as a result of the ongoing COVID-19 pandemic, as part of our long-term business plan, we are seeking to expand our employee base to increase our managerial, scientific, operational, manufacturing supply, commercial, financial and other resources and to hire more consultants and contractors, including in and outside of our headquarters in San Diego, California. For example, in addition to our headquarters in San Diego, we currently have operations in Boston, Massachusetts and Zug, Switzerland. Future growth will impose significant additional responsibilities on our management, including the need to identify, recruit, maintain, motivate and integrate additional employees, consultants and contractors. Also, our management may need to divert attention away from our day-to-day activities and devote a substantial amount of time to managing these growth activities. We may not be able to effectively manage the expansion of our operations, which may result in weaknesses in our infrastructure, give rise to operational mistakes, loss of business opportunities, loss of employees and reduced productivity among remaining employees. Our future growth could require significant capital expenditures and may divert financial resources from other projects, such as the development of additional product candidates. Moreover, if our management is unable to effectively manage our growth, our expenses may increase more than expected, our ability to generate and/or grow revenues could be reduced, and we may not be able to implement our business strategy. Our future financial performance and our ability to develop and then commercialize any approved products and compete effectively will depend, in part, on our ability to effectively manage any future growth.

* Data generated or analyzed with respect to product use in the market or required postmarketing or other studies or trials may result in decreased demand, lower sales, product recall, regulatory action or litigation.

An NDA holder (or the equivalent outside the United States) is responsible for assessing and monitoring the safety of a drug that has been approved for marketing, including reviewing reports of adverse safety events. In addition, NDA holders often conduct additional studies or trials or analyze new or previous data related to an approved drug, including with respect to required postmarketing studies and in connection with seeking additional regulatory approvals in new territories.

Any new data generated, including from adverse event reports or required postmarketing, registration or other studies or trials, may result in label changes, adversely affect sales or development, result in withdrawal of the drug from the market, or result in litigation. In addition, analyses of previous data can have similar risks. Regulatory agencies may consider the new data or analyses in reviewing marketing applications for drug candidates in their territories or impose post-approval requirements that require significant additional expenditures. For example, in February 2020, the FDA requested that Eisai withdraw lorcaserin (previously marketed in the United States as BELVIQ and BELVIQ XR) from the U.S. market based on the FDA’s analysis of data from a study completed by Eisai and a change in the FDA’s risk-benefit assessment of BELVIQ, and regulators in other countries have taken similar steps. Eisai agreed to voluntarily withdraw lorcaserin products from the U.S. market, as requested by the FDA, and from foreign markets. Following these events, lawsuits relating to lorcaserin against us and others have been filed in the United States and abroad.

The discovery of significant problems with a product or class of products similar to any approved drug could have an adverse effect on our or our collaborator’s or licensee’s commercialization.

If we license or otherwise partner our drugs, our failure to maintain such agreements or poor performance or results under such agreements could negatively impact our business.

Our collaborators and licensees may have primary responsibility for the regulatory approval, marketing and distribution, and, in certain circumstances, development, of our drug candidate(s) in the territory or territories under the applicable collaboration. We may have limited or no control over our collaborator’s decisions, including the amount and timing of resources that any of these collaborators will dedicate to such activities. This is the case for our ralinepag exclusive license agreement with United Therapeutics and our lorcaserin Transaction Agreement with Eisai.

When we enter collaboration and license agreements, we are subject to a number of other risks, including:

We or our collaborators or licensees might terminate our agreements in certain circumstances or amend the terms of our agreement, and investors and analysts may not view any termination or amendment as favorable.

* We rely on other companies, including third-party manufacturers and sole-source suppliers, to manufacture all our drugs and drug candidates, and we or such other companies may encounter failures or difficulties or not receive or provide adequate supply, which could adversely affect development or commercialization.

We do not own or operate manufacturing facilities that can produce active pharmaceutical ingredient, or API, intermediates and other material required to make our drug candidates. Instead, we rely on other companies to supply API, intermediates and other materials. Certain of these materials are available from only one or a small number of suppliers, and using a new supplier, if available, could result in substantial delay and greater cost. Our and our manufacturers’ dependence on single or limited sources of materials may adversely affect our ability to develop and deliver drug products on a timely and competitive basis, or at all.

Any performance failure on the part of us or a third-party manufacturer could result in a product recall or seizure, delay or otherwise adversely affect sales of an approved product or the clinical development or regulatory approval of one or more of our other

drug candidates. We or third-party manufacturers may encounter difficulties involving production yields, regulatory compliance, lot release, quality control and quality assurance, as well as shortages of qualified personnel.

The ability to adequately and timely manufacture and supply drug product is dependent on the uninterrupted and efficient operation of the manufacturing facilities, which is impacted by many manufacturing variables, including:

In addition, we or our third-party manufacturers may encounter delays and problems in manufacturing our drug candidates or drugs for a variety of reasons, including accidents during operation, failure of equipment, delays in receiving materials, natural or other disasters, health epidemics (including COVID-19), political or governmental unrest or changes, social unrest, intentional misconduct or other factors inherent in operating complex manufacturing facilities. Commercially available starting materials, reagents and excipients may be or become scarce or more expensive to procure, and we may not be able to obtain favorable terms in agreements with subcontractors. We or our third-party manufacturers may not be able to operate our respective manufacturing facilities in a cost-effective manner or in a time frame that is consistent with our expected future manufacturing needs. If we or our third-party manufacturers cease or interrupt production or if our third-party manufacturers and other service providers fail to supply materials, products or services to us for any reason, such interruption could delay progress on our programs, or interrupt the commercial supply, with the potential for additional costs and lost revenues. If this were to occur, we may also need to seek alternative means to fulfill our manufacturing needs.

We may not be able to enter into or maintain agreements with manufacturers whose facilities and procedures comply with applicable law. Manufacturers are subject to ongoing periodic inspection (which may be unannounced) by the FDA, the DEA, corresponding state and foreign authorities and other regulatory authorities to ensure strict compliance with Current Good Manufacturing Practices, or cGMPs, regulations and other applicable government regulations and corresponding foreign standards. We do not have control over a third-party manufacturer’s compliance with these regulations and standards. If we or one of our manufacturers or other company in the supply chain fail to maintain compliance or otherwise experience setbacks, we or they could be subject to civil or criminal penalties, the production of one or more of our drug candidates or any approved products could be interrupted or suspended, or our product could be recalled or withdrawn, resulting in delays, additional costs and potentially lost revenues.

Our drug candidates are subject to extensive regulation, and we may not receive required regulatory approvals, or timely approvals, for any of our drug candidates.

Preclinical and clinical development, manufacturing, labeling, packaging, storage, recordkeeping, advertising, promotion, export, marketing and distribution, and other activities relating to developing and manufacturing drugs are subject to extensive regulation by the FDA and other regulatory agencies. We and others we contract with are subject to periodic inspections (which may be unannounced) by the FDA, the DEA and other regulatory agencies. Failure to comply with applicable regulatory requirements may, either before or after product approval, subject us to administrative or judicially imposed sanctions that may negatively impact research and development or commercialization, or otherwise negatively impact our business. Regulatory agencies have in the past inspected certain aspects of our business, and we were provided with observations of objectionable conditions or practices with respect to our business. There is no assurance that regulatory agencies will not provide us with observations in future inspections or that we satisfactorily addressed observations provided to us in past inspections.

Regulatory approval of a drug candidate is not guaranteed, and our business and reputation may be harmed by any failure or significant delay in receiving regulatory approval. The number and types of preclinical studies and clinical trials that will be required for FDA approval varies depending on the drug candidate, the disease or condition that the drug candidate is designed to target and the regulations applicable to any particular drug candidate. Despite the time and expense exerted in preclinical and clinical studies, failure can occur at any stage, and we could encounter problems that cause us to abandon clinical trials or to repeat or perform additional preclinical studies and clinical trials.

We cannot predict when or whether, or assure you that, our collaborators’ or our past or any future regulatory submissions or responses will be sufficient to the applicable regulatory authority or others, that the applicable regulatory authority or others will consider data or our analyses, interpretations or procedures related to any of our drug candidates as sufficient or persuasive, or that any regulatory authority will ever approve any of our drug candidates in the future.

To market any drugs outside of the United States, we and our current or future collaborators must comply with numerous and varying regulatory requirements of other countries. Approval procedures vary among countries and can involve additional product testing and additional administrative review periods. The time required to obtain approval in other countries might differ from that required to obtain FDA approval. The regulatory approval process in other countries may include all of the risks associated with FDA approval as well as additional risks, some of which may be unanticipated. Approval by the FDA or any other regulatory authority does not assure or predict with any certainty that any other regulatory authority will approve the drug.

In addition, existing regulatory policies and laws may change. We cannot predict the likelihood, nature or extent of new government regulation, either in the United States or in other countries, or the impact on our drug candidates or drugs. For example, new FDA regulation could delay or prevent marketing approvals, increase the cost of research and development, and result in narrower product labeling and expensive post-marketing requirements.

* Fast Track, Breakthrough Therapy, Accelerated Approval, Priority Review, or similar designations by the FDA or other applicable regulatory agencies may not lead to a faster development or review process.

The FDA may grant Fast Track, Breakthrough Therapy, Accelerated Approval, Priority Review, or other designation to product candidates that meet applicable guidelines in order to speed the availability of certain drugs. Other applicable regulatory agencies may grant similar designations. These designations may apply only to the combination of a product candidate and a specific indication or patient population. Product candidates that receive these designations may not actually receive faster clinical development or regulatory review or approval any sooner than other product candidates that do not have such designation, or at all. Furthermore, a product’s receipt of such a designation does not increase the likelihood that the product candidate will receive marketing approval. The FDA or other regulatory agency may also withdraw a designation if it determines that the product candidate no longer meets the relevant criteria.

For example, the FDA has granted Fast Track designation for APD418 for treatment of decompensated heart failure, or DHF, which we refer to as acute heart failure, or AHF, in patients who have heart failure with reduced ejection fraction, or HFrEF. Despite receiving Fast Track designation, such designation may be withdrawn in the future, and in any event APD418 may not actually receive faster clinical development or regulatory review or approval any sooner than other product candidates that do not have such designation, or at all.

Our activities and drugs will still be subject to extensive postmarketing regulation if approved.

Following regulatory approval of any of our drug candidates, we and our collaborators will be subject to ongoing obligations and continued regulatory review from the FDA and other applicable regulatory agencies, such as continued adverse event reporting requirements. There may also be additional postmarketing obligations imposed by the FDA or other regulatory agencies. These obligations may result in significant expense and limit the ability to commercialize such drugs.

The FDA or other regulatory agencies may also require that the sponsor of the NDA or foreign equivalent, as applicable, conduct additional clinical trials to further assess approved drugs after approval under a post-approval commitment. Such additional studies may be costly and may impact the commercialization of the drug. Unfavorable trial results from postmarketing studies could negatively impact market acceptance of the drug, limit the revenues we generate from sales, result in the drug’s withdrawal from the market, negatively impact the potential approval of the drug in other territories and result in litigation.

The FDA or other regulatory agencies may also impose significant restrictions on the indicated uses for which a drug may be marketed. Additionally, the FDA may require a Risk Evaluation and Mitigation Strategies, or REMS, study, including in connection with a drug’s approval, to help ensure that the benefits of the drug outweigh its risks. A REMS may be required to include various elements, such as a medication guide or patient package insert, a communication plan to educate healthcare providers of the drug’s

risks, limitations on who may prescribe or dispense the drug, requirements that patients enroll in a registry or undergo certain health evaluations or other measures that the FDA deems necessary to ensure the safe use of the drug.

With regard to any drug that receives regulatory approval, the labeling, packaging, adverse event reporting, storage, advertising and promotion for the drug will be subject to extensive regulatory requirements. We and the manufacturers of our products are also required to comply with cGMP regulations, which include requirements relating to quality control and quality assurance, as well as the corresponding maintenance of records and documentation. Further, regulatory agencies must approve these manufacturing facilities before they can be used to manufacture our products, and these facilities are subject to ongoing regulatory inspections. In addition, regulatory agencies subject a drug, its manufacturer and the manufacturer’s facilities to continual review and inspections. The subsequent discovery of previously unknown problems with a drug, including adverse events of unanticipated severity or frequency, or problems with the facility where the drug is manufactured, may result in restrictions on the marketing of that drug, up to and including withdrawal of the drug from the market. In the United States, the DEA and comparable state-level agencies also heavily regulate the manufacturing, holding, processing, security, recordkeeping and distribution of drugs that are considered controlled substances, and the DEA periodically inspects facilities for compliance with its rules and regulations.

Our ability to generate revenues from any of our drugs that receive regulatory approval will be subject to a variety of risks, many of which are out of our control.

Any drug that may be approved for marketing may not gain market acceptance among patients, healthcare providers, healthcare payers or the medical community. We believe that the degree of market acceptance and our ability to generate revenues from such products will depend on a number of factors, including:

If our approved drugs fail to achieve market acceptance, we may not be able to generate significant revenues to be profitable.

Collaboration and license agreement relationships may lead to disputes, divert management’s attention, expose us to liability and delay drug development and commercialization, and we may not realize the full commercial potential of our drug candidates or drugs.

We may have conflicts with our prospective, current or past collaborators or licensees, such as conflicts concerning rights and obligations under our agreements (including, for example, relating to indemnification for product liability claims and losses), the interpretation of preclinical or clinical data, the achievement of milestone or other payments, the ownership of intellectual property, or research and development, regulatory, commercialization, litigation or other strategy. Collaborators or licensees may stop supporting our drug candidates or drugs, including if they no longer view the program as in their best financial or other interests or they develop or obtain rights to competing drug candidates or drugs. In addition, collaborators or licensees may fail to effectively develop, obtain approval for or commercialize our drugs, which may result in us not realizing their full commercial potential. If any conflicts arise with any of our current, past or prospective collaborators or licensees, the other party may act in a manner that is adverse to our interests. Any such disagreement could result in one or more of the following, each of which could delay, or lead to termination of, development or commercialization of our drug candidates or drugs, and in turn prevent us from generating revenues or cause us to incur liabilities:

Setbacks and consolidation in the pharmaceutical and biotechnology industries could make entering into agreements with pharmaceutical companies to collaborate or commercialize our drugs more difficult and diminish our revenues.

Setbacks in the pharmaceutical and biotechnology industries, such as those caused by safety concerns relating to drugs or drug candidates, as well as competition from generic drugs, litigation and industry consolidation, may have an adverse effect on us, including by making it more difficult to enter into agreements with pharmaceutical companies to collaborate or commercialize our drugs and diminishing our revenues. For example, the FDA may be more cautious in approving our drug candidates based on safety concerns relating to these or other drugs or drug candidates, or pharmaceutical companies may be less willing to enter into new collaborations or continue existing collaborations if they are integrating a new operation as a result of a merger or acquisition or if their therapeutic areas of focus change following a merger.

We and our collaborators rely on third parties to conduct clinical trials and preclinical studies. If those parties do not comply with regulatory and contractual requirements, successfully carry out their contractual obligations or meet expected deadlines, our drug candidates may not advance in a timely manner or at all.

In the course of our discovery, preclinical testing and clinical trials, we and our collaborators rely on third parties, including investigators, clinical research organizations, manufacturers and laboratories, to perform critical services. For example, we rely on third parties to conduct our clinical trials and many of our preclinical studies. Clinical research organizations are responsible for many aspects of the trials, including finding and enrolling participants for testing and administering the trials. Although we rely on these third parties to conduct our clinical trials, we are responsible for ensuring that each of our clinical trials is conducted in accordance with its investigational plan and protocol. Moreover, the FDA and foreign regulatory authorities require us to comply with regulations and standards, commonly referred to as Good Clinical Practices, or GCPs, for conducting, monitoring, recording and reporting the results of clinical trials to ensure that the data and results are scientifically credible and accurate and that the trial participants are adequately informed of the potential risks of participating in clinical trials. Our reliance on third parties does not relieve us of these responsibilities and requirements. These third parties may not be available when we need them or, if they are available, may not comply with all legal, regulatory and contractual requirements or may not otherwise perform their services in a timely or acceptable manner, and we may need to enter into new arrangements with alternative third parties and our preclinical studies or clinical trials may be extended, delayed or terminated. These independent third parties may also have relationships with other commercial entities, some of which may compete with us. In addition, if such third parties fail to perform their obligations in compliance with legal and

regulatory requirements and our protocols, our preclinical studies or clinical trials may not meet regulatory requirements or may need to be repeated. As a result of our dependence on third parties, we may face delays or failures outside of our direct control. These risks also apply to the development activities of collaborators, and we do not control their research and development, clinical trial or regulatory activities.

We may participate in new strategic transactions that could impact our liquidity, increase our expenses, present significant distractions to our management and be viewed as unfavorable.

From time to time we consider strategic transactions, such as out-licensing or in-licensing of compounds or technologies, acquisitions of companies, asset purchases and spin-offs. Additional potential transactions we may consider include a variety of different business arrangements, such as strategic collaborations, joint ventures, restructurings, divestitures, business combinations and investments. In addition, another entity may pursue us as an acquisition target. Any such transaction may be viewed as unfavorable by our stockholders or others and may require us to incur non-recurring or other charges, may create potential liabilities, may increase our near- and long-term expenditures and may pose significant integration challenges, require additional expertise or disrupt our management or business, which could harm our operations and financial results.

When we evaluate significant proposed transactions we conduct business, legal and financial due diligence with the goal of identifying and evaluating material risks involved in the transaction. Despite our efforts, we ultimately may be unsuccessful in ascertaining or evaluating all such risks and, as a result, might not realize the intended advantages of the transaction. If we fail to realize the expected benefits from any transaction we may consummate, whether as a result of unidentified risks, integration difficulties, regulatory setbacks or other events, our business, results of operations and financial condition could be adversely affected.

* We may incur substantial liabilities for any product liability claims or otherwise as a drug product developer.

We develop, test, manufacture and expect to commercialize drugs for use by humans. We face an inherent risk of product liability exposure related to the testing of our drug candidates in clinical trials, and a risk with the commercialization of lorcaserin (previously marketed in the United States as BELVIQ and BELVIQ XR) as well as any other drug that may be approved for marketing.

Whether or not we are ultimately successful in any product liability or related litigation, such litigation would consume substantial amounts of our financial and managerial resources, and might result in adverse publicity, all of which would impair our business. In addition, damages awarded in a product liability action could be substantial and could have a negative impact on our financial condition.

An individual may bring a liability claim against us if one of our drugs or drug candidates causes, or merely appears to have caused, an injury. Regardless of merit or eventual outcome, liability claims may result in:

We have limited product liability insurance that covers our clinical trials and products, as well as indemnification protection in certain of our collaboration or license agreements. Our insurance costs continue to rise, and we may not be able to maintain or obtain insurance coverage at a reasonable cost, we may not have insurance coverage that will be adequate to satisfy any liability that may arise, and our collaborators or licensees may not indemnify us, which could have an adverse effect on our results of operations and financial condition.

For example, in December 2016, we granted Eisai an exclusive, royalty-bearing license, or transferred intellectual property, to develop, manufacture and commercialize lorcaserin in all countries and territories of the world. Our subsidiary Arena Pharmaceuticals GmbH in Liquidation, or Arena GmbH, previously manufactured BELVIQ, as well as other products for commercialization or clinical trials, up until the sale of our manufacturing business to Siegfried effective March 31, 2018. Under our agreements with Eisai, we and Eisai will each bear 50% of losses arising from any alleged defective manufacturing of BELVIQ by Arena GmbH prior to the date of

the sale to Siegfried, and Eisai will be solely responsible for any expenses and losses associated with other product liability claims. In February 2020, the FDA requested that Eisai withdraw lorcaserin (previously marketed in the United States as BELVIQ and BELVIQ XR) from the U.S. market based on the FDA’s analysis of data from a study completed by Eisai and a change in the FDA’s risk-benefit assessment of BELVIQ, and regulators in other countries have taken similar steps. Eisai agreed to voluntarily withdraw lorcaserin products from the U.S. market, as requested by the FDA, and from foreign markets. Following these events, lawsuits relating to lorcaserin against us and others have been filed in the United States and abroad. Any damages awarded in connection with lorcaserin litigation could be substantial and have a negative impact on our financial condition. Eisai or others could also take the position that some or all claims fall outside their indemnification obligations, or they could be unable to indemnify us, in connection with litigation or other claims, and seeking to enforce rights to indemnification could require significant financial resources and management attention. Even if we are successful in defending against all claims or are fully indemnified or insured, such claims could still consume significant financial resources and management attention and result in adverse publicity, all of which could have a negative impact on our financial condition and our business.

We have significant contractual obligations that may adversely affect our cash flow, cash position and stock price.

We have long-term leases on real properties and other contractual obligations, and limited revenues. If we are unable to generate cash from operations in the future sufficient to meet our financial obligations we will need to obtain additional funds from other sources, and we may not be able to do so at all or on terms favorable to our stockholders or us.

Also, if we do not have sufficient cash in the future and are unable to generate cash from operations or obtain additional funds from other sources sufficient to meet our contractual obligations, we may have to delay or curtail some or all of our development and commercialization programs, sell or license some or all of our assets on terms that you or others may view as unfavorable, or default on obligations under our agreements.

* We may be subject, directly or indirectly, to federal, state, and international healthcare laws and regulations, including but not limited to fraud and abuse and false claims laws. If we are unable to comply, or have not fully complied, with such laws or regulations, we could face substantial penalties and prosecution.

In the United States, drug manufacturers and marketers are subject to various state and federal fraud and abuse laws, including, without limitation, the Federal Anti-Kickback Statute and Federal False Claims Act. There are similar laws in other countries. These laws may impact, among other things, the research, manufacturing, sales, marketing and education programs for our drugs.

The Federal Anti-Kickback Statute prohibits persons and entities from knowingly and willingly soliciting, offering, receiving or providing any remuneration, directly or indirectly, in exchange for or to induce either the referral of an individual, or the purchase, lease, order or the furnishing or arranging for, a good, item, facility or service, for which payment may be made, in whole or in part, under a federal healthcare program such as the Medicare and Medicaid programs. Several courts have interpreted the statute’s intent requirement to mean that if any one purpose of an arrangement involving remuneration is to induce referrals of federal healthcare covered business, the statute has been violated. The Federal Anti-Kickback Statute is broad and, despite a series of narrow statutory exceptions and regulatory safe harbors, prohibits many arrangements and practices that are lawful in businesses outside of the healthcare industry. Moreover, the ACA, among other things, amended the intent requirement of the Federal Anti-Kickback Statute and certain criminal healthcare fraud statutes. A person or entity no longer needs to have actual knowledge of these statutes or specific intent to violate them. The ACA also provides that the government may assert that 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 Civil False Claims Act. Many states have also adopted laws similar to the Federal Anti-Kickback Statute, some of which apply to the referral of patients for healthcare items or services reimbursed by any source, not only the Medicare and Medicaid programs.

The Federal Civil False Claims Act prohibits, among other things, persons or entities from knowingly presenting, or causing to be presented, a false claim to, or the knowing use of false statements to obtain payment from the federal government. Suits filed under the Federal Civil False Claims Act can be brought by any individual on behalf of the government, known as “qui tam” actions, and such individuals, commonly known as “whistleblowers,” may share in any amounts paid by the entity to the government in fines or settlement. The filing of qui tam actions has caused a number of pharmaceutical, medical device and other healthcare companies to have to defend a Federal Civil False Claims Act action. When an entity is determined to have violated the Federal Civil False Claims Act, it may be required to pay up to three times the actual damages sustained by the government, plus civil penalties for each separate false claim, in addition to other penalties that may apply. Various states have also enacted laws modeled after the Federal Civil False Claims Act, some of which are broader in scope and may apply regardless of payer.

The Federal Health Insurance Portability and Accountability Act of 1996, or HIPAA, created federal criminal statutes that prohibit, among other actions, knowingly and willfully executing, or attempting to execute, a scheme to defraud any healthcare benefit program, including private third-party payers, 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 statement in connection with the delivery of or payment for healthcare benefits, items or services. Additionally, the civil monetary penalties statute imposes penalties against any person or entity that, among other things, is determined to have presented or caused to be presented a claim to a federal health program that the person knows or should know is for an item or service that was not provided as claimed or is false or fraudulent.

The Federal Physician Payments Sunshine Act, created under the ACA, and its implementing regulations requires certain manufacturers of drugs, devices, biologicals and medical supplies for which payment is available under Medicare, Medicaid or the Children’s Health Insurance Program (with certain exceptions) to report annually to the U.S. Department of Health and Human Services, or HHS, information related to payments or other transfers of value made to physicians (defined to include doctors, dentists, optometrists, podiatrists and chiropractors) and teaching hospitals, as well as ownership and investment interests held by physicians and their immediate family members.

We may be subject to healthcare data privacy and security regulation by both the federal government and the states in which we conduct our business. HIPAA, as amended by the Health Information Technology for Economic and Clinical Health Act, or HITECH, and their respective implementing regulations, impose specified requirements on certain healthcare providers, health plans, and healthcare clearinghouses, known as covered entities, as well as their business associates that perform services involving the use or disclosure of individually identifiable health information relating to the privacy, security and transmission of individually identifiable health information. Further, we may also be subject to state health information privacy and data breach notification laws which govern the collection, use, disclosure, and protection of health-related and other personal information, many of which differ from each other in significant ways and often are not pre-empted by HIPAA, thus requiring additional compliance efforts.

Additionally, the Drug Supply Chain Security Act imposes obligations on manufacturers of pharmaceutical products, among others, related to product tracking and tracing. Among the requirements, manufacturers will be required to provide certain information regarding the drug product to individuals and entities to which product ownership is transferred, label drug product with a product identifier, and keep certain records regarding the drug product. The transfer of information to subsequent product owners by manufacturers will eventually be required to be done electronically. Manufacturers will also be required to verify that purchasers of the manufacturers’ products are appropriately licensed. Further, manufacturers will have drug product investigation, quarantine, disposition, and notification responsibilities related to counterfeit, diverted, stolen, and intentionally adulterated products, as well as products that are the subject of fraudulent transactions or which are otherwise unfit for distribution such that they would be reasonably likely to result in serious health consequences or death.

Outside the United States, interactions between pharmaceutical companies and physicians are also governed by strict laws, such as national anti-bribery and kickback laws of European countries, regulations, industry self-regulation codes of conduct, and physicians’ codes of professional conduct. Failure to comply with these requirements could result in reputational risk, public reprimands, administrative penalties, fines, or imprisonment. Risks associated with these laws may increase as new laws and regulations are adopted and as enforcement agencies adopt or increase enforcement efforts.

We are unable to predict whether we could be subject to actions under any of these fraud and abuse or other laws, or the impact of such actions. If we are found to be in violation of any of the laws described above and other applicable federal, state and international laws, we may be subject to penalties, including significant civil, criminal and/or administrative penalties, damages, fines, individual imprisonment, disgorgement, possible exclusion from government healthcare reimbursement programs, integrity oversight and reporting obligations to resolve allegations of non-compliance with these laws, and the curtailment or restructuring of our operations, all of which could have a material adverse effect on our business and results of operations.

* We may be subject to a variety of laws regarding data privacy and protection, which carry potentially significant penalties for non-compliance.

Across the United States and globally, laws and regulations governing data privacy and security continue to develop and evolve. The data privacy and security laws and regulations to which we are subject will likely impact (possibly significantly) our business activities. Many of the laws and regulations that apply to us contain ambiguous provisions or impose requirements that differ from country to country, creating uncertainty. Compliance with the enhanced obligations imposed by such laws and regulations may require us to revise our business practices, allocate more resources to privacy and security, and implement new technologies. Such efforts may result in significant costs to our business.

For example, the European Union, Switzerland and certain other foreign territories have restrictions on the transfer, use and maintenance of certain personal data, including providing that transfers of personal data outside of their territories may only take place if the country to which the personal data is transferred ensures an “adequate” level of privacy protection. The European Commission has previously found that the United States did not provide adequate levels of protection. In addition, the European Commission has approved a data protection regulation, known as the General Data Protection Regulation, or GDPR, which became effective on May

25, 2018. The GDPR contains provisions specifically directed at the processing of health information, higher sanctions and extra-territoriality measures intended to bring non-EU companies under the regulation. We conduct clinical trials in the EU, and in the future we may expand our business operations to include additional operations in the EU. With such expansion, we would be subject to increased governmental regulation, including the GDPR, in the EU countries in which we operate, including restrictions on data transfers that may negatively impact our ability and increase our costs to maintain international operations. Penalties for non-compliance with the GDPR are steep, with potential fines of up to 4% of our global revenue.

Additionally, the California Consumer Privacy Act, or CCPA, went into effect on January 1, 2020. The CCPA created new individual privacy rights for consumers (as that word is broadly defined in the law) and places increased privacy and security obligations on entities handling personal data of consumers or households. It requires covered companies to provide new disclosures to California consumers, provide such consumers new ways to opt-out of certain sales of personal information, and allow for a new cause of action for data breaches. The CCPA may impact our business activities and exemplifies the vulnerability of our business to not only cyber threats but also the evolving regulatory environment related to personal data and protected health information.

Failure to comply with data privacy and security laws and regulations could result in regulatory penalties and significant legal liability and could have a material adverse impact on our financial results.

* We may not be able to effectively integrate, manage or maintain our international operations, and such difficulty could adversely affect our business operations, financial condition, results of operations and stock price.

We have certain clinical operations personnel in Switzerland, and we engage in clinical trials and manufacturing activities in many territories outside of the United States. There are significant risks associated with foreign operations, including but not limited to:

We and third parties we contract with use hazardous materials in our operations.

Our activities involve the use of materials that could be hazardous to human health and safety or the environment. We cannot completely eliminate the risks associated with their use, storage or disposal, which could cause:

In such an event, we may be held liable for any resulting damages, and any such liability could exceed our resources. Although we carry insurance in amounts and type that we consider commercially reasonable, we cannot be certain that the coverage or coverage limits of our insurance policies will be adequate, and we do not have insurance coverage for losses relating to an interruption of our research and development efforts caused by contamination.

* Our business, including our preclinical and clinical programs, may be significantly and adversely affected by the COVID-19 pandemic.

Coronavirus disease 2019, or COVID-19, has spread globally, including in the United States and Switzerland, where we have operations, and in many other countries where we are conducting or plan to conduct clinical trials or perform manufacturing activities. COVID-19 is impacting domestic and worldwide economic activity, including global financial markets on which we rely for financing to fund our operations. The COVID-19 pandemic poses the risk that we or our clinical trial participants, employees, contractors, collaborators and vendors may be prevented from conducting certain clinical trials or other business activities for an indefinite period of time, including due to “stay-at-home” orders or shutdowns that have been or may be requested or mandated by governmental authorities. Beginning the week of March 16, 2020, substantially all of our workforce began working from home either all or substantially all of the time. The stay-at-home orders and our work-from-home policies may negatively impact productivity, disrupt our business and delay our development programs, and may delay our regulatory and commercialization timelines, the magnitude of which will depend, in part, on the length and severity of the restrictions and other limitations on our ability to conduct our business in the ordinary course.

The COVID-19 pandemic has impacted and may continue to impact our clinical programs, including our etrasimod, olorinab, and APD418 programs. For example, some clinical site activations and patient enrollment and screening rates have slowed. In addition, the multiple-ascending dose portion of the three-part, Phase 1 study of LP352, currently pursued by Longboard Pharmaceuticals, Inc. (a company we founded that was formerly wholly owned by us prior to October 2020), has been impacted by the ongoing COVID-19 pandemic, and this portion of the study is planned to be initiated in early 2021. These changes, however, have been highly variable and their aggregate impact remains uncertain. As a result, it is not possible at this time to estimate the impact COVID-19 could have on our clinical programs. If the COVID-19 pandemic continues to spread in the United States and around the world, we may experience, or continue to experience, disruptions that could severely impact our preclinical studies and clinical trials, including:

The COVID-19 pandemic continues to rapidly evolve. The extent to which the outbreak impacts our business, preclinical studies and clinical programs will depend on future developments, which are highly uncertain and cannot be predicted with confidence, such as the ultimate geographic spread of the disease, the duration of the pandemic, stay-at-home orders, travel restrictions and “social distancing” in the United States, Switzerland and other countries, business closures or business disruptions and the effectiveness of actions taken in the United States and other countries to contain and treat the disease.

* Our business and operations might be disrupted or adversely affected by catastrophic events and security breaches, including any cybersecurity incidents.

Our U.S. operations are primarily located in a business park in San Diego. We also have certain operations in Boston, Massachusetts, and Zug, Switzerland. We depend on our facilities and on collaborators, licensees, contractors and vendors for the continued operation of our business, some of whom are located in Europe and Asia. As a result, natural disasters or other catastrophic events in various parts of the world, including interruptions in the supply of natural resources, political and governmental changes, disruption in transportation networks or delivery services, severe weather conditions, wildfires and other fires, explosions, actions of animal rights activists, terrorist attacks, earthquakes, wars and public health issues (including the COVID-19 pandemic) could disrupt our operations or those of our collaborators, contractors and vendors or contribute to unfavorable economic or other conditions that could adversely impact us.

In addition, we depend on the efficient and uninterrupted operation of our computer and communications systems, which we use for, among other things, sensitive company data, including our financial data, intellectual property and other proprietary business information.

While certain of our operations have business continuity and disaster recovery plans and other security measures intended to prevent and minimize the impact of IT-related interruptions, our IT infrastructure and the IT infrastructure of our current and any future collaborators, contractors and vendors are vulnerable to damage from cyberattacks, computer viruses, unauthorized access, electrical failures and natural disasters or other catastrophic events. We could experience failures in our information systems and computer servers, which could result in an interruption of our normal business operations and require substantial expenditure of financial and administrative resources to remedy. System failures, accidents or security breaches can cause interruptions in our operations and can result in a material disruption of our research and development programs and other business operations. The loss of data from completed or future studies or clinical trials could result in delays in our research, development or regulatory approval efforts and significantly increase our costs to recover or reproduce the data. Similarly, we and our licensees rely on third parties to conduct studies and clinical trials of our drug candidates and manufacture our drug candidates, and similar events relating to these third parties’ computer systems could also have a material adverse effect on our business. To the extent that any disruption or security breach were to result in a loss of, or damage to, our data or applications, or inappropriate disclosure of confidential or proprietary information, we could incur liabilities and the development of any of our other drug candidates and the commercialization of drugs could be delayed or otherwise adversely affected.

Even though we believe we carry commercially reasonable business interruption and liability insurance, and our contractors may carry liability insurance that protect us in certain events, we might suffer losses as a result of business interruptions that exceed the coverage available under our and our contractors’ insurance policies or for which we or our contractors do not have coverage. For example, we are not insured against a terrorist attack. Any natural disaster or catastrophic event could have a significant negative impact on our operations and financial results. Moreover, any such event could delay our research and development programs and adversely affect, which may include stopping, our commercial production.

* We and our employees and directors may be named as defendants in litigation that could result in substantial costs and divert management’s attention.

Securities class action litigation may be brought against a company following a decline in the market price of its securities. This risk is especially relevant for us because companies in the pharmaceuticals industry often experience significant stock price volatility. For example, beginning in 2010, a number of lawsuits were filed against us and certain of our employees and directors alleging we and the other defendants violated the federal securities laws by making materially false and misleading statements regarding our lorcaserin trials, thereby artificially inflating the price of our common stock. These lawsuits were settled in 2018.

While we carry liability insurance, any losses we incur in connection with any current or future lawsuits may not be covered by insurance in an amount sufficient to cover our losses or at all, and our assets may be insufficient to cover any amounts that exceed our insurance coverage. We may have to pay damage awards or otherwise may enter into settlement arrangements in connection with any future claims. A settlement of any of future lawsuit against us could also involve the issuance of common stock or other equity, which may dilute your ownership interest. Any payments or settlement arrangements could have material adverse effects on our business, operating results, financial condition or your ownership interest. Even if the plaintiffs’ claims are not successful, any future lawsuit against us and/or our directors or executive officers could result in substantial costs and significantly and adversely impact our reputation and divert our management’s attention and resources, which could have a material adverse effect on our business, operating results or financial condition. In addition, any such lawsuits may make it more difficult to finance our operations, obtain certain types of insurance (including directors’ and officers’ liability insurance), and attract and retain qualified executive officers, other employees and directors.

* Negative U.S. and global economic conditions may pose challenges to our business strategy, which relies on funding from collaborators or the financial markets, and may create other financial risks for us.

While significant uncertainty remains as to the potential impact of the COVID-19 pandemic on our operations and liquidity, and on the global economy as a whole, the COVID-19 pandemic has already had a significant adverse impact on domestic and global economies, as well as global financial markets. Negative conditions in the U.S. or global economy, including financial markets, may adversely affect our business and the business of our current and prospective collaborators, distributors and licensees, which we sometimes refer to generally as our collaborators, and others with which we do or may conduct business. The duration and severity of these conditions is uncertain. If negative economic conditions persist or worsen, we may be unable to secure funding to sustain our operations or to find suitable collaborators to advance our internal programs, even if we achieve positive results from our research and development or business development efforts. Such negative conditions could also impact commercialization of any drugs we and our collaborators and licensees develop, as well as our financial condition. From time to time, we may maintain a portfolio of investments in marketable debt securities, which are recorded at fair value. Although we have established investment guidelines relative to diversification and maturity with the objectives of maintaining safety of principal and liquidity, we rely on credit rating agencies to help evaluate the riskiness of investments, and such agencies may not accurately predict such risk. In addition, such agencies may reduce the credit quality of our individual holdings, which could adversely affect their value. Lower credit quality and other market events, such as changes in interest rates and deterioration in credit markets, may have an adverse effect on the fair value of our investment holdings and cash position.

We primarily spend and generate cash in U.S. dollars and present our consolidated financial statements in U.S. dollars. However, a portion of our expected and potential payments and receipts, including relating to our Swiss operations and under certain of our agreements, are in foreign currencies. A fluctuation of the exchange rates of foreign currencies versus the U.S. dollar may, thus, adversely affect our financial results, including cash balances, expenses and revenues. We may in the future enter into hedging transactions to try to reduce our foreign currency exposure, but there is no assurance that such transactions will occur or be successful.

* Our ability to use net operating losses and certain other tax attributes to offset future taxable income or taxes may be limited.

As of December 31, 2019, we had federal and state net operating loss carryforwards of $933.2 million. Portions of our federal net operating loss carryforwards of $539.3 million will begin to expire, if not utilized, beginning in 2029, and our state net operating loss carryforwards of $393.9 million begin expiring in 2028. Our net operating loss carryforwards could expire unused and be unavailable to offset future income tax liabilities. In January 2019, a taxable income-generating event, the transaction pursuant to the United Therapeutics Agreement, resulted in it being more likely than not that a portion of our net operating loss carryforwards would be used to offset our estimates of taxable income in 2019. If the estimates we have made, or the assumptions on which we relied, in estimating our taxable income in 2019 prove inaccurate, our net operating loss carryforwards to be used to offset our taxable income in 2019 may vary from our estimates. Under the TCJA, as modified by the Coronavirus Aid, Relief, and Economic Security Act, or CARES Act, federal net operating losses incurred in 2018 and in future years may be carried forward indefinitely, but the deductibility of such federal net operating losses 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 federal tax laws. In addition, under Sections 382 and 383 of the Internal Revenue Code of 1986, as amended, 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 net operating loss carryforwards and other pre-change tax attributes to offset its post-change income or taxes may be limited. We have experienced ownership changes in the past and we may experience additional ownership changes in the future as a result of subsequent shifts in our stock ownership, some of which may be outside of our control. If an ownership change occurs and our ability to use our net operating loss carryforwards is materially limited, it would harm our future operating results by effectively increasing our future tax obligations.

Our success is dependent on intellectual property rights held by us and third parties and our interest in these rights is complex and uncertain.

Our success will depend on our own and on current or future collaborators’ abilities to obtain, maintain and defend patents. In particular, the patents directed to our drug candidates and drugs are important to developing and commercializing drugs and to our revenue. We have numerous U.S. and foreign patents issued and patent applications pending for our technologies. There is no assurance that any of our patent applications will issue, or that any of the patents will be enforceable or will cover a drug or other commercially significant technology or method, or that the patents will be held to be valid for their expected terms.

The procedures for obtaining a patent are complex. These procedures require an analysis of the scientific technology related to the invention and many sophisticated legal issues. Obtaining patent rights outside the United States often requires the translation of highly technical documents and an improper translation may jeopardize our patent protection. Ensuring adequate quality of translators and foreign patent attorneys is often very challenging. Consequently, the process for having our pending patent applications issue as patents will be difficult, complex, time consuming and expensive. Our patent position is very uncertain and we do not know when, or if, we will obtain additional patents, or if the scope of the patents obtained will be sufficient to protect our drugs, or be considered sufficient by parties reviewing our patent positions pursuant to a potential marketing, licensing or financing transaction.

In addition, other entities may challenge the validity or enforceability of our patents in litigation or administrative proceedings. We cannot make assurances as to how much protection, if any, our patents will provide if we attempt to enforce them or they are challenged. It is possible that a competitor or a generic pharmaceutical provider may successfully challenge our patents and those challenges may result in reduction or elimination of our patent coverage.

We also rely on confidentiality agreements and trade secrets to protect our technologies. However, such information is difficult to protect. We require our employees to contractually agree not to improperly use our confidential information or disclose it to others, but we may be unable to determine if our employees have conformed or will conform to their legal obligations under these agreements. We also enter into confidentiality agreements with prospective collaborators, collaborators, service providers and consultants, but we may not be able to adequately protect our trade secrets or other proprietary information in the event of any unauthorized use or disclosure or the lawful development by others of this information. Many of our employees and consultants were, and many of them may currently be, parties to confidentiality agreements with other pharmaceutical and biotechnology companies, and the use of our technologies could violate these agreements. In addition, third parties may independently discover our trade secrets or other proprietary information.

Some of our research and development collaborators and scientific consultants have rights to publish data and information to which we have rights. We generally seek to prevent our collaborators and consultants from disclosing scientific discoveries before we have the opportunity to file patent applications on such discoveries. In some of our collaborations, we do not control our collaborators’ ability to disclose their own discoveries under the collaboration and in some of our academic relationships we are limited to relatively short periods to review a proposed publication and file a patent application. If we cannot maintain confidentiality in connection with our collaborations and relationships, our ability to receive patent protection or protect our proprietary information will be impaired.

We believe that the United States is by far the largest single market for pharmaceuticals in the world. Because of the critical nature of patent rights to our industry, changes in U.S. patent laws could have a profound effect on our future profits, if any. It is unknown which, if any, patent laws will change, how changes to patent laws would ultimately be enforced by the courts and how they would impact our business.

A dispute regarding the infringement or misappropriation of our proprietary rights or the proprietary rights of others could be costly and result in delays or termination of our future research, development, manufacturing and sales activities.

Our commercial success depends upon our ability to develop and manufacture our drugs and drug candidates, market and sell drugs, and conduct our research and development activities without infringing or misappropriating the proprietary rights of others. There are many issued patents and pending patent applications owned by others relating to research and development programs that could be determined to be similar, identical or superior to ours or our licensors or collaborators. We may be exposed to future litigation by others based on claims that our drugs, drug candidates, technologies or activities infringe the intellectual property rights of others. Numerous issued patents and pending patent applications owned by others exist in the areas of our research and development, including some which purport to allow the patent holder to control the use of all drugs that modulate a particular drug target regardless of whether the infringing drug bears any structural resemblance to a chemical compound known to the patent holder at the time of patent filing. Numerous issued patents and pending patent applications owned by others also exist in the therapeutic areas in which we are developing drugs. There are also numerous issued patents and pending patent applications owned by others that are directed to chemical compounds or synthetic processes that may be necessary or useful to our research, development, manufacturing or commercialization activities. These could materially affect our ability to develop our drug candidates or manufacture, import or sell drugs, and our activities, or those of our licensors or collaborators, could be determined to infringe these patents. Because patent applications can take many years to issue, there may be currently pending applications, unknown to us, which may later result in issued patents that our drugs, drug candidates or technologies may infringe. There also may be existing patents owned by others, of which we are not aware, that our drug candidates or technologies may infringe. Further, there may be issued patents or pending patent applications owned by others in fields relevant to our business, of which we are or may become aware, that we believe (i) are invalid, unenforceable, or we do not infringe; (ii) relate to immaterial portions of our overall research and development, manufacturing and commercialization efforts; or (iii) in the case of pending patent applications, the resulting patent would not be granted or, if granted, would not likely be enforced in a manner that would materially impact such efforts. We cannot assure you that others holding any of these patents or patent applications will not assert infringement claims against us and seek

damages or enjoinment of our activities. We also cannot assure you that, in the event of litigation, we will be able to successfully assert non-infringement, unenforceability, invalidity or immateriality, or that any infringement claims will be resolved in our favor.

In addition, others may infringe or misappropriate our proprietary rights. We may have to institute costly legal action to protect our intellectual property rights, or we may not be able to afford the costs of enforcing or defending our intellectual property rights.

There could be significant litigation and other administrative proceedings in our industry that affect us regarding patent and other intellectual property rights. Any legal action or administrative action against us, or our collaborators, claiming damages or seeking to enjoin commercial activities relating to our research and development, manufacturing and commercialization activities could:

Furthermore, because of the substantial amount of pre-trial document and witness discovery required in connection with intellectual property litigation, there is a risk that some of our confidential information could be compromised. In addition, during the course of intellectual property litigation, there could be public announcements of the results of hearings, motions or other interim proceedings or developments. If securities analysts or investors perceive these results to be negative, it could have a substantial adverse effect on the trading price of our common stock.

We are aware of third-party patents, as well as third-party patent applications, that could adversely affect the potential commercialization of etrasimod. For example, we are aware of third-party patents, as well as a third-party patent application, with broad claims to administering an S1P modulator by starting with a lower dose and then increasing to a higher, standard daily dose. While we do not believe that any such claims that would cover the potential commercialization of etrasimod are valid and enforceable, we may be incorrect in this belief.

We have been contacted from time to time by third parties regarding their intellectual property rights, sometimes asserting that we may need a license to use their technologies. If we fail to obtain any required licenses or make any necessary changes to our technologies, we may become involved in expensive and time-consuming litigation or we may be unable to develop or commercialize some or all of our drugs or drug candidates.

We cannot predict the outcome of any litigation matter. For example, our existing patents could be invalidated, found unenforceable or found not to cover a generic form of our drugs.

Filing, prosecuting, defending and enforcing patents on all of our drug candidates throughout the world would be prohibitively expensive. The laws of some foreign countries do not protect intellectual property rights to the same extent as the laws of the United States, and many companies have encountered significant problems in protecting and defending such rights in foreign jurisdictions. Many countries, including certain countries in Europe, have compulsory licensing laws under which a patent owner may be compelled to grant licenses to third parties (for example, the patent owner has failed to “work” the invention in that country or the third party has patented improvements). In addition, many countries limit the enforceability of patents against government agencies or government contractors. In these countries, the patent owner may have limited remedies, which could materially diminish the value of the patent. Compulsory licensing of life-saving drugs is also becoming increasingly popular in developing countries either through direct legislation or international initiatives. Such compulsory licenses could be extended to include some of our drug candidates, which could limit our potential revenue opportunities. Moreover, the legal systems of certain countries, particularly certain developing countries, do not favor the aggressive enforcement of patents and other intellectual property protection, particularly those relating to pharmaceuticals, which makes it difficult for us to stop the infringement of our patents. Proceedings to enforce our patent rights in foreign jurisdictions could result in substantial cost and divert our efforts and attention from other aspects of our business.

* Our stock price will likely be volatile, and your investment in our stock could decline in value.

Our stock price has fluctuated historically. From January 1, 2019 to November 4, 2020, the market price of our stock was as low as $32.95 per share and as high as $90.19 per share. The stock market, particularly in recent years, has experienced significant volatility particularly with respect to pharmaceutical and biotechnology stocks, and this trend may continue. The ongoing COVID-19 pandemic, for example, has previously negatively affected the stock market and investor sentiment and has resulted in significant volatility, and the COVID-19 pandemic may have these effects in the future.

Very few drug candidates being tested will ultimately receive regulatory approval, and companies in our industry sometimes experience significant volatility in their stock price. Our stock price may fluctuate significantly depending on a variety of factors, including:

We are not able to control many of these factors. If our financial or scientific results in a particular period do not meet stockholders’ or analysts’ expectations, our stock price may decline, and such decline could be significant.

* Any future equity or debt issuances or other financing transactions may have dilutive or adverse effects on our existing stockholders.

We have been opportunistic in our efforts to obtain cash, and we expect we will evaluate various funding alternatives from time to time. We may issue additional shares of common stock or convertible securities that could dilute your ownership in our company and may include terms that give new investors rights that are superior to yours. We have effective registration statements to sell shares of our common stock and certain other securities, and we may elect to sell shares pursuant to such registration from time to time. In February 2020, we entered into a sales agreement with Credit Suisse Securities (USA) LLC, SVB Leerink LLC and Cantor Fitzgerald & Co., pursuant to which we may sell and issue shares of our common stock having an aggregate offering price of up to $250.0 million from time to time in transactions that are deemed to be “at-the-market offering” as defined in Rule 415(a)(4) under the Securities Act of 1933, as amended, or Securities Act. As of September 30, 2020, and the date of this report, we have not sold any shares of our common stock under the sales agreement.

Moreover, any issuances by us of equity securities may be at or below the prevailing market price of our common stock and in any event may have a dilutive impact on your ownership interest, which could cause the market price of our common stock to decline. In addition, we may also raise additional funds through the incurrence of debt or other financing transaction, and the investors may have rights superior to your rights in the event we are not successful and are forced to seek the protection of bankruptcy laws or the transaction may otherwise adversely affect our business prospects and existing stockholders.

Our executive officers and directors may sell shares of their stock, and these sales could adversely affect our stock price.

Sales of our stock by our executive officers and directors, or the perception that such sales may occur, could adversely affect the market price of our stock. Our executive officers and directors may sell stock in the future, either as part, or outside, of trading plans under Rule 10b5-1 of the SEC.

* There are a substantial number of shares of our common stock that may become eligible for future sale in the public market, and the sale of our common stock could cause the market price of our common stock to fall.

As of November 4, 2020, there were (i) options to purchase 8,908,566 shares of our common stock outstanding under our equity incentive plans at a weighted-average exercise price of $39.30 per share, (ii) 226,961 restricted stock unit awards outstanding under our equity incentive plans, (iii) performance restricted stock units outstanding under our equity incentive plans under which up to 403,320 shares of common stock may be issuable upon achievement of all specified performance goals, (iv) 2,306,058 additional shares of common stock remaining issuable under our Amended and Restated 2020 Long-Term Incentive Plan, and (v) 962,449 shares issuable under our 2019 Employee Stock Purchase Plan.

Once issued, the shares described above will be available for immediate resale in the public market. The market price of our common stock could decline as a result of such resales due to the increased number of shares available for sale in the market. As of November 4, 2020, there were 58,164,022 shares of our common stock outstanding.

The holders of our common stock and other securities may take actions that are contrary to your interests, including selling their stock.

A small number of stockholders may hold or acquire a significant amount of our outstanding stock. From time to time, there is a large short interest in our stock. These holders of such stock or positions may seek control of us, may support transactions that we or you do not believe are favorable, and may have interests that are different from yours. In addition, sales of a large number of shares of our stock by these large stockholders or other stockholders within a short period of time could adversely affect our stock price.

We may also be involved in disagreements with the holders of our stock, warrants or other securities in the future. Such disagreements may lead to proxy contests or litigation, which may be expensive and consume management’s time, involve settlements, the terms of which may not be favorable to us, or result in other negative consequences to our business.

Certain of our agreements, provisions in our charter documents, possible future agreements and Delaware law could delay or prevent a change in management or a takeover attempt that you may consider to be in your best interests.

There is a standstill provision in our transaction agreement with Eisai, and we may enter into agreements with similar provisions. In addition, we may in the future adopt a stockholders’ rights agreement, which would cause substantial dilution to any person who attempts to acquire us in a manner or on terms not approved by our board of directors. These provisions or agreements, as well as other provisions in our certificate of incorporation and bylaws and under Delaware law, could delay or prevent the removal of

directors and management and could make more difficult a merger, tender offer or proxy contest involving us that you may consider to be in your best interests. For example, our charter provisions:

* Our bylaws provides that the Court of Chancery of the State of Delaware and the federal district courts of the United States of America are the exclusive forums for substantially all disputes between us and our stockholders, which could limit our stockholders’ ability to obtain a favorable judicial forum for disputes with us or our directors, officers, or employees.

Our bylaws provide that the Court of Chancery of the State of Delaware will be the exclusive forum for (a) any derivative action or proceeding brought on behalf of us, (b) any action asserting a claim of breach of a fiduciary duty owed by any of our directors or any of our officers or other employees to us or our stockholders, (c) any action asserting a claim against us or any of our directors or any of our officers or other employees arising pursuant to any provision of the Delaware General Corporation Law, our certificate of incorporation or our bylaws, or (d) any action asserting a claim against us or any of our directors or any of our officers or other employee governed by the internal affairs doctrine. This provision does not apply to suits brought to enforce a duty or liability created by the Securities Act or the Exchange Act. Furthermore, Section 22 of the Securities Act creates concurrent jurisdiction for federal and state courts over all such Securities Act actions. Accordingly, both state and federal courts have jurisdiction to entertain such claims. To prevent having to litigate claims in multiple jurisdictions and the threat of inconsistent or contrary rulings by different courts, among other considerations, our bylaws further provides that, unless we consent in writing to the selection of an alternative forum, the federal district courts of the United States of America will be the exclusive forum for the resolution of any complaint asserting a cause of action arising under the Securities Act. While the Delaware courts have determined that such choice of forum provisions are facially valid, a stockholder may nevertheless seek to bring a claim in a venue other than those designated in the exclusive forum provisions. In such instance, we would expect to vigorously assert the validity and enforceability of the exclusive forum provisions of our bylaws. This may require significant additional costs associated with resolving such action in other jurisdictions and there can be no assurance that the provisions will be enforced by a court in those other jurisdictions.

These exclusive forum provisions may limit a stockholder’s ability to bring a claim in a judicial forum that it finds favorable for disputes with us or our directors, officers, or other employees, which may discourage lawsuits against us and our directors, officers and other employees. If a court were to find either exclusive forum provision in our bylaws to be inapplicable or unenforceable in an action, we may incur further significant additional costs associated with resolving the dispute in other jurisdictions, all of which could seriously harm our business.

Laws, rules and regulations, including relating to public companies, may be costly and impact our ability to attract and retain directors and executive officers.

Laws and regulations affecting public companies, including rules adopted by the SEC and by Nasdaq, judicial rulings and other laws and regulations, including, for example, of state, federal and foreign governments and relating to privacy, may result in increased costs to us, particularly as we continue to develop the required capabilities in the United States and abroad to develop and commercialize our products. These laws, rules and regulations could make it more difficult or costly for us to obtain certain types of insurance, including directors’ and officers’ liability insurance, and we may be forced to accept reduced policy limits and coverage or incur substantially higher costs to obtain the same or similar coverage. These laws, rules and regulations could also make it more difficult for us to attract and retain qualified persons to serve on our board of directors, on our board committees or as executive officers. We cannot estimate accurately the amount or timing of additional costs we may incur to respond to these laws, rules and regulations.

Changes in funding for the FDA, the SEC and other government agencies 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, 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. 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, 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.

The withdrawal of the United Kingdom from the European Union, commonly referred to as “Brexit,” may adversely impact our ability to obtain regulatory approvals of our product candidates in the European Union, result in restrictions or imposition of taxes and duties for importing our product candidates into the European Union, and may require us to incur additional expenses in order to develop, manufacture and commercialize our product candidates in the European Union.

Following the result of a referendum in 2016, the United Kingdom left the European Union on January 31, 2020, commonly referred to as “Brexit.” Pursuant to the formal withdrawal arrangements agreed between the United Kingdom and the European Union, the United Kingdom will be subject to a transition period until December 31, 2020, or the Transition Period, during which EU rules will continue to apply. Negotiations between the United Kingdom and the European Union are expected to continue in relation to the customs and trading relationship between the United Kingdom and the European Union following the expiry of the Transition Period.

Since a significant proportion of the regulatory framework in the United Kingdom applicable to our business and our product candidates is derived from EU directives and regulations, Brexit, following the Transition Period, could materially impact the regulatory regime with respect to the development, manufacture, importation, approval and commercialization of our product candidates in the United Kingdom or the European Union. For example, as a result of the uncertainty surrounding Brexit, the EMA relocated to Amsterdam from London. Following the Transition Period, the United Kingdom will no longer be covered by the centralized procedures for obtaining EU-wide marketing authorization from the EMA and, unless a specific agreement is entered into, a separate process for authorization of drug products, including our product candidates, will be required in the United Kingdom, the potential process for which is currently unclear. Any delay in obtaining, or an inability to obtain, any marketing approvals, as a result of Brexit or otherwise, would prevent us from commercializing our product candidates in the United Kingdom or the European Union and restrict our ability to generate revenue and achieve and sustain profitability. In addition, we may be required to pay taxes or duties or be subjected to other hurdles in connection with the importation of our product candidates into the European Union, or we may incur expenses in establishing a manufacturing facility in the European Union in order to circumvent such hurdles. If any of these outcomes occur, we may be forced to restrict or delay efforts to seek regulatory approval in the United Kingdom or the European Union for our product candidates, or incur significant additional expenses to operate our business, which could significantly and materially harm or delay our ability to generate revenues or achieve profitability of our business. Any further changes in international trade, tariff and import/export regulations as a result of Brexit or otherwise may impose unexpected duty costs or other non-tariff barriers on us. These developments, or the perception that any of them could occur, may significantly reduce global trade and, in particular, trade between the impacted nations and the United Kingdom.

Our disclosure controls and procedures and our internal control over financial reporting may not prevent potential errors and fraud.

Our management does not expect that our disclosure controls and procedures or our internal control over financial reporting will prevent all potential errors and fraud. A control system, no matter how well conceived and operated, can provide only reasonable, not absolute, assurance that the objectives of the control system are met. There are inherent limitations in all control systems, and no system of controls can provide absolute assurance that all control issues and instances of fraud, if any, or misstatements due to error, if any, within the company have been detected. While we believe that our disclosure controls and procedures and internal control over financial reporting are and have been effective at the reasonable assurance level, we intend to continue to examine and refine our disclosure controls and procedures and internal control over financial reporting and to monitor ongoing developments in these areas.

* Current and future tax laws and regulation could adversely affect our business and financial condition.

New income, sales, use or other tax laws, statutes, rules, regulations or ordinances could be enacted at any time, which could affect the tax treatment of our domestic and foreign earnings. Any new taxes could adversely affect our domestic and international business operations, and our business 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 TCJA significantly revised the Internal Revenue

Code of 1986, as amended. Future guidance from the Internal Revenue Service and other tax authorities with respect to the TCJA may affect us, and certain aspects of the TCJA could be repealed or modified in future legislation. For example, the CARES Act modified certain provisions of the TCJA. In addition, it is uncertain if and to what extent various states will conform to the TCJA, the 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 TCJA 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.

Changes or modifications in financial accounting standards, including those related to revenue recognition, may harm our results of operations.

From time to time, the Financial Accounting Standards Board, or FASB, either alone or jointly with other organizations, promulgates new accounting principles that could have an adverse impact on our financial position, results of operations or reported cash flows. Any difficulties in adopting or implementing any new accounting standard, or updating or modifying our internal controls as needed on a timely basis, could result in our failure to meet our financial reporting obligations, which could result in regulatory discipline and harm investors’ confidence in us. In addition, if we were to change our critical accounting estimates, including those related to the recognition of revenue, our operating results could be significantly affected.

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

Delaware		23-2908305
(State or other jurisdiction of incorporation or organization)		(I.R.S. Employer Identification No.)

6154 Nancy Ridge Drive, San Diego, CA		92121
(Address of principal executive offices)		(Zip Code)

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

Class		Number of Shares Outstanding
Common Stock, $0.0001 par value		58,164,022

PART I—FINANCIAL INFORMATION
Item 1.	Financial Statements	1
	Condensed Consolidated Balance Sheets - As of September 30, 2020, and December 31, 2019	1
	Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) - Three and Nine Months Ended September 30, 2020, and 2019	2
	Condensed Consolidated Statements of Stockholders’ Equity - Three and Nine Months Ended September 30, 2020, and 2019	3
	Condensed Consolidated Statements of Cash Flows - Nine Months Ended September 30, 2020, and 2019	5
	Notes to Unaudited Condensed Consolidated Financial Statements	6
Item 2.	Management’s Discussion and Analysis of Financial Condition and Results of Operations	12
Item 3.	Quantitative and Qualitative Disclosures About Market Risk	18
Item 4.	Controls and Procedures	18
PART II—OTHER INFORMATION
Item 1.	Legal Proceedings	20
Item 1A.	Risk Factors	21
Item 6.	Exhibits	49
Signatures		50

Level 1	-	Observable inputs such as unadjusted quoted prices in active markets for identical instruments.

Level 2	-	Quoted prices for similar instruments in active markets or inputs that are observable for the asset or liability, either directly or indirectly.

Level 3	-	Significant unobservable inputs based on our assumptions.

Large accelerated filer	☒	Accelerated filer	☐
Non-accelerated filer	☐	Small reporting company	☐
Emerging growth company	☐

	Fair Value Measurements Using
	Balance		Quoted Prices in Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
September 30, 2020:
Assets:
Money market funds(1)	$	388,943	$	388,943	$	—	$	—
US government and government agency notes(2)		409,494		409,494		—		—
Corporate debt instruments(2)		331,511		—		331,511		—
					.
December 31, 2019:
Assets:
Money market funds(1)	$	147,752	$	147,752	$	—	$	—
US government and government agency notes(3)		398,419		398,419		—		—
Corporate debt instruments(3)		483,788		—		483,788		—

September 30, 2020:	Maturity in years	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
US government and government agency notes	< 1	$	379,993	$	460	$	(16	)	$	380,437
Corporate debt securities	< 1		326,392		941		(51	)		327,282
Short-term investments, available-for-sale		$	706,385	$	1,401	$	(67	)	$	707,719

US government and government agency notes	1 – 5	$	29,055	$	2	$	—		$	29,057
Corporate debt securities	1 – 5		4,162		67		—			4,229
Investments, available-for-sale		$	33,217	$	69	$	—		$	33,286

December 31, 2019:	Maturity in years	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
US government and government agency notes	< 1	$	201,046	$	292	$	(5	)	$	201,333
Corporate debt securities	< 1		294,481		495		(18	)		294,958
Short-term investments, available-for-sale		$	495,527	$	787	$	(23	)	$	496,291

US government and government agency notes	1 – 5	$	197,157	$	85	$	(155	)	$	197,087
Corporate debt securities	1 – 5		173,322		603		(74	)		173,851
Investments, available-for-sale		$	370,479	$	688	$	(229	)	$	370,938

	Options			Weighted- Average Exercise Price
Outstanding at January 1, 2020		8,535		$	34.31
Granted		2,531			47.26
Exercised		(1,498	)		25.23
Forfeited/cancelled/expired		(598	)		43.19
Outstanding at September 30, 2020		8,970		$	38.89

In millions	Three months ended
	September 30,
Type of expense	2020		2019
External clinical and preclinical study fees	$	54.4	$	38.1
Salary and other personnel costs (excluding non-cash share-based compensation)		16.5		11.8
Non-cash share-based compensation		6.6		6.7
Facility costs		1.7		1.4
Other		0.6		2.3
Total research and development expenses	$	79.8	$	60.3

EXHIBIT NO.		DESCRIPTION

3.1		Fifth Amended and Restated Certificate of Incorporation of Arena (incorporated by reference to Exhibit 3.1 to Arena’s quarterly report on Form 10-Q for the quarter ended June 30, 2002, filed with the Securities and Exchange Commission on August 14, 2002, Commission File No. 000-31161)
3.2		Certificate of Amendment of the Fifth Amended and Restated Certificate of Incorporation of Arena (incorporated by reference to Exhibit 4.2 to Arena’s registration statement on Form S-8 filed with the Securities and Exchange Commission on June 28, 2006, Commission File No. 333-135398)
3.3		Certificate of Amendment No. 2 of the Fifth Amended and Restated Certificate of Incorporation of Arena, as amended (incorporated by reference to Exhibit 4.3 to Arena’s registration statement on Form S-8 filed with the Securities and Exchange Commission on June 30, 2009, Commission File No. 333-160329)
3.4		Certificate of Amendment No. 3 of the Fifth Amended and Restated Certificate of Incorporation of Arena, as amended (incorporated by reference to Exhibit 3.4 to Arena’s registration statement on Form S-8 filed with the Securities and Exchange Commission on June 20, 2012, Commission File No. 333-182238)
3.5		Certificate of Amendment No. 4 of the Fifth Amended and Restated Certificate of Incorporation of Arena, as amended (incorporated by reference to Exhibit 3.1 to Arena’s current report on Form 8-K filed with the Securities and Exchange Commission on June 15, 2017, Commission File No. 000-31161)
3.6		Certificate of Amendment No. 5 of the Fifth Amended and Restated Certificate of Incorporation of Arena, as amended (incorporated by reference to Exhibit 3.1 to Arena’s current report on Form 8-K filed with the Securities and Exchange Commission on June 16, 2020, Commission File No. 000-31161)
3.7		Amended and Restated Bylaws of Arena (incorporated by reference to Exhibit 3.2 to Arena’s current report on Form 8-K filed with the Securities and Exchange Commission on June 16, 2020, Commission File No. 000-31161)
4.1		Form of common stock certificate (incorporated by reference to Exhibit 4.7 to Arena’s registration statement on Form S-8, filed with the Securities and Exchange Commission on June 22, 2017, Commission File No. 333-218905)
10.1*		Arena’s Amended and Restated 2020 Long-Term Incentive Plan, amended as of October 14, 2020
31.1		Certification of principal executive officer pursuant to Rule 13a-14(A) promulgated under the Securities Exchange Act of 1934
31.2		Certification of principal financial officer pursuant to Rule 13a-14(A) promulgated under the Securities Exchange Act of 1934
32.1		Certification of principal executive officer and principal financial officer pursuant to 18 U.S.C. Section 1350 and Rule 13a-14(B) promulgated under the Securities Exchange Act of 1934
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		Cover Page Interactive Data File (formatted as inline XBRL with applicable taxonomy extension information contained in Exhibit 101. INS)

Date:	November 9, 2020	ARENA PHARMACEUTICALS, INC.

		By:	/s/ Amit D. Munshi
			Amit D. Munshi
			President and Chief Executive Officer (principal executive officer)

		By:	/s/ Laurie D. Stelzer
			Laurie D. Stelzer
			Executive Vice President and Chief Financial Officer (principal financial and accounting officer)