10-K

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

Indicate by check mark if the Registrant is not required to file reports pursuant to Section 13 or 15(d) of the Act. Yes ☐ No ☒

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, 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 has filed a report on and attestation to its management’s assessment of the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report. ☒

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

The aggregate market value of the voting and non-voting common equity held by non-affiliates of the Registrant, based on the closing price of the shares of common stock on The New York Stock Exchange on June 30, 2021, was $1,378,544,861. This excludes 7,359,105 shares of the Registrant’s Common Stock held by executive officers, directors and stockholders affiliated with directors, as well as 13,813,029 shares held by Gilead Sciences, Inc. at June 30, 2021. Exclusion of such shares should not be construed to indicate that any such person possesses the power, direct or indirect, to direct or cause the direction of the management or policies of the registrant or that such person is controlled by or under common control with the registrant.

The number of shares of Registrant’s Common Stock outstanding as of February 12, 2022 was 71,061,867.

This Annual Report on Form 10-K (Annual Report) includes forward-looking statements. All statements regarding future events, results or other future matters contained in this Annual Report are forward-looking statements, including, but not limited to, statements about:

The words “believe,” “may,” “will,” “estimate,” “continue,” “anticipate,” “design,” “intend,” “expect,” “could,” “plan,” “potential,” “predict,” “seek,” “should,” “would” or the negative version of these words and similar expressions are intended to identify forward-looking statements. We have based these forward-looking statements on our current expectations and projections about future events and trends that we believe may affect our financial condition, results of operations, strategy, short- and long-term business operations and objectives and financial needs.

These forward-looking statements are subject to a number of risks, uncertainties and assumptions, including those described in the Risk Factor Summary below and in Item 1A of this Annual Report, “Risk Factors.” Moreover, we operate in a very competitive and rapidly changing environment. New risks emerge from time to time. It is not possible for our management to predict all risks, nor can we assess the impact of all factors on our business or the extent to which any factor, or combination of factors, may cause actual results to differ materially from those contained in any forward-looking statements we may make. In light of these risks, uncertainties and assumptions, the forward-looking events and circumstances discussed in this Annual Report may not occur and actual results could differ materially and adversely from those anticipated or implied in the forward-looking statements.

You should not rely upon forward-looking statements as predictions of future events. Although we believe that the expectations reflected in the forward-looking statements are reasonable, we cannot guarantee that the future results, advancements, discoveries, levels of activity, performance or events and circumstances reflected in the forward-looking statements will be achieved or occur. Moreover, except as required by law, neither we nor any other person assumes responsibility for the accuracy and completeness of the forward-looking statements. We undertake no obligation to update publicly any forward-looking statements for any reason after the date of this Annual Report to conform these statements to actual results or to changes in our expectations.

In addition, statements that “we believe” and similar statements reflect our beliefs and opinions on the relevant subject. These statements are based upon information available to us as of the date of this Annual Report on Form 10-K, and while we believe such information forms a reasonable basis for such statements, such information may be limited or incomplete, and our statements should not be read to indicate that we have conducted an exhaustive inquiry into, or review of, all potentially available relevant information. These statements are inherently uncertain and investors are cautioned not to unduly rely upon these statements.

We are a clinical-stage biopharmaceutical company focused on creating best-in-class cancer therapies. Using our robust and highly efficient drug discovery capability, we have now advanced six investigational products into clinical development, with our most advanced molecule, an anti-TIGIT antibody, now in two Phase 3 registrational studies. Our deep portfolio of novel small molecules and enabling antibodies allows us to create highly differentiated combination therapies, which we are developing to treat multiple large tumor types including lung, colorectal, prostate and pancreatic cancers. We expect our clinical-stage portfolio to continue to expand and to include molecules targeting both immuno-oncology and cancer cell-intrinsic pathways. Our vision is to create, develop and commercialize highly differentiated combination cancer therapies that have a meaningful impact on patients.

The following chart summarizes our clinical pipeline and ongoing clinical studies. In 2020, we entered into an Option, License and Collaboration Agreement (Gilead Collaboration Agreement) with Gilead Sciences, Inc. (Gilead), whereby Gilead obtained an exclusive license to zimberelimab and time-limited exclusive options to all of our then-current and future programs during the 10-year collaboration term. In December 2021, Gilead obtained rights to an additional four of our investigational products: domvanalimab, etrumadenant, quemliclustat and AB308, for which we subsequently received a total of $725 million in option exercise payments. For each program to which Gilead exercised or exercises its option, the parties will co-develop globally and co-commercialize the program in the U.S., subject to certain exceptions, and Gilead will have the right to commercialize the program outside of the United States, subject to the rights of our existing partners in certain territories. In 2017, we entered into an Option and License Agreement (Taiho Agreement) with Taiho Pharmaceutical Co., Ltd. (Taiho) pursuant to which Taiho has time-limited options to exclusively license the development and commercialization rights to each of our programs for Japan and certain other territories in Asia (excluding China). Taiho has exercised its option rights to our adenosine receptor antagonist program (including etrumadenant), our anti-PD-1 program (including zimberelimab), and, in November 2021, it exercised its option right to our anti-TIGIT program (including domvanalimab and AB308).

Doce: docetaxel; dom: domvanalimab; durva: durvalumab; etruma: etrumadenant; gem/nab-pac: gemcitabine/nab-paclitaxel; quemli: quemliclustat; rego: regorafenib; zim: zimberelimab

CRC: colorectal cancer; mCRPC: metastatic castrate-resistant prostate cancer; NSCLC: non-small cell lung cancer; PDAC: pancreatic ductal adenocarcinoma

Our clinical-stage portfolio of six investigational products includes three enabling antibodies and three potentially first- and/or best-in-class small molecules:

We conduct our clinical trials in the U.S. and internationally in geographic regions that are impacted by COVID-19 to varying degrees. While we have seen relatively robust enrollment across our ongoing Arcus-sponsored studies, we expect to see volatility as local governments respond to resurgences and the emergence of new strains, each of which may result in the prolonged reinstitution, extension or enhancement of shelter-in-place measures. The American Cancer Society has also reported that the pandemic has led to declines in screening, diagnosis and treatment for cancer patients, which will impact the enrollment of patients in clinical trials targeting early-stage cancers and retention of patients overall in our trials. Patient safety remains our paramount concern and we continue to collaborate with our existing and with new investigational sites to implement measures to minimize disruptions to patients and ensure continued access to treatment, in accordance with health authority guidance. We are unable to predict the full impact of this pandemic on our clinical programs.

Our overarching vision is to create a broad portfolio of best-in-class oncology therapeutics and develop combinations that bring transformative clinical benefits over current treatment options. Our clinical development approach aims to generate meaningful data in the most efficient manner possible in order to rapidly advance our investigational products through clinical trials. Some of the key elements of our strategy include:

We currently have three enabling antibodies in clinical development: two anti-TIGIT antibodies and an anti-PD-1 antibody.

Because of our early belief that anti-TIGIT antibodies have the potential to become the next backbone immunotherapy, we in-licensed domvanalimab in 2016 and are rapidly advancing this molecule through clinical development, including the initiation of our first registrational trial in 2021.

TIGIT is now widely believed to play an important role in suppressing the immune response to cancer. The primary ligand for TIGIT (T-cell immunoreceptor with Ig and ITIM domains) is CD155, a protein that plays both inhibitory and stimulatory roles in regulating the activity of effector immune cells such as T and NK cells. TIGIT is an inhibitory receptor highly expressed on T cells displaying an exhausted phenotype, tumor-infiltrating Treg, and NK cells. During the past couple of years, expression of TIGIT, along with PD-1, on precursor exhausted T cells (Tpex), a key population that mediates some of the therapeutic effects of anti-PD-1 agents, has become well documented. The ligands for TIGIT, including CD155, are broadly expressed on multiple cell types in the tumor microenvironment, including cancer cells. CD155 binding to TIGIT results in inhibition of immune cells. In December 2021, Roche announced data from their randomized Phase 2 CITYSCAPE trial, investigating their anti-TIGIT antibody combined with their anti-PD-L1 antibody compared with their anti-PD-L1 antibody alone, in PD-L1-positive metastatic non-small cell lung cancer. The data demonstrated that the addition of the anti-TIGIT antibody improved overall response rates and reduced the risk of disease worsening or death.

As T cells are important in the immune response, domvanalimab was engineered to lack Fc-receptor binding in order to minimize the risk of depleting such cells, which we believe may provide domvanalimab with an advantage over Fc-enabled anti-TIGIT antibodies.

In our Phase 1 dose-escalation study of domvanalimab, we demonstrated the ability to achieve complete target coverage at very low doses. We have established three intravenous dosing schedules (every 2 weeks, 3 weeks and 4 weeks) to give us flexibility based on the dosing regimen of the combination partners.

Our ongoing ARC-7 study is a 150-patient, randomized Phase 2 study evaluating the combination of domvanalimab plus zimberelimab (to which we refer as the “doublet”) vs. domvanalimab plus zimberelimab plus etrumadenant (to which we refer as the “triplet”) vs. zimberelimab monotherapy in first-line metastatic, PD-L1≥50% NSCLC. We initiated this study in early 2020 based on our strong belief that anti-TIGIT antibodies can build upon the efficacy of monotherapy anti-PD-(L)1 treatment in this patient population. In our second interim analysis in 2021, both domvanalimab combination arms demonstrated differentiated activity compared to that of zimberelimab alone and the triplet arm numerically outperformed the doublet arm. No unexpected safety signals were observed in the second

interim analysis and the safety profile for each arm of the ARC-7 study appeared to be consistent with known immune checkpoint inhibitors in this setting. We expect to present data from this study in the second half of 2022.

Our first registrational trial for domvanalimab, ARC-10, is evaluating domvanalimab in combination with zimberelimab versus zimberelimab monotherapy versus chemotherapy in the same patient population as ARC-7. This trial has been designed to support potential regulatory filings for both domvanalimab and zimberelimab combination therapy and zimberelimab monotherapy. In addition, in January 2022, AstraZeneca initiated the registrational PACIFIC-8 trial, which is evaluating domvanalimab in combination with durvalumab following chemoradiation in Stage 3 NSCLC, a setting in which durvalumab is already approved. With Gilead, we expect to initiate at least two new registrational trials for domvanalimab in combination with other therapies in various tumor types in 2022.

There has been significantly increased activity from competitors evaluating anti-TIGIT combination therapies across multiple tumor types. In particular, Beigene, Genentech and Merck all have substantial clinical development programs for their anti-TIGIT antibodies, with multiple Phase 2 and Phase 3 studies ongoing.

We believe that we are one of a few companies with both an Fc-silent and Fc-enabled anti-TIGIT antibody in clinical development, and that an Fc-enabled anti-TIGIT antibody may allow us to extend the activity of our TIGIT portfolio to certain tumor types, including hematologic malignancies. Similarly to an Fc-silent anti-TIGIT antibody, an Fc-enabled anti-TIGIT antibody can also block the effects of TIGIT in those cells that express TIGIT. In addition, an Fc-enabled anti-TIGIT antibody is able to engage with Fc receptors on immune cells, inducing antibody dependent cellular toxicity, or death, of TIGIT-expressing cells, such as hematological cancer cells that express TIGIT.

In 2021, we initiated ARC-12, our Phase 1/1b study for AB308, identified a recommended dose for AB308 in combination with zimberelimab and opened the expansion cohorts. We are now enrolling the following five expansion cohorts of ARC-12: first-line NSCLC, second-line melanoma, second-line cervical cancer, second-line gastric / esophageal cancer, late-line diffuse large B-cell lymphoma and multiple myeloma.

In 2017, we in-licensed zimberelimab, a fully human IgG4 antibody, from WuXi Biologics. We are currently using zimberelimab as the cornerstone of our combination strategy and evaluating it with various intra-portfolio combination partners in nearly all our ongoing clinical studies. Our global registrational ARC-10 study includes a zimberelimab monotherapy arm and is designed to support the potential approval of zimberelimab as monotherapy. To date, we have evaluated zimberelimab, either alone or in combination with other agents, in over 700 patients.

Etrumadenant is a small molecule targeting the ATP-adenosine pathway. Under conditions of cellular damage or cell death, such as in response to certain chemotherapies, large amounts of adenosine triphosphate (ATP) are released into the extracellular environment, where it is converted into adenosine monophosphate by the enzyme CD39 and then into adenosine by the enzyme CD73. The generation of large amounts of extracellular adenosine results in an immunosuppressive response that counteracts some of the potentially beneficial effects of chemotherapy.

Etrumadenant, which is an orally bioavailable, highly potent and reversible antagonist of the adenosine A2aand A2b receptors, is unlike most other clinical-stage adenosine receptor antagonists, which only target one of the two receptors. We believe that activation of the A2a receptors on T cells and NK cells mediates a significant portion of the immunosuppressive effects of adenosine but that binding of adenosine to A2b receptors on myeloid cells also contributes significantly to intra-tumoral immune suppression; consequently, etrumadenant could prove to have more robust anti-tumor effects and activity in a broader range of tumor types than other A2a or A2b antagonists in clinical development.

We have evaluated etrumadenant across multiple tumor types and with different combination therapies, including with zimberelimab and standard-of-care chemotherapies. In all these studies, etrumadenant demonstrated a tolerable safety profile.

We have three ongoing additional studies evaluating etrumadenant combinations against active comparators:

In January 2022, we announced that etrumadenant in combination with zimberelimab and chemotherapy arm did not show differentiated activity compared to zimberelimab plus chemotherapy in our ARC-4 study in patients with EGFR+ NSCLC that have progressed on at least one tyrosine kinase inhibitor therapy; as a result, we have de-prioritized this clinical setting.

All these studies are designed to support the potential of etrumadenant in multiple types that represent substantial market opportunities with significant unmet need. In 2022, we expect to initiate additional clinical studies for etrumadenant, including the triplet combination of etrumadenant, domvanalimab and zimberelimab.

Quemliclustat targets the ATP-adenosine pathway, specifically the CD73 enzyme, which plays a critical role in the last step of the process of extracellular ATP conversion into adenosine. CD73 inhibition should therefore be a highly effective approach to inhibiting adenosine-mediated immune suppression, as it could significantly suppress adenosine generation.

We believe quemliclustat was the first small-molecule CD73 inhibitor to enter clinical development. While there are several anti-CD73 antibodies in development, we believe that a small-molecule approach to CD73 inhibition could offer several advantages, including more complete inhibition of CD73 enzymatic activity, deeper tumor penetration, and potential for both intravenous and oral delivery.

We are currently evaluating quemliclustat in ARC-8, our Phase 1/1b clinical study in metastatic pancreatic cancer, in combination with gemcitabine and nab-paclitaxel, standard-of-care chemotherapies used for advanced pancreatic cancer, plus zimberelimab. In 2021, we completed enrollment of both the dose-expansion and randomized portions of this study in first-line metastatic pancreatic cancer patients. The 90-patient randomized portion is evaluating quemliclustat plus gemcitabine/nab-paclitaxel ± zimberelimab and is designed to determine whether an anti-PD-1 antibody adds activity to the combination to inform our Phase 3 study design. We expect to present the results from the randomized portion of ARC-8 in the second half of 2022.

In 2021, we also initiated another cohort within ARC-8 to evaluate quemliclustat plus gemcitabine/nab-paclitaxel plus zimberelimab in second-line metastatic pancreatic cancer, an area of significant unmet need. We expect to initiate new clinical studies to explore quemliclustat in additional tumor types.

HIF-2α is a master transcriptional regulator of multiple genes involved in tumor progression. In 2021, the first HIF-2α inhibitor, belzutifan (WELIREG™), was approved by the FDA for the treatment of patients with VHL disease who require therapy for associated RCC.

AB521 is our oral, small-molecule inhibitor of HIF-2α and is our first investigational product against a cancer cell-intrinsic target to enter clinical development. In addition to having activity in VHL-associated RCC, we believe that AB521 could have activity in other tumor types, particularly when combined with our investigational products targeting the CD73-adeonsine pathway.

In 2021, we initiated our healthy volunteer study for AB521 (ARC-14) which is designed to provide information on the pharmacokinetic properties and safety profile of this molecule, and to determine the starting dose for our Phase 1 study of AB521 in cancer patients. These data might also provide important information on the potential competitive advantages of AB521 relative to other HIF-2α inhibitors. We expect to share initial data from this study in the first half of 2022 and to start our Phase 1 study in cancer patients in mid-2022.

We have active early-stage discovery efforts focused on the creation of additional development candidates aimed at regulating various aspects of the anti-tumor immune response as well as other cancer-intrinsic pathways which we believe play an important role in many human cancers. These include AB598, our recently selected antibody development candidate that targets CD39, which represents another key node along the ATP-adenosine pathway and rounds out our portfolio of ATP-adenosine targeting molecules, as well as several small molecules aimed at modulating key biological pathways in various types of cancer that are responsible for the abnormal growth and resistance to current therapies.

In 2021, we added a research collaboration to our Gilead Collaboration Agreement under which we will lead the discovery and early development of drug candidates against two novel oncology targets jointly selected by us and Gilead.

We have also initiated our first research program for a non-oncology target; this program is supported with funding from BVF Partners and is focused on the discovery and development of a potentially first-in-class small molecule that may be useful in a wide range of inflammatory conditions.

Subject to timely exercise of their respective option rights, the Taiho Agreement provides us with a potential commercialization partner for Japan and certain other Asian countries, and the Gilead Collaboration Agreement provides us with a potential commercialization partner for the rest of the world. Under our Gilead Collaboration Agreement, we retain co-promotion rights for the U.S. Therefore, we intend to build the necessary infrastructure and sales, marketing and commercial product distribution capabilities to co-promote our products, if approved, for the United States. Clinical data, the size of the addressable patient population, and the size of the commercial infrastructure and manufacturing needs may all influence or alter our commercialization plans.

In May 2020, we entered into the Gilead Collaboration Agreement, a Common Stock Purchase Agreement, and an Investor Rights Agreement, (collectively, the Gilead Agreements), each with Gilead. Pursuant to the Gilead Collaboration Agreement, Gilead obtained an exclusive license to zimberelimab and time-limited exclusive options to all of our then-current and future clinical programs during the 10-year collaboration term, and, for those programs that enter clinical development prior to the end of the collaboration term, for up to an additional three years thereafter. Gilead's option rights for the 10-year collaboration term were contingent upon payments totaling $400 million consisting of a $100 million payment due on the second anniversary and an additional $100 million of payments due at Gilead's option on each of the fourth, sixth, and eighth anniversaries of the agreement. Gilead's option, on a program-by-program basis, will expire after a prescribed period, following the achievement of a clinical development milestone in such program and our delivery to Gilead of the requisite data package. Gilead may exercise its option, on a program-by-program basis, at any time prior to the expiration of the option and upon payment of an option fee ranging from $200 million to $275 million per program for our clinical programs in existence at the date of the agreement, and $150 million per program for all of our other programs that enter clinical development thereafter. With respect to our anti-TIGIT program, we would also be eligible to receive up to $500 million in potential U.S. regulatory approval milestones with respect to domvanalimab.

Upon closing of Gilead’s exercise of its option to a program, the two companies will co-develop and equally share global development costs for the joint development program, subject to opt-out rights applicable to certain programs, expense caps on our spending and true-up adjustments. For each optioned program, provided we have not exercised our opt-out rights (if applicable), we have an option to co-promote in the United States with equal sharing of related profits and losses. Gilead has the right to exclusively commercialize any optioned programs outside of the

U.S., subject to the rights of our existing partners to any territories, and Gilead will pay to us tiered royalties as a percentage of revenues ranging from the high teens to the low twenties.

The Gilead Collaboration Agreement is subject to termination by either party for the other party’s uncured material breach or insolvency, and by Gilead with sufficient prior written notice. Other customary termination rights are further provided in the Gilead Collaboration Agreement.

Pursuant to the Gilead Collaboration Agreement, upon closing, Gilead made a $175 million upfront cash payment and obtained an exclusive license to our zimberelimab program.

In November 2021, we entered into an amendment to our Gilead Collaboration Agreement under which Gilead exercised its options to three programs—our anti-TIGIT program (including domvanalimab and AB308), adenosine receptor antagonist program (including etrumadenant) and CD73 program (including quemliclustat). In connection with Gilead’s exercise of its options to three programs, the parties agreed to (i) slightly reduce the royalties for these programs, such that Gilead will pay us tiered royalties as a percentage of revenues ranging from the mid-teens to the low twenties and (ii) remove the $100 million option continuation payment due on the second anniversary of the Gilead Collaboration Agreement.

In addition, the parties agreed to collaborate on two research programs for which we will lead discovery and early development activities. With respect to these two research programs, Gilead has the right to exercise its option, on a program-by-program basis, upon our completion of certain IND-enabling activities for an option payment of $60 million. If the option is exercised by Gilead at this stage, the collaboration terms for optioned programs will be applicable to each research program except, with respect to commercialization outside of the U.S., Gilead would pay us tiered royalties as a percentage of revenues ranging from high single digits to low double digits. If Gilead declines to exercise its option at this stage, Gilead maintains an option, on a program-by-program basis, which must be exercised prior to the expiration of a prescribed period following the achievement of a clinical development milestone in such program and our delivery to Gilead of the requisite data package. If the option is exercised by Gilead at this later clinical stage for an option payment of $150 million, the collaboration terms for optioned programs will be applicable to the joint development program including that, with respect to commercialization outside of the U.S., Gilead would pay us tiered royalties as a percentage of revenues ranging from the high-teens to the low twenties.

With Gilead's exercise to these three programs, Gilead has exercised its option to all of the clinical programs in existence at the date of the 2020 agreement, and we may not exercise our opt-out rights for any of these programs. With respect to domvanalimab, we remain eligible to receive up to $500 million in potential U.S. regulatory approval milestones. The amendment transaction closed in December 2021 and we received option payments totaling $725 million for the three option exercises in January 2022.

In addition to the Gilead Collaboration Agreement, we and Gilead entered into a Common Stock Purchase Agreement and Investor Rights Agreement. Under the Common Stock Purchase Agreement, Gilead made an upfront equity investment of $200 million by purchasing from us 5,963,029 shares of our common stock at a purchase price of $33.54 per share. Gilead also has the right, at its option, to purchase additional shares from us, up to a maximum ownership of 35% of our then-outstanding voting common stock, from time to time over five years from closing of the initial Gilead Agreements, at a purchase price per share equal to the greater of a 20% premium to market (based on a trailing five-day average closing price) at the time Gilead exercises such option, and the $33.54 initial purchase price. In January 2021, we and Gilead entered into an Amended and Restated Common Stock Purchase Agreement, which amended and restated in its entirety the Common Stock Purchase Agreement, pursuant to which Gilead purchased from us 5,650,000 shares of our common stock at a purchase price of $39.00 per share. The Investor Rights Agreement includes a three-year standstill and a two-year lockup and provides Gilead with registration rights commencing at the end of the lockup period, pro rata participation rights in certain future financings and the right to designate two individuals to be appointed to our Board of Directors.

In 2017, we entered into the Taiho Agreement, pursuant to which Taiho provided $35.0 million of non-refundable, non-creditable cash payments to us during the first three years of the agreement in exchange for an exclusive option to in-license development and commercialization rights to clinical stage investigational products from our portfolio (each, an Arcus Program) arising during a five-year period ending September 2022 (the Option Period) for Japan and certain other territories in Asia (excluding China) (the Taiho Territory). As of December 31, 2019, Taiho had paid us the full $35.0 million obligation pursuant to the terms of the agreement. If Taiho elects to exercise any such

options, Taiho is obligated to pay an option exercise payment for each option exercise of between $3.0 million to $15.0 million, with the amount dependent on the development stage of the applicable Arcus Program for which the option is exercised. In addition, Taiho is obligated to pay to us clinical, regulatory and commercialization milestones of up to $275.0 million with respect to each program for which Taiho exercises the option, as well as royalties on net sales in Taiho’s territories ranging from high single digits to mid-teens. Royalties will be payable on a licensed product-by-licensed product and country-by-country basis during the period of time commencing on the first commercial sale of a licensed product in a country and ending upon the later of: (i) ten (10) years from the date of first commercial sale of such licensed product in such country; and (ii) expiration of the last-to-expire valid claim of our patents covering the manufacture, use or sale or exploitation of such licensed product in such country.

In November 2021, Taiho exercised its option to our anti-TIGIT program (including domvanalimab and AB308). Taiho previously exercised its option to our adenosine receptor antagonist program (including etrumadenant) and our anti-PD-1 program (including zimberelimab). As of December 31, 2021, we have received option fees totaling $26.0 million under the Taiho Agreement. Upon such exercises, Taiho is responsible for the development and commercialization of licensed products from within the programs in the Taiho Territory.

This agreement will remain in effect until expiry of all royalty terms for the licensed products.

Our PD-1 license agreement (the WuXi PD-1 Agreement) with WuXi Biologics Ireland Limited (successor-in-interest to WuXi Biologics (Cayman) Inc., WuXi Biologics), which we entered into in 2017 as subsequently amended, provides us with an exclusive license to develop, use, manufacture, and commercialize products that include an anti-PD-1 antibody, including zimberelimab, throughout the world except for Greater China. From the inception of the WuXi PD-1 Agreement through December 31, 2021, we have made upfront and milestone payments totaling $41.0 million and incurred sub-license fees of $11.3 million. We may be required to make additional clinical and regulatory milestone payments, commercialization milestone payments up to $375.0 million, and royalty payments that range from high single-digits to low teens of net sales beginning on the first commercial sale and ending on the later of (i) ten (10) years following such first commercial sale and (ii) the expiry of all patents that may subsequently be issued or granted that cover the product in such country, hereafter referred to as the royalty term. We are also required to pay WuXi Biologics a percentage in the low double digits of certain sublicense income that we receive from our sublicensees in direct connection with our sublicensees’ rights to use WuXi Biologics’s patents, patent applications and know-how. For the year ended December 31, 2021, we made milestone payments of $10.0 million, recorded within research and development expense, and incurred no sub-license fees under the WuXi PD-1 Agreement.

We are obligated to appoint WuXi Biologics as our exclusive manufacturer of such licensed products for a specified period of time subject to certain exceptions. Our sublicensees, however, may manufacture, at any time, certain portions of their requirements for such product subject to certain conditions. We made certain covenants not to commercialize any anti-PD-1 antibody licensed or obtained by us after the date of the license agreement with WuXi Biologics other than anti-PD-1 antibodies licensed from WuXi Biologics, subject to certain exceptions as set forth in the WuXi Agreement. This agreement terminates, on a licensed product-by-licensed product and country-by-country basis, on expiration of the royalty term for such licensed product for the applicable country.

In 2016, we entered into a license agreement (the Abmuno Agreement) with Abmuno Therapeutics LLC (Abmuno) for a worldwide exclusive license to develop, use, manufacture, and commercialize products that include an anti-TIGIT antibody, including domvanalimab. Under the agreement, we have made upfront and milestone payments totaling $14.6 million as of December 31, 2021 and we may be required to make additional clinical, regulatory and commercialization milestone payments of up to $93.0 million.

The Abmuno Agreement terminates on the latest of (i) the expiry of the last-to-expire Abmuno licensed patent that covers a product that contains an anti-TIGIT antibody, (ii) the date on which there is no longer an Abmuno licensed patent application that is still pending and has been pending for a certain period of time that covers a product that contains an anti-TIGIT antibody and (iii) 10 years from the date of first commercial sale.

We do not own or operate, and currently have no plans to establish, any manufacturing facilities. We rely, and expect to continue to rely, on third parties for the manufacture of our investigational products for preclinical and clinical testing, as well as for commercial manufacture if any of our investigational products obtain marketing approval. We also rely, and expect to continue to rely, on third parties to package, label, store and distribute our investigational products, as well as for our commercial products if marketing approval is obtained. We believe that this strategy allows us to maintain a more efficient infrastructure by eliminating the need for us to invest in our own manufacturing facilities, equipment and personnel while also enabling us to focus our expertise and resources on the development of our investigational products. Our third-party contract manufacturers are operating at or near normal levels despite the continuing COVID-19 pandemic; however, some of our supply chain logistics providers have been more challenged by prolonged government-imposed lockdowns. We are actively monitoring our manufacturing and supply chain needs in order to prevent or minimize the impact of any disruptions to our clinical programs.

To date, we have obtained active pharmaceutical ingredients (API) and drug product for our investigational products from single-source third party contract manufacturers. We are in the process of developing our supply chain for each of our investigational products and intend to put in place framework agreements under which third-party contract manufacturers will generally provide us with necessary quantities of API and drug product on a project-by-project basis based on our development needs. With respect to zimberelimab, we agreed, as part of our license agreement with WuXi Biologics, that WuXi Biologics would be our exclusive manufacturer of zimberelimab with respect to clinical and commercial supplies until a certain number of years after marketing approval for zimberelimab, subject to certain exceptions.

As we advance our investigational products through development, we will consider our lack of redundant supply for the API and drug product for each of our investigational products to protect against any potential supply disruptions. We generally expect to rely on third parties for the manufacture of any companion diagnostics we may develop.

The pharmaceutical and biotechnology industries are characterized by rapidly advancing technologies, intense competition and a strong emphasis on proprietary products. While we believe that our technology, development experience and scientific knowledge provide us with competitive advantages, we face potential competition from many different sources, including large pharmaceutical and biotechnology companies, academic institutions, government agencies and other public and private research organizations that conduct research, seek patent protection and establish collaborative arrangements for the research, development, manufacturing and commercialization of cancer immunotherapies. Any investigational products that we successfully develop and commercialize will compete with new immunotherapies that may become available in the future.

We will compete in the segments of the pharmaceutical, biotechnology and other related markets that develop immuno-oncology treatments. There are many other companies that have commercialized and/or are developing immuno-oncology treatments for cancer including large pharmaceutical and biotechnology companies, such as AstraZeneca, Beigene, Bristol-Myers Squibb, Merck, Novartis, Pfizer, Regeneron in partnership with Sanofi Genzyme, and Roche/Genentech.

For our anti-TIGIT antibodies, domvanalimab and AB308, we are aware of several pharmaceutical companies developing antibodies against this target, including Agenus, Beigene, Biothera, Bristol-Myers Squibb, Compugen, Roche/Genentech, Innovent, iTeos/GSK, Junshi/Coherus, Merck, EMD Serono, Mereo and SeaGen. AstraZeneca and Innovent are developing TIGIT-PD-1 bispecific antibodies. To our knowledge, there are no approved anti-TIGIT antibodies and the most advanced agents are in Phase 3 development.

For our dual adenosine receptor antagonist, etrumadenant, we are aware that Incyte and Merck KGaA have initiated clinical development of dual adenosine receptor antagonists and we are aware of clinical-stage selective adenosine A2aR antagonists being developed by other companies, including AstraZeneca, Corvus, CStone, Exscientia, Incyte, iTeos, Novartis and Tarus, and clinical-stage selective adenosine A2bR antagonists being developed by Palobiofarma, Tarus and Teon. To our knowledge, there are no adenosine receptor antagonists approved for the treatment of cancer and the most advanced is in Phase 2 development.

For our small molecule CD73 inhibitor, quemliclustat, we are aware of several pharmaceutical companies developing antibodies against this target, including Akeso, AstraZeneca, Bristol-Myers Squibb, Corvus, Incyte, Innate, Innovent, Jacobio, Novartis, Shanghai Henlius Biotech, Symphogen/Servier and Tracon/I-Mab, all of whom have advanced their CD73 antibodies into clinical development. Other pharmaceutical companies have

small-molecule programs against this target, of which only Antengene and ORIC are believed to be in clinical development. To our knowledge, there are no approved CD73 molecules and the most advanced is in Phase 3 development.

For our anti-PD-1 antibody, zimberelimab, multiple large pharmaceutical companies have already received regulatory approvals for their anti-PD-1/PD-L1 antibodies, including AstraZeneca, Bristol-Myers Squibb, Merck, Pfizer in partnership with Merck KGaA, Regeneron in partnership with Sanofi Genzyme and Roche/Genentech, and there are also many other anti-PD-1 and anti-PD-L1 antibodies in clinical development.

For our HIF-2α inhibitor, AB521, we are aware that Merck received approval for belzutifan in 2021. Other pharmaceutical companies, including Novartis and NiKang Therapeutics have small-molecule HIF-2α inhibitors in development. Arrowhead Pharmaceuticals has an RNA-based anti-HIF-2α agent in Phase 2 development.

Many of the companies against which we may compete have significantly greater financial resources and expertise in research and development, manufacturing, preclinical testing, conducting clinical trials, obtaining regulatory approvals and marketing approved drugs than we do. Mergers and acquisitions in the pharmaceutical, biotechnology and diagnostic industries may result in even more resources being concentrated among a smaller number of our competitors. Smaller or early-stage companies may also prove to be significant competitors, particularly through collaborative arrangements with large and established companies. These potential competitors also compete with us in recruiting and retaining qualified scientific and management personnel and establishing clinical trial sites and enrolling subjects for our clinical trials, as well as in acquiring technologies complementary to, or necessary for, our programs.

We could see a reduction or elimination of our commercial opportunity if our competitors develop and commercialize products that are safer, more effective, have fewer or less severe side effects, are more convenient or are less expensive than any products that we or our collaborators may develop. Our competitors also may obtain FDA or foreign regulatory approval for their products more rapidly than we may obtain approval for ours, which could result in our competitors establishing a strong market position before we or our collaborators are able to enter the market. The key competitive factors affecting the success of all of our investigational products, if approved, are likely to be their efficacy, safety, convenience, price, the effectiveness of companion diagnostics (if required), the level of biosimilar or generic competition and the availability of reimbursement from government and other third-party payors.

Our commercial success depends in large part on our ability to obtain and maintain patent protection in the United States and other countries for our investigational products, to operate without infringing valid and enforceable patents and proprietary rights of others, and to prevent others from infringing on our proprietary or intellectual property rights. We seek to protect our proprietary position by filing, in the United States and other foreign jurisdictions, patent applications intended to cover the composition of matter of our investigational products, their methods of use, and related discoveries, technologies, inventions and improvements that may be commercially important to our business. We may also rely on trade secrets to protect aspects of our business that are not amenable to, or that we do not consider appropriate for, patent protection. We also intend to take advantage of regulatory protection afforded through data exclusivity, market exclusivity and patent term extensions where available.

As of February 1, 2022, we have issued U.S. patents directed to compositions of matter with respect to our PD-1, adenosine receptor antagonist, CD73 inhibitor and TIGIT programs. As of February 1, 2022, our company-owned and licensed patent portfolio consists of 35 pending or issued U.S. patent applications, 4 pending Patent Cooperation Treaty (PCT) patent applications, and approximately 295 pending or issued foreign patent applications directed to compositions of matter, methods of synthesis and methods of use. The term of any patents that issue will vary in accordance with the laws of each jurisdiction, but is typically 20 years from the earliest effective filing date. Our issued patents and any patents that may issue in the future from our company-owned or licensed pending applications are projected to expire between 2035 and 2042, absent any patent term adjustments or extensions.

The patent positions for biotechnology and pharmaceutical companies like us are generally uncertain and can involve complex legal, scientific and factual issues. Changes in either the patent laws or their interpretation in the United States and other countries may diminish our ability to protect our investigational products and enforce the patent rights that we own or license, and could affect the value of such intellectual property. With respect to both company-owned and licensed intellectual property, we cannot guarantee that the patent applications we are currently

pursuing or may file in the future will issue as patents in any particular jurisdiction or whether the claims of any issued patents will provide sufficient proprietary protection from competitors. Our competitors may independently develop similar investigational products or technologies that are outside the scope of the rights granted under any issued patents that we own or exclusively in-license. We cannot be sure that any patents granted to us will be commercially useful in protecting our products or their methods of use or manufacture. Moreover, even issued patents do not guarantee us the right to commercialize our products. For example, third parties may have blocking patents that could be used to prevent us from commercializing or manufacturing our investigational products.

Because of the extensive time required for development, testing and regulatory review of an investigational product, it is possible that, before a product can be commercialized, any patent protection for such product may expire or remain in force for only a short period following commercialization, thereby reducing the commercial advantage the patent provides. In the United States, the term of a patent covering an FDA-approved product may, in certain cases, be eligible for a patent term extension under the Hatch-Waxman Act as compensation for the loss of patent term during the FDA regulatory review process. The period of extension may be up to five years, but cannot extend the remaining term of a patent beyond a total of 14 years from the date of product approval. Only one patent among those eligible for an extension and only those claims covering the approved product, a method for using it or a method for manufacturing it may be extended. Similar provisions are available in Europe and in certain other jurisdictions to extend the term of a patent that covers an approved product. While we intend to seek patent term extensions in any jurisdictions where they are available, there is no guarantee that the applicable authorities, including the FDA, will agree with our assessment of whether such extensions should be granted, and even if granted, the length of such extensions.

Government authorities in the United States, at the federal, state and local level, and in other countries and jurisdictions, including the European Union, extensively regulate, among other things, the research, development, testing, manufacture, quality control, approval, packaging, storage, recordkeeping, labeling, advertising, promotion, distribution, marketing, post-approval monitoring and reporting, and import and export of therapeutic products. The processes for obtaining regulatory approvals in the United States and in foreign countries and jurisdictions, along with subsequent compliance with applicable statutes and regulations and other regulatory authorities, require the expenditure of substantial time and financial resources.

In the United States, the Food and Drug Administration (FDA) regulates drugs and biological products under the Federal Food, Drug, and Cosmetic Act (FDCA), the Public Health Service Act (PHSA), and implementing regulations. These laws and other federal and state statutes and regulations, govern, among other things, the research, development, testing, manufacture, storage, recordkeeping, approval, labeling, promotion and marketing, distribution, post-approval monitoring and reporting, sampling, and import and export of therapeutic products. The process of obtaining regulatory approvals and the subsequent compliance with applicable federal, state, local and foreign statutes and regulations require the expenditure of substantial time and financial resources. Failure to comply with applicable U.S. requirements may subject a company to a variety of administrative or judicial sanctions, such as clinical hold, FDA refusal to approve pending regulatory applications, warning or untitled letters, product recalls, product seizures, total or partial suspension of production or distribution, injunctions, fines, civil penalties, and criminal prosecution.

The process required by the FDA before a drug or biological product may be marketed in the United States generally includes the following:

Satisfaction of FDA pre-market approval requirements typically takes many years and the actual time required may vary substantially based upon the type, complexity, and novelty of the investigational product or disease. A clinical hold may occur at any time during the life of an IND and may affect one or more specific trials or all trials conducted under the IND.

Preclinical tests include laboratory evaluation of an investigational product’s chemistry, formulation, and toxicity, as well as animal trials to assess the characteristics and potential safety and efficacy of the investigational product. The conduct of the preclinical tests must comply with federal regulations and requirements, including GLP. The results of preclinical testing are submitted to the FDA as part of an IND along with other information, including information about an investigational product’s chemistry, manufacturing and controls, and a proposed clinical trial protocol. Long term preclinical tests, such as animal tests of reproductive toxicity and carcinogenicity, may continue after the IND is submitted. A 30-day waiting period after the submission of each IND is required prior to the commencement of clinical testing in humans. If the FDA has neither commented on nor questioned the IND within this 30-day period, the clinical trial proposed in the IND may begin. Clinical trials involve the administration of the investigational product to healthy volunteers or subjects under the supervision of a qualified investigator. Clinical trials must be conducted: (i) in compliance with federal regulations; (ii) in compliance with GCP, an international standard meant to protect the rights and health of subjects and to define the roles of clinical trial sponsors, administrators, and monitors; as well as (iii) under protocols detailing the objectives of the trial, the parameters to be used in monitoring safety, and the effectiveness criteria to be evaluated. Each protocol involving testing on U.S. subjects and subsequent protocol amendments must be submitted to the FDA as part of the IND.

The FDA may order the temporary or permanent discontinuation of a clinical trial at any time, or impose other sanctions if it believes that the clinical trial either is not being conducted in accordance with FDA requirements or presents an unacceptable risk to the clinical trial subjects. The trial protocol and informed consent information for subjects in clinical trials must also be submitted to an institutional review board (IRB) for approval. An IRB may also require the clinical trial at the site to be halted, either temporarily or permanently, for failure to comply with the IRB’s requirements, or may impose other conditions. The study sponsor may also suspend a clinical trial at any time on various grounds, including a determination that the subjects are being exposed to an unacceptable health risk.

Clinical trials to support NDAs/BLAs for marketing approval are typically conducted in three sequential phases, but the phases may overlap. In Phase 1, the initial introduction of the investigational product usually into healthy human subjects, the investigational product is tested to assess metabolism, pharmacokinetics, pharmacological actions, side effects associated with increasing doses, and, if possible, early evidence on effectiveness. Phase 2 usually involves trials in a limited patient population to determine the effectiveness of the investigational product for a particular indication, dosage tolerance, and optimal dosage, and to identify common adverse effects and safety risks. If an investigational product demonstrates evidence of effectiveness and an acceptable safety profile in Phase 2

evaluations, Phase 3 trials are undertaken to obtain additional information about clinical efficacy and safety in a larger number of subjects, typically at geographically dispersed clinical trial sites, to permit the FDA to evaluate the overall benefit risk relationship of the investigational product and to provide adequate information for the labeling of the investigational product. In most cases, the FDA requires two adequate and well-controlled Phase 3 clinical trials to demonstrate the efficacy of the investigational product. A single Phase 3 trial may be sufficient in certain circumstances.

Concurrent with clinical trials, sponsors usually complete additional animal safety studies and also develop additional information about the chemistry and physical characteristics of the investigational product and finalize a process for manufacturing commercial quantities of the investigational product in accordance with cGMP requirements. The manufacturing process must be capable of consistently producing quality batches of the investigational product and the manufacturer must develop methods for testing the quality, purity and potency of the investigational product. Additionally, appropriate packaging must be selected and tested and stability studies must be conducted to demonstrate that the investigational product does not undergo unacceptable deterioration over its proposed shelf-life. After completion of the required clinical testing, an NDA, for a drug investigational product, or a BLA, for a biological investigational product, is prepared and submitted to the FDA. FDA approval of the NDA or BLA is required before marketing of the product may begin in the United States. The NDA or BLA must include the results of all preclinical, clinical, and other testing and a compilation of data relating to the investigational product’s pharmacology, chemistry, manufacture, and controls. The cost of preparing and submitting an NDA or BLA is substantial. The submission of most NDAs and BLAs is additionally subject to a substantial application user fee, and the applicant under an approved NDA or BLA is also subject to program user fees. These fees are typically increased annually.

The FDA has 60 days from its receipt of an NDA or BLA to determine whether the application will be accepted for filing based on the agency’s threshold determination that it is sufficiently complete to permit substantive review. The FDA may refuse to file any NDA or BLA that it deems incomplete or not properly reviewable at the time of submission, and may request additional information. In this event, the NDA or BLA must be resubmitted with the additional information and the resubmitted application also is subject to review before the FDA accepts it for filing. Once the submission is accepted for filing, the FDA begins an in-depth review. The FDA has agreed to certain performance goals in the review of NDAs and BLAs. Most such applications for standard review investigational products are reviewed within ten months of the date the FDA files the NDA or BLA; most applications for priority review investigational products are reviewed within six months of the date the FDA files the NDA or BLA. Priority review can be applied to an investigational product that the FDA determines has the potential to treat a serious or life-threatening condition and, if approved, would be a significant improvement in safety or effectiveness compared to available therapies. The review process for both standard and priority review may be extended by the FDA for three additional months to consider certain late-submitted information, or information intended to clarify information already provided in the submission.

Among other things, the FDA reviews an NDA to determine whether the product is safe and effective for its intended use, a BLA to determine whether the product is safe, pure, and potent, and in each case, whether the investigational product is being manufactured in accordance with cGMP. The FDA may also refer applications for novel investigational products, or investigational products that present difficult questions of safety or efficacy, to an advisory committee—typically a panel that includes clinicians and other experts—for review, evaluation, and a recommendation as to whether the application should be approved. The FDA is not bound by the recommendation of an advisory committee, but it generally follows such recommendations.

Before approving an NDA or BLA, the FDA will typically inspect one or more clinical sites to assure compliance with GCP. Additionally, the FDA will inspect the facility or the facilities at which the investigational product is manufactured. The FDA will not approve the investigational product unless it determines that the manufacturing processes and facilities are in compliance with cGMP requirements and adequate to assure consistent production of the product within required specifications. To assure GCP and cGMP compliance, an applicant must incur significant expenditures of time, money and effort in the areas of training, record keeping, production and quality control.

Notwithstanding the submission of relevant data and information, the FDA may ultimately decide that the NDA or BLA does not satisfy the criteria for approval and deny approval. Data obtained from clinical trials are not always conclusive. The FDA may disagree with our trial design or interpret data from preclinical studies and clinical trials differently than we interpret the same data. If the agency decides not to approve the NDA or BLA in its present

form, the FDA will issue a complete response letter that describes all of the specific deficiencies in the application identified by the FDA. The deficiencies identified may be minor, for example, requiring labeling changes, or major, for example, requiring additional clinical trials. If a complete response letter is issued, the applicant may either resubmit the NDA or BLA, addressing the deficiencies identified in the letter, or withdraw the application. If, or when, those deficiencies have been addressed to the FDA’s satisfaction in a resubmission of the NDA or BLA, the FDA will issue an approval letter. An approval letter authorizes commercial marketing of the drug or biological product in the United States with specific prescribing information for specific indications.

Even if an investigational product receives regulatory approval, the approval may be significantly limited to specific indications and dosages or the indications for use may otherwise be limited, which could restrict the commercial value of the product. Further, the FDA may require that certain contraindications, warnings or precautions be included in the product labeling. The FDA may impose restrictions and conditions on product distribution, prescribing, or dispensing in the form of a risk evaluation and mitigation strategy (REMS), or otherwise limit the scope of any approval. REMS can include medication guides, communication plans for healthcare professionals, and elements to assure safe use (ETASU). ETASU can include, but are not limited to, special training or certification for prescribing or dispensing, dispensing only under certain circumstances, special monitoring, and the use of patient registries. The requirement for a REMS can materially affect the potential market and profitability of the product. In addition, the FDA may require post marketing clinical trials, sometimes referred to as “Phase 4” clinical trials, designed to further assess a product’s safety and effectiveness, and testing and surveillance programs to monitor the safety of approved products that have been commercialized.

The FDA will accept as support for an IND, NDA, or BLA a well-designed, well-conducted, non-IND foreign clinical trial if it was conducted in accordance with GCP and the FDA is able to validate the data from the trial through an on-site inspection, if necessary. A sponsor or applicant who wishes to rely on a non-IND foreign clinical trial to support an IND must submit the following supporting information to the FDA to demonstrate that the trial conformed to GCP:

Regulatory applications based solely on foreign clinical data meeting these criteria may be approved if the foreign data are applicable to the U.S. population and U.S. medical practice, the trials have been performed by clinical

investigators of recognized competence, and the data may be considered valid without the need for an on-site inspection by FDA or, if FDA considers such an inspection to be necessary, FDA is able to validate the data through an on-site inspection or other appropriate means. Failure of an application to meet any of these criteria may result in the application not being approvable based on the foreign data alone.

The FDA has various programs, including Fast Track, priority review, accelerated approval and breakthrough therapy, which are intended to expedite or simplify the process for reviewing investigational products, or provide for the approval of an investigational product on the basis of a surrogate endpoint. Even if an investigational product qualifies for one or more of these programs, the FDA may later decide that the investigational product no longer meets the conditions for qualification or that the time period for FDA review or approval will be lengthened. Generally, investigational products that are eligible for these programs are those for serious or life-threatening conditions, those with the potential to address unmet medical needs and those that offer meaningful benefits over existing treatments. For example, Fast Track is a process designed to facilitate the development and expedite the review of investigational products to treat serious or life-threatening diseases or conditions and fill unmet medical needs. Priority review is designed to give an investigational product that treats a serious condition and, if approved, would provide a significant improvement in safety or effectiveness, an initial review within eight months as compared to a standard review time of twelve months.

Although Fast Track and priority review do not affect the standards for approval, the FDA will attempt to facilitate early and frequent meetings with a sponsor of a Fast Track designated investigational product and expedite review of the application for an investigational product designated for priority review. Accelerated approval provides for an earlier approval for a new investigational product that meets the following criteria: is intended to treat a serious or life-threatening disease or condition, generally provides a meaningful advantage over available therapies and demonstrates an effect on a surrogate endpoint that is reasonably likely to predict clinical benefit or on a clinical endpoint that can be measured earlier than irreversible morbidity or mortality (IMM) that is reasonably likely to predict an effect on IMM or other clinical benefit. A surrogate endpoint is a laboratory measurement or physical sign used as an indirect or substitute measurement representing a clinically meaningful outcome. As a condition of approval, the FDA may require that a sponsor of an investigational product receiving accelerated approval perform post-marketing clinical trials to verify and describe the predicted effect on irreversible morbidity or mortality or other clinical endpoint, and the product may be subject to accelerated withdrawal procedures.

In addition to the Fast Track, accelerated approval and priority review programs discussed above, the FDA also provides Breakthrough Therapy designation. A sponsor may seek FDA designation of an investigational product as a “breakthrough therapy” if the investigational product is intended, alone or in combination with one or more other therapeutics, to treat a serious or life-threatening disease or condition, and preliminary clinical evidence indicates that the investigational product may demonstrate substantial improvement over existing therapies on one or more clinically significant endpoints, such as substantial treatment effects observed early in clinical development.

Under the Orphan Drug Act, the FDA may grant orphan drug designation to a drug or biological product intended to treat a rare disease or condition—generally a disease or condition that affects fewer than 200,000 individuals in the United States, or if it affects more than 200,000 individuals in the United States, there is no reasonable expectation that the cost of developing and making a product available in the United States for such disease or condition will be recovered from sales of the product.

Orphan drug designation must be requested before submitting a marketing application for the therapeutic for that particular disease or condition. After the FDA grants orphan drug designation, the generic identity of the therapeutic agent and its potential orphan use are disclosed publicly by the FDA. Orphan Drug Designation entitles a party to financial incentives such as opportunities for grant funding toward clinical trial costs, tax advantages and user-fee waivers. Orphan drug designation does not convey any advantage in, or shorten the duration of, the regulatory review and approval process. The FDA may revoke orphan drug designation, and if it does, it will publicize the drug is no longer designated as an orphan drug.

If an investigational product with orphan drug designation subsequently receives the first FDA approval for the disease for which it has such designation, the investigational product is entitled to orphan product exclusivity, which means that the FDA may not approve any other applications to market the same investigational product for the same

indication, except in very limited circumstances, for seven years. Orphan drug exclusivity, however, could also block the approval of one of our investigational products for seven years if a competitor obtains approval of the same investigational product as defined by the FDA or if our investigational product is determined to be contained within the competitor’s investigational product for the same indication or disease.

After approval, owners of relevant drug or biological product patents may apply for up to a five year patent extension under the Drug Price Competition and Patent Term Restoration Act of 1984, referred to as the Hatch-Waxman Act. The allowable patent term extension is calculated as half of the product’s testing phase—the time between IND and NDA or BLA submission—and all of the review phase—the time between NDA or BLA submission and approval, up to a maximum of five years. The time can be shortened if the FDA determines that the applicant did not pursue approval with due diligence. The total patent term after the extension may not exceed 14 years.

For patents that might expire during the application phase, the patent owner may request an interim patent extension. An interim patent extension increases the patent term by one year and may be renewed up to four times. For each interim patent extension granted, the post-approval patent extension is reduced by one year. The director of the U.S. Patent and Trademark Office must determine that approval of the investigational product covered by the patent for which a patent extension is being sought is likely. Interim patent extensions are not available for an investigational product for which an NDA or BLA has not been submitted.

Market exclusivity provisions under the FDCA also can delay the submission or the approval of certain applications. The FDCA provides a five-year period of non-patent marketing exclusivity within the U.S. to the first applicant to gain approval of an NDA for a new chemical entity. An investigational product is a new chemical entity if the FDA has not previously approved any other new investigational product containing the same active moiety, which is the molecule or ion responsible for the action of the investigational product substance. During the exclusivity period, the FDA may not accept for review an abbreviated new drug application (ANDA) or a 505(b)(2) NDA submitted by another company for another version of such investigational product where the applicant does not own or have a legal right of reference to all the data required for approval. However, an application may be submitted after four years if it contains a certification of patent invalidity or non-infringement. The FDCA also provides three years of marketing exclusivity for an NDA, 505(b)(2) NDA or supplement to an approved NDA if new clinical investigations, other than bioavailability studies, that were conducted or sponsored by the applicant are deemed by the FDA to be essential to the approval of the application, for example, for new indications, dosages or strengths of an existing investigational product. This three-year exclusivity covers only the conditions associated with the new clinical investigations and does not prohibit the FDA from approving ANDAs for investigational products containing the original active agent. Five-year and three-year exclusivity will not delay the submission or approval of a full NDA. However, an applicant submitting a full NDA would be required to conduct or obtain a right of reference to all of the preclinical studies and adequate and well-controlled clinical trials necessary to demonstrate safety and effectiveness.

The Biologics Price Competition and Innovation Act of 2009 (BPCIA) created an abbreviated approval pathway for biological investigational products shown to be highly similar to or interchangeable with an FDA licensed reference biological product. Biosimilarity sufficient to reference a prior FDA-approved product requires that there be no differences in conditions of use, route of administration, dosage form, and strength, and no clinically meaningful differences between the biological investigational product and the reference product in terms of safety, purity, and potency. Biosimilarity must be shown through analytical trials, animal trials, and a clinical trial or trials, unless the Secretary of Health and Human Services waives a required element. A biosimilar investigational product may be deemed interchangeable with a prior approved product if it meets the higher hurdle of demonstrating that it can be expected to produce the same clinical results as the reference product and, for products administered multiple times, the biologic and the reference biologic may be switched after one has been previously administered without increasing safety risks or risks of diminished efficacy relative to exclusive use of the reference biologic.

A reference biologic is granted 12 years of exclusivity from the time of first licensure of the reference product, and no application for a biosimilar can be submitted for four years from the date of licensure of the reference product. The first biologic investigational product submitted under the abbreviated approval pathway that is determined to be

interchangeable with the reference product has exclusivity against a finding of interchangeability for other biologics for the same condition of use for the lesser of (i) one year after first commercial marketing of the first interchangeable biosimilar, (ii) 18 months after the first interchangeable biosimilar is approved if there is no patent challenge, (iii) 18 months after resolution of a lawsuit over the patents of the reference biologic in favor of the first interchangeable biosimilar applicant, or (iv) 42 months after the first interchangeable biosimilar’s application has been approved if a patent lawsuit is ongoing within the 42-month period.

Once an approval is granted, the FDA may withdraw the approval if compliance with regulatory requirements is not maintained or if problems occur after the product reaches the market. Later discovery of previously unknown problems with a product may result in restrictions on the product or even complete withdrawal of the product from the market. After approval, some types of changes to the approved product, such as adding new indications, manufacturing changes and additional labeling claims, are subject to further FDA review and approval. In addition, the FDA may under some circumstances require testing and surveillance programs to monitor the effect of approved products that have been commercialized, and the FDA under some circumstances has the power to prevent or limit further marketing of a product based on the results of these post-marketing programs. Any product manufactured or distributed by us or our collaborators pursuant to FDA approvals are subject to continuing regulation by the FDA, including, among other things:

The FDA and other agencies actively enforce the laws and regulations prohibiting the promotion of off-label uses, and a company that is found to have improperly promoted off-label may be subject to significant liability. However, physicians may, in their independent medical judgment, prescribe legally available products for off-label uses. The FDA does not regulate the behavior of physicians in their choice of treatments but the FDA does restrict manufacturer’s communications on the subject of off-label use of their products.

Manufacturers, their subcontractors, and other entities involved in the manufacture and distribution of approved drug and biological products are required to register their establishments with the FDA and certain state agencies and are subject to periodic unannounced inspections by the FDA and some state agencies for compliance with cGMP, including data integrity requirements, and other laws. The FDA periodically inspects manufacturing facilities to assess compliance with ongoing regulatory requirements, including cGMP, which impose extensive procedural, substantive and record-keeping requirements upon us and third-party manufacturers engaged by us if our products are approved. In addition, changes to the manufacturing process are strictly regulated, and, depending on the significance of the change, may require FDA approval before being implemented. FDA regulations would also require investigation and correction of any deviations from cGMP and impose reporting and documentation requirements upon us and our third-party manufacturers. Accordingly, manufacturers must continue to expend time, money and effort in the area of production and quality control to maintain compliance with cGMP and other aspects of regulatory compliance. Failure to comply with the statutory and regulatory requirements can subject a manufacturer to possible legal or regulatory actions, such as warning letters, suspension of manufacturing, seizures of products, injunctive actions or other civil penalties. We cannot be certain we or our present or future third-party manufacturers or suppliers will be able to comply with the cGMP regulations and other ongoing FDA regulatory requirements. If we or our present or future third-party manufacturers or suppliers are not able to comply with these requirements, the FDA may halt our clinical trials or require us to recall a product from distribution.

In addition, therapeutic manufacturers in the United States must comply with applicable provisions of the Drug Supply Chain Security Act and provide and receive product tracing information, maintain appropriate licenses, ensure they only work with other properly licensed entities, and have procedures in place to identify and properly handle suspect and illegitimate product.

Sponsors of clinical drug trials (other than Phase 1 trials) are required to register and disclose certain clinical trial information. Information related to the investigational product, comparator(s), patient population, phase of investigation, trial sites and investigators and other aspects of the clinical trial is made public as part of the registration. Sponsors are also obligated to disclose the results of their clinical trials after completion. Disclosure of the results of certain trials may be delayed until the new product or new indication being studied has been approved. However, there are evolving rules and increasing requirements for publication of trial-related information, and it is possible that data and other information from trials involving drugs that never garner approval could in the future be required to be disclosed. In addition, publication policies of major medical journals mandate certain registration and disclosures as a pre-condition for potential publication, even when this is not presently mandated as a matter of law. Competitors may use this publicly available information to gain knowledge regarding the progress of development programs.

To help reduce the increased risk of the introduction of adventitious agents, the PHSA emphasizes the importance of manufacturing controls for products whose attributes cannot be precisely defined. The PHSA also provides authority to the FDA to immediately suspend licenses in situations where there exists a danger to public health, to prepare or procure products in the event of shortages and critical public health needs, and to authorize the creation and enforcement of regulations to prevent the introduction or spread of communicable diseases in the United States and between states.

After a BLA is approved, the biological product may also be subject to official lot release as a condition of approval. As part of the manufacturing process, the manufacturer is required to perform certain tests on each lot of the product before it is released for distribution. If the product is subject to official release by the FDA, the manufacturer submits samples of each lot of product to the FDA together with a release protocol showing a summary of the history of manufacture of the lot and the results of all of the manufacturer’s tests performed on the lot. The FDA may also perform certain confirmatory tests on lots of some products, such as viral vaccines, before releasing the lots for distribution by the manufacturer.

In addition, the FDA conducts laboratory research related to the regulatory standards on the safety, purity, potency, and effectiveness of biological products. As with drugs, after approval of biological products, manufacturers must address any safety issues that arise, are subject to recalls or a halt in manufacturing, and are subject to periodic inspection after approval.

If use of an in vitro diagnostic is essential to safe and effective use of a drug or biologic product, then the FDA generally will require approval or clearance of the diagnostic, known as a companion diagnostic and regulated by FDA as a medical device, at the same time that the FDA approves the investigational product. The review of an in vitro companion diagnostic in conjunction with the review of an investigational product involves coordination of review between internal organizations within FDA. Most companion diagnostics require approval of a premarket approval application (PMA). The PMA process, including the gathering of clinical and preclinical data and the submission to and review by the FDA, can take several years or longer. It involves a rigorous premarket review during which the applicant must prepare and provide the FDA with reasonable assurance of the device’s safety and effectiveness and information about the device and its components regarding, among other things, device design, manufacturing and labeling. PMAs are subject to a substantial application fee. In addition, PMAs for certain devices must generally include the results from extensive preclinical and adequate and well-controlled clinical trials to establish the safety and effectiveness of the device for each indication for which FDA approval is sought. In particular, for a diagnostic, the applicant must demonstrate that the diagnostic produces reproducible results when the same sample is tested multiple times by multiple users at multiple laboratories. As part of the PMA review, the

FDA will typically inspect the manufacturer’s facilities for compliance with the Quality System Regulation (QSR) which imposes elaborate testing, control, documentation and other quality assurance requirements.

PMA approval is not guaranteed, and the FDA may ultimately respond to a PMA submission with a not approvable determination based on deficiencies in the application and require additional clinical trial or other data that may be expensive and time-consuming to generate and that can substantially delay approval. If the FDA’s evaluation of the PMA application is favorable, the FDA typically issues an approvable letter requiring the applicant’s agreement to specific conditions, such as changes in labeling, or specific additional information, such as submission of final labeling, in order to secure final approval of the PMA. If the FDA concludes that the applicable criteria have been met, the FDA will issue a PMA for the approved indications, which can be more limited than those originally sought by the applicant. The PMA can include post-approval conditions that the FDA believes necessary to ensure the safety and effectiveness of the device, including, among other things, restrictions on labeling, promotion, sale and distribution.

After a device is placed on the market following appropriate approval or clearance from the FDA, it remains subject to significant regulatory requirements. Medical devices may be marketed only for the uses and indications for which they are cleared or approved. Device manufacturers must also establish registration and device listings with the FDA. A medical device manufacturer’s manufacturing processes and those of its suppliers are required to comply with the applicable portions of the QSR, which cover the methods and documentation of the design, testing, production, processes, controls, quality assurance, labeling, packaging and shipping of medical devices. Domestic facility records and manufacturing processes are subject to periodic unscheduled inspections by the FDA. The FDA also may inspect foreign facilities that export products to the United States.

In the United States, our activities are potentially subject to regulation by various federal, state and local authorities in addition to the FDA, including but not limited to, the Centers for Medicare & Medicaid Services (CMS) other divisions of the U.S. Department of Health and Human Services (HHS), such as the Office of Inspector General and the Health Resources and Service Administration, the U.S. Department of Justice (DOJ) and individual U.S. Attorney offices within the DOJ, and state and local governments. For example, sales, marketing and scientific/educational grant programs may have to comply with the anti-fraud and abuse provisions of the Social Security Act, the false claims laws, the privacy and security provisions of the Health Insurance Portability and Accountability Act (HIPAA) and similar state laws, each as amended, as applicable.

The federal Anti-Kickback Statute prohibits, among other things, any person or entity, from knowingly and willfully offering, paying, soliciting or receiving any remuneration, directly or indirectly, overtly or covertly, in cash or in kind, to induce or in return for purchasing, leasing, ordering or arranging for the purchase, lease or order of any item or service reimbursable, in whole or in part, under Medicare, Medicaid or other federal healthcare programs. The term remuneration has been interpreted broadly to include anything of value. The Anti-Kickback Statute has been interpreted to apply to arrangements between therapeutic product manufacturers on one hand and prescribers, purchasers, and formulary managers on the other. There are a number of statutory exceptions and regulatory safe harbors protecting some common activities from prosecution. The exceptions and safe harbors are drawn narrowly and practices that involve remuneration that may be alleged to be intended to induce prescribing, purchasing or recommending may be subject to scrutiny if they do not qualify for an exception or safe harbor. Failure to meet all of the requirements of a particular applicable statutory exception or regulatory safe harbor does not make the conduct per se illegal under the Anti-Kickback Statute. Instead, the legality of the arrangement will be evaluated on a case-by-case basis based on a cumulative review of all of its facts and circumstances. Our practices may not in all cases meet all of the criteria for protection under a statutory exception or regulatory safe harbor.

Additionally, the intent standard under the Anti-Kickback Statute was amended by the Patient Protection and Affordable Care Act, as amended by the Health Care and Education Reconciliation Act of 2010 (ACA), to a stricter standard such that a person or entity no longer needs to have actual knowledge of the statute or specific intent to violate it in order to have committed a violation. In addition, the ACA codified case law 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 False Claims Act (FCA) (discussed below).

The federal false claims, including the FCA, which imposes significant penalties and can be enforced by private citizens through civil qui tam actions, and civil monetary penalty laws prohibit any person or entity from, among other things, knowingly presenting, or causing to be presented, a false or fraudulent claim for payment to, or

approval by, the federal healthcare programs, including Medicare and Medicaid, or knowingly making, using, or causing to be made or used a false record or statement material to a false or fraudulent claim to the federal government. A claim includes “any request or demand” for money or property presented to the U.S. government. For instance, historically, pharmaceutical and other healthcare companies have been prosecuted under these laws for allegedly providing free product to customers with the expectation that the customers would bill federal programs for the product. Other companies have been prosecuted for causing false claims to be submitted because of the companies’ marketing of the product for unapproved, off-label, and thus generally non-reimbursable, uses.

HIPAA created additional federal criminal statutes that prohibit, among other things, knowingly and willfully executing, or attempting to execute, a scheme to defraud or to obtain, by means of false or fraudulent pretenses, representations or promises, any money or property owned by, or under the control or custody of, any healthcare benefit program, including private third-party payors, willfully obstructing a criminal investigation of a healthcare offense, and knowingly and willfully falsifying, concealing or covering up by trick, scheme or device, 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. Like the Anti-Kickback Statute, the ACA amended the intent standard for certain healthcare fraud statutes under HIPAA such that a person or entity no longer needs to have actual knowledge of the statute or specific intent to violate it in order to have committed a violation.

Also, many states have similar, and typically more prohibitive, fraud and abuse statutes or regulations that apply to items and services reimbursed under Medicaid and other state programs, or, in several states, apply regardless of the payor. Additionally, to the extent that our product is sold in a foreign country, we may be subject to similar foreign laws.

We may be subject to data privacy and security regulations 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 (HITECH) and its implementing regulations, imposes requirements on “covered entities,” including certain healthcare providers, health plans, and healthcare clearinghouses, and their respective “business associates” that create, receive, maintain or transmit individually identifiable health information for or on behalf of a covered entity as well as their covered subcontractors relating to the privacy, security and transmission of individually identifiable health information. Among other things, HITECH makes HIPAA’s privacy and security standards directly applicable to business associates. HITECH also created four new tiers of civil monetary penalties, amended HIPAA to make civil and criminal penalties directly applicable to business associates, and gave state attorneys general new authority to file civil actions for damages or injunctions in federal courts to enforce HIPAA and seek attorneys’ fees and costs associated with pursuing federal civil actions. In addition, many state laws govern the privacy and security of health information in specified circumstances, many of which differ from each other in significant ways, are often not pre-empted by HIPAA, and may have a more prohibitive effect than HIPAA, thus complicating compliance efforts.

Certain of our products, once approved, may be administered by a physician. Under currently applicable U.S. law, certain products not usually self-administered (including injectable drugs) may be eligible for coverage under Medicare through Medicare Part B. Medicare Part B is part of original Medicare, the federal health care program that provides health care benefits to the aged and disabled, and covers outpatient services and supplies, including certain pharmaceutical products, that are medically necessary to treat a beneficiary’s health condition. As a condition of receiving Medicare Part B reimbursement for a manufacturer’s eligible drugs or biologicals, the manufacturer is required to participate in other government healthcare programs, including the Medicaid Drug Rebate Program and the 340B Drug Pricing Program. The Medicaid Drug Rebate Program requires pharmaceutical manufacturers to enter into and have in effect a national rebate agreement with the Secretary of HHS as a condition for states to receive federal matching funds for the manufacturer’s outpatient drugs furnished to Medicaid patients. Under the 340B Drug Pricing Program, the manufacturer must extend discounts to entities that participate in the program.

In addition, many pharmaceutical manufacturers must calculate and report certain price reporting metrics to the government, such as average sales price (ASP) and best price. Penalties may apply in some cases when such metrics are not submitted accurately and timely. Further, these prices for drugs may be reduced by mandatory discounts or rebates required by government healthcare programs or private payors and by any future relaxation of laws that presently restrict imports of drugs from countries where they may be sold at lower prices than in the United States. It is difficult to predict how Medicare coverage and reimbursement policies will be applied to our products in the

future and coverage and reimbursement under different federal healthcare programs are not always consistent. Medicare reimbursement rates may also reflect budgetary constraints placed on the Medicare program.

Additionally, the federal Physician Payments Sunshine Act (Sunshine Act) within the ACA, and its implementing regulations, require that certain manufacturers of drugs, devices, biological and medical supplies for which payment is available under Medicare, Medicaid or the Children’s Health Insurance Program (with certain exceptions) report annually to CMS information related to certain payments or other transfers of value made or distributed to physicians (defined to include doctors, dentists, optometrists, podiatrists and chiropractors), other healthcare professionals (such as physician assistants and nurse practitioners), and teaching hospitals, or to entities or individuals at the request of, or designated on behalf of, the physicians and teaching hospitals and to report annually certain ownership and investment interests held by physicians and their immediate family members. Failure to report accurately could result in penalties. In addition, many states also govern the reporting of payments or other transfers of value, many of which differ from each other in significant ways, are often not pre-empted, and may have a more prohibitive effect than the Sunshine Act, thus further complicating compliance efforts.

In order to distribute products commercially, we must comply with state laws that require the registration of manufacturers and wholesale distributors of drug and biological products in a state, including, in certain states, manufacturers and distributors who ship products into the state even if such manufacturers or distributors have no place of business within the state. Some states also impose requirements on manufacturers and distributors to establish the pedigree of product in the chain of distribution, including some states that require manufacturers and others to adopt new technology capable of tracking and tracing product as it moves through the distribution chain. Several states have enacted legislation requiring pharmaceutical and biotechnology companies to establish marketing compliance programs, file periodic reports with the state, make periodic public disclosures on sales, marketing, pricing, clinical trials and other activities, and/or register their sales representatives, as well as to prohibit pharmacies and other healthcare entities from providing certain physician prescribing data to pharmaceutical and biotechnology companies for use in sales and marketing, and to prohibit certain other sales and marketing practices. All of our activities are potentially subject to federal and state consumer protection and unfair competition laws.

Ensuring business arrangements with third parties comply with applicable healthcare laws and regulations is a costly endeavor. If our operations are found to be in violation of any of the federal and state healthcare laws described above or any other current or future governmental regulations that apply to us, we may be subject to significant penalties, including without limitation, civil, criminal and/or administrative penalties, damages, fines, disgorgement, imprisonment, exclusion from participation in government programs, such as Medicare and Medicaid, injunctions, private “qui tam” actions brought by individual whistleblowers in the name of the government, or refusal to allow us to enter into government contracts, contractual damages, reputational harm, administrative burdens, diminished profits and future earnings, additional reporting obligations and oversight if we become subject to a corporate integrity agreement or other agreement to resolve allegations of non-compliance with these laws, and the curtailment or restructuring of our operations, any of which could adversely affect our ability to operate our business and our results of operations.

Significant uncertainty exists as to the coverage and reimbursement status of any investigational products for which we may obtain regulatory approval. In the United States and in foreign markets, sales of any products for which we receive regulatory approval for commercial sale will depend, in part, on the extent to which third-party payors provide coverage and establish adequate reimbursement levels for such products. In the United States, third-party payors include federal and state healthcare programs, private managed care providers, health insurers and other organizations. Adequate coverage and reimbursement from governmental healthcare programs, such as Medicare and Medicaid in the United States, and commercial payors are critical to new product acceptance.

Our ability to commercialize any products successfully also will depend in part on the extent to which coverage and reimbursement for these products and related treatments will be available from government health administration authorities, private health insurers and other organizations. Government authorities and third-party payors, such as private health insurers and health maintenance organizations, decide which therapeutics they will pay for and

establish reimbursement levels. Coverage and reimbursement by a third-party payor may depend upon a number of factors, including the third-party payor’s determination that use of a therapeutic is:

We cannot be sure that reimbursement will be available for any product that we commercialize and, if coverage and reimbursement are available, what the level of reimbursement will be. Coverage may also be more limited than the purposes for which the product is approved by the FDA or comparable foreign regulatory authorities. Reimbursement may impact the demand for, or the price of, any product for which we obtain regulatory approval. Additionally, our collaborators will be required to obtain coverage and reimbursement for any companion diagnostic tests they develop separate and apart from the coverage and reimbursement we seek for our product candidates, once approved.

Third-party payors are increasingly challenging the price, examining the medical necessity, and reviewing the cost-effectiveness of medical products, therapies and services, in addition to questioning their safety and efficacy. Obtaining reimbursement for our products may be particularly difficult because of the higher prices often associated with branded drugs and drugs administered under the supervision of a physician. We may need to conduct expensive pharmacoeconomic studies in order to demonstrate the medical necessity and cost-effectiveness of our products, in addition to the costs required to obtain FDA approvals. Our investigational products may not be considered medically necessary or cost-effective. Obtaining coverage and reimbursement approval of a product from a government or other third-party payor is a time-consuming and costly process that could require us to provide to each payor supporting scientific, clinical and cost-effectiveness data for the use of our product on a payor-by-payor basis, with no assurance that coverage and adequate reimbursement will be obtained. A payor’s decision to provide coverage for a product does not imply that an adequate reimbursement rate will be approved. Further, one payor’s determination to provide coverage for a product does not assure that other payors will also provide coverage for the product. Adequate third-party reimbursement may not be available to enable us to maintain price levels sufficient to realize an appropriate return on our investment in product development. If reimbursement is not available or is available only at limited levels, we may not be able to successfully commercialize any investigational product that we successfully develop.

Different pricing and reimbursement schemes exist in other countries. In the European Union, governments influence the price of pharmaceutical products through their pricing and reimbursement rules and control of national health care systems that fund a large part of the cost of those products to consumers. Some jurisdictions operate positive and negative list systems under which products may only be marketed once a reimbursement price has been agreed. To obtain reimbursement or pricing approval, some of these countries may require the completion of clinical trials that compare the cost effectiveness of a particular investigational product to currently available therapies. Other member states allow companies to fix their own prices for medicines, but monitor and control company profits. The downward pressure on health care costs has become intense. As a result, increasingly high barriers are being erected to the entry of new products. In addition, in some countries, cross-border imports from low-priced markets exert a commercial pressure on pricing within a country.

The marketability of any investigational products for which we receive regulatory approval for commercial sale may suffer if the government and third-party payors fail to provide adequate coverage and reimbursement. In addition, emphasis on managed care, the increasing influence of health maintenance organizations, and additional legislative changes in the United States has increased, and we expect will continue to increase, the pressure on healthcare pricing. The downward pressure on the rise in healthcare costs in general, particularly prescription medicines, medical devices and surgical procedures and other treatments, has become very intense. Coverage policies and third-party reimbursement rates may change at any time. Even if favorable coverage and reimbursement status is attained for one or more products for which we receive regulatory approval, less favorable coverage policies and reimbursement rates may be implemented in the future.

In the United States and some foreign jurisdictions, there have been, and continue to be, several legislative and regulatory changes and proposed changes regarding the healthcare system that could prevent or delay marketing approval of investigational products, restrict or regulate post-approval activities, and affect the ability to profitably sell investigational products for which marketing approval is obtained. Among policy makers and payors in the United States and elsewhere, there is significant interest in promoting changes in healthcare systems with the stated goals of containing healthcare costs, improving quality and/or expanding access. In the United States, the pharmaceutical industry has been a particular focus of these efforts and has been significantly affected by major legislative initiatives.

For example, the ACA has substantially changed healthcare financing and delivery by both governmental and private insurers. Among the ACA provisions of importance to the pharmaceutical and biotechnology industries, in addition to those otherwise described above, are the following:

There have been legal and political challenges to certain aspects of the ACA. For example, in December 2017, Congress repealed the tax penalty for an individual’s failure to maintain ACA-mandated health insurance that is commonly referred to as the “individual mandate” as part of a tax reform bill. For example, on June 17, 2021 the U.S. Supreme Court dismissed a challenge on procedural grounds that argued the ACA is unconstitutional in its entirety because the "individual mandate" was repealed by Congress. Thus, the ACA will remain in effect in its current form. Prior to the U.S. Supreme Court ruling, on January 28, 2021, President Biden issued an executive order that initiated a special enrollment period for purposes of obtaining health insurance coverage through the ACA marketplace. The executive order also instructed certain governmental agencies to review and reconsider their

existing policies and rules that limit access to healthcare, including among others, reexamining Medicaid demonstration projects and waiver programs that include work requirements, and policies that create unnecessary barriers to obtaining access to health insurance coverage through Medicaid or the ACA. It is possible that the ACA will be subject to judicial or Congressional challenges in the future. It is unclear how such challenges and the healthcare reform measures of the Biden administration will impact the ACA and our business.

Further legislation or regulation could be passed that could harm our business, financial condition and results of operations. Other legislative changes have been proposed and adopted since the ACA was enacted. For example, in August 2011, President Obama signed into law the Budget Control Act of 2011, which, among other things, created the Joint Select Committee on Deficit Reduction to recommend to Congress proposals in spending reductions. The Joint Select Committee on Deficit Reduction did not achieve a targeted deficit reduction of at least $1.2 trillion for fiscal years 2012 through 2021, triggering the legislation’s automatic reduction to several government programs. This includes aggregate reductions to Medicare payments to providers of up to 2% per fiscal year, which went into effect beginning on April 1, 2013 and, due to subsequent legislation, including the Infrastructure Investment and Jobs Act, will stay in effect through 2031 unless additional Congressional action is taken. However, the Medicare sequester reductions under the Budget Control Act of 2011 are suspended from May 1, 2020 through March 31, 2022 due to COVID-19 relief legislation. Under current legislation the actual reduction in Medicare payments will vary from 1% in 2022 to up to 3% in the final fiscal year of this sequester. Additionally, on March 11, 2021, President Biden signed the American Rescue Plan Act of 2021 into law, which eliminates the statutory Medicaid drug rebate cap, currently set at 100% of a drug’s average manufacturer price, for single source and innovator multiple source drugs, beginning January 1, 2024.

Additionally, there has been increasing legislative and enforcement interest in the United States with respect to specialty drug pricing practices. Specifically, there have been several recent U.S. Congressional inquiries and proposed federal legislation designed to, among other things, bring more transparency to drug pricing, reduce the cost of prescription drugs under Medicare, review the relationship between pricing and manufacturer patient programs, and reform government program reimbursement methodologies for drugs. For example, on July 24, 2020 and September 13, 2020, the Trump administration announced several executive orders related to prescription drug pricing that attempt to implement several of the administration’s proposals. The FDA concurrently released a final rule and guidance in September 2020 implementing a portion of the importation executive order providing pathways for states to build and submit importation plans for drugs from Canada. In July 2021, the Biden administration released an executive order, “Promoting Competition in the American Economy,” with multiple provisions aimed at prescription drugs. In response to Biden’s executive order, on September 9, 2021, HHS released a Comprehensive Plan for Addressing High Drug Prices that outlines principles for drug pricing reform and sets out a variety of potential legislative policies that Congress could pursue as well as potential administrative actions HHS can take to advance these principles. No legislation or administrative actions have been finalized to implement these principles. It is unclear whether these or similar policy initiatives will be implemented in the future. Individual states in the United States have also become increasingly aggressive in passing legislation and implementing 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.

We anticipate that current and future healthcare reform measures could result in additional downward pressure on coverage and the price that we receive for any approved product, and could seriously harm our business. Any reduction in reimbursement from Medicare and other government programs may result in a similar reduction in payments from private payors. The implementation of cost containment measures or other healthcare reforms may prevent us from being able to generate revenue, attain profitability from product sales, or commercialize our products. Such reforms could have an adverse effect on anticipated revenue from investigational products that we may successfully develop and for which we may obtain regulatory approval and may affect our overall financial condition and ability to develop investigational products. Further, it is possible that additional government action is taken in response to the COVID-19 pandemic.

The Foreign Corrupt Practices Act (FCPA), prohibits any U.S. individual or business from paying, offering, or authorizing payment or offering of anything of value, directly or indirectly, to any foreign official, political party or candidate for the purpose of influencing any act or decision of the foreign entity in order to assist the individual or business in obtaining or retaining business. The FCPA also obligates companies whose securities are listed in the United States to comply with accounting provisions requiring us to maintain books and records that accurately and fairly reflect all transactions of the corporation, including international subsidiaries, and to devise and maintain an adequate system of internal accounting controls for international operations.

In addition to the foregoing, state and federal laws regarding environmental protection and hazardous substances, including the Occupational Safety and Health Act, the Resource Conservancy and Recovery Act and the Toxic Substances Control Act, affect our business. These and other laws govern our use, handling and disposal of various biological, chemical and radioactive substances used in, and wastes generated by, our operations. If our operations result in contamination of the environment or expose individuals to hazardous substances, we could be liable for damages and governmental fines. We believe that we are in material compliance with applicable environmental laws and that continued compliance therewith will not have a material adverse effect on our business. We cannot predict, however, how changes in these laws may affect our future operations.

We are also subject to numerous federal, state and local laws relating to such matters as safe working conditions, manufacturing practices, environmental protection, fire hazard control, and disposal of hazardous or potentially hazardous substances. We may incur significant costs to comply with such laws and regulations now or in the future.

In addition to regulations in the United States, we will be subject to a variety of regulations in other jurisdictions governing, among other things, clinical trials and any commercial sales and distribution of our products. Whether or not we obtain FDA approval to conduct clinical trials or market a product, we must obtain the requisite approvals from regulatory authorities in foreign jurisdictions prior to the commencement of clinical trials or marketing of the product in those countries. The requirements and process governing the conduct of clinical trials, product licensing, pricing and reimbursement vary from country to country. In all cases, again, the clinical trials must be conducted in accordance with GCP and the applicable regulatory requirements. Because biologically sourced raw materials are subject to unique contamination risks, their use may be restricted in some countries.

Conducting clinical trials for therapeutic drug candidates in Australia is subject to regulation by Australian regulatory bodies. The Therapeutic Goods Administration (TGA) and the National Health and Medical Research Council set the codes of Good Clinical Practice (GCP) for clinical research in Australia, and compliance with these codes is mandatory. Australia has also adopted international codes, such as those promulgated by the International Conference on Harmonization of Technical Requirements for Registration of Pharmaceuticals for Human Use (the ICH). The ICH guidelines must be complied with across all fields of clinical research, including those related to pharmaceutical quality, nonclinical and clinical data requirements and trial designs. The basic requirements for preclinical data to support a first-in-human trial under ICH guidelines are applicable in Australia. Requirements related to adverse event reporting in Australia are similar to those required in other major jurisdictions.

Clinical trials conducted using “unapproved therapeutic goods” in Australia, being those which have not yet been evaluated by the TGA for quality, safety and efficacy must occur pursuant to either the Clinical Trial Notification Scheme (CTN Scheme), or the Clinical Trial Exemption Scheme (CTX Scheme). In each case, the trial is supervised by a Human Research Ethics Committee (HREC) an independent review committee set up under guidelines of the Australian National Health and Medical Research Council that ensures the protection of rights, safety and well-being of human subjects involved in a clinical trial. A HREC does this by reviewing, approving and providing continuing examination of trial protocols and amendments, and of the methods and material to be used in obtaining and documenting informed consent of the trial subjects.

A sponsor cannot commence a trial under the CTX Scheme until written advice has been received from the TGA regarding the application and approval for the conduct of the trial has been obtained from an ethics committee and the institution at which the trial will be conducted.

Approval for inclusion in the Australian Register of Therapeutic Goods (ARTG) is required before a pharmaceutical product may be marketed (or imported, exported or manufactured) in Australia. In order to obtain registration of the product on the ARTG, it is required that:

Similar to the United States and Australia, the conduct of clinical trials in the EU are subject to regulatory controls. Under the current EU Clinical Trials Directive 2001/20/EC (Directive), before a clinical trial can be initiated in the EU, it must be approved in each of the EU countries where the trial is to be conducted by two distinct bodies: the national Competent Authority and one or more Ethics Committees. In 2014, the EU adopted a new Clinical Trials Regulation 536/2014 (Regulation) to replace the current Directive, with a three-year transition period. The Regulation aims to simplify and streamline the approval of clinical trials in the EU. For example, the sponsor shall submit a single application for approval of a clinical trial via the EU portal. As part of the application process, the sponsor shall propose a reporting Member State, who will coordinate the validation and evaluation of the application. The reporting Member State shall consult and coordinate with the other concerned Member States. If an application is rejected, it can be amended and resubmitted through the EU portal. If an approval is issued, the sponsor can start the clinical trial in all concerned Member States. However, a concerned Member State can in limited circumstances declare an “opt-out” from an approval. In such a case, the clinical trial cannot be conducted in that Member State. The Regulation also aims to streamline and simplify the rules on safety reporting, and introduces enhanced transparency requirements such as mandatory submission of a summary of the clinical trial results to the EU database. The Regulation will become directly applicable in all EU Member States once the centralized portal and database for clinical trials are fully functional.

The Directive will still apply for three years from the date of application of the Regulation for clinical trial applications submitted before the date of application of the Regulation and for clinical trial applications submitted under the Directive within one year after the date of application of the Regulation.

Commercialization of our investigational products may only occur in the EU following approval of a marketing application, which can be obtained through either a centralized or a decentralized procedure:

We will be subject to additional regulations with respect to any activities we conduct in the EU. For example, the EU General Data Protection Regulation (GDPR) applies to health-related and other personal data of individuals in the European Union. The GPDR, which went into effect in May 2018, imposes more stringent operational requirements on processors and controllers of personal data, including, for example, expanded disclosures about how personal data is collected, used and shared, limitations on retention of personal data, more stringent requirements pertaining to genetic, biometric and health data, mandatory data breach notification requirements, and higher standards for controllers to demonstrate valid consent for certain data processing activities. The GDPR further provides that European Union Member States may implement their own additional laws and regulations in relation to the processing of genetic, biometric or health data, which could result in differences in the GDPR’s implementation among Member States. The GDPR increases our responsibility and liability in relation to personal data that we process, and we must put in place additional mechanisms to ensure compliance with the new EU data protection rules.

Our culture and values can be defined by one overarching concept: We do the right things for the right reasons. We take pride in hard work and approach our mission—to create, develop and commercialize highly differentiated combination cancer therapies that have the potential to cure—with a great sense of urgency. We recognize that our employees are a critical component to our success and we strive to attract the best talent from a range of sources, including an internship program through which we have developed strong relationships with multiple universities to foster talent and attract skilled graduates. In 2021, we added 174 new employees to our team and expect even more growth in 2022, with a focus on expanding our clinical development capabilities and overall infrastructure.

We recognize that attracting skilled talent is only one part of the equation. We endeavor to retain and motivate our employees by empowering them to make the decisions they are most qualified and best positioned to decide and by providing opportunities for growth and development, such as through our education reimbursement program. We focus on wellness through our company-funded lunch program, a quarterly stipend to assist with wellness and commuter expenses, and our coverage of 95% of the costs for healthcare benefits.

Since the COVID pandemic, we have increased our focus on safety and wellness. For our on-site employees, consisting primarily of our laboratory-based employees, we instituted a mandatory vaccine policy with continued weekly COVID-19 testing in order to minimize the risk to our employees. Our office-based employees continue to work from home. We believe our commitment to our employees is reflected by our turnover rate, which is below the 50th percentile for our industry.

As of February 1, 2022, we had 366 full-time employees, approximately 120 of whom hold Ph.D. or M.D. degrees or R.N. certifications. Of our employees, 297 were engaged in research and development activities and 69 were engaged in general and administrative activities. None of our employees are represented by labor unions or covered by collective bargaining agreements. We consider our relationship with our employees to be good.

We were incorporated under the laws of the State of Delaware in April 2015. Our principal executive offices are located at 3928 Point Eden Way, Hayward, CA 94545, and our telephone number is (510) 694-6200. Our website address is www.arcusbio.com. The information on, or that can be accessed through, our website is not incorporated by reference into this Annual Report on Form 10-K.

We operate and manage our business as one reportable and operating segment. See Note 2 to our audited financial statement included elsewhere in this Annual Report on Form 10-K for additional information.

We file Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q, Current Reports on Form 8-K and other information with the Securities and Exchange Commission (SEC). Our filings with the SEC are available free of charge on the SEC’s website at www.sec.gov and on our website under the “Investors” tab as soon as reasonably practicable after we electronically file such material with, or furnish it to, the SEC.

You should consider carefully the following risk factors, together with all the other information in this report, including our consolidated financial statements and notes thereto, and in our other public filings with the SEC. The occurrence of any of the following risks could harm our business, financial condition, results of operations and/or growth prospects or cause our actual results to differ materially from those contained in forward-looking statements we have made in this report and those we may make from time to time. You should consider all of the risk factors described when evaluating our business.

The impact of the COVID-19 pandemic and related risks could have a material adverse impact on our research and development programs and financial condition.

The degree to which COVID-19 impacts our business operations, research and development programs and financial condition remains highly uncertain and will depend on future developments, including the ultimate duration and/or severity of the pandemic, the impact of any resurgences and new variants that emerge, actions by government authorities to contain the spread of the virus, the availability, adoption and effectiveness of vaccines and boosters, and when and to what extent normal economic and operating conditions can resume. We conduct our clinical trials in the U.S. and internationally in geographic regions that are impacted by COVID-19 to varying degrees, and disruptions caused by the COVID-19 pandemic, including the reinstitution of shelter-in-place measures, will continue to impact our ability to initiate, supply, enroll, conduct or complete our ongoing or planned clinical trials. For example, in the first half of 2020, the pandemic led to a decline in screening, diagnosis and treatment for cancer patients. While cancer screening rates have rebounded, resurgences due to new variants may cause patients to delay screening and treatment for fear of exposure to COVID-19, thereby adversely impact the enrollment of patients in clinical trials targeting early-stage cancers and retention of patients overall in our trials. Furthermore, the disruptions caused by the COVID-19 pandemic have led to missed study visits, missed data collections and other deviations from our protocols, which may negatively impact the integrity, reliability, or robustness of the data from our clinical trials. Global shipping has also been challenged by the evolving pandemic and has led to delays in our receipt of materials and supplies, including our investigational product and other standard-of-care drugs used in the conduct of our clinical trials. We are unable to predict the ultimate impact of this pandemic on our programs.

Due to the availability of vaccines and our mandatory vaccine policy, our laboratory operations are operating at or near normal levels and we are permitting periodic in-person meetings for our office-based employees, who continue to work remotely. The safety, health and well-being of our employees remains a primary concern. We may restrict our business activities or modify our employee work arrangements in response to new developments in the COVID-19 pandemic in order to reduce the risk of exposure among our employees, which may adversely affect our productivity.

The impact of the COVID-19 pandemic, including governmental and other actions to combat it such as the imposition of shelter-in-place and other public health orders, may exacerbate the effects of the risks described below.

Risks Related to our Limited Operating History, Financial Position and Capital Requirements

We are an early-stage immuno-oncology company with a limited operating history. We have never generated any revenue from product sales and anticipate that we will continue to incur significant losses for the foreseeable future.

We are an early-stage immuno-oncology company with a limited operating history that may make it difficult to evaluate the success of our business to date and to assess our future viability. All of our investigational products are in development, and none have been approved for commercial sale nor have we ever generated any revenue from

product sales. In 2021, we recognized our first annual net income since commencing operations as a result of option payments totaling $725 million due to us from Gilead following its exercise of options to three of our programs. For the years ended December 31, 2021 and 2020, we had net income of $52.8 million and net losses of $122.9 million, respectively. As of December 31, 2021, we had an accumulated deficit of $275.4 million. We expect that it will be several years, if ever, before we have an investigational product ready for commercialization. Despite net income in 2021 of $52.8 million, we expect to incur substantial and increasing levels of operating losses over the next several years and for the foreseeable future as we advance our investigational products. Our prior losses, combined with expected future losses, have had and will continue to have an adverse effect on our stockholders’ equity and working capital.

To become and remain profitable on a sustained basis, we must develop and eventually commercialize a product with significant market potential. This will require us to be successful in a range of challenging activities, including completing preclinical studies and clinical trials of our investigational products, obtaining marketing approval for these investigational products, manufacturing, marketing and selling those products for which we may obtain marketing approval and satisfying any post-marketing requirements. We may never succeed in these activities and, even if we succeed in commercializing one or more of our investigational products, we may never generate revenues that are significant or large enough to achieve sustained profitability. In addition, as a young business, we may encounter unforeseen expenses, difficulties, complications, delays and other known and unknown challenges. If we do achieve profitability from product sales, we may not be able to sustain or increase profitability on a quarterly or annual basis and we will continue to incur substantial research and development and other expenditures to develop and market additional investigational products. Our failure to become and remain profitable on a sustained basis would decrease the value of the company and could impair our ability to raise capital, maintain our research and development efforts, expand our business or continue our operations. A decline in the value of our company could also cause our stockholders to lose all or part of their investment.

We may need to obtain additional funding to finance our operations and complete the development and any commercialization of our investigational products. If we do not receive substantial opt-in, milestone or royalty payments from our existing collaboration agreements, or are unable to raise additional capital when needed, we may be forced to restrict our operations or delay, reduce or eliminate our product development programs.

The development of biopharmaceutical investigational products is capital intensive. Since our inception, we have used substantial amounts of cash to fund our operations and expect our expenses to increase substantially during the next few years as our investigational products enter and advance into and through large late-stage or registrational clinical trials and we expand our clinical, regulatory, quality and manufacturing capabilities. In addition, if we obtain marketing approval for any of our investigational products, we expect to incur significant commercialization expenses related to marketing, sales, manufacturing and distribution.

As of December 31, 2021, we had $681.3 million of cash, cash equivalents and investments. With the receipt of the option exercise payments from Gilead Sciences, Inc. (Gilead) totaling $725 million in January 2022, we believe that our cash position will be sufficient to fund our operations into 2026. However, our future capital requirements will depend on many factors, including:

We cannot guarantee that future financing will be available in sufficient amounts or on terms acceptable to us, if at all. Any additional fundraising efforts may divert our management from their day-to-day activities, which may adversely affect our ability to develop and commercialize our investigational products. If we are unable to raise capital when needed or on attractive terms, we would be forced to delay, reduce or eliminate our research and development programs or future commercialization efforts. In addition, if we are able to raise additional capital, raising additional capital may cause dilution to our stockholders, restrict our operations or require us to relinquish rights to our technologies or investigational products.

We are relatively early in our development efforts. If we are unable to develop, obtain regulatory approval for and commercialize our investigational products, or experience significant delays in doing so, our business will be materially harmed.

We have no products approved for sale and we only initiated our first registrational trial in 2021. We may subsequently learn of certain information or data that the FDA may request, which may necessitate conducting additional preclinical studies or generating additional information at significant cost in terms of both time and expense, including under a clinical hold imposed on an investigational new drug application (IND). For example, the FDA recently published guidance on “Project Optimus”, an initiative to reform dose selection in oncology drug development. If the FDA does not believe we have sufficiently demonstrated that the selected doses for our investigational products maximize not only the efficacy of the investigational product, but the safety and tolerability as well, our ability to initiate new studies may be delayed. Even if we conducted the additional studies or generated the additional information requested, the FDA could disagree that we have satisfied their requirements, all of which will cause significant delays and expense to our programs.

To support the advancement of our clinical programs, we need to expand our clinical operations, quality and regulatory capabilities. In part because of our limited infrastructure, experience conducting clinical trials as a company and regulatory interactions, we cannot be certain that our clinical trials will be completed on time, that our planned clinical trials will be initiated on time, if at all, that our planned development programs would be acceptable to the FDA or other comparable foreign regulatory authorities, or that, if approval is obtained, such investigational products can be successfully commercialized.

Our ability to generate product revenue, which we do not expect will occur for many years, if ever, will depend heavily on our ability to successfully complete the above activities and any other activities required for the successful development and eventual commercialization of one or more of our investigational products. The success of our investigational products will further depend on factors such as:

If we do not achieve one or more of these factors in a timely manner, we could experience significant delays or an inability to successfully commercialize our investigational products, which would materially harm our business.

Clinical drug development is a lengthy, expensive and uncertain process. The results of preclinical studies and early clinical trials are not always predictive of future results. Any investigational product that we advance into clinical trials may not achieve favorable results in later clinical trials, if any, or receive marketing approval.

The research and development of drugs and biological products is an extremely risky industry. Only a small percentage of investigational products that enter the development process ever receive marketing approval. Before obtaining marketing approval from regulatory authorities for the sale of any investigational product, we must complete preclinical development and then conduct extensive clinical trials to demonstrate the safety and efficacy of our investigational products in humans. Clinical testing is expensive, can take many years to complete and its outcome is uncertain.

The results of preclinical and early clinical trials of our investigational products and other products with the same mechanism of action may not be predictive of the results of later-stage clinical trials. Clinical trial failure may result from a multitude of factors including flaws in study design, dose selection, placebo effect, patient enrollment criteria and failure to demonstrate favorable safety or efficacy traits. As such, failure in clinical trials can occur at any stage of testing. A number of companies in the biopharmaceutical industry have suffered setbacks in the advancement of clinical trials due to lack of efficacy or adverse safety profiles, notwithstanding promising results in earlier trials. Based upon negative or inconclusive results, we may decide, or regulators may require us, to conduct additional clinical trials or preclinical studies. In addition, data obtained from clinical trials are susceptible to varying interpretations, and regulators may not interpret our data as favorably as we do, which may further delay, limit or prevent marketing approval. In particular, results from uncontrolled trials, meaning trials in which there is no control group such as a placebo group, are inherently difficult to interpret. Clinical trials evaluating two or more investigational products in combination that have not yet been approved can compound these difficulties. As a key element of our strategy is the development of intra-portfolio combinations, our early clinical trials may test more than one investigational product in uncontrolled studies, such as our Phase 1/1b clinical trial for AB308 which is evaluating AB308 in combination with zimberelimab. Furthermore, as more investigational products within a particular class of drugs proceed through clinical development to regulatory review and approval, the amount and type of clinical data that may be required by regulatory authorities may increase or change.

We currently have six investigational products in clinical development and their risk of failure is high. We are unable to predict if these investigational products or any of our future investigational products that advance into clinical trials will prove safe or effective in humans or will obtain marketing approval. If we are unable to complete preclinical or clinical trials of current or future investigational products, due to safety concerns, or if the results of these trials are not satisfactory to convince regulatory authorities of their safety or efficacy, we will not be able to

obtain marketing approval for commercialization. For example, since a key element of our strategy is the development of intra-portfolio combinations, regulatory authorities may disagree that we have sufficiently demonstrated the contribution of each investigational product or other agent in our combination trials and require further studies. Even if we are able to obtain marketing approvals for any of our investigational products, those approvals may be for indications that are not as broad as desired or may contain other limitations that would adversely affect our ability to generate revenue from sales of those products. Moreover, if we are not able to differentiate our product against other approved products within the same class of drugs, or if any of the other circumstances described above occur, our business would be materially harmed and our ability to generate revenue from that class of drugs would be severely impaired.

Enrollment and retention of subjects in clinical trials is expensive and time consuming, can be made more difficult or rendered impossible by competing treatments, clinical trials of competing investigational products, and public health epidemics, each of which could result in significant delays and additional costs in our product development activities, or in the failure of such activities.

We may encounter delays in enrolling, or be unable to enroll and maintain, a sufficient number of subjects to complete any of our clinical trials. Patient enrollment and retention in clinical trials is a significant factor in the timing of clinical trials and depends on many factors, including the size of the patient population required for analysis of the trial’s primary endpoints, the nature of the trial protocol, our ability to recruit clinical trial investigators with the appropriate competencies and experience, the existing body of safety and efficacy data with respect to the investigational product, the number and nature of competing products or investigational products and ongoing clinical trials of competing investigational products for the same indication, the proximity of subjects to clinical trial sites, the eligibility criteria for the clinical trial and our ability to obtain and maintain subject consents.

For example, enrollment of oncology subjects in our clinical trials evaluating zimberelimab may be hampered by nivolumab from Bristol-Myers Squibb and pembrolizumab from Merck, both of which are approved and on the market. Subjects may opt to be treated with an approved product rather than our anti-PD-1 antibody investigational product. In addition, Roche/Genentech, Merck and Beigene have initiated numerous Phase 3 trials with their respective anti-TIGIT antibodies, which could reduce the number of clinical sites and subjects available for our registrational program for domvanalimab (our anti-TIGIT antibody), including ARC-10, our Phase 3 trial in PD-L1 high non-small cell lung cancer, and our planned Phase 3 trials with Gilead in lung and gastrointestinal cancers.

Public health outbreaks, such as the COVID-19 pandemic, will also have an adverse impact our clinical trial operations. Regulatory authorities and ethics committees may divert resources, prolonging the time for review of new studies and any protocol or other amendments for ongoing studies. Investigational sites have intermittently diverted resources in order to respond to the ongoing health crisis, causing delays and limiting their ability to initiate new studies. The limited resources at investigational sites further hinders their ability to screen and enroll subjects, conduct and report all patient assessments and collect all patients samples, thereby impacting our ability to assess the activity of our investigational products in a timely manner. Furthermore, supply chain challenges during the COVID-19 pandemic has made it more difficult to procure standard-of-care chemotherapy drugs utilized in our trials and timely ship materials to investigational sites, which has and may continue to delay or limit their screening and enrollment of patients.

In addition, recruiting and retaining subjects in our clinical trials may be adversely impacted by negative results that we report in our other clinical trials using the same investigational products or by negative results reported by others using investigational products with the same mechanism of action as our investigational products. Delays in patient enrollment may result in increased costs or may affect the timing or outcome of the planned clinical trials, which could prevent completion of these trials and adversely affect our ability to advance the development of our investigational products. Failures in planned subject enrollment or retention may result in increased costs or program delays and could render further development impossible.

If we do not achieve our product development goals in the time frames we announce and expect, the commercialization of our investigational products may be delayed, our share price may decline and our commercial prospects may be adversely affected.

Drug development is inherently risky and uncertain. The actual timing of our development milestones can vary significantly compared to our estimates, in some cases for reasons beyond our control, for any number of reasons, including:

These and other factors may also lead to the suspension or termination of clinical trials, and ultimately the denial of regulatory approval of an investigational product. Any delays in achieving our development goals may allow our competitors to bring products to market before we do and adversely affect our commercial prospects and cause our stock price to decline.

Preliminary and interim data from our clinical studies that we announce or publish from time to time are subject to audit and verification procedures that could result in material changes in the final data and may change as more patient data become available.

From time to time, we publish preliminary or interim data from our clinical studies. Preliminary data remain subject to audit confirmation and verification procedures that may result in the final data being materially different from the preliminary data we previously published. Interim data are also subject to the risk that one or more of the clinical outcomes may materially change as patient enrollment continues and more patient data become available. As a result, preliminary and interim data should be viewed with caution until the final data are available. Material adverse changes in the final data could significantly harm our business prospects.

Serious adverse events, undesirable side effects or other unexpected properties of our investigational products may be identified during development or after approval, which could lead to the discontinuation of our clinical development programs, refusal by regulatory authorities to approve our investigational products or limitations on the use of our investigational products or, if discovered following marketing approval, revocation of marketing authorizations or subsequent limitations on the use of our investigational products.

To date, we have only tested our clinical-stage investigational products in a relatively small number of oncology subjects. As we continue our development of these investigational products and initiate clinical trials of our additional investigational products, serious adverse events, undesirable side effects or unexpected characteristics may emerge causing us to abandon these investigational products or limit their development to more narrow uses or subpopulations in which the serious adverse events, undesirable side effects or other characteristics are less prevalent, less severe or more acceptable from a risk-benefit perspective. Even if our investigational products initially show promise in these early clinical trials, the side effects of drugs are frequently only detectable after they are tested in large, Phase 3 clinical trials or, in some cases, after they are made available to patients on a commercial scale after approval. Sometimes, it can be difficult to determine if the serious adverse or unexpected side effects were caused by the investigational product or another factor, especially in oncology subjects who may suffer from other medical conditions and be taking other medications. If serious adverse or unexpected side effects are identified during development and are determined to be attributed to our investigational product, we may be required to develop a Risk Evaluation and Mitigation Strategy (REMS) to mitigate those serious safety risks, which could impose significant distribution and use restrictions on our products.

Drug-related side effects could also affect subject recruitment or the ability of enrolled subjects to complete the trial or result in potential product liability claims. Any of these occurrences may harm our business prospects significantly.

In addition, if one or more of our investigational products 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:

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

Adverse findings from clinical trials conducted by third parties investigating the same investigational products as us in different territories could adversely affect our development program.

Lack of efficacy, adverse events, undesirable side effects or other adverse findings may emerge in clinical trials conducted by third parties investigating the same investigational products as us in different territories. For example, we and Guangzhou Gloria Biosciences, Co. (Gloria Biosciences, formerly known as Harbin Gloria Pharmaceuticals Co. Ltd.) each licensed our rights to the same anti-PD-1 antibody (which we refer to as zimberelimab) from WuXi Biologics (Cayman) Inc. (WuXi Biologics). Gloria Biosciences refers to this antibody as GLS-010 and is conducting clinical trials with GLS-010 in China. We have no control over their clinical trials or development program, and adverse findings from the results or their conduct of clinical trials could adversely affect our development of zimberelimab or even the viability of zimberelimab as an investigational product. We may be required to report Gloria Biosciences’ adverse events or unexpected side effects to the FDA or comparable foreign regulatory authorities, which could, among other things, order us to cease further development of zimberelimab. We may face similar risks from any independent development conducted with our investigational products by Gilead and Taiho, following any exercise of their respective options to our programs.

A key element of our strategy is the development of intra-portfolio combinations. If we are not successful in discovering, developing and commercializing investigational products that take advantage of different

mechanisms of action to achieve superior outcomes relative to the use of single agents or other combination therapies, our ability to achieve our strategic objectives would be impaired.

A key element of our strategy is to build a broad portfolio of investigational products that will allow for the development of intra-portfolio combinations. We believe that by developing or licensing these investigational products, we can control the combinations we pursue and, if and when approved, maximize the commercial potential of these combinations. However, these combinations have not been tested before and may fail to demonstrate synergistic activity against immunological targets, may fail to achieve superior outcomes relative to the use of single agents or other combination therapies, may exacerbate adverse events associated with one of the investigational products when used as monotherapy, or may fail to demonstrate sufficient safety or efficacy traits in clinical trials to enable us to complete those clinical trials or obtain marketing approval for the combination therapy. In addition, our early clinical trials may test more than one investigational product in uncontrolled studies, and it may be difficult to interpret the results of those uncontrolled trials or evaluate the contribution of each investigational agent in such combination.

We expect that our anti-PD-1 antibody, zimberelimab, will form the backbone of many of our intra-portfolio combinations. In the event that zimberelimab were to fail to demonstrate sufficient safety and efficacy, we would need to identify alternatives for accessing an anti-PD-1 antibody. In the event we are unable to do so or are unable to do so on commercially reasonable terms, our business and prospects would be materially harmed.

All of our investigational products are targeting mechanisms that other companies are pursuing as either monotherapy or combination products. As such, even if we are successful in developing combination therapies, competition from other investigational products in the same class which are either already approved or further along in development than ours may prevent us from realizing the commercial potential of our combination therapies and prevent us from achieving our strategic objectives.

Our intra-portfolio combination strategy relies on discovering, developing and commercializing highly differentiated small molecules. If we are not able to differentiate our small molecules from other products which are approved or in development, our business prospects would be materially adversely affected.

Our combination therapy strategy relies on discovering and developing differentiated small molecules with ideal pharmacologic properties for the targeted pathway to complement our antibody investigational products, which we believe will form the backbone of our combination therapies. We conduct in our laboratories those activities that we consider to be critical for creating a development candidate with optimal properties. These activities include medicinal chemistry, assay development, assessment of compound potency and selectivity, in vitro and in vivo pharmacokinetic profile evaluation, in vivo pharmacology and exploratory safety evaluation, among others. As such, we have invested heavily in these internal capabilities and over 75% of our current workforce is dedicated to research and development.

In addition, any small molecules we discover and design may, on further study, be shown to have harmful side effects or other characteristics that indicate that they are unlikely to be medicines that will receive marketing approval and achieve market acceptance. If we are unable to identify suitable compounds with ideal pharmacological properties and which are differentiated from other investigational products in development for preclinical and clinical development, our business and prospects would be materially harmed.

Certain of our investigational products may require companion diagnostics in certain indications. Failure to successfully develop, validate and obtain regulatory clearance or approval for such tests could harm our product development strategy or prevent us from realizing the full commercial potential of our investigational products.

Companion diagnostics are subject to regulation by the FDA and comparable foreign regulatory authorities as a medical device and may require separate regulatory authorization prior to commercialization. Certain clinical trials that we are conducting, such as our Phase 2 ARC-7 trial and our Phase 3 ARC-10 trial, each being conducted in patients with PD-L1≥50% non-small cell lung cancer, include the use of a diagnostic test to help identify eligible patients. Our future trials may also use a diagnostic test to help identify eligible patients. In addition, we have significant efforts directed to identifying changes in various cells and proteins to understand their relationship, if any, to the clinical activity observed in our clinical trials and to assess if such cells and/or proteins could be used as predictive biomarkers to select for patients more likely to respond to our investigational products. However, we cannot be certain that we will be able to identify any such biomarkers, that such biomarkers will result in us identifying the appropriate patients for our investigational products or that we or any third-party collaborators will be able to validate any diagnostic tests incorporating any predictive biomarkers we may identify.

We currently do not have any plans to develop diagnostic tests internally. We are therefore dependent on the sustained cooperation and effort of third-party collaborators in developing and, if our investigational products are approved for use only with an approved companion diagnostic test, obtaining approval and commercializing these tests. If these parties are unable to successfully develop companion diagnostics for these investigational products, or experience delays in doing so, the development of our investigational products may be adversely affected and we may not be able to obtain marketing authorization for these investigational products. Furthermore, our ability to market and sell, as well as the commercial success, of any of our investigational products that require a companion diagnostic will be tied to, and dependent upon, the receipt of required regulatory authorization and the continued ability of such third parties to make the companion diagnostic commercially available on reasonable terms in the relevant geographies. Any failure to develop, validate, obtain and maintain marketing authorization and supply for a companion diagnostic we need will harm our business prospects.

The design or our execution of our ongoing and future clinical trials may not support marketing approval.

The design or execution of a clinical trial can determine whether its results will support marketing approval, and flaws in the design or execution of a clinical trial may not become apparent until the clinical trial is well advanced. In some instances, there can be significant variability in safety or efficacy results between different trials with the same investigational product due to numerous factors, including differences in trial protocols, size and type of the patient populations, variable adherence to the dosing regimen or other protocol requirements and the rate of dropout among clinical trial participants. The FDA and comparable foreign regulatory authorities have substantial discretion in the approval process and in determining when or whether marketing approval will be obtained for any of our investigational products. Our investigational products may not be approved even if they achieve their primary endpoints in any Phase 3 clinical trials or registrational trials we or our collaborators conduct. The FDA or comparable foreign regulatory authorities may disagree with our trial designs and our interpretation of data from preclinical studies or clinical trials. In addition, any of these regulatory authorities may change requirements for the approval of an investigational product even after reviewing and providing comments or advice on a protocol for a pivotal Phase 3 or registrational clinical trial that has the potential to result in FDA or other comparable foreign regulatory authorities’ approval. Any of these regulatory authorities may also approve an investigational product for fewer or more limited indications than we request or may grant approval contingent on the performance of costly post-marketing clinical trials. Even if the FDA or comparable foreign regulatory authorities approve an investigational product, they may not approve the labeling claims that we believe would be necessary or desirable for the successful commercialization of our investigational products.

We have conducted, and continue to conduct, portions of our clinical trials outside the United States, and the FDA may not accept data from trials conducted in foreign locations.

We have conducted, and we expect to continue to conduct, portions of our clinical trials outside the United States. For example, ARC-10, our Phase 3 trial evaluating zimberelimab monotherapy and zimberelimab plus domvanalimab combination therapy versus chemotherapy, does not include any clinical sites in the United States. Although the FDA may accept data from clinical trials conducted outside the United States, acceptance of these data is subject to certain conditions imposed by the FDA. For example, the clinical trial must be well designed and conducted and performed by qualified investigators in accordance with ethical principles. The trial population must also adequately represent the U.S. population, and the data must be applicable to the U.S. population and U.S. medical practice in ways that the FDA deems clinically meaningful. In general, the patient population for any clinical trials conducted outside the United States must be representative of the population for whom we intend to label the product in the United States. In addition, while these clinical trials are subject to the applicable local laws, FDA acceptance of the data will be dependent upon its determination that the trials also complied with all applicable U.S. laws and regulations. We cannot assure you that the FDA will accept data from trials conducted outside the United States. If the FDA does not accept the data from such clinical trials, we would likely need to conduct additional trials, which would be costly and time-consuming and delay or permanently halt our development of our investigational products.

We expect to depend on our collaboration with Gilead for the research, development, manufacture and commercialization of our investigational products. If this collaboration is not successful, our business could be adversely affected.

In May 2020, we entered into the Gilead Collaboration Agreement whereby Gilead obtained an exclusive license to zimberelimab and time-limited exclusive options to all of our then current and future programs during the 10-year collaboration term. In November 2021, we amended the Gilead Collaboration Agreement, and in connection with such amendment, Gilead exercised its option to three programs to obtain exclusive licenses to domvanalimab, AB308, etrumadenant and quemliclustat, and the parties added a research collaboration. Upon closing of Gilead’s exercise of its option to a program, the companies will co-develop and equally share global development costs for the joint development program, subject to opt-out rights applicable to certain programs, and expense caps on our spending and true-up adjustments. For each optioned program, provided we have not exercised our opt-out rights (if applicable), we have an option to co-promote in the United States with equal sharing of related profits and losses. Gilead has the right to exclusively commercialize any optioned programs outside of the U.S., subject to the rights of our existing partners to any territories, and will pay us tiered royalties as a percentage of revenues. In connection with the entry into the Gilead Collaboration Agreement in May 2020, we and Gilead also entered into a common stock purchase agreement and an investor rights agreement. Our agreements with Gilead pose a number of risks including, but not limited to, the following:

We rely on third parties to conduct our clinical trials and perform some of our research and preclinical studies. If these third parties do not satisfactorily carry out their contractual duties or fail to meet expected deadlines, our development programs may be delayed or subject to increased costs, each of which may have an adverse effect on our business and prospects.

We do not have the ability to conduct all aspects of our preclinical testing or clinical trials ourselves. As a result, we are and expect to remain dependent on third parties to conduct our ongoing clinical trials and any future clinical trials of our investigational products. The timing of the initiation and completion of these trials will therefore be partially controlled by such third parties and may result in delays to our development programs. Specifically, we expect CROs, clinical investigators, and consultants to play a significant role in the conduct of these trials and the subsequent collection and analysis of data. However, we will not be able to control all aspects of their activities. Nevertheless, we are responsible for ensuring that each of our trials is conducted in accordance with the applicable

protocol and legal, regulatory and scientific standards, and our reliance on the CROs and other third parties does not relieve us of our regulatory responsibilities. We and our CROs are required to comply with GCP requirements, which are regulations and guidelines enforced by the FDA, the Competent Authorities of the Member States of the European Economic Area, Australian Therapeutic Goods Administration and comparable foreign regulatory authorities for all of our investigational products in clinical development. Regulatory authorities enforce these GCP requirements through periodic inspections of trial sponsors, clinical trial investigators and clinical trial sites. If we or any of our CROs or clinical trial sites fail to comply with applicable GCP requirements, the data generated in our clinical trials may be deemed unreliable, and the FDA or comparable foreign regulatory authorities may require us to perform additional clinical trials before approving our marketing applications. In addition, our clinical trials must be conducted with product produced under cGMP regulations. Our failure to comply with these regulations may require us to stop and/or repeat clinical trials, which would delay the marketing approval process.

There is no guarantee that any such CROs, clinical trial investigators or other third parties on which we rely will devote adequate time and resources to our development activities or perform as contractually required. Many of these third parties have suffered from personnel constraints during the COVID-19 pandemic. If any of these third parties fail to meet expected deadlines, adhere to our clinical protocols or meet regulatory requirements, otherwise performs in a substandard manner, or terminates its engagement with us, the timelines for our development programs may be extended or delayed or our development activities may be suspended or terminated. If any of our clinical trial sites terminates for any reason, we may experience the loss of follow-up information on subjects enrolled in such clinical trials unless we are able to transfer those subjects to another qualified clinical trial site, which may be difficult or impossible. In addition, clinical trial investigators for our clinical trials may serve as scientific advisors or consultants to us from time to time and may receive cash or equity compensation in connection with such services. If these relationships and any related compensation result in perceived or actual conflicts of interest, or the FDA or comparable foreign regulatory authorities concludes that the financial relationship may have affected the interpretation of the trial, the integrity of the data generated at the applicable clinical trial site may be questioned and the utility of the clinical trial itself may be jeopardized, which could result in the delay or rejection of any marketing application we submit by the FDA or any comparable foreign regulatory authority. Any such delay or rejection could prevent us from commercializing our investigational products.

Furthermore, these third parties may also have relationships with other entities, some of which may be our competitors. If these third parties do not successfully carry out their contractual duties, meet expected deadlines or conduct our clinical trials in accordance with regulatory requirements or our stated protocols, we will not be able to obtain, or may be delayed in obtaining, marketing approvals for our investigational products and will not be able to, or may be delayed in our efforts to, successfully commercialize our products.

We contract with third parties for the manufacturing and supply of investigational products for use in preclinical testing and clinical trials, which supply may become limited or interrupted or may not be of satisfactory quality and quantity.

We do not have any manufacturing facilities. We produce in our laboratory relatively small quantities of compounds for evaluation in our research programs. We rely, and expect to continue to rely, on third parties for the manufacture of our investigational products for preclinical and clinical testing, as well as for commercial manufacture if any of our investigational products are approved. We currently have limited manufacturing arrangements and expect that each of our investigational products will only be covered by single source suppliers for the foreseeable future. In particular, we have an exclusive relationship with WuXi Biologics, located in China, for the manufacture of our investigational biologics, including zimberelimab, domvanalimab and AB308. Our contract manufacturers are subject to import and export rules and restrictions, which may impact their ability to acquire materials used in the manufacturing of our investigational product or export our manufactured investigational products to the countries where our clinical trials are conducted. We closely monitor the inventory for each of our investigational products in order to prevent or minimize the impact of potential disruptions, and have not yet experienced any disruptions in our ability to manufacture our investigational products as a result of the COVID-19 health crisis. However, the pandemic has prevented the U.S. Commerce Department from conducting an inspection of WuXi Biologics in connection with purchases of hardware that are subject to U.S. export controls. As a result, WuXi Biologics has been placed on the U.S.'s "Unverified List". At this time, we do not anticipate any impact to our 2022 manufacturing plans with WuXi Biologics and WuXi Biologics expects the matter to be resolved relatively soon. Furthermore, the pandemic has severely challenged supply chains, increasing the lead time for us and our contract manufacturers to obtain raw materials used in the manufacturing of our investigational products. Our reliance on limited manufacturing and use of a single global distributor increases the risk that we will not have sufficient quantities of

our investigational products for use in our clinical trials or, if approved, quantities of product at an acceptable cost or quality, which could delay, prevent or impair our development or commercialization efforts.

Furthermore, all entities involved in the preparation of therapeutics for clinical trials or commercial sale, including our existing contract manufacturers for our investigational products, are subject to extensive regulation. Components of a finished therapeutic product approved for commercial sale or used in clinical trials must be manufactured in accordance with cGMP requirements. These regulations govern manufacturing processes and procedures, including record keeping, and the implementation and operation of quality systems to control and assure the quality of investigational products and products approved for sale. Poor control of production processes can lead to the introduction of contaminants, or to inadvertent changes in the properties or stability of our investigational products that may not be detectable in final product testing. We or our contract manufacturers must supply all necessary documentation in support of a New Drug Application (NDA) or Biologics License Application (BLA) on a timely basis and must adhere to the FDA’s Good Laboratory Practice regulations and cGMP regulations enforced by the FDA through its facilities inspection program. Comparable foreign regulatory authorities may require compliance with similar requirements. The facilities and quality systems of our third-party contractor manufacturers must pass a pre-approval inspection for compliance with the applicable regulations as a condition of marketing approval of our investigational products. We do not control the manufacturing process of, and are completely dependent on, our contract manufacturing partners for compliance with cGMP regulations.

In the event that any of our manufacturers fails to comply with such requirements or to perform its obligations to us in relation to quality, timing or otherwise, or if our supply of components or other materials becomes limited or interrupted for other reasons, we may be forced to manufacture the materials ourselves, for which we currently do not have the capabilities or resources, or enter into an agreement with another third party, which we may not be able to do on commercially reasonable terms, if at all. In particular, any replacement of our manufacturers could require significant effort and expertise because there may be a limited number of qualified replacements. In some cases, the technical skills or technology required to manufacture our investigational products may be unique or proprietary to the original manufacturer and we may have difficulty transferring such skills or technology to another third party and a feasible alternative may not exist. These factors would increase our reliance on such manufacturer or require us to obtain a license from such manufacturer in order to have another third party manufacture our investigational products. If we are required to change manufacturers for any reason, we will be required to verify that the new manufacturer maintains facilities and procedures that comply with quality standards and with all applicable regulations and guidelines. The delays associated with the verification of a new manufacturer could negatively affect our ability to develop investigational products in a timely manner or within budget. Our or a third party’s failure to execute on our manufacturing requirements, to do so on commercially reasonable terms and comply with cGMP could adversely affect our business in a number of ways, including:

We, or our third-party manufacturers, may be unable to successfully produce or scale-up manufacturing of our investigational products in sufficient quality and quantity, which would delay or prevent us and/or our third-party collaborators from conducting clinical trials and developing our investigational products.

We, or our third-party manufacturers, will need to manufacture and supply large quantities of our investigational products to support our clinical development plans. With respect to investigational products from optioned programs, we, or our third-party manufacturers, may need to produce additional quantities to support the scope of our joint clinical development program with Gilead, Gilead’s additional evaluations with its own proprietary

products or Taiho’s independent clinical development plans. We are also a party to various collaboration and supply arrangements, such as our clinical trial collaboration with AstraZeneca to evaluate domvanalimab in combination with durvalumab in patients with unresectable Stage 3 non-small cell lung cancer and our clinical trial collaboration with Genentech to evaluate etrumadenant and atezolizumab utilizing the MORPHEUS platform. Furthermore, the COVID-19 pandemic has increased the lead time to obtain raw materials used in the manufacturing of our investigational products. Accordingly, we, or our manufacturing partners, may be unable to successfully increase the manufacturing capacity for any of our investigational products in a timely or cost-effective manner, or at all, to support these collective needs. In addition, quality issues may arise during scale-up activities. If we or our manufacturing partners are unable to successfully produce or scale up the manufacture of our investigational products in sufficient quality and quantity, the development, testing and clinical trials of that investigational product may be delayed or become infeasible, and marketing approval or commercial launch of any resulting product may be delayed or not obtained, which could significantly harm our business.

Changes in methods of investigational product manufacturing or formulation may result in additional costs or delay.

As investigational products progress through preclinical to late stage clinical trials to marketing approval and commercialization, it is common that various aspects of the development program, such as the investigational product’s specifications, manufacturing methods and formulation, are altered along the way in an effort to optimize yield and manufacturing batch size, minimize costs and achieve consistent quality and results. Such changes carry the risk that they will not achieve these intended objectives. Any of these changes could cause our investigational products to perform differently and affect the results of planned clinical trials or other future clinical trials conducted with the altered materials. This could delay completion of clinical trials, require the conduct of bridging clinical trials or the repetition of one or more clinical trials, increase clinical trial costs, delay approval of our investigational products and jeopardize our ability to commercialize our investigational products and generate revenue.

The manufacture of biologics is complex and our third-party manufacturers may encounter difficulties in production. If any of our third-party manufacturers encounter such difficulties, our ability to provide supply of our investigational products for clinical trials or our products for patients, if approved, could be delayed or prevented.

Manufacturing biologics, especially in large quantities, is often complex and may require the use of innovative technologies to handle living cells. Each lot of an approved biologic must undergo thorough testing for identity, strength, quality, purity and potency. Manufacturing biologics requires facilities specifically designed for and validated for this purpose, and sophisticated quality assurance and quality control procedures are necessary. Slight deviations anywhere in the manufacturing process, including filling, labeling, packaging, storage and shipping and quality control and testing, may result in lot failures, product recalls or spoilage. When changes are made to the manufacturing process, we may be required to provide preclinical and clinical data showing the comparable identity, strength, quality, purity or potency of the products before and after such changes. If microbial, viral or other contaminations are discovered at the facilities of our manufacturer, such facilities may need to be closed for an extended period of time to investigate and remedy the contamination, which could delay clinical trials and adversely harm our business. The use of biologically derived ingredients can also lead to allegations of harm, including infections or allergic reactions, or closure of product facilities due to possible contamination.

In addition, there are risks associated with large scale manufacturing for clinical trials or commercial scale including, among others, cost overruns, potential problems with process scale-up, process reproducibility, stability issues, compliance with good manufacturing practices, lot consistency and timely availability of raw materials. Even if we obtain marketing approval for any of our investigational products, there is no assurance that our manufacturers will be able to manufacture the approved product to specifications acceptable to the FDA or other comparable foreign regulatory authorities, to produce it in sufficient quantities to meet the requirements for the potential commercial launch of the product or to meet potential future demand. If our manufacturers are unable to produce sufficient quantities for clinical trials or for commercialization, our development and commercialization efforts would be impaired, which would have an adverse effect on our business, financial condition, results of operations and growth prospects.

Our reliance on third parties requires us to share our trade secrets, which increases the possibility that a competitor will discover them or that our trade secrets will be misappropriated or disclosed.

Because we rely on third parties to research and develop and to manufacture our investigational products, we must share trade secrets with them. We seek to protect our proprietary technology in part by entering into confidentiality agreements and, if applicable, material transfer agreements, consulting agreements or other similar agreements with our advisors, employees, third-party contractors and consultants prior to beginning research or disclosing proprietary information. These agreements typically limit the rights of the third parties to use or disclose our confidential information, including our trade secrets. Despite the contractual provisions employed when working with third parties, the need to share trade secrets and other confidential information increases the risk that such trade secrets become known by our competitors, are inadvertently incorporated into the technology of others, or are disclosed or used in violation of these agreements. Given that our proprietary position is based, in part, on our know-how and trade secrets, a competitor’s independent discovery of our trade secrets or other unauthorized use or disclosure would impair our competitive position and may have a material adverse effect on our business.

In addition, these agreements typically restrict the ability of our advisors, employees, third-party contractors and consultants to publish data potentially relating to our trade secrets, although our agreements may contain certain limited publication rights. For example, any academic institution that we may collaborate with will likely expect to be granted rights to publish data arising out of such collaboration and any joint research and development programs may require us to share trade secrets under the terms of our research and development or similar agreements. Despite our efforts to protect our trade secrets, our competitors may discover our trade secrets, either through breach of our agreements with third parties, independent development or publication of information by any of our third-party collaborators. A competitor’s discovery of our trade secrets would impair our competitive position and have an adverse impact on our business.

Our employees, clinical trial investigators, CROs, consultants, vendors, collaboration partners and any potential commercial partners may engage in misconduct or other improper activities, including non-compliance with regulatory standards and requirements and insider trading.

We are exposed to the risk of fraud or other misconduct by our employees, clinical trial investigators, CROs, consultants, vendors, collaboration partners and any potential commercial partners. Misconduct by these parties could include intentional, reckless and/or negligent conduct or disclosure of unauthorized activities to us that violates: (i) FDA laws and regulations or those of comparable foreign regulatory authorities, including those laws that require the reporting of true, complete and accurate information, (ii) manufacturing standards, (iii) federal and state health and data privacy, security, fraud and abuse, government price reporting, transparency reporting requirements, and other healthcare laws and regulations in the United States and abroad, or (iv) laws that require the true, complete and accurate reporting of financial information or data. Such misconduct could also involve the improper use of information obtained in the course of clinical trials, which could result in regulatory sanctions and cause serious harm to our reputation. We have adopted a code of conduct applicable to all of our employees, as well as a disclosure program and other applicable policies and procedures, but it is not always possible to identify and deter employee misconduct, and the precautions we take to detect and prevent this activity may not be effective in controlling unknown or unmanaged risks or losses or in protecting us from governmental investigations or other actions or lawsuits stemming from a failure to comply with these laws or regulations. If any such actions are instituted against us, and we are not successful in defending ourselves or asserting our rights, those actions could have a significant impact on our business, including the imposition of significant fines or other sanctions.

Even if we receive marketing approval, we may not be successful in commercializing our investigational products.

We have no sales, marketing or distribution capabilities or experience. If any of our investigational products ultimately obtains regulatory approval, we, whether alone or in collaboration with Gilead for programs that we commercialize together, may not be able to effectively or successfully market the product due to a number of factors, including:

If any of our investigational products for which we have or retain sales and marketing responsibilities are approved, we must either develop a sales and marketing organization, which would be expensive and time consuming, or outsource these functions to other third parties. We may be unable to recruit and retain adequate numbers of effective sales and marketing personnel, and if we enter into arrangements with third parties to perform sales, marketing and distribution services our product revenue or the profitability of these product revenue to us are likely to be lower than if we were to market and sell any medicines that we develop ourselves.

Our or our collaborators’ inability to successfully market and sell any of our investigational products, if approved, could have a material adverse effect on our business and our overall financial condition.

Even if we receive marketing approval for one or more of our investigational products, our commercial success is dependent on obtaining coverage and reimbursement approval for a product from a government or other third-party payor, which coverage may be delayed or may not be sufficient to cover our costs.

Our commercial success is dependent on obtaining coverage and reimbursement approval for a product from a government or other third-party payor, which is a time-consuming and costly process that could require us and any collaborators to provide supporting scientific, clinical and cost effectiveness data for the use of our products to the payor. There may be significant delays in obtaining such coverage and reimbursement for newly approved products, and coverage may be more limited than the purposes for which the product is approved by the FDA or comparable foreign regulatory authorities. Moreover, eligibility for coverage and reimbursement does not imply that a product will be paid for in all cases or at a rate that covers our costs, including research, development, intellectual property, manufacture, sale and distribution expenses. Interim reimbursement levels for new products, if applicable, may also not be sufficient to cover our costs and may not be made permanent. Obtaining reimbursement for our products may be particularly difficult because of the higher prices often associated with branded therapeutics and therapeutics administered under the supervision of a physician. Additionally, our collaborators, will be required to obtain coverage and reimbursement for any related companion diagnostics tests they develop separate and apart from the coverage and reimbursement we seek for our product candidates, once approved.

Reimbursement may also impact the demand for, and the price of, any product for which we obtain marketing approval. Assuming we obtain coverage for a given product by a third-party payor, the resulting reimbursement payment rates may not be adequate or may require co-payments that patients find unacceptably high. Patients who are prescribed medications for the treatment of their conditions, and their prescribing physicians, generally rely on third-party payors to reimburse all or part of the costs associated with those medications. Patients are unlikely to use our products unless coverage is provided and reimbursement is adequate to cover all or a significant portion of the cost of our products. Therefore, coverage and adequate reimbursement is critical to new product acceptance and we expect to experience pricing pressures in connection with the sale of any of our investigational products due to the trend toward managed healthcare, the increasing influence of health maintenance organizations, and additional legislative changes.

Our ability to obtain coverage and reimbursement approval for any of our investigational products, if approved, could have a material adverse effect on the demand for that investigational product, and on our business and our overall financial condition.

Even if our investigational products are approved by the FDA, they may never be approved or commercialized outside the United States, which would limit our ability to realize their full market potential.

In order to market any products outside the United States, we or our collaborators must establish and comply with numerous and varying regulatory requirements of other countries regarding safety and efficacy. Clinical trials conducted in one country may not be accepted by regulatory authorities in other countries, and regulatory approval in one country does not mean that regulatory approval will be obtained in any other country. Approval procedures vary among countries and can involve additional product testing and validation and additional administrative review

periods. Seeking foreign regulatory approvals could result in significant delays, difficulties and costs for us or our collaborators and may require additional preclinical studies or clinical trials which would be costly and time consuming. Regulatory requirements can vary widely from country to country and could delay or prevent the introduction of our products in those countries. Satisfying these and other regulatory requirements is costly, time consuming, uncertain and subject to unanticipated delays. In addition, our or our collaborators’ failure to obtain regulatory approval in any country may delay or have negative effects on the process for regulatory approval in other countries. We do not have any investigational products approved for sale in any jurisdiction, including international markets, and we do not have experience in obtaining regulatory approval in international markets. If we or our collaborators fail to comply with regulatory requirements in international markets or fail to obtain and maintain required approvals, our ability to realize the full market potential of our products will be harmed.

Any investigational products for which we intend to seek approval as biologic products may face competition sooner than anticipated.

The Biologics Price Competition and Innovation Act of 2009 (BPCIA) created an abbreviated approval pathway for biological products that are biosimilar to or interchangeable with an FDA-licensed reference biological product. Under the BPCIA, an application for a biosimilar product may not be submitted to the FDA until four years following the date that the reference product was first licensed by the FDA. In addition, the approval of a biosimilar product may not be made effective by the FDA until twelve years from the date on which the reference product was first licensed. During this twelve-year period of exclusivity, another company may still market a competing version of the reference product if the FDA approves a full BLA for the competing product containing the sponsor’s own preclinical data and data from adequate and well-controlled clinical trials to demonstrate the safety, purity and potency of its product. The law is complex and is still being interpreted and implemented by the FDA. As a result, any such processes could have a material adverse effect on the future commercial prospects for our biological products.

Zimberelimab, domvanalimab and AB308 are biological products and we may develop additional biological products in the future. We believe that any of our current and future investigational products approved as a biological product under a BLA should qualify for the twelve-year period of exclusivity. However, there is a risk that this exclusivity could be shortened due to Congressional action or otherwise, or that the FDA will not consider our investigational products to be reference products for competing products, potentially creating the opportunity for biosimilar competition sooner than anticipated. Other aspects of the BPCIA, some of which may impact the BPCIA exclusivity provisions, have also been the subject of recent litigation. Moreover, the extent to which a biosimilar, once approved, could be substituted for any one of our reference products in a way that is similar to traditional generic substitution for non-biological products will depend on a number of marketplace and regulatory factors that are still developing.

We are currently party to several in-license agreements under which we acquired rights to use, develop, manufacture and/or commercialize certain of our investigational products. If we breach our obligations under these agreements, we may be required to pay damages, lose our rights to these investigational products or both, which would adversely affect our business and prospects.

We rely, in part, on license and other strategic agreements, which subject us to various obligations, including diligence obligations with respect to development and commercialization activities, reporting and notification obligations, payment obligations for achievement of certain milestones and royalties on product sales, negative covenants and other material obligations. We may need to devote substantial time and attention to ensuring that we successfully integrate these transactions into our existing operations and are compliant with our obligations under these agreements, which may divert management’s time and attention away from our research and development programs or other day-to-day activities. If we fail to comply with the obligations under our license agreements or use the intellectual property licensed to us in an unauthorized manner, we may be required to pay damages and our licensors may have the right to terminate the license. If our license agreements are terminated, we may not be able to develop, manufacture, market or sell the products covered by our agreements and those being tested or approved in combination with such products. Such an occurrence could materially adversely affect the value of the investigational product being developed under any such agreement and any other investigational products being developed or tested in combination. For example, zimberelimab, which we in-licensed from WuXi Biologics, is intended to be used as the cornerstone of our combination strategy. Domvanalimab, which we in-licensed from Abmuno Therapeutics, is already being evaluated in ARC-7, a Phase 2 study, and ARC-10, a Phase 3 study, and we

are planning at least two additional Phase 3 studies with Gilead to evaluate domvanalimab in additional settings. In the event we breach our license agreement with WuXi Biologics and/or Abmuno Therapeutics, and our license agreements are terminated, we would be unable to pursue our intra-portfolio combination strategy, or we would have to negotiate a new or reinstated agreement, which may not be available to us on equally favorable terms, or at all.

In addition, the agreements under which we license intellectual property or technology to or from third parties are complex, and certain provisions in such agreements may be susceptible to multiple interpretations. The resolution of any contract interpretation disagreement that may arise could narrow what we believe to be the scope of our rights to the relevant intellectual property or technology, or increase what we believe to be our financial or other obligations under the relevant agreement, either of which could have a material adverse effect on our business, financial condition, results of operations and prospects. Moreover, if disputes over intellectual property that we have licensed prevent or impair our ability to maintain our current licensing arrangements on commercially acceptable terms, we may be unable to successfully develop and commercialize the affected investigational products.

If we are unable to successfully obtain rights to required third-party intellectual property rights or maintain the existing intellectual property rights we have, we may have to abandon development of the relevant research program or investigational product and our business, financial condition, results of operations and prospects could suffer.

We may not realize the benefits of any acquisitions, in-license or other collaborations or strategic alliances that we enter into.

We have entered into in-license agreements with multiple licensors and option agreements to enable the development and commercialization of our investigational products worldwide. In the future, we may seek to enter into acquisitions or additional licensing arrangements with third parties to expand our pipeline or that we believe will complement or augment our development and commercialization efforts with respect to our investigational products and any future investigational products that we may develop. These transactions can entail numerous operational and financial risks, including exposure to unknown liabilities, disruption of our business and diversion of our management’s time and attention in order to manage a collaboration or develop acquired products, investigational products or technologies, incurrence of substantial debt or dilutive issuances of equity securities to pay transaction consideration or costs, higher than expected collaboration, acquisition or integration costs, write-downs of assets or goodwill or impairment charges, increased amortization expenses, difficulty and cost in facilitating the collaboration or combining the operations and personnel of any acquired business, impairment of relationships with key suppliers, manufacturers or customers of any acquired business due to changes in management and ownership and the inability to retain key employees of any acquired business. As a result, if we enter into in-license, acquisition or collaboration agreements, or strategic partnerships, we may not be able to realize the benefit of such transactions if we are unable to successfully integrate them with our existing operations and company culture, which could delay our timelines or otherwise adversely affect our business.

We also cannot be certain that, following a strategic transaction or license, we will achieve the revenue or specific net income that justifies such transaction or such other benefits that led us to enter into the arrangement. For example, under the Gilead Collaboration Agreement, for each additional clinical program that Gilead exercises its option to, it will pay an option fee of $150 million per program, and for each research program that Gilead exercises its option to at the IND-enabling stage, it will pay an option fee of $60 million per program. Furthermore, we and Gilead will equally share global co-development costs for the joint development program, as well as profits and losses for the United States, subject to opt-out rights applicable to certain programs, and expense caps on our spending and true-up adjustments. If Gilead does not exercise its option to develop a program, our capital requirements relating to that development program will significantly increase and we may need to seek a new partner in order to develop and commercialize our investigational products from that program. Failure to realize the benefits of any collaborations or strategic alliances may further cause us to curtail the development of an investigational product, reduce or delay its development program or one or more of our other development programs, delay its potential commercialization or reduce the scope of any planned sales or marketing activities, or increase our expenditures and undertake development or commercialization activities at our own expense. If we elect to fund and undertake development or commercialization activities on our own, we will need to obtain additional expertise and additional capital, which may not be available to us on acceptable terms or at all. If we fail to enter into collaborations and do not have sufficient funds or expertise to undertake the necessary development and commercialization activities, we may not be able to further develop our investigational products or bring them to

market and generate product sales revenue, which would harm our business prospects, financial condition and results of operations.

We may wish to acquire rights to future assets through in-licensing or may attempt to form collaborations in the future with respect to our investigational products, but may not be able to do so, which may cause us to alter or delay our development and commercialization plans.

The development and potential commercialization of our investigational products may require substantial additional capital to fund expenses. Pursuant to the Gilead Collaboration Agreement, Gilead has an exclusive option to acquire an exclusive license to all of our then current and future clinical programs during the 10-year collaboration term. Given the breadth of the collaboration, our ability to form new collaborations in the future will be limited. If Gilead declines to exercise its option to a program, we may need to enter into new collaborations for such programs with companies that have more resources and experience than us. We may not be successful in these efforts because third parties may not view our investigational products as having the requisite potential to demonstrate safety and efficacy. If and when we collaborate with a third party for development and commercialization of an investigational product, we can expect to relinquish some or all of the control over the future success of that investigational product to the third party. Our ability to reach a definitive agreement for a collaboration will depend, among other things, upon our assessment of the collaborator’s resources and expertise, the terms and conditions of the proposed collaboration and the proposed collaborator’s evaluation of a number of factors. Those factors may include the following:

The collaborator may also consider alternative investigational products or technologies for similar indications that may be available to collaborate on and whether such a collaboration could be more attractive than the one with us for our investigational product. We may also be restricted under any license agreements from entering into agreements on certain terms or at all with potential collaborators. Collaborations are complex and time-consuming to negotiate and document. In addition, there have been a significant number of recent business combinations among large pharmaceutical companies that have resulted in a reduced number of potential future collaborators and changes to the strategies of the combined company. As a result, we may not be able to negotiate collaborations on a timely basis, on acceptable terms, or at all. If we are unable to do so, we may have to curtail the development of such investigational product, reduce or delay one or more of our other development programs, delay the potential commercialization or reduce the scope of any planned sales or marketing activities for such investigational product, or increase our expenditures and undertake development, manufacturing or commercialization activities at our own expense. If we elect to increase our expenditures to fund development, manufacturing or commercialization activities on our own, we may need to obtain additional capital, which may not be available to us on acceptable terms or at all. If we do not have sufficient funds, we may not be able to further develop our investigational products or bring them to market and generate product revenue.

Our operating activities may be restricted by certain covenants in our license and other strategic agreements, which could limit our development and commercial opportunities.

In connection with certain of our acquisitions, in-license or other collaborations or strategic alliances, we may agree to and be bound by negative covenants which may limit our development and commercial opportunities. For example, pursuant to our in-license of anti-PD-1 antibodies from WuXi Biologics, we made certain covenants to not commercialize any anti-PD-1 antibody licensed or obtained by us after the date of the license agreement with WuXi Biologics other than anti-PD-1 antibodies licensed from WuXi Biologics, subject to certain exceptions as set forth in our license agreement with WuXi Biologics. Furthermore, we agreed in our license agreement that WuXi Biologics

would be our exclusive manufacturer of anti-PD-1 antibodies licensed thereunder until a certain number of years has elapsed following commercialization of such an anti-PD-1 antibody and that we would utilize WuXi Biologics as our exclusive provider of CMC development services for our biologic investigational products for five years from the date of our license agreement, subject to certain exceptions in each case. These exclusivity provisions may inhibit our development efforts, prevent us from forming strategic collaborations to develop and potentially commercialize any other anti-PD-1 antibody investigational products and may materially harm our business, financial condition, results of operations and prospects.

If we are unable to obtain and maintain sufficient intellectual property protection for our investigational products, or if the scope of the intellectual property protection is not sufficiently broad, our competitors could develop and commercialize products similar or identical to ours, and our ability to successfully commercialize our products may be adversely affected.

Our success depends in large part on our ability to obtain and maintain patent protection in the United States and other countries with respect to our investigational products and research programs. We seek to protect our proprietary position by filing patent applications in the United States and abroad related to our novel discoveries and technologies that are important to our business, however, we cannot predict:

Obtaining and enforcing patents is expensive and time-consuming, and we may not be able to file and prosecute all necessary or desirable patent applications, or maintain and/or enforce patents that may issue based on our patent applications, at a reasonable cost or in a timely manner. It is also possible that we will fail to identify patentable aspects of our research and development results before it is too late to obtain patent protection. Although we enter into non-disclosure and confidentiality agreements with parties who have access to patentable aspects of our research and development output, such as our employees, corporate collaborators, outside scientific collaborators, contract research organizations, contract manufacturers, consultants, advisors and other third parties, any of these parties may breach these agreements and disclose such results before a patent application is filed, thereby jeopardizing our ability to seek patent protection.

We also cannot be certain that the claims in our pending patent applications directed to our investigational products and/or technologies will be considered patentable by the U.S. Patent and Trademark Office (USPTO) or by patent offices in foreign countries. One aspect of the determination of patentability of our inventions depends on the scope and content of the “prior art,” information that was or is deemed available to a person of skill in the relevant art prior to the priority date of the claimed invention. There may be prior art of which we are not aware that may affect the patentability of our patent claims or, if issued, affect the validity or enforceability of a patent claim. Even if the patents do issue based on our patent applications, third parties may challenge the validity, enforceability or scope thereof, which may result in such patents being narrowed, invalidated or held unenforceable. Furthermore, even if they are unchallenged, patents in our portfolio may not adequately exclude third parties from practicing relevant technology or prevent others from designing around our claims. If the breadth or strength of our intellectual property position with respect to our investigational products is threatened, it could dissuade companies from collaborating with us to develop and threaten our ability to commercialize our investigational products. In the event of litigation or administrative proceedings, we cannot be certain that the claims in any of our issued patents will be considered valid by courts in the United States or foreign countries.

We may not identify relevant third-party patents or may incorrectly interpret the relevance, scope or expiration of a third-party patent which might adversely affect our ability to develop and market our products.

We cannot guarantee that any of our patent searches or analyses, including the identification of relevant patents, the scope of patent claims or the expiration of relevant patents, are complete or thorough, nor can we be certain that we have identified each and every third-party patent and pending application in the United States and abroad that is relevant to or necessary for the commercialization of our investigational products in any jurisdiction.

The scope of a patent claim is determined by an interpretation of the law, the written disclosure in a patent and the patent’s prosecution history. Our interpretation of the relevance or the scope of a patent or a pending application may be incorrect, which may negatively impact our ability to market our products. We may incorrectly determine that our products are not covered by a third-party patent or may incorrectly predict whether a third party’s pending application will issue with claims of relevant scope. Our determination of the expiration date of any patent in the United States or abroad that we consider relevant may be incorrect, which may negatively impact our ability to develop and market our investigational products. Our failure to identify and correctly interpret relevant patents may negatively impact our ability to develop and market our products.

In the future, we may need to obtain additional licenses of third-party technology that may not be available to us or are available only on commercially unreasonable terms, and which may cause us to operate our business in a more costly or otherwise adverse manner that was not anticipated.

From time to time we may be required to license technology from additional third parties to further develop or commercialize our investigational products. Should we be required to obtain licenses to any third-party technology, including any such patents required to manufacture, use or sell our investigational products, such licenses may not be available to us on commercially reasonable terms, or at all. The inability to obtain any third-party license required to develop or commercialize any of our investigational products could cause us to abandon any related efforts, which could seriously harm our business and operations.

We may become involved in lawsuits alleging that we have infringed the intellectual property rights of third parties or to protect or enforce our patents or other intellectual property, which litigation could be expensive, time consuming and adversely affect our ability to develop or commercialize our investigational products.

The coverage of patents is subject to interpretation by the courts, and the interpretation is not always uniform. There is a substantial amount of intellectual property litigation in the biotechnology and pharmaceutical industries, and we may become party to, or threatened with, litigation or other adversarial proceedings regarding intellectual property rights with respect to our products candidates. Third parties may assert infringement claims against us based on existing or future intellectual property rights. For example, we are aware of certain patents owned or licensed by Bristol-Myers Squibb having claims directed broadly to treating cancer with anti-PD-1 antibodies (the BMS Patents), which expire in 2023 and 2024. The BMS Patents have been and may in the future be the subject of litigation. In addition, we are aware of certain patents held by Genentech relating to methods of using an anti-PD-1 or anti-PD-L1 antibody in combination with an anti-TIGIT antibody for the treatment of cancer (the Genentech Patents), which expire in 2034. Merck has challenged the Genentech Patents in proceedings before the USPTO. If the validity of the BMS Patents and Genentech Patents are upheld following all challenges, and if we receive regulatory approval for zimberelimab prior to expiration of the BMS Patents or domvanalimab or AB308 in combination with zimberelimab prior to expiration of the Genentech Patents, then we may need to delay commercialization or we may need to obtain a license, which license may not be available on commercially reasonable terms, or at all.

If we were sued for patent infringement, we would need to demonstrate that our investigational products, products or methods either do not infringe the patent claims of the relevant patent or that the patent claims are invalid or unenforceable, and we may not be able to do this. Proving invalidity may be difficult. For example, in the United States, proving invalidity in court requires a showing of clear and convincing evidence to overcome the presumption of validity enjoyed by issued patents. If we are found to infringe a third party’s intellectual property rights, we could be forced, including by court order, to cease developing, manufacturing or commercializing the infringing investigational product or product. Alternatively, we may be required to obtain a license from such third party in order to use the infringing technology and continue developing, manufacturing or marketing the infringing investigational product. However, we may not be able to obtain any required license on commercially reasonable terms or at all. Even if we were able to obtain a license, it could be non-exclusive, thereby giving our competitors access to the same technologies licensed to us. In addition, we could be found liable for monetary damages,

including treble damages and attorneys’ fees if we are found to have willfully infringed a patent. A finding of infringement could prevent us from commercializing our investigational products or force us to cease some of our business operations, which could materially harm our business.

In addition, we may find that competitors are infringing our patents, trademarks, copyrights or other intellectual property. To counter infringement or unauthorized use, we may be required to file infringement claims, which can be expensive and time consuming and divert the time and attention of our management and scientific personnel. Any claims we assert against perceived infringers could provoke these parties to assert counterclaims against us alleging that we infringe their patents, in addition to counterclaims asserting that our patents are invalid or unenforceable, or both. In any patent infringement proceeding, there is a risk that a court will decide that a patent of ours is invalid or unenforceable, in whole or in part, and that we do not have the right to stop the other party from using the invention at issue. There is also a risk that, even if the validity of such patents is upheld, the court will construe the patent’s claims narrowly or decide that we do not have the right to stop the other party from using the invention at issue on the grounds that our patent claims do not cover the invention. An adverse outcome in a litigation or proceeding involving our patents could limit our ability to assert our patents against those parties or other competitors, and may curtail or preclude our ability to exclude third parties from making and selling similar or competitive products. Any of these occurrences could adversely affect our competitive business position, business prospects and financial condition. Similarly, if we assert trademark infringement claims, a court may determine that the marks we have asserted are invalid or unenforceable, or that the party against whom we have asserted trademark infringement has superior rights to the marks in question. In this case, we could ultimately be forced to cease use of such trademarks. Even if we establish infringement, the court may decide not to grant an injunction against further infringing activity and instead award only monetary damages, which may or may not be an adequate remedy.

Furthermore, because of the substantial amount of discovery required in connection with intellectual property litigation, there is a risk that some of our confidential information could be compromised by disclosure during litigation. There could also be public announcements of the results of hearings, motions or other interim proceedings or developments. If securities analysts or investors perceive these results to be negative, it could have a material adverse effect on the price of shares of our common stock. Moreover, we cannot assure you that we will have sufficient financial or other resources to defend or pursue such litigation, which typically last for years before they are concluded. Even if we are successful in these proceedings, we may incur substantial costs and the time and attention of our management and scientific personnel could be diverted in pursuing these proceedings, which could have a material adverse effect on our business and operations. In addition, we may not have sufficient resources to bring these actions to a successful conclusion.

Because of the expense and uncertainty of litigation, we may not be in a position to enforce our intellectual property rights against third parties.

Because of the expense and uncertainty of litigation, we may conclude that even if a third party is infringing our issued patent, any patents that may be issued as a result of our pending or future patent applications or other intellectual property rights, the risk-adjusted cost of bringing and enforcing such a claim or action may be too high or not in the best interest of our company or our stockholders. In such cases, we may decide that the more prudent course of action is to simply monitor the situation or initiate or seek some other non-litigious action or solution.

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

We could in the future be subject to claims that we or our employees have inadvertently or otherwise used or disclosed alleged trade secrets or other confidential information of former employers or competitors. Although we try to ensure that our employees and consultants do not use the intellectual property, proprietary information, know-how or trade secrets of others in their work for us, we may become subject to claims that we caused an employee to breach the terms of his or her non-competition or non-solicitation agreement, or that we or these individuals have, inadvertently or otherwise, used or disclosed the alleged trade secrets or other proprietary information of a former employer or competitor.

While we may litigate to defend ourselves against these claims, even if we are successful, litigation could result in substantial costs and could be a distraction to management. If our defenses to these claims fail, in addition to requiring us to pay monetary damages, a court could prohibit us from using technologies or features that are essential to our investigational products, if such technologies or features are found to incorporate or be derived from the trade secrets or other proprietary information of the former employers. Moreover, any such litigation or the

threat thereof may adversely affect our reputation, our ability to form strategic alliances or sublicense our rights to collaborators, engage with scientific advisors or hire employees or consultants, each of which would have an adverse effect on our business, results of operations and financial condition.

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

Patents are of national or regional effect, and filing, prosecuting and defending patents on all of our investigational products throughout the world would be prohibitively expensive. As such, we may not be able to prevent third parties from practicing our inventions in all countries outside the United States, or from selling or importing products made using our inventions in and into the United States or other jurisdictions. Further, the legal systems of certain countries, particularly certain developing countries, do not favor the enforcement of patents and other intellectual property protection, particularly those relating to pharmaceuticals or biologics, which could make it difficult for us to stop the infringement of our patents or marketing of competing products in violation of our proprietary rights generally. In addition, certain developing countries, including China and India, have compulsory licensing laws under which a patent owner may be compelled to grant licenses to third parties. In those countries, we and our licensors may have limited remedies if patents are infringed or if we or our licensors are compelled to grant a license to a third party, which could materially diminish the value of those patents. This could limit our potential revenue opportunities. Accordingly, our efforts to enforce our intellectual property rights around the world may be inadequate to obtain a significant commercial advantage from the intellectual property that we develop or license.

Changes in patent law in the United States and other jurisdictions could diminish the value of patents in general, thereby impairing our ability to protect our investigational products.

As is the case with other biopharmaceutical companies, our success is heavily dependent on intellectual property, particularly patents. However, the patent position of biopharmaceutical companies generally is highly uncertain, involves complex legal and factual questions and has in recent years been the subject of much litigation, resulting in court decisions, including Supreme Court decisions, that have increased uncertainties as to the ability to obtain and enforce patent rights in the future. Changes in either the patent laws or interpretation of the patent laws in the United States and other countries could increase the uncertainties and costs. For example, in September 2011 the Leahy-Smith America Invents Act (the America Invents Act) was signed into law and included a number of significant changes to U.S. patent law as then existed. These include provisions that affect the way patent applications are prosecuted, redefine prior art and provide more efficient and cost-effective avenues for competitors to challenge the validity of patents. These include allowing third-party submission of prior art to the USPTO during patent prosecution and additional procedures to attack the validity of a patent by USPTO administered post-grant proceedings, including post-grant review, inter partes review, and derivation proceedings. After March 2013, under the America Invents Act, the United States transitioned to a first inventor to file system in which, assuming that the other statutory requirements are met, the first inventor to file a patent application will be entitled to the patent on an invention regardless of whether a third party was the first to invent the claimed invention. However, the America Invents Act and its implementation could increase the uncertainties and costs surrounding the prosecution of our patent applications and the enforcement or defense of our issued patents, all of which could have a material adverse effect on our business, financial condition, results of operations and prospects.

The U.S. Supreme Court has ruled on several patent cases in recent years, either narrowing the scope of patent protection available in certain circumstances or weakening the rights of patent owners in certain situations. Depending on future actions by the U.S. Congress, the U.S. courts, the USPTO and the relevant law-making bodies in other countries, the laws and regulations governing patents could change in unpredictable ways that would weaken our ability to obtain new patents or to enforce our existing patents and patents that we might obtain in the future.

We may rely on trade secret and proprietary know-how which can be difficult to trace and enforce and, if we are unable to protect the confidentiality of our trade secrets, our business and competitive position would be harmed.

In addition to seeking patents for some of our technology and investigational products, we may also rely on trade secrets, including unpatented know-how, technology and other proprietary information, to maintain our competitive position. Elements of our investigational product, including processes for their preparation and manufacture, may involve proprietary know-how, information, or technology that is not covered by patents, and thus for these aspects we may consider trade secrets and know-how to be our primary intellectual property. Any disclosure, either intentional or unintentional, by our employees, the employees of third parties with whom we share our facilities or third-party consultants and vendors that we engage to perform research, clinical trials or manufacturing activities, or

misappropriation by third parties (such as through a cybersecurity breach) of our trade secrets or proprietary information could enable competitors to duplicate or surpass our technological achievements, thus eroding our competitive position in our market.

Trade secrets and know-how can be difficult to protect. We require our employees to enter into written employment agreements containing provisions of confidentiality and obligations to assign to us any inventions generated in the course of their employment. We and any third parties with whom we share facilities enter into written agreements that include confidentiality and intellectual property obligations to protect each party’s property, potential trade secrets, proprietary know-how, and information. We further seek to protect our potential trade secrets, proprietary know-how, and information in part, by entering into non-disclosure and confidentiality agreements with parties who are given access to them, such as our corporate collaborators, outside scientific collaborators, contract research organizations, contract manufacturers, consultants, advisors and other third parties. With our consultants, contractors, and outside scientific collaborators, these agreements typically include invention assignment obligations. Despite these efforts, any of these parties may breach the agreements and disclose our proprietary information, including our trade secrets, and we may not be able to obtain adequate remedies for such breaches. Enforcing a claim that a party illegally disclosed or misappropriated a trade secret is difficult, expensive and time-consuming, and the outcome is unpredictable. In addition, some courts inside and outside the United States are less willing or unwilling to protect trade secrets. If any of our trade secrets were to be lawfully obtained or independently developed by a competitor or other third party, we would have no right to prevent them from using that technology or information to compete with us. If any of our trade secrets were to be disclosed to or independently developed by a competitor or other third party, our competitive position would be harmed.

We may become subject to claims challenging the inventorship or ownership of our patents and other intellectual property.

We may be subject to claims that former employees, collaborators or other third parties have an interest in our patents or other intellectual property as an inventor or co-inventor. The failure to name the proper inventors on a patent application can result in the patents issuing thereon being unenforceable. Inventorship disputes may arise from conflicting views regarding the contributions of different individuals named as inventors, the effects of foreign laws where foreign nationals are involved in the development of the subject matter of the patent, conflicting obligations of third parties involved in developing our investigational products or as a result of questions regarding co-ownership of potential joint inventions. Litigation may be necessary to resolve these and other claims challenging inventorship and/or ownership. Alternatively, or additionally, we may enter into agreements to clarify the scope of our rights in such intellectual property. If we fail in defending any such claims, in addition to paying monetary damages, we may lose valuable intellectual property rights, such as exclusive ownership of, or right to use, valuable intellectual property. Such an outcome could have a material adverse effect on our business. Even if we are successful in defending against such claims, litigation could result in substantial costs and be a distraction to management and other employees.

Patent terms may be inadequate to protect our competitive position on our investigational products for an adequate amount of time.

Patent rights are of limited duration. Given the amount of time required for the development, testing and regulatory review of new investigational products, patents protecting such candidates might expire before or shortly after such investigational products are commercialized. Even if patents covering our investigational products are obtained, once the patent life has expired for a product, we may be open to competition from biosimilar or generic products. A patent term extension based on regulatory delay may be available in the United States. However, only a single patent can be extended for each marketing approval, and any patent can be extended only once, for a single product. Moreover, the scope of protection during the period of the patent term extension does not extend to the full scope of the claim, but instead only to the scope of the product as approved. Laws governing analogous patent term extensions in foreign jurisdictions vary widely, as do laws governing the ability to obtain multiple patents from a single patent family. Additionally, we may not receive an extension if we fail to apply within applicable deadlines, fail to apply prior to expiration of relevant patents or otherwise fail to satisfy applicable requirements. If we are unable to obtain patent term extension or restoration, or the term of any such extension is less than we request, the period during which we will have the right to exclusively market our product will be shortened and our competitors may obtain approval of competing products following our patent expiration, and our revenue could be reduced, possibly materially.

We expect to expand our research and development capabilities and, as a result, we may encounter difficulties in managing our growth, which could disrupt our operations.

In order to maximize the potential of our Gilead Collaboration Agreement, we expect to significantly grow our clinical development capabilities, including increasing the number of employees in clinical operations, biostatistics and data management, quality, and regulatory affairs, as well as expanding our overall infrastructure. If any of our investigational products receives marketing approval, we will also need to add sales, marketing and distribution capabilities. To manage our anticipated future growth, we must:

Our future financial performance and our ability to develop, manufacture and commercialize our investigational products will depend, in part, on our ability to effectively manage any future growth, and our management may also have to divert financial and other resources, and a disproportionate amount of its attention away from day-to-day activities in order to devote a substantial amount of time, to managing these growth activities.

If we are not able to effectively expand our organization by hiring new employees and expanding our groups of consultants and contractors, we may not be able to successfully implement the tasks necessary to further develop and commercialize our investigational products and, accordingly, may not achieve our research, development and commercialization goals.

Our future success depends on our ability to retain key employees, consultants and advisors and to attract, retain and motivate qualified personnel.

Our ability to compete in the highly competitive biopharmaceuticals industry depends upon our ability to attract, retain and motivate highly skilled and experienced personnel with scientific, medical, regulatory, manufacturing and management skills and experience. We conduct our operations in the San Francisco Bay Area, a region that is home to many other biopharmaceutical companies as well as many academic and research institutions, resulting in fierce competition for qualified personnel and rapidly increasing wages. Our industry also has experienced a high rate of turnover in recent years, which has worsened during the COVID-19 pandemic. While we have expanded a number of our in-office roles to permit remote work arrangements, allowing us to seek talent from outside the San Francisco Bay Area, we still may not be able to attract or retain qualified personnel in the future due to the intense competition for a limited number of qualified personnel among biopharmaceutical companies. Many of the other biopharmaceutical companies against which we compete have greater financial and other resources, different risk profiles and a longer history in the industry than we do. Our competitors may provide higher compensation, more diverse opportunities and/or better opportunities for career advancement. Any or all of these competing factors may limit our ability to continue to attract and retain high quality personnel, which could negatively affect our ability to successfully develop and commercialize our investigational products and to grow our business and operations as currently contemplated.

We are highly dependent on the services of our founders, Terry Rosen, Ph.D., who serves as our Chief Executive Officer, and Juan Jaen, Ph.D., who serves as our President.

We are highly dependent on the services of our founders, Terry Rosen, Ph.D., who serves as our Chief Executive Officer, and Juan Jaen, Ph.D., who serves as our President. Although we have entered into employment agreements with them, they are not for a specific term and each of them may terminate their employment with us at any time, though we are not aware of any present intention of either of these individuals to leave us.

Drs. Rosen and Jaen have significant experience identifying and developing biopharmaceuticals. We believe that their drug discovery and development experience, and overall biopharmaceutical company management experience, would be difficult to replace. However, the historical results, past performance and/or acquisitions of companies with which they were affiliated do not necessarily predict or guarantee similar results for our company. Further, Drs. Rosen and Jaen have certain other business and personal commitments outside of serving as the Chief Executive Officer and President of Arcus, including serving on the boards of other companies and foundations, which may result in diversion of their focus and attention on our company.

We face substantial competition, which may result in others discovering, developing or commercializing products more quickly or marketing them more successfully than us. If their investigational products are shown to be safer or more effective than ours, then our commercial opportunity will be reduced or eliminated.

We compete in the segments of the pharmaceutical, biotechnology and other related markets that develop immunotherapies for the treatment of cancer, which is highly competitive with rapidly changing standards of care. As such, our commercial opportunity could be reduced or eliminated if our competitors develop and commercialize products that are safer, more effective, have fewer or less severe side effects, are more convenient, or are less expensive than any products that we may develop or that would render any products that we may develop obsolete or non-competitive. Our competitors also may obtain marketing approval for their products more rapidly than we may obtain approval for ours, which could result in our competitors establishing a strong market position before we are able to enter the market.

Some of the other products in the same class as our investigational products have already been approved or are further along in development. With respect to our anti-TIGIT antibodies, domvanalimab and AB308, we are aware of several pharmaceutical companies developing antibodies against this target, including Agenus, Beigene, Biothera, Bristol-Myers Squibb, Compugen, Roche/Genentech, Innovent, iTeos/GSK, Junshi/Coherus, Merck, EMD Serono, Mereo and SeaGen. AstraZeneca and Innovent are developing TIGIT-PD-1 bispecific antibodies. To our knowledge, there are no approved anti-TIGIT antibodies and the most advanced agents are in Phase 3 development. With respect to our dual adenosine receptor antagonist, etrumadenant, we are aware that Incyte and Merck KGaA have initiated clinical development of dual adenosine receptor antagonists and we are aware of clinical-stage selective adenosine A2aR antagonists being developed by other companies, including AstraZeneca, Corvus, CStone, Exscientia, Incyte, iTeos, Novartis and Tarus, and clinical-stage selective adenosine A2bR antagonists being developed by Palobiofarma, Tarus and Teon. For our small-molecule CD73 inhibitor, quemliclustat, we are aware of several pharmaceutical companies developing antibodies against this target, including Akeso, AstraZeneca, Bristol-Myers Squibb, Corvus, Incyte, Innate, Innovent, Jacobio, Novartis, Shanghai Henlius Biotech, Symphogen/Servier and Tracon/I-Mab, all of whom have advanced their CD73 antibodies into clinical development. Other pharmaceutical companies have small-molecule programs against this target, of which only Antengene and ORIC are believed to be in clinical development. Regarding our anti-PD-1 antibody, zimberelimab, multiple large pharmaceutical companies have already received regulatory approvals for their anti-PD-1/PD-L1 antibodies, including AstraZeneca, Bristol-Myers Squibb, Merck, Pfizer in partnership with Merck KGaA, Regeneron in partnership with Sanofi Genzyme and Roche/Genentech, and there are also many other anti-PD-1 and anti-PD-L1 antibodies in clinical development. For our HIF-2α inhibitor, AB521, we are aware that Merck received approval for belzutifan in 2021. Other pharmaceutical companies, including Novartis and NiKang Therapeutics have small-molecule HIF-2α inhibitors in development. Arrowhead Pharmaceuticals has advanced an RNA-based anti-HIF-2α agent into the clinic.

As more investigational products within a particular class of drugs proceed through clinical development to regulatory review and approval, the amount and type of clinical data that may be required by regulatory authorities may increase or change. Consequently, the results of our clinical trials for investigational products in that class will likely need to show a risk benefit profile that is competitive with or more favorable than those products and investigational products in order to obtain marketing approval or, if approved, a product label that is favorable for commercialization. If the risk benefit profile is not competitive with those products or investigational products, or if the approval of other agents for an indication or patient population significantly alters the standard of care with which we tested our investigational products, we may have developed a product that is not commercially viable, that we are not able to sell profitably or that is unable to achieve favorable pricing or reimbursement. In such circumstances, our future product revenue and financial condition would be materially and adversely affected.

Many of our competitors, such as large pharmaceutical and biotechnology companies like AstraZeneca, Bristol-Myers Squibb, Merck, Novartis and Roche/Genentech, have longer operating histories and significantly greater financial resources and expertise in research and development, manufacturing, preclinical studies, conducting clinical trials, obtaining regulatory approvals and marketing approved products than we do. Mergers and acquisitions in the pharmaceutical and biotechnology industries may result in even more resources being concentrated among a smaller number of our competitors. Smaller and other early-stage companies may also prove to be significant competitors, particularly through collaborative arrangements with large and established companies. These third parties compete with us in recruiting and retaining qualified scientific and management personnel, establishing clinical trial sites and subject enrollment for clinical trials, as well as in acquiring technologies complementary to, or necessary for, our programs.

The key competitive factors affecting the success of all of our programs are likely to be their efficacy, safety, convenience, and availability of reimbursement. If we are not successful in developing, commercializing and achieving higher levels of reimbursement than our competitors, we will not be able to compete against them and our business would be materially harmed.

The development and commercialization of zimberelimab may face strong competition from other anti-PD-1 antibodies that have already received marketing approval by larger companies with substantial resources and more experience developing, manufacturing and commercializing biologic compounds.

As discussed above, some companies, such as AstraZeneca, Bristol-Myers Squibb, Merck, Pfizer in partnership with Merck KGaA, Regeneron in partnership with Sanofi Genzyme and Roche/Genentech, have anti-PD-1/PD-L1 antibodies that are approved and on the market, and continue to develop and seek regulatory approval for their respective anti-PD-1/PD-L1 antibodies for additional oncology indications. For example, in October 2020, the U.S. FDA approved an expanded label for Keytruda® (pembrolizumab) as monotherapy for the treatment of adult patients with relapsed or refractory classical Hodgkin lymphoma. Many other companies are developing anti-PD-1/PD-L1 antibodies for various oncology indications that are further along in development than zimberelimab. This competitive environment could limit our development opportunities for zimberelimab or compromise our ability to successfully enroll our ongoing and future clinical trials with zimberelimab by limiting the availability of clinical trial investigators, sites and/or subjects which could slow, delay or limit the progress of zimberelimab’s development. As a result of these or other problems and risks, we may never receive marketing approval for zimberelimab, may not realize the full commercial potential of zimberelimab as monotherapy or in combination with our other investigational products, may never recoup our financial investment or may never generate significant value or revenue from this asset.

Our internal information technology systems, and those of our third-party CROs and other third parties upon which we rely, are subject to failure, security breaches and other disruptions, which could result in a material disruption of our investigational products’ development programs, jeopardize sensitive information, prevent us from accessing critical information or result in a loss of our assets, and potentially expose us to notification obligations, loss, liability or reputational damage and otherwise adversely affect our business.

We are increasingly dependent upon information technology systems, infrastructure and data to operate our business. In the ordinary course of business, we collect, store and transmit confidential information, including but not limited to intellectual property, proprietary business information and personal information. It is critical that we do so in a secure manner to maintain the confidentiality, integrity and availability of such confidential information. We also have outsourced elements of our operations to third parties, and as a result we manage a number of third-party contractors who have access to our confidential information.

Despite the implementation of security measures, given their size and complexity and the increasing amounts of confidential information that they maintain, our internal information technology systems and those of our third-party CROs and other third parties upon which we rely are vulnerable to breakdown or other damage or interruption from service interruptions, system malfunction, natural disasters, terrorism, war and telecommunication and electrical failures, as well as security breaches from inadvertent or intentional actions by our employees, contractors, consultants, business partners, and/or other third parties, or from cyberattacks by malicious third parties (including the deployment of harmful malware, ransomware, denial-of-service attacks, social engineering and other means to affect service reliability and threaten the confidentiality, integrity and availability of information and other assets), which may compromise our system infrastructure, lead to data leakage, impair key business processes or other critical business operations, delay our development programs, or result in the loss of assets or other liability. We have monitoring systems in place and have detected at least one intrusion into our computer systems and attempts to exfiltrate our data. Although our investigation in each case indicates that it did not have a material adverse effect on our operations nor result in any compromise of our information, there can be no assurance of a similar result in the future. The COVID-19 pandemic and our reliance on internet technology and the number of our employees who are working remotely has increased the opportunities for cybercriminals to exploit vulnerabilities. Overall, there has been a significant increase in fraud schemes, including a successful social engineering attack against us through one of our employees. We cannot assure you that our data protection efforts and our investment in information technology will prevent breakdowns, data leakages, breaches in our systems or other cyber incidents that could have a material adverse effect upon our reputation, business, operations or financial condition.

Furthermore, as the cyber threat landscape evolves, these attacks are growing in frequency, sophistication and intensity, and becoming increasingly difficult to detect. There can be no assurance that we and our third-party CROs

and other third parties upon which we rely will be successful in detecting, preventing or fully recovering systems or data from all breakdowns, service interruptions, attacks or breaches of systems that could adversely affect our business and operations and/or result in the loss or disclosure of critical or sensitive data or other assets, which could result in financial, legal, business or reputational harm to us. Ransomware attacks have risen dramatically and we may be forced to pay to unlock our data and information, re-access our systems and resume our ability to conduct business operations. The loss of clinical trial data for our investigational products could significantly increase our costs to recover or reproduce the data and result in delays in our development programs, impair our ability to obtain marketing approval and reduce the commercial opportunity for our investigational products.

Moreover, significant disruptions of our internal information technology systems or security breaches could result in the loss, misappropriation, and/or unauthorized access, use, or disclosure of, or the prevention of access to, confidential information (including trade secrets or other intellectual property, proprietary business information, and personal information), which could result in financial, legal, business, and reputational harm to us. In particular, any such event that leads to unauthorized access, use, or disclosure of personal information, including personal information regarding our clinical trial subjects or employees, could harm our reputation directly, compel us to comply with federal and/or state breach notification laws and foreign law equivalents, subject us to mandatory corrective action, and otherwise subject us to liability under laws and regulations that protect the privacy and security of personal information, which could result in significant legal and financial exposure and reputational damages that could potentially have an adverse effect on our business.

Although we maintain insurance coverage to insure against losses suffered as a result of malicious intrusions and cyberattacks, such coverage may be insufficient to fully compensate us for the loss or there may be disputes with our insurers about the availability of insurance coverage for our claims. Cyber insurance may become increasingly difficult to maintain and we may not be able to maintain coverage at a reasonable cost or in an amount adequate to compensate for any loss or satisfy any liability that may arise.

Unfavorable global economic and trade conditions could adversely affect our business, financial condition or results of operations.

Our results of operations could be adversely affected by general conditions in the global economy and in the global financial markets and global trade. The current global economic conditions are highly volatile due to the COVID-19 pandemic and government restrictions on movement, which may lead to disruptions in the capital and credit markets and reduce our ability to raise additional capital when needed on acceptable terms, if at all. Furthermore, we conduct, and we expect to continue to conduct, portions of our clinical trials outside the United States, and unfavorable economic conditions resulting in the weakening of the U.S. dollar would make those clinical trials more costly to operate. A weak or declining economy could also strain our suppliers, possibly resulting in supply disruption.

Adverse trade relations may further impact our operations and/or financial condition by limiting or preventing the activities of third parties that we engage or increasing the cost of our operations. For example, we have an exclusive relationship with WuXi Biologics, located in China, for the manufacture of our investigational biologics, including zimberelimab, domvanalimab and AB308, and for biologics CMC development. The U.S. Commerce Department recently added thirty-three entities from China to its "Unverified List", including WuXi Biologics, which may impact WuXi Biologics' ability to purchase certain hardware used in the manufacturing of our antibodies. In addition, if tariffs were to be imposed on the investigational products they manufacture for us, such tariffs would have an adverse impact on our operating results and financial condition. Any of the foregoing could harm our business and we cannot anticipate all of the ways in which the current economic climate and financial market conditions could adversely impact our business.

Our future growth may depend, in part, on our ability to operate in foreign markets, where we would be subject to additional regulatory burdens and other risks and uncertainties.

Our future profitability may depend, in part, on our ability to commercialize our investigational products in foreign markets for which we may rely on collaboration with third parties. We are not permitted to market or promote any of our investigational products before we receive marketing approval from the applicable regulatory authority in that foreign market, and we may never receive such marketing approval for any of our investigational products. To obtain marketing approval in many foreign countries, we must comply with numerous and varying regulatory requirements of such countries regarding safety and efficacy and governing, among other things, clinical trials and commercial sales, pricing and distribution of our investigational products, and we cannot predict success in these

jurisdictions. If we obtain approval of our investigational products and ultimately commercialize our investigational products in foreign markets, we would be subject to additional risks and uncertainties, including:

Foreign sales of our investigational products could also be adversely affected by the imposition of governmental controls, political and economic instability, trade restrictions and changes in tariffs.

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

Our headquarters and main research facility are located in the San Francisco Bay Area, which in the past has experienced severe earthquakes and fires. In addition, fires and other natural disasters may increase in frequency and severity over time due to climate change. If these earthquakes, fires, other natural disasters, terrorism and similar unforeseen events beyond our control prevented us from using all or a significant portion of our headquarters or research facility, it may be difficult or, in certain cases, impossible for us to continue our business for a substantial period of time. We do not have a disaster recovery or business continuity plan in place and may incur substantial expenses as a result of the absence or limited nature of our internal or third-party service provider disaster recovery and business continuity plans, which, particularly when taken together with our lack of earthquake insurance, could have a material adverse effect on our business. Furthermore, integral parties in our supply chain are operating from single sites, increasing their vulnerability to natural disasters or other sudden, unforeseen and severe adverse events. If such an event were to affect our supply chain, it could have a material adverse effect on our ability to conduct our clinical trials, our development plans and business.

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

We have incurred substantial losses during our history and our ability to generate profits in the future is uncertain. Unused net operating loss carryforwards (NOLs) for the tax year ended December 31, 2017 and prior tax years will carry forward to offset future taxable income, if any, until such unused NOLs expire. Unused NOLs generated after December 31, 2017, under current tax law will not expire and may be carried forward indefinitely, but the future deductibility of such NOLs will be limited to 80% of current year taxable income in any given year. In addition, both our current and our future unused losses and tax credit carryforwards may be subject to limitation under Sections 382 and 383 of the Internal Revenue Code (IRC) of 1986, as amended, if we undergo an “ownership change,” generally defined as a greater than 50 percentage point change (by value) in its equity ownership by certain stockholders over a three-year period. We performed an analysis under IRC Section 382 and 383 through October 31, 2020 with respect to our net operating loss and credit carryforwards. We concluded that an ownership change, as defined under IRC Section 382, occurred in previous years. While we do not expect such ownership changes to result in the expiration of our net operating loss and credit carryforwards prior to utilization, we are subject to an annual limitation on the use of tax attributes. The limitation on our ability to use our net operating loss and credit

carryforwards could reduce our ability to use a portion of our tax attributes to offset future taxable income, which could result in us being required to make material cash tax payments.

In addition, our sale of 5,650,000 shares of our common stock to Gilead in February 2021, as well as future equity issuances, may result in additional ownership changes. As a result, our ability to use all of our pre-change NOLs and other pre-change tax attributes (such as research tax credits) to offset our post-change income or taxes may be subject to limitations that could result in increased future tax liability to us. Similar provisions of state tax law may also apply to limit our use of accumulated state tax attributes. In addition, at the state level, there may be periods during which the use of NOLs is suspended or otherwise limited. For example, California enacted a franchise tax law limiting the usability of California state NOLs to offset taxable income in taxable years 2020 and 2021, and similar laws in the future could accelerate or permanently increase state taxes owed. Therefore, even if we attain sustained profitability, we may be unable to use all or a material portion of our NOLs and other tax attributes, which could adversely affect our future cash flows.

Changes in tax laws and regulations or exposure to additional tax liabilities could adversely affect our financial results.

Beginning in 2022, the Tax Cuts and Jobs Act of 2017 eliminates the option to deduct research and development expenditures currently and requires taxpayers to amortize them over five years pursuant to IRC Section 174. Although Congress is considering legislation that would defer the amortization requirement to later years, we have no assurance that the provision will be repealed or otherwise modified. If the requirement is not modified, it may materially reduce our cash flows beginning in 2022.

Product liability lawsuits against us could cause us to incur substantial liabilities and could limit our commercialization of any investigational products that we may develop.

We face an inherent risk of product liability exposure related to the testing of our investigational products in human clinical trials and will face an even greater risk if we commercially sell any products that we may develop. If we cannot successfully defend ourselves against claims that our investigational products or products caused injuries, we could incur substantial liabilities. Regardless of merit or eventual outcome, product liability claims may result in:

Although we maintain product liability insurance coverage, it may not be adequate to cover all liabilities that we may incur. We anticipate that we will need to increase our insurance coverage as our investigational products advance through clinical trials and if we successfully commercialize any products. Insurance coverage is increasingly expensive. We may not be able to maintain insurance coverage at a reasonable cost or in an amount adequate to satisfy any liability that may arise.

Failure to comply with health and data protection laws and regulations could lead to government enforcement actions (which could include civil or criminal penalties), private litigation, and/or adverse publicity and could negatively affect our operating results and business.

We and any potential collaborators may be subject to federal, state, and foreign data protection laws and regulations (i.e., laws and regulations that address privacy and data security). In the United States, numerous federal and state

laws and regulations, including federal health information privacy laws, state data breach notification laws, state health information privacy laws, and federal and state consumer protection laws (e.g., Section 5 of the FTC Act), that govern the collection, use, disclosure, and protection of health-related and other personal information could apply to our operations or the operations of our collaborators. In addition, we may obtain health information from third parties (including research institutions from which we obtain clinical trial data) that are subject to privacy and security requirements under federal Health Insurance Portability and Accountability Act of 1996 (HIPAA) as amended by the Health Information Technology for Economic and Clinical Health Act of 2009 (HITECH). Depending on the facts and circumstances, we could be subject to significant penalties if we violate HIPAA.

The legislative and regulatory landscape for privacy and data security continues to evolve, and we expect that there will continue to be new proposed laws, regulations and industry standards relating to privacy and data security in the United States, the EU and other jurisdictions. This increased focus on privacy and data security issues may negatively affect our operating results and our business. For example, the California Consumer Privacy Act of 2018 (CCPA), which took effect on January 1, 2020, gives California residents expanded rights to access and require deletion of their personal information, opt out of certain personal information sharing, and receive detailed information about how their personal information is used. In addition, the CCPA authorizes private lawsuits to recover statutory damages for certain data breaches. While it exempts some data regulated by HIPAA and certain clinical trials data, the CCPA may increase our compliance costs and potential liability with respect to other personal information we collect about California residents. Some observers note that the CCPA could mark the beginning of a trend toward more stringent privacy legislation in the U.S., which could increase our potential liability and adversely affect our business.

International data protection laws also apply to health-related and other personal data obtained outside the United States. In the European Union, Regulation (EU) 2016/679 (General Data Protection Regulation) took effect in May 2018 and imposes, in some cases, stricter obligations than data protection laws in the United States on the use of health-related and other personal data. These requirements include the obligation to appoint data protection officers in certain circumstances, rights for individuals to be “forgotten” and to data portability, and the obligation to make public notification of significant data breaches. Under the General Data Protection Regulation, data protection authorities can also impose administrative fines of up to 4% of our total worldwide turnover or up to €20 million (whichever is higher). In addition, the General Data Protection Regulation only permits the transfer of personal data outside the European Economic Area (EEA) to countries that offer a level of data protection deemed adequate by the European Commission, unless an approved data transfer mechanism is in place. One such mechanism was invalidated by the European Court of Justice, adding to the complexity of transferring personal data outside the EEA. The General Data Protection Regulation increases our responsibility and liability in relation to personal data that we process, and we must put in place additional mechanisms to ensure compliance with the new EU data protection rules.

Failure to comply with U.S. and international data protection laws and regulations could result in government enforcement actions (which could include civil or criminal penalties), private litigation, and/or adverse publicity and could negatively affect our operating results and business. Moreover, clinical trial subjects about whom we or our potential collaborators obtain information, as well as the providers who share this information with us, may contractually limit our ability to use and disclose the information. Claims that we have violated individuals’ privacy rights, failed to comply with data protection laws, or breached our contractual obligations, even if we are not found liable, could be expensive and time-consuming to defend and could result in adverse publicity that could harm our business.

Our business operations expose us to broadly applicable fraud and abuse, transparency, government price reporting, and other healthcare laws and regulations. If we are unable to comply, or have not fully complied, with such laws, we could face substantial penalties.

Our operations are subject, either directly or indirectly through our customers and third-party payors, to various U.S. federal and state health care laws, including fraud and abuse, transparency and other healthcare laws and regulations, and similar laws in other jurisdictions in which we conduct our business. These laws may impact, among other things, our research and proposed sales, marketing and education programs and constrain the business of financial arrangements and relationships with healthcare providers, physicians and other parties through which we market, sell and distribute our products for which we obtain marketing approval. The laws that may affect our ability to operate include, but are not limited to the federal Anti-Kickback Statute; federal civil and criminal false claims laws, such as the False Claims Act (FCA); HIPAA; federal and state consumer protection and unfair competition laws; the

federal transparency requirements under the Physician Payments Sunshine Act; state and foreign law equivalents of each of these federal laws; and state and foreign laws that require pharmaceutical companies to implement compliance programs. Many of these laws are discussed in detail in “Item 1. Business - Government Regulation - Other U.S. Healthcare Laws and Compliance Requirements”.

The scope and enforcement of each of these laws is uncertain and subject to rapid change in the current environment of healthcare reform. Federal and state enforcement bodies have continued their scrutiny of interactions between healthcare companies and healthcare providers, which has led to a number of investigations, prosecutions, convictions and settlements in the healthcare industry. Responding to investigations can be time-and resource-consuming and can divert management’s attention from the business. Any such investigation or settlement could increase our costs or otherwise have an adverse effect on our business.

Ensuring that our business arrangements with third parties comply with applicable healthcare laws and regulations will likely be costly. We have entered into consulting and advisory board arrangements with physicians and other healthcare providers, including some who could influence the use of our investigational products, if approved. Because of the complex and far-reaching nature of these laws, regulatory agencies may view these transactions as prohibited arrangements that must be restructured, or discontinued, or for which we could be subject to other significant civil, criminal and administrative penalties such as fines, disgorgement, imprisonment, exclusion from government funded healthcare programs, such as Medicare and Medicaid, contractual damages, reputational harm, diminished profits and future earnings, additional reporting obligations and oversight if we become subject to a corporate integrity agreement or other agreement to resolve allegations of non-compliance with these laws, and the curtailment or restructuring of our operations, any of which could substantially disrupt our operations. If any of the physicians or other healthcare providers or entities with whom we expect to do business is found to be not in compliance with applicable laws, they may be subject to criminal, civil or administrative sanctions, including exclusions from government funded healthcare programs.

Changes in healthcare law and implementing regulations, as well as changes in healthcare policy, may impact our business in ways that we cannot currently predict, and may have a significant adverse effect on our business and results of operations.

We are subject to certain U.S. and foreign anti-corruption, anti-money laundering, export control, sanctions, and other trade laws and regulations. We can face serious consequences for violations.

U.S. and foreign anti-corruption, anti-money laundering, export control, sanctions, and other trade laws and regulations (collectively, Trade Laws) prohibit, among other things, companies and their employees, agents, clinical research organizations, legal counsel, accountants, consultants, contractors, and other partners from authorizing, promising, offering, providing, soliciting, or receiving directly or indirectly, corrupt or improper payments or anything else of value to or from recipients in the public or private sector. Violations of Trade Laws can result in substantial criminal fines and civil penalties, imprisonment, the loss of trade privileges, debarment, tax reassessments, breach of contract and fraud litigation, reputational harm, and other consequences. We have direct or indirect interactions with officials and employees of government agencies or government-affiliated hospitals, universities, and other organizations. We also expect our non-U.S. activities to increase over time. We expect to rely on third parties for research, preclinical studies, and clinical trials and/or to obtain necessary permits, licenses, patent registrations, and other marketing approvals. We can be held liable for the corrupt or other illegal activities of our personnel, agents, or partners, even if we do not explicitly authorize or have prior knowledge of such activities.

If we fail to comply with environmental, health and safety laws and regulations, we could become subject to fines or penalties or incur costs that could have a material adverse effect on the success of our business.

We, and the third parties with whom we share our facilities, are subject to numerous environmental, health and safety laws and regulations, including those governing laboratory procedures and the handling, use, storage, treatment and disposal of hazardous materials and wastes. Each of our operations involve the use of hazardous and flammable materials, including chemicals and biological and radioactive materials. Each of our operations also produce hazardous waste products. We generally contract with third parties for the disposal of these materials and wastes. We cannot eliminate the risk of contamination or injury from these materials. We could be held liable for any resulting damages in the event of contamination or injury resulting from the use of hazardous materials by us or the third parties with whom we share our facilities, and any liability could exceed our resources. We also could incur significant costs associated with civil or criminal fines and penalties.

Although we maintain workers’ compensation insurance to cover us for costs and expenses we may incur due to injuries to our employees resulting from the use of hazardous materials, this insurance may not provide adequate coverage against potential liabilities. We do not maintain insurance for environmental liability or toxic tort claims that may be asserted against us in connection with our storage or disposal of biological, hazardous or radioactive materials.

In addition, we may incur substantial costs in order to comply with current or future environmental, health and safety laws and regulations. These current or future laws and regulations may impair our research and development. Failure to comply with these laws and regulations also may result in substantial fines, penalties or other sanctions.

The stock price of our common stock has been and may continue to be volatile or may decline regardless of our operating performance.

The market price of our common stock has fluctuated and may fluctuate significantly in response to numerous factors, many of which are beyond our control, including:

In addition, the stock markets have experienced extreme price and volume fluctuations that have affected and continue to affect the market prices of equity securities of many immuno-oncology companies. Stock prices of many immuno-oncology companies have fluctuated in a manner unrelated or disproportionate to the operating performance of those companies. In the past, stockholders have filed securities class action litigation following periods of market volatility. If we were to become involved in securities litigation, it could subject us to substantial costs, divert resources and the attention of management from our business and adversely affect our business.

The amount of our future losses is uncertain and our quarterly operating results may fluctuate significantly or may fall below the expectations of investors or securities analysts, each of which may cause our stock price to fluctuate or decline.

Our quarterly and annual operating results may fluctuate significantly in the future due to a variety of factors, many of which are outside of our control and may be difficult to predict, including the following:

The cumulative effects of these factors could result in large fluctuations and unpredictability in our quarterly and annual operating results. As a result, comparing our operating results on a period-to-period basis may not be meaningful. This variability and unpredictability could also result in our failing to meet the expectations of industry or financial analysts or investors for any period. If our revenue or operating results fall below the expectations of analysts or investors or below any forecasts we may provide to the market, or if the forecasts we provide to the market are below the expectations of analysts or investors, the price of our common stock could decline substantially. Such a stock price decline could occur even when we have met any previously publicly stated guidance we may provide.

The concentration of our stock ownership will likely limit our stockholders’ ability to influence corporate matters, including the ability to influence the outcome of director elections and other matters requiring stockholder approval.

Based upon shares outstanding as of December 31, 2021, our executive officers, directors and the holders of more than 5% of our outstanding common stock, in the aggregate, beneficially owned approximately 43.5% of our common stock. In particular, Gilead owns approximately 19.5% of our outstanding common stock, and we have appointed its two designees to our board of directors pursuant to the terms of our investor rights agreement. As a result, these stockholders, acting together, will have significant influence over all matters that require approval by our stockholders, including the election of directors and approval of significant corporate transactions. Corporate actions might be taken even if other stockholders oppose them. This concentration of ownership might also have the effect of delaying or preventing a change of control of our company that other stockholders may view as beneficial.

Delaware law and provisions in our amended and restated certificate of incorporation and amended and restated bylaws could make a merger, tender offer or proxy contest difficult, thereby depressing the trading price of our common stock.

Our status as a Delaware corporation and the anti-takeover provisions of the Delaware General Corporation Law may discourage, delay or prevent a change in control by prohibiting us from engaging in a business combination with an interested stockholder for a period of three years after the person becomes an interested stockholder, even if

a change of control would be beneficial to our existing stockholders. In addition, our amended and restated certificate of incorporation and amended and restated bylaws contain provisions that may make the acquisition of our company more difficult, including the following:

In addition, as a Delaware corporation, we are subject to Section 203 of the Delaware General Corporation Law. These provisions may prohibit large stockholders, in particular those owning 15% or more of our outstanding voting stock, from merging or combining with us for a certain period of time. A Delaware corporation may opt out of this provision by express provision in its original certificate of incorporation or by amendment to its certificate of incorporation or bylaws approved by its stockholders. However, we have not opted out of this provision.

These and other provisions in our amended and restated certificate of incorporation, amended and restated bylaws and Delaware law could make it more difficult for stockholders or potential acquirers to obtain control of our board of directors or initiate actions that are opposed by our then-current board of directors, including delay or impede a merger, tender offer or proxy contest involving our company. The existence of these provisions could negatively affect the price of our common stock and limit opportunities for our stockholders to realize value in a corporate transaction.

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

Our amended and restated certificate of incorporation and our bylaws provide that the Court of Chancery of the State of Delaware is the exclusive forum for any derivative action or proceeding brought on our behalf, any action asserting a breach of fiduciary duty, any action asserting a claim against us arising pursuant to the Delaware General Corporation Law, our certificate of incorporation or our bylaws or any action asserting a claim against us that is governed by the internal affairs doctrine. In addition, 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 provide that the federal district courts of the United States will be the exclusive forum for resolving any complaint asserting a cause of action arising under the Securities Act of 1933, as amended. These choice of 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 and may discourage these types of lawsuits. While the Delaware courts have determined that these types 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 these provisions, which 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.

Sales of substantial amounts of our outstanding shares may cause the price of our common stock to decline.

The price of our common stock could decline if there are substantial sales of our common stock, particularly sales by our directors, executive officers and significant stockholders, or if there is a large number of shares of our common stock available for sale and the market perceives that sales will occur. Certain of our stockholders have rights, subject to some conditions, to require us to file registration statements covering their shares or to include their shares in registration statements that we may file for ourselves or our stockholders, subject to market standoff and lockup agreements. We have also registered shares of common stock that we have issued and may issue under our employee equity incentive plans. These shares can be sold freely in the public market upon issuance, subject to vesting conditions and, in the case of our affiliates, volume limitations under Rule 144 under the Securities Act of 1933, as amended.

If we fail to maintain proper and effective internal controls, our ability to produce accurate and timely financial statements could be impaired, which could result in sanctions or other penalties that would harm our business.

We are subject to the reporting requirements of the Exchange Act, the Sarbanes-Oxley Act and the rules and regulations of the New York Stock Exchange. The Sarbanes-Oxley Act requires, among other things, that we maintain effective disclosure controls and procedures and internal controls over financial reporting.

Our internal control over financial reporting is a process designed to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements in accordance with generally accepted accounting principles. Our internal control over financial reporting will not prevent or detect all errors and all fraud. A control system, no matter how well designed and operated, can provide only reasonable, not absolute, assurance that the control system’s objectives will be met. Because of the inherent limitations in all control systems, no evaluation of controls can provide absolute assurance that misstatements due to error or fraud will not occur or that all control issues and instances of fraud will be detected. Accordingly, we cannot assure you that we will not in the future identify one or more material weaknesses in our internal control over financial reporting, which may have a negative impact on our ability to timely and accurately produce financial statements, may result in a material misstatement of our consolidated financial statements or may negatively impact the confidence level of our stockholders and other market participants with respect to our reported financial information.

Ensuring that we have adequate internal controls over financial reporting is a costly and time-consuming effort that needs to be re-evaluated frequently. Remote work arrangements as a result of the COVID-19 pandemic have led to changes in work patterns that can make it more difficult to properly perform our controls and may create risks that result in deficiencies in the design of our controls. To the extent necessary, implementing any changes to our internal controls may distract our officers and employees, entail substantial costs to modify our existing processes and take significant time to complete. These changes may not, however, be effective in maintaining the adequacy of our internal controls, and any failure to maintain that adequacy, or consequent inability to produce accurate financial statements on a timely basis, could increase our operating costs and harm our business.

As of December 31, 2021, our corporate headquarters, which includes executive offices and research and development and business operations, consist of approximately 136,293 square feet of leased office and laboratory space in an office park in Hayward, California. We also lease approximately 109,237 square feet of office space in Brisbane, California. The lease terms for both facilities expire in 2031, subject to options for us to extend the lease term. We intend to add new facilities or expand existing facilities as we add employees and enter new locations, and

we believe that suitable additional or substitute space will be available as needed to accommodate any such expansion of our operations.

We are not currently a party to any material legal proceedings. From time to time, we may become involved in legal proceedings arising in the ordinary course of our business. Regardless of outcome, litigation can have an adverse impact on us due to defense and settlement costs, diversion of management resources, negative publicity, reputational harm and other factors.

Item 5. Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities

Our common stock trades on the New York Stock Exchange under the symbol “RCUS.”

As of January 31, 2022, we had 48 stockholders of record as reported by our transfer agent. This does not include beneficial owners whose shares are held in street name.

We have never declared or paid cash dividends on our capital stock. We intend to retain all available funds and any future earnings, if any, to fund the development and expansion of our business and we do not anticipate paying any cash dividends in the foreseeable future. Any future determination to declare dividends will be made at the discretion of our board of directors.

The following graph compares the cumulative stockholders returns from March 15, 2018 (first day of trading of our common stock), through December 31, 2021 for (i) our common stock, (ii) the S&P Biotechnology Index and (iii) S&P 500 Index, assuming $100 invested on March 15, 2018, and reinvestment of dividends if paid. The stockholder return shown on the graph below is not necessarily indicative of future performance, and we do not make or endorse any predictions as to future stockholder returns. This graph shall not be deemed “soliciting material” or be deemed “filed” for purposes of Section 18 of the Exchange Act, or otherwise subject to the liabilities under that Section, and shall not be deemed to be incorporated by reference into any of our filings under the Securities Act, whether made before or after the date hereof and irrespective of any general incorporation language in any such filing.

The following table summarizes repurchases of our common stock during the fourth quarter of fiscal 2021:

All of the shares repurchased, as reflected in the table above, were repurchases of unvested shares of our common stock that had been issued upon early exercise of stock options. Upon termination of employment of a person holding unvested shares, we are entitled to repurchase the unvested shares.

Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations

You should read the following discussion and analysis of our financial condition and results of operations together with our financial statements and related notes included elsewhere in this Annual Report. This discussion and other parts of this report contain forward-looking statements that involve risk and uncertainties, such as statements of our plans, objectives, expectations, and intentions. Our actual results could differ materially from those discussed in these forward-looking statements. Factors that could cause or contribute to such differences include, but are not limited to, those discussed in the section of this report titled “Risk Factors.”

In May 2020, we entered into an Option, License and Collaboration Agreement (Gilead Collaboration Agreement) with Gilead Sciences, Inc. (Gilead), whereby Gilead obtained an exclusive license to zimberelimab and time-limited exclusive options to all of our then-current and future programs during the 10-year collaboration term. In December 2021, Gilead obtained rights to an additional four of our investigational products: domvanalimab, etrumadenant, quemliclustat and AB308, for which we subsequently received a total of $725 million in option exercise payments. For each program to which Gilead exercised or exercises its option, the parties will co-develop globally and co-commercialize the program in the U.S., subject to certain exceptions, and Gilead will have the right to commercialize the program outside of the United States, subject to the rights of our existing partners in certain territories. In 2017, we entered into an Option and License Agreement (Taiho Agreement) with Taiho Pharmaceutical Co., Ltd. (Taiho) pursuant to which Taiho has time-limited options to exclusively license the development and commercialization rights to each of our programs for Japan and certain other territories in Asia (excluding China). Taiho has exercised its option rights to our adenosine receptor antagonist program (including etrumadenant), our anti-PD-1 program (including zimberelimab), and, in December 2021, they exercised their option right to our anti-TIGIT program (including domvanalimab and AB308).

In connection with our entry into the Gilead Collaboration Agreement in 2020, we also entered into a Common Stock Purchase Agreement pursuant to which Gilead has the right, at its option from time to time over five years from closing of the initial transaction, to purchase up to a maximum ownership of 35% of our then-outstanding voting common stock, and an Investor Rights Agreement that provides for a three-year standstill, two-year lockup and the right to designate two individuals to be appointed to our Board of Directors. Gilead currently owns approximately 19.5% of our outstanding common stock.

We conduct our clinical trials in the U.S. and internationally in geographic regions that are impacted by COVID-19 to varying degrees. While we have seen relatively robust enrollment in most of our ongoing Arcus-sponsored studies, disruptions caused by the COVID-19 pandemic will continue to impact our ability to initiate, supply, enroll, conduct or complete our ongoing or planned clinical trials. For example, in the first half of 2020, the pandemic led to a decline in screening, diagnosis and treatment for cancer patients. While cancer screening rates have rebounded, resurgences due to new variants may cause patients to delay screening and treatment for fear of exposure to COVID-19, thereby adversely impacting the enrollment of patients in clinical trials targeting early-stage cancers and retention of patients overall in our trials. At times, investigative sites have needed to divert resources away from our studies in order to respond to the ongoing health crisis, hindering their ability to conduct study assessments and report data. Patient safety remains our paramount concern and we continue to collaborate with our existing and with new investigational sites to implement measures to minimize disruptions to patients and ensure continued access to treatment, in accordance with health authority guidance. We are unable to predict the ultimate impact of this pandemic on our ongoing and planned clinical programs.

With respect to manufacturing and supply, our third-party contract manufacturers continue to operate at or near normal levels. However, global shipping has been severely challenged by the evolving pandemic, leading to delays in our receipt of materials and supplies, including standard-of-care drugs used in the conduct of our clinical trials. We actively manage the inventory for each of our investigational products and our overall supply chain needs in order to prevent or minimize the impact of any disruptions to our clinical programs.

Due to the availability of vaccines and our mandatory vaccine policy, our laboratory operations are operating at or near normal levels and we are permitting periodic in-person meetings for our office-based employees, who continue to work remotely. The safety, health and well-being of our employees remains a primary concern, and we may restrict our business activities or modify our employee work arrangements in response to new developments in the COVID-19 pandemic in order to reduce the risk of exposure among our employees.

The COVID-19 pandemic continues to evolve and future developments, which are unpredictable, may result in a material, negative impact to our operations and financial condition.

Since commencing operations in 2015, we have devoted substantially all of our efforts and financial resources to building our research and development capabilities, advancing our investigational product pipeline, and establishing our corporate infrastructure.

To date, we have derived all of our revenue from non-refundable payments we received under the Gilead Collaboration Agreement (as amended) and the Taiho Agreement. We have not generated any revenue from product sales and have not had a profitable fiscal year prior to 2021. Prior to 2021, we incurred annual net losses and we had an accumulated deficit of $275.4 million as of December 31, 2021. We reported net income of $52.8 million during the year ended December 31, 2021 primarily due to the recognition of $328.8 million in license revenues due to Gilead's 2021 exercise of its option to our anti-TIGIT program. We do not expect to generate revenue from product sales unless and until we obtain regulatory marketing approval and commercially launch a product candidate. We cannot assure you that we will ever generate significant revenue or profits.

Through December 31, 2021, we have financed our operations primarily through net proceeds of approximately $677.1 million from equity offerings and proceeds of approximately $656.4 million from our collaboration and stock purchase agreements, excluding the receipt of $725 million in option exercise payments from Gilead in January 2022. As of December 31, 2021, we had $681.3 million of cash, cash equivalents and investments. Upon the receipt of $725 million in option exercise payments from Gilead in January 2022, our cash, cash equivalents and investments totaled approximately $1.4 billion, which we believe will be sufficient to fund our planned operations into 2026. We have based this estimate on assumptions that may prove to be wrong, and we could utilize our available capital resources sooner than we expect.

We expect to incur substantial expenditures in the foreseeable future as we expand our pipeline and advance our investigational products through clinical development, the regulatory approval process and, if approved, commercial launch activities. Specifically, in the near term we expect to incur substantial expenses relating to our ongoing and planned clinical trials, the development and validation of our manufacturing processes, and other preclinical, research and discovery development activities. These expenditures will be partially offset by cost-sharing reimbursements from Gilead for certain expenses incurred on optioned programs. For the years ended December 31, 2021 and 2020, we recognized reductions of research and development expense due to reimbursements of $24.9 million and $3.4 million, respectively, for shared expenses incurred on optioned programs. We expect these reimbursements to increase in the short term due to Gilead's opt-in on three additional programs in December 2021.

We have no internal manufacturing facilities, and thus all of our manufacturing activities are contracted to third parties. We currently utilize third-party clinical research organizations to manage and execute various aspects of our clinical development and trials.

We will need substantial additional funding to support our continuing operations and pursue our development strategy. Until such time that we can generate significant revenue from sales of our product candidates, if ever, we expect to finance our operations through the sale of equity, debt financings or other capital sources, including existing or potential collaborations with other companies or other strategic transactions. Adequate funding may not be available to us on acceptable terms, or at all. If we fail to raise capital or enter into such agreements as, and when, needed, we may have to significantly delay, scale back, or discontinue the development and commercialization of our product candidates or delay our efforts to expand our product pipeline.

In May 2020, we entered into the Gilead Collaboration Agreement (as subsequently amended), Common Stock Purchase Agreement (as subsequently amended and restated) and Investor Rights Agreement. From the inception of the agreement through December 31, 2021, Gilead has funded $420.4 million under the stock purchase agreements and provided $175.0 million for our programs pursuant to the collaboration agreement. These amounts do not include the $725 million in option exercise payments we received in January 2022 nor amounts received from Gilead's participation in our May 2020 public offering. Gilead obtained rights to four Arcus Programs: our anti-PD-1 program (including zimberelimab), anti-TIGIT program (including domvanalimab and AB308), adenosine receptor antagonist program (including etrumadenant), and CD73 inhibitor program (including quemliclustat). Gilead also has options to our earlier stage programs.

As of December 31, 2021, Gilead held approximately 19.5% of our outstanding common stock and the right to purchase up to a maximum of 35% of our then-outstanding common stock.

The following discussion should be read in conjunction with "Item 1. Business - License and Collaboration Agreements - Gilead Agreements" and the consolidated financial statements and related notes in Item 8 of this Annual Report.

Pursuant to the terms of the Gilead Collaboration Agreement, as amended (the Amended Gilead Collaboration Agreement), Gilead obtained exclusive licenses to zimberelimab, domvanalimab, AB308, etrumadenant, and quemliclustat, and time-limited exclusive options to all of our current and future clinical programs during the 10-year collaboration term and, for those programs that enter clinical development prior to the end of the collaboration term, for up to an additional three years thereafter. Gilead’s option rights to future programs are contingent upon Gilead's payments of up to $300 million in option continuation payments. Gilead may exercise its option, on a program-by-program basis, at any time prior to the expiration of the option and upon payment of an option fee of $150 million per program. With respect to domvanalimab, we are also eligible to receive up to $500 million in potential U.S. regulatory approval milestones.

Upon closing of Gilead’s exercise of its option to a program, the two companies will co-develop and equally share global development costs for the joint development program, subject to opt-out rights applicable to certain programs and expense caps on our spending and true-up adjustments. For each optioned program, provided we have not exercised our opt-out rights (if applicable), we have an option to co-promote in the United States with equal sharing of related profits and losses. Gilead has the right to exclusively commercialize any optioned programs outside of the U.S., subject to the rights of our existing partners to any territories, and Gilead will pay to us tiered royalties as a percentage of revenues.

As of December 31, 2021, Gilead has exercised its option to all of the clinical programs in existence at the date of the 2020 agreement, and we may not exercise our opt-out rights for any of these programs. The amendment to the Gilead Collaboration Agreement closed in December 2021 and we received option payments totaling $725 million for the three option exercises in January 2022.

Pursuant to the Stock Purchase Agreement, Gilead has the right, at its option, to purchase additional shares from us, up to a maximum ownership of 35% of our then-outstanding voting common stock, from time to time over five years from closing of the initial Gilead Agreements, at a purchase price per share equal to the greater of a 20% premium to market (based on a trailing five-day average closing price) at the time Gilead exercises such option, and the $33.54 initial purchase price. The Investor Rights Agreement also includes a three-year standstill and a two-year lockup and provides Gilead with registration rights commencing at the end of the lockup period, pro rata participation rights in certain future financings and the right to designate two individuals to be appointed to our Board of Directors.

In the year ended December 31, 2020, Gilead made an equity investment of approximately $200 million in us by purchasing 5,963,029 shares of our common stock at a per share price of $33.54 pursuant to the Stock Purchase Agreement. Gilead made an additional equity investment in us of approximately $56.7 million, net of offering costs, by purchasing 2,200,000 shares of our common stock at a per share price of $27.50 in our May 2020 public offering.

In January 2021, we and Gilead entered into an Amended and Restated Common Stock Purchase Agreement, which amended and restated in its entirety the Common Stock Purchase Agreement, pursuant to which Gilead purchased from us 5,650,000 shares of our common stock at a purchase price of $39.00 per share. All other terms of the original Common Stock Purchase Agreement, including Gilead’s option to purchase additional shares from us, up to a maximum ownership of 35% of our then-outstanding common stock, remain unchanged.

As of December 31, 2021, Gilead held 19.5% of our outstanding common stock. Pursuant to the Investor Rights Agreement, we appointed two Gilead designees to our Board of Directors.

In September 2017, we entered into the Taiho Agreement under which we granted Taiho exclusive options to Arcus programs arising over a five-year period ending September 2022 (the Option Period). If Taiho timely exercises its option, Taiho obtains exclusive development and commercialization rights to investigational products from such Arcus Program for Japan and certain other territories in Asia (excluding China) (the Taiho Territory).

In November 2021, Taiho exercised its option to our anti-TIGIT program, including domvanalimab and AB308, in exchange for a $15.0 million option exercise fee. We identified one performance obligation which was the delivery of the license, recognized as licensing revenue during the year ended December 31, 2021. Upon the option exercise, Taiho has sole responsibility for the development and commercialization of the licensed products from this program within the Taiho Territory.

As of December 31, 2021, Taiho had exercised its options to etrumadenant (exercised in 2018), zimberelimab (exercised in 2019), and our anti-TIGIT program (exercised in 2021) in exchange for option fees totaling $26.0 million.

We in-licensed rights to zimberelimab and CD39 from WuXi Biologics, and in-licensed rights to products that include an anti-TIGIT antibody, including domvanalimab, from Abmuno Therapeutics LLC (Abmuno). We also have co-development, collaboration and research and development arrangements with AstraZeneca, BVF Partners L.P. (BVF), and Strata Oncology, Inc. (Strata).

Our collaboration and license revenue consists of revenue recognized from the nonrefundable upfront payments received from Gilead and Taiho, for licenses or research and development services performed by us to develop our investigational products under the terms of our collaboration agreements, and from any option exercise payments.

Our research and development expenses consist of expenses incurred in connection with the research and development of our pipeline programs. These expenses include pre-clinical and clinical expenses, payroll and personnel expenses, including stock-based compensation for our employees, laboratory supplies, product licenses, consulting costs, contract research, and depreciation. Shared facility expenses are allocated to functional groups proportionally based on usage. Under certain collaboration agreements we agree to share research and development expenses with our partners. Such cost sharing arrangements may result in receiving reimbursement from our partners or require that we reimburse our partners for qualified expenses. We expense both internal and external research and development costs as they are incurred. We record advance payments for services that will be used or rendered for future research and development activities as prepaid expenses and recognize them as an expense as the related services are performed. We recognize reimbursement for shared costs incurred by us and reimbursed by our partners as a reduction in research and development expense.

We do not allocate our costs by investigational product, as a significant amount of research and development expenses include internal costs, such as payroll and other personnel expenses, and certain external costs that are not recorded at the investigational product level. In particular, with respect to internal costs, several of our departments support multiple research and development programs, and we do not allocate those costs by investigational product.

In December 2021, Gilead obtained rights to four of our investigational products: domvanalimab, etrumadenant, quemliclustat and AB308, for which we subsequently received a total of $725 million in option exercise payments. We expect our research and development expenses to increase substantially during the next few years as we pursue joint development programs with Gilead for our five optioned molecules and advance these programs towards

regulatory approval. We also expect to advance new programs into the clinic. All of this will require significant growth in our development capabilities and infrastructure. In addition, our joint development program with Gilead for the optioned molecules are anticipated to include a significant number of later-stage clinical trials, which typically include a larger number of subjects, are of a longer duration and include more geographic regions. As we advance our clinical-stage programs and prepare to seek regulatory approval, we will also need to conduct certain validation activities with respect to our manufacturing processes for the investigational products in each program. As a result, we expect our preclinical, clinical, and contract manufacturing expenses to increase significantly relative to what we have incurred to date.

The level of our future research and development investment will depend on a number of factors and uncertainties, including the breadth of the joint development program agreed to with Gilead for the optioned programs, the outcome of our efforts, and the amount of cost reimbursements or milestone payments we receive from our collaborators. In addition, under our license agreements with WuXi Biologics and Abmuno, and our co-development, collaboration and research and development arrangements with AstraZeneca, BVF, and Strata we may be required to pay additional clinical and regulatory milestone payments based on the development progress of our investigational products. We may also be required to pay royalties to these parties in the event of a successful product launch and our receipt of commercial revenues. Therefore, we are unable to predict the timing or the final cost to complete our clinical programs or validation of our manufacturing and supply processes and delays may occur due to numerous factors. Factors that could cause or contribute to delays or additional costs include, but are not limited to, those discussed in “Item 1A. Risk Factors.”

General and administrative expenses consist principally of personnel-related costs including payroll and stock-based compensation for personnel in executive, finance, human resources, information technology, business and corporate development, and other administrative functions. Shared facility expenses are allocated to functional groups proportionally based on usage. Our general and administrative expenses also include professional fees for legal, consulting, and accounting services, rent and other facilities costs, fixed asset depreciation, and other general operating expenses not otherwise classified as research and development expenses.

We anticipate that our general and administrative expenses will increase substantially during the next few years as we support our growing research and development activities, including due to staff expansion, additional occupancy costs, and other costs associated with increased infrastructure needs.

Other non-operating income, net consists primarily of interest earned on our investments in fixed-income marketable securities, activity related to our equity method investment in PACT Pharma, Inc. (PACT Pharma). To date, gains have consisted of gains on dilution of our investment in PACT Pharma, typically occurring upon PACT Pharma’s new issuances of equity securities. Losses associated with the investment consist of our share of PACT Pharma’s net losses.

Our consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (GAAP). The preparation of these consolidated financial statements requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the consolidated financial statements, as well as the reported revenue and expenses incurred during the reporting periods. Our estimates are based on our historical experience and on various other factors that we believe are reasonable under the circumstances, the results of which form the basis for making judgments about the carrying value of assets and liabilities that are not readily apparent from other sources. Actual results may differ from these estimates under different assumptions or conditions. We believe that the accounting policies discussed below are critical to understanding our historical and future performance, as these policies relate to the more significant areas involving management’s significant judgments and estimates.

While our significant accounting policies are described in the notes to our consolidated financial statements, we believe that the following critical accounting policies are most important to understanding and evaluating our reported financial results.

At the inception of an arrangement, we evaluate if a counterparty to a contract is a customer, if the arrangement is within the scope of revenue from contracts with customers guidance, and the term of the contract. We recognize revenue when our customer obtains control of promised goods or services in a contract for an amount that reflects the consideration we expect to receive in exchange for those goods or services. For contracts with customers, we perform the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) we satisfy each performance obligation. We only apply the five-step model to contracts when it is probable that we will collect the consideration we are entitled to in exchange for the goods or services we transfer to the customer. As part of the accounting for contracts with customers, we must develop assumptions that require judgment to determine the standalone selling price of each performance obligation identified in the contract. We then allocate the total transaction price to each performance obligation based on their estimated standalone selling prices. We then recognize as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied.

The estimation of the standalone selling price may include such estimates as forecasted revenues or costs, development timelines, discount rates, and probabilities of technical and regulatory success. We evaluate each performance obligation to determine if it can be satisfied at a point in time or over time, and we measure the services delivered to the customer, which we periodically review based on the progress of the related program. The effect of any change made to an estimated input component and, therefore revenue or expense recognized, would be recorded as a change in estimate. In addition, variable consideration (e.g. milestone payments) must be evaluated to determine if it is constrained and, therefore, excluded from the transaction price.

The following table summarizes our results of operations for the periods indicated (in thousands):

Collaboration and license revenue increased $305.4 million, from $77.5 million for the year ended December 31, 2020 to $382.9 million for the year ended December 31, 2021. The increase was primarily driven by Gilead's exercise of its option to three of our programs and consisted of increases of $288.7 million in license revenues, $15.5 million in collaboration revenues, and $1.1 million in license and development services revenues. See Note 8 to our consolidated financial statements in Item 8 for further discussion of the amount and timing of revenues recognized from our collaboration agreements.

Research and development expenses increased $97.0 million, or 61%, from $159.3 million for the year ended December 31, 2020 to $256.3 million for the year ended December 31, 2021. The increase in research and development expenses was driven by costs incurred to support our expanded clinical and development activities. Our growing headcount and our 2021 stock awards drove a $46.7 million increase in employee compensation costs, including approximately $17.1 million of increased non-cash stock-based compensation. Costs for our ongoing clinical studies and related manufacturing increased $41.6 million and $11.3 million, respectively, as a result of the increased number of clinical-stage programs and trials compared to the prior year. We incurred increases of $9.5 million in office facilities and technology expense, $7.0 million in consulting services, and $5.2 million in lab supplies and equipment, as we expanded our development efforts. The overall increase in research and development expense was partially offset by a net $21.4 million increase in reimbursement from collaboration partners for shared expenses and a $3.5 million decrease in expense for scientific licenses. In the year ended December 31, 2021, we recognized reimbursement of approximately $24.9 million for certain applicable costs of developing zimberelimab in accordance with the Gilead Collaboration Agreement.

General and administrative expenses increased $29.9 million, or 70%, from $42.4 million for the year ended December 31, 2020 to $72.3 million for the year ended December 31, 2021. The increase in general and administrative expenses was primarily driven by the increased complexity of supporting our expanding clinical pipeline and partnership obligations, as well as costs associated with being a public company. Our growing headcount and our 2021 stock awards drove a $23.5 million increase in employee compensation costs, including approximately $15.6 million in increased non-cash stock-based compensation. We also incurred an approximately $4.1 million increase in office facilities expense due to our expanding headcount and office space and an increase of $2.2 million in consulting expenses incurred in corporate development activities.

Non-operating income, net decreased $1.0 million or 71%, from $1.4 million for the year ended December 31, 2020 to $0.4 million for the year ended December 31, 2021. The decrease was primarily due to lower interest income resulting from lower investment yields on our portfolio of marketable fixed-income securities during the year ended December 31, 2020 as compared to the same period in the prior year.

Income tax expense increased $1.8 million, from zero for the year ended December 31, 2020 to $1.8 million for the year ended December 31, 2021. The increase in income tax expense was due to taxes incurred on our net income for the year ended December 31, 2021, resulting from Gilead's exercise of its option to three of our programs in 2021.

The following table summarizes our results of operations for the periods indicated (in thousands):

Collaboration and license revenue increased $62.5 million, from $15.0 million for the year ended December 31, 2019 to $77.5 million for the year ended December 31, 2020. The increase in collaboration and license revenue was primarily due to the recognition of $55.1 million in revenue from the zimberelimab license granted to Gilead and $15.4 million related to Gilead’s ongoing rights to access our intellectual property in accordance with the Gilead Collaboration Agreement, partially offset by the recognition in 2019 of $8.0 million in revenue from Taiho’s exercise of its option for our anti-PD-1 antibody program, including zimberelimab.

Research and development expenses increased $80.8 million, or 103%, from $78.5 million for the year ended December 31, 2018 to $159.3 million for the year ended December 31, 2019. The increase in research and development expenses was primarily due to an increase of $27.8 million in manufacturing costs required to supply our clinical studies, an increase of $24.2 million in clinical costs for our ongoing clinical studies, and an increase of $20.1 million in employee compensation costs primarily due to additional headcount, approximately $7.1 million of which consists of non-cash stock-based compensation. Expenses related to sublicense fees and milestone payments also increased $7.4 million, from $11.2 million for the year ended December 31, 2019 to $18.6 million for the year ended December 31, 2020, largely as a result of sublicense fees paid to WuXi. We incurred a $1.5 million additional increase on telecommunications and remote work infrastructure due to shelter-in-place orders amid the COVID pandemic, partially offset by a decrease of $1.3 million in lab supplies and equipment due to decreased lab activities for the same reason.

General and administrative expenses increased $17.2 million, or 68%, from $25.2 million for the year ended December 31, 2019 to $42.4 million for the year ended December 31, 2020. The increase in general and administrative expenses was due primarily to $7.6 million in employee compensation costs primarily due to additional headcount, approximately $5.8 million of which consists of non-cash stock-based compensation. We also incurred increased expense of $3.8 million in consulting expenses incurred in corporate development activities and $3.8 million in legal and accounting expenses incurred to support our expanding operations and ongoing compliance with public company requirements. We further incurred a $1.5 million additional increase on telecommunications and remote work infrastructure due to shelter-in-place orders amid the COVID pandemic.

Non-operating income, net decreased $2.6 million or 66%, from $4.0 million for the year ended December 31, 2019 to $1.4 million for the year ended December 31, 2020. The decrease was primarily due to lower interest income resulting from lower investment yields on our portfolio of marketable fixed-income securities during the year ended December 31, 2020 as compared to the same period in the prior year.

To date, we have financed our operations primarily through net proceeds of approximately $677.1 million from equity offerings and proceeds of approximately $656.4 million from our collaboration and stock purchase agreements, excluding the receipt of $725 million in option exercise payments from Gilead in January 2022.

We also receive cost-sharing reimbursements from Gilead for certain shared expenses incurred on optioned programs. For the years ended December 31, 2021 and 2020, we recognized reductions of research and development expense due to reimbursements of $24.9 million and $3.4 million, respectively, for shared expenses incurred on optioned programs. We expect these reimbursements to increase in the short term due to Gilead's opt-in on three additional programs in 2021.

As of December 31, 2021, we had $681.3 million of cash, cash equivalents and investments in marketable securities. Upon the receipt of $725 million in option exercise payments from Gilead in January 2022, our cash, cash equivalents and investments totaled approximately $1.4 billion, which we believe will be sufficient to fund our planned operations into 2026. Our cash and investments are held in a variety of interest-bearing instruments, including money market funds, U.S. government treasury obligations, and investments in corporate securities.

Our cash flow and financing requirements are determined by analyses of operating and capital spending budgets. It is challenging to predict the nature, timing and estimated long-range costs of the efforts that will be necessary to complete the development of, and obtain regulatory approval for, any of our investigational products. This is made more challenging by events outside of our control, such as the recent COVID-19 pandemic. Accordingly, our operating plan may change, including as a result of factors currently unknown to us, and we may need to seek additional funds sooner than planned. Such financing may result in dilution to stockholders, imposition of debt covenants and repayment obligations, or other restrictions that may adversely affect our business. In addition, we may seek additional capital due to favorable market conditions or strategic considerations even if we believe we have sufficient funds for our current or future operating plans.

See “Risk Factors” for additional risks associated with our substantial capital requirements.

The following table sets forth the primary sources and uses of cash, cash equivalents and restricted cash for each of the periods presented below (in thousands):

Net cash used in operating activities for the year ended December 31, 2021 was $256.2 million as compared to $111.2 million cash provided by operating activities for the prior year. The change in cash flow from operating activities is primarily due to the expenses incurred to support our expanded clinical development activities and general and administrative costs incurred to support our operations, partially offset by our net income of $52.8 million and the timing of payments from Gilead. The increase in expenses incurred for development activities is partially offset by year-over-year changes in non-cash items, including $32.7 million increased expense from stock-based compensation, and changes in our asset and liability balances due to the timing of payments to or from our vendors and collaborators.

Net cash provided by operating activities for the year ended December 31, 2020 was $111.2 million as compared to a use of $73.5 million for the prior year. The net $184.7 increase in cash provided is primarily due to $265.6 million in cash received at the close of the Gilead Collaboration Agreement in July 2020. The overall increase in net cash provided is partially offset by the $38.1 million increase in our net loss to $122.9 million and changes in non-cash items, including $12.8 million of increased expense from stock-based compensation, and changes in our asset and liability balances due to the timing of payments to or from our vendors and collaborators.

Cash used in investing activities was $3.9 million for the year ended December 31, 2021 compared to $434.4 million cash provided in the prior year. The change in cash flow was primarily due to net maturities of our investments in fixed-income marketable securities, partially offset by purchases of property and equipment.

Cash used in investing activities was $434.4 million for the year ended December 31, 2020 compared to $59.2 million cash provided in the prior year. The change in cash flow was primarily due to net purchases of our investments in fixed-income marketable securities, as we invested proceeds received from our May 2020 public offering, the Gilead Collaboration Agreement, and the Stock Purchase Agreement.

Cash provided by financing activities was $237.3 million for the year ended December 31, 2021 compared to $438.7 million in the prior year. In February 2021 we received $220.4 million from Gilead pursuant to the terms of the Amended and Restated Stock Purchase Agreement. In 2020, we received $326.2 million, net of direct offering costs, from our May 2020 public offering, as well as $107.5 million, net of direct offering costs, from the Gilead Stock Purchase Agreement.

Cash provided by financing activities was $438.7 million for the year ended December 31, 2020 compared to $1.1 million in the prior year. The increase in cash provided is primarily due to $326.2 million in net cash received from our May 2020 public offering, $107.5 million in net cash received under the Stock Purchase Agreement with Gilead, and funds received during the year for issuance of common stock pursuant to equity award plans.

The following table summarizes our current and noncurrent anticipated cash requirements under contractual obligations as of December 31, 2021 (in thousands):

(1) Consists of cash payments due to landlord for our leased office and laboratory space. As of December 31, 2021, we had obligations consisting of operating leases for our operating facilities for approximately 245,530 square feet. Under the terms of the agreements, we have lease obligations consisting of $158.5 million in undiscounted minimum lease payments through 2031.

(2) Consists of current balance of estimated contingent milestone and royalty payments under the BVF Agreement (see Note 7 to our consolidated financial statements in Item 8 for further discussion).

(3) We have not included contingent milestone or royalty payments or other contractual payment obligations in the table to the extent the timing and amount of such obligations are unknown or uncertain.

We enter into contracts in the normal course of business with third parties for clinical trial management and execution, non-clinical studies and testing, manufacturing, and other services and products for operating purposes. These contracts are generally cancelable on 30 days’ notice, and therefore we believe that our non-cancelable obligations under these agreements are not material.

Since our inception, we have not engaged in any off-balance sheet arrangements, as defined in the rules and regulations of the SEC.

See “Recent Accounting Pronouncements” in Note 2 to our consolidated financial statements in Item 8 for a discussion of recently adopted accounting pronouncements.

The market risk inherent in our financial instruments and in our financial position represents the potential loss arising from adverse changes in interest rates or exchange rates. As of December 31, 2021, we had cash, cash equivalents and investments of $681.3 million, consisting of interest-bearing money market accounts and

investments in corporate notes and U.S. government securities, for which the fair market value would be affected by changes in the general level of United States interest rates. However, due to the short-term maturities and the low-risk profile of our investments, an immediate 10% change in interest rates would not have a material effect on the fair market value of our cash, cash equivalents and investments.

In addition, we are also exposed to foreign currency exchange rate risk inherent in our contracts with research institutions, contract research organizations, and contract manufacturing organizations as certain services are performed by them outside the United States. We made payments in the aggregate amount of $6.9 million AUD and $5.3 million AUD to our Australian vendors during the years ended December 31, 2021 and 2020. We are subject to exposure due to fluctuations in foreign exchange rates in connection with these agreements and with our cash balance denominated in Australian dollars.

We do not believe that inflation, interest rate changes, or exchange rate fluctuations had a significant impact on our results of operations for any periods presented herein.

We have audited the accompanying consolidated balance sheets of Arcus Biosciences, Inc. (the Company) as of December 31, 2021 and 2020, the related consolidated statements of operations and comprehensive income (loss), stockholders’ equity, and cash flows for each of the three years in the period ended December 31, 2021, and the related notes (collectively referred to as the “consolidated financial statements”). In our opinion, the consolidated financial statements present fairly, in all material respects, the financial position of the Company at December 31, 2021 and 2020, and the results of its operations and its cash flows for each of the three years in the period ended December 31, 2021, in conformity with U.S. generally accepted accounting principles.

We also have audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States) (PCAOB), the Company's internal control over financial reporting as of December 31, 2021, based on criteria established in Internal Control-Integrated Framework issued by the Committee of Sponsoring Organizations of the Treadway Commission (2013 framework) and our report dated February 23, 2022 expressed an unqualified opinion thereon.

These financial statements are the responsibility of the Company's management. Our responsibility is to express an opinion on the Company’s financial statements based on our audits. We are a public accounting firm registered with the PCAOB and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud. Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. We believe that our audits provide a reasonable basis for our opinion.

The critical audit matter communicated below is a matter arising from the current period audit of the financial statements that was communicated or required to be communicated to the audit committee and that: (1) relates to accounts or disclosures that are material to the financial statements and (2) involved our especially challenging, subjective or complex judgments. The communication of the critical audit matter does not alter in any way our opinion on the consolidated financial statements, taken as a whole, and we are not, by communicating the critical audit matter below, providing a separate opinion on the critical audit matter or on the accounts or disclosures to which it relates.

The accompanying notes are an integral part of these Consolidated Financial Statements

Note 2. Summary of Significant Accounting Policies

Basis of Presentation

The consolidated financial statements and accompanying notes have been prepared in accordance with generally accepted accounting principles in the United States of America (U.S. GAAP) and include all adjustments necessary for the fair presentation of the Company’s financial position for the periods presented. Prior year amounts on our consolidated balance sheets related to long-term contract liabilities under the Gilead contract have been reclassed to deferred revenues to conform to the current year presentation.

Principles of Consolidation

The accompanying consolidated financial statements are comprised of Arcus Biosciences, Inc. and its wholly-owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation.

Use of Estimates

The preparation of the Company’s consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses, as well as related disclosure of contingent assets and liabilities. Estimates were used to determine the standalone selling price of performance obligations and the timing of revenue recognition, the value of stock-based awards and other issuances, accruals for research and development costs, useful lives of long-lived assets, uncertain tax positions, and valuation allowance for deferred tax assets. Actual results could differ materially from the Company’s estimates.

Risks and Uncertainties

The Company’s future results of operations involve a number of risks and uncertainties. Factors that could affect the Company’s future operating results and cause actual results to vary materially from expectations include, but are not limited to, uncertainty of clinical trial results and achievement of milestones, uncertainty of regulatory approval of the Company’s potential drug candidates, uncertainty of market acceptance of the Company’s product candidates, competition from substitute products and larger companies, securing and protecting proprietary technology, strategic relationships and dependence on key individuals and sole source suppliers.

The Company’s investigational products require approval from the U.S. Food and Drug Administration (FDA) and comparable foreign regulatory agencies prior to commercial sales in their respective jurisdictions. There can be no assurance that any investigational products will receive the necessary approvals. If the Company does not obtain

regulatory approval and does not successfully commercialize any of its investigational products, it would have a materially adverse impact on the Company.

Segments

The Company operates and manages its business as one reportable and operating segment, which is the business of developing and commercializing cancer therapies. The Company’s chief executive officer, who is the chief operating decision maker, reviews financial information on an aggregate basis for purposes of allocating and evaluating financial performance. All long-lived assets are maintained in the United States of America.

Cash Equivalents and Investments

Cash equivalents consist of marketable securities having an original maturity of three months or less at the time of purchase. Short-term investments have maturities of greater than three months and up to 12 months at the time of purchase. Long-term investments have maturities greater than 12 months at the time of purchase. Collectively, cash equivalents, short-term and long-term investments are considered available-for-sale and are recorded at fair value. Unrealized gains and losses are recorded in accumulated other comprehensive loss. Realized gains and losses are included in interest and other income, net in the consolidated statements of operations and comprehensive loss. The basis on which the cost of a security sold or amount reclassified out of accumulated other comprehensive income into earnings is determined using the specific identification method.

Reconciliation of Cash, Cash Equivalents, and Restricted Cash as Reported in Consolidated Statements of Cash Flows

Restricted cash at December 31, 2021 and 2020 represents cash balances held as security in connection with the Company’s facility lease agreements. The following table provides a reconciliation of cash, cash equivalents, and restricted cash within the consolidated balance sheets to the total shown in the consolidated statements of cash flows (in thousands):


	December 31, 2021		December 31, 2020
Cash and cash equivalents	$	147,914	$	173,415
Restricted cash		3,005		203
Cash, cash equivalents and restricted cash	$	150,919	$	173,618

Fair Value Measurements

Fair value accounting is applied for all financial assets and liabilities, including short-term and long-term investments, and non-financial assets and liabilities that are recognized or disclosed at fair value in the consolidated financial statements on a recurring basis (at least annually). The carrying amount of the Company’s financial instruments, including receivable from a related party, accounts payable, accrued expenses, other current liabilities and the liability for sale of future royalties approximate fair value due to their short-term maturities.

Concentration of Credit Risk

Cash equivalents, short-term and long-term investments are financial instruments that potentially subject the Company to concentrations of credit risk. The Company invests in money market funds, treasury bills and notes, government bonds, commercial paper and corporate notes. The Company limits its credit risk associated with cash equivalents, short-term and long-term investments by placing them with banks and institutions it believes are highly credit worthy and in highly rated investments.

Property and Equipment

Property and equipment are stated at cost and depreciated using the straight-line method over the estimated useful lives of the assets, ranging from one to five years. Leasehold improvements are amortized over the shorter of their estimated useful lives or the related lease term. Upon retirement or sale, the cost and related accumulated depreciation are removed from the consolidated balance sheet and the resulting gain or loss is reflected in the consolidated statement of operations and comprehensive loss.

Impairment of Long-Lived Assets

The Company reviews long-lived assets, including property and equipment, for impairment whenever events or changes in business circumstances indicate that the carrying amount of the assets may not be fully recoverable. An impairment charge would be recorded when estimated undiscounted future cash flows expected to result from the use of the asset and its eventual disposition are less than its carrying amount. Impairment, if any, is assessed using discounted cash flows or other appropriate measures of fair value. The Company did not recognize any impairment charges for the years ended December 31, 2021, 2020 and 2019.

Collaborative Arrangements and Contracts with Customers

The Company assesses whether its collaboration agreements are subject to Accounting Standards Codification (ASC) Topic 808, Collaborative Arrangements (ASC 808) based on whether they involve joint operating activities and whether both parties have active participation in the arrangement and are exposed to significant risks and rewards. To the extent that the arrangement falls within the scope of ASC 808, the Company applies the unit of account guidance under ASC Topic 606, Revenue from Contracts with Customers (ASC 606), to identify distinct performance obligations, and then determine whether a customer relationship exists for each distinct performance obligation. If the Company determines a performance obligation within the arrangement is with a customer, it applies the guidance in ASC 606. If a portion of a distinct bundle of goods or services within an arrangement is not with a customer, then the unit of account is not within the scope of ASC 606, and the recognition and measurement of that unit of account shall be based on analogy to authoritative accounting literature or, if there is no appropriate analogy, a reasonable, rational, and consistently applied accounting policy election.

The Company recognizes revenue when its customer obtains control of promised goods or services in a contract for an amount that reflects the consideration the Company expects to receive in exchange for those goods or services. For contracts with customers, the Company performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) the Company satisfies each performance obligation. The Company only applies the five-step model to contracts when it is probable that Company will collect the consideration it is entitled to in exchange for the goods or services it transfers to the customer. As part of the accounting for contracts with customers, the Company must develop assumptions that require judgment to determine the standalone selling price of each performance obligation identified in the contract. The Company then allocates the total transaction price to each performance obligation based on their estimated standalone selling prices. The Company then recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when (or as) the performance obligation is satisfied.

The accounting for these arrangements requires the Company to develop estimates and assumptions that require judgment to determine the underlying stand-alone selling price for each performance obligation which determines how the transaction price is allocated among the performance obligation. These estimates may include items such as forecasted revenues or costs, development timelines, discount rates, and probabilities of technical and regulatory success. The Company evaluates each performance obligation to determine if it can be satisfied at a point in time or over time, and measures the services delivered to the customer. The effect of any change made to an estimated input and, therefore, a change to revenue or expense recognized, would be recorded as a change in estimate. In addition, variable consideration such as milestone payments must be evaluated to determine if it is constrained and, therefore, excluded from the transaction price.

The Company enters into collaborative arrangements that typically include one of more of the following: (i) license fees; (ii) milestone payments related to the achievement of developmental, regulatory, or commercial goals; (iii) royalties on net sales of licensed products; (iv) fees attributable to options to intellectual property; and (v) cost-sharing or research and development (R&D) funding arrangements. When a portion of non‑refundable upfront fees

or other payments received are allocated to continuing performance obligations under the terms of a collaborative arrangement, they are recorded as deferred revenue and recognized as revenue when (or as) the underlying performance obligation is satisfied. Fees attributable to options are deferred until the option expires or is exercised. The Company classifies contract liabilities, including deferred revenue, as current when it expects to satisfy its performance obligations within one year, and noncurrent when the Company expects to satisfy those performance obligations in greater than one year.

Upfront Payments and License Fees

When an option is exercised, the performance obligations associated with the option are identified, which will determine the accounting for the transaction price attributable to the option. If a license to the Company’s intellectual property is determined to be distinct from the other performance obligations identified in the arrangement, the Company recognizes revenues from non-refundable, upfront fees allocated to the license when the license is transferred to the licensee and the licensee is able to use and benefit from the license. For licenses that are bundled with other promises, the Company utilizes judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition.

Milestone Payments and Variable Consideration

At the inception of each arrangement that includes milestone payments or variable consideration, the Company evaluates whether the milestones are considered probable of being reached and estimates the amount to be included in the transaction price using the most likely amount method. If it is probable that a significant revenue reversal would not occur, the associated value is included in the transaction price. Milestone payments that are not within the control of the Company or the Company’s collaboration partner, such as regulatory approvals, are generally not considered probable of being achieved until those approvals are received. The transaction price is then allocated to each performance obligation on a relative stand-alone selling price basis, for which the Company recognizes revenue as or when the performance obligations under the contract are satisfied. At the end of each subsequent reporting period, the Company re-evaluates the probability of achievement of such milestones and any related constraint, and if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect license, collaboration or other revenues and earnings in the period of adjustment.

Royalties

For arrangements that include sales-based royalties, including milestone payments based on the level of sales, and for which the license is deemed to be the predominant item to which the royalties relate, the Company recognizes revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). To date, the Company has not recognized any royalty revenue resulting from any of its collaborative arrangements.

Cost-Sharing Arrangements

Under certain collaborative arrangements, the Company is reimbursed for a portion of the research and development expenses, including costs of drug supplies. When these R&D expenses are incurred under a reimbursement or cost sharing model with a collaboration partner, the Company records the related reimbursements as a reduction of R&D expense in its consolidated statements of operations.

Research and Development Expenses

Research and development costs are expensed as incurred. Research and development expenses consist primarily of personnel costs for the Company’s research and development employees, costs incurred to third-party service providers for the conduct of research, preclinical and clinical studies, laboratory supplies and equipment maintenance costs, consulting and other related expenses. Also included are payments we make under license and collaborative arrangements, including up-front and milestone payments, license and option fees and expense reimbursements to collaboration partners, as well as non-personnel costs such as professional fees payable to third

parties for preclinical and clinical studies and research services, laboratory supplies and equipment maintenance, product licenses, and other consulting costs. We recognize reimbursement for shared costs incurred by us and reimbursed by our partners as a reduction in research and development expense.

The Company estimates research, preclinical and clinical service organizations, based on services performed, pursuant to contracts with third-party research and development organizations that conduct and manage research, preclinical and clinical activities on its behalf. Most of the Company’s clinical studies are performed by third-party contract research organizations (CROs), and as a result clinical study costs are a significant component of research and development expenses. The Company estimates these expenses based on discussions with internal management personnel and external service providers as to the progress or stage of completion of services and the contracted fees to be paid for such services. If the actual timing of the performance of services or the level of effort varies from the original estimates, the Company will adjust the accrual accordingly. Payments associated with licensing agreements to acquire licenses to develop, use, manufacture and commercialize products that have not reached technological feasibility and do not have alternative future use are expensed as incurred. Payments made to third parties under these arrangements in advance of the performance of the related services by the third parties are recorded as prepaid expenses until the services are rendered.

Leases and Rent Expense

As of December 31, 2021, the Company's corporate headquarters, which includes executive offices and research and development and business operations, consist of approximately 136,293 square feet of leased office and laboratory space in an office park in Hayward, California. The Company also leases approximately 109,237 square feet of office space in Brisbane, California. The lease terms for both facilities expire in 2031, subject to options for the Company to extend the lease term. Prior to January 1, 2020, the Company recognized related rent expense on a straight-line basis over the term of the lease. Incentives granted under the Company’s facilities lease, including allowances for leasehold improvements and rent holidays, were recognized as reductions to rental expense on a straight-line basis over the term of the lease. Deferred rent consisted of the difference between cash payments and the rent expense recognized.

Subsequent to the adoption of the new leasing standard on January 1, 2020, the Company recognizes a lease asset for its right to use the underlying asset and a lease liability for the corresponding lease obligation. The Company determines whether an arrangement is or contains a lease at contract inception. Operating lease right-of-use assets and liabilities are recognized at the lease commencement date based on the present value of lease payments over the lease term. In determining the net present value of lease payments, the Company uses its incremental borrowing rate based on the information available at the lease commencement date. The incremental borrowing rate represents the interest rate the Company would incur at lease commencement to borrow an amount equal to the lease payments on a collateralized basis over the term of a lease. The Company considers a lease to have commenced when the lessor has made the underlying asset available for use, a determination made after considering whether the asset is complete and whether the Company has the right to enter the property, among other factors. The Company considers a lease term to be the noncancelable period that it has the right to use the underlying asset, including any periods where it is reasonably assured the Company will exercise the option to extend the contract. Periods covered by an option to extend are included in the lease term if the lessor controls the exercise of that option. Operating leases are included in operating lease right-of-use assets, other accrued liabilities, and operating lease liabilities, noncurrent in the Company's consolidated balance sheet at December 31, 2021 and 2020.

The Company elected to not apply the recognition requirements of the new leasing standard to short-term leases with terms of 12 months or less which do not include an option to purchase the underlying asset that the Company is reasonably certain to exercise. For short-term leases, lease payments are recognized as operating expenses on a straight-line basis over the lease term.

Stock-Based Compensation

The Company accounts for stock-based compensation arrangements in accordance with ASC 718, Stock Compensation. Stock-based awards granted include stock options and restricted stock units (RSUs). Accounting standards require the recognition of compensation expense, using a fair value-based method, for costs related to all stock-based payments. The Company’s determination of the fair value of stock options with time-based vesting on the date of grant utilizes the Black-Scholes option-pricing model, and is impacted by the Company’s common stock price as well as other variables including, but not limited to, expected term that options will remain outstanding, expected common stock price volatility over the term of the option awards, risk-free interest rates and expected dividends. Compensation expense associated with restricted stock units is based on the fair value of common stock on the date of the grant.

The fair value of a stock-based award is recognized over the period during which an optionee is required to provide services in exchange for the option award, known as the requisite service period (usually the vesting period) on a straight-line basis. Stock-based compensation expense is recognized based on the fair value determined on the date of grant and is reduced for forfeitures as they occur. Non-employee stock-based compensation expense was not material for all periods presented.

Estimating the fair value of equity-settled awards as of the grant date using valuation models, such as the Black-Scholes option pricing model, is affected by assumptions regarding a number of complex variables. Changes in the assumptions can materially affect the fair value and ultimately how much stock-based compensation expense is recognized. These inputs are subjective and generally require significant analysis and judgment to develop.

Income Taxes

The Company provides for income taxes under the asset and liability method. Current income tax expense or benefit represents the amount of income taxes expected to be payable or refundable for the current year. Deferred income tax assets and liabilities are determined based on differences between the financial statement reporting and tax bases of assets and liabilities and net operating loss and credit carryforwards, and are measured using the enacted tax rates and laws that will be in effect when such items are expected to reverse. Deferred income tax assets are reduced, as necessary, by a valuation allowance when management determines it is more likely than not that some or all of the tax benefits will not be realized.

The Company accounts for uncertain tax positions in accordance with ASC 740-10, Accounting for Uncertainty in Income Taxes. The Company assesses all material positions taken in any income tax return, including all significant uncertain positions, in all tax years that are still subject to assessment or challenge by relevant taxing authorities. Assessing an uncertain tax position begins with the initial determination of the position’s sustainability and is measured at the largest amount of benefit that is greater than fifty percent likely of being realized upon ultimate settlement. As of each balance sheet date, unresolved uncertain tax positions must be reassessed, and the Company will determine whether (i) the factors underlying the sustainability assertion have changed and (ii) the amount of the recognized tax benefit is still appropriate. The recognition and measurement of tax benefits requires significant judgment. Judgments concerning the recognition and measurement of a tax benefit might change as new information becomes available.

The Company includes any penalties and interest expense related to income taxes as a component of other expense and interest income, net, as necessary.

On March 18, 2020, the Families First Coronavirus Response act (FFCR Act), and on March 27, 2020, the Coronavirus Aid, Relief, and Economic Security Act (CARES Act) were each enacted in response to the COVID-19 pandemic. The FFCR Act and the CARES Act contain numerous tax-related provisions relating to refundable payroll tax credits, deferment of employer side social security payments, net operating loss carryback periods, alternative minimum tax credit refunds, modifications to the net interest deduction limitations and technical corrections to tax depreciation methods for qualified improvement property. On June 29, 2020 California State Assembly Bill 85 (the Trailer Bill) was enacted which suspended the use of California net operating loss (NOL) deductions and limited the use of certain tax credits, including research and development tax credits, for the 2020 and 2021 tax years.

The FFCR Act, CARES Act and Trailer Bill did not have a material impact on the Company’s consolidated financial statements as of December 31, 2021; however, the Company continues to examine the impacts the FFCR Act, CARES Act and Trailer Bill may have on its business, results of operations, financial condition and liquidity.

Comprehensive Income (Loss)

Comprehensive income (loss) includes net income (loss) and net unrealized income and losses on available-for-sale securities, which are presented in a single continuous statement. Other comprehensive income (loss) is also disclosed in the consolidated balance sheets and statements of stockholders’ equity in accumulated other comprehensive income (loss), and is stated net of related tax effects, if any.

Net Income (Loss) per Share

Basic net income (loss) per share is calculated by dividing the net income (loss) by the weighted-average number of common shares outstanding during the period, without consideration for potentially dilutive securities. Diluted net income (loss) per share is computed by dividing the net income (loss) by the weighted-average number of common shares and potentially dilutive securities outstanding for the period. The Company excludes the weighted-average shares subject to repurchase from its calculation of weighted average of common shares outstanding. For purposes of the diluted net income (loss) per share calculation, outstanding common stock options are considered to be potentially dilutive securities. Because the Company reported a net loss for the years ended December 31, 2020 and 2019, and the inclusion of the potentially dilutive securities would be antidilutive, diluted net loss per share is the same as basic net loss per share for those periods.

Recently Adopted Accounting Standards

In February 2016, the FASB issued ASU No. 2016-02 (Topic 842), Leases (ASU 2016-02). ASU 2016-02 requires an entity to recognize assets and liabilities arising from a lease for both financing and operating leases. The ASU will also require new qualitative and quantitative disclosures to help investors and other financial statement users better understand the amount, timing, and uncertainty of cash flows arising from leases. In July 2018, the FASB issued ASU No. 2018-10, Codification Improvements to Topic 842, Leases and ASU No. 2018-11, Leases (Topic 842): Targeted Improvements, which offers a practical expedient for transitioning at the adoption date.

The Company adopted this standard on January 1, 2020 using the modified retrospective approach and elected the package of practical expedients permitted under transition guidance, which allowed the Company to carry forward its historical assessments of: 1) whether contracts are or contain leases, 2) lease classification and 3) initial direct costs. The Company did not elect the practical expedient allowing the use-of-hindsight which would require the Company to reassess the lease term of its leases based on all facts and circumstances through the effective date and did not elect the practical expedient pertaining to land easements as this is not applicable to the current contract portfolio. The Company elected the post-transition practical expedient to not separate lease components from nonlease components for all existing lease classes. The Company also elected a policy of not recording leases on its consolidated balance sheets when the leases have a term of 12 months or less and the Company is not reasonably certain to elect an option to purchase the leased asset.

The adoption of this standard resulted in the recognition of a right-of-use (ROU) asset of $5.8 million and lease liabilities of $10.1 million, comprised of $1.2 million and $8.9 million of current and noncurrent liabilities, respectively. The adoption also resulted in the derecognition of the deferred rent balance of $4.3 million as of January 1, 2020. The adoption of the standard had no impact on the Company’s consolidated statements of operations and comprehensive loss or to its cash flows from or used in operating, financing, or investing activities

on its consolidated statements of cash flows. No cumulative-effect adjustment within accumulated deficit was required to be recorded as a result of adopting this standard.

Note 3. Fair Value Measurements

Financial assets and liabilities are recorded at fair value. The accounting guidance for fair value provides a framework for measuring fair value, clarifies the definition of fair value and expands disclosures regarding fair value measurements. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability (an exit price) in an orderly transaction between market participants at the reporting date. The accounting guidance establishes a three-tiered hierarchy, which prioritizes the inputs used in the valuation methodologies in measuring fair value as follows:

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

Level 2—Inputs (other than quoted market prices included in Level 1) are either directly or indirectly observable for the asset or liability through correlation with market data at the measurement date and for the duration of the instrument’s anticipated life.

Level 3—Inputs reflect management’s best estimate of what market participants would use in pricing the asset or liability at the measurement date. Consideration is given to the risk inherent in the valuation technique and the risk inherent in the inputs to the model.

Assets and liabilities measured at fair value are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. The Company’s assessment of the significance of a particular input to the fair value measurement in its entirety requires management to make judgments and consider factors specific to the asset or liability.

During the periods presented, the Company has not changed the manner in which it values assets and liabilities that are measured at fair value. The Company recognizes transfers between levels of the fair value hierarchy as of the end of the reporting period. There were no transfers within the hierarchy during the years ended December 31, 2021 and 2020. The following tables set forth the Company’s financial instruments (excluding restricted cash) that were measured at fair value on a recurring basis by level within the fair value hierarchy (in thousands):


	December 31, 2021
	Total		Level 1		Level 2		Level 3
Money market funds	$	147,914	$	147,914	$	-	$	-
U.S. treasury securities		112,170		-		112,170		-
Corporate securities and commercial paper		421,214		-		421,214		-
Total assets measured at fair value	$	681,298	$	147,914	$	533,384	$	-


	December 31, 2020
	Total		Level 1		Level 2		Level 3
Money market funds	$	146,468	$	146,468	$	-	$	-
U.S. treasury securities		301,112		-		301,112		-
U.S. Government agency obligations		25,001		-		25,001
Corporate securities and commercial paper		262,505		-		262,505		-
Total assets measured at fair value	$	735,086	$	146,468	$	588,618	$	-

As of December 31, 2021, the fair value of the liability for sale of future royalties is based on the Company's current estimates of future contingent milestones and royalties expected to be paid to BVF over the term of the BVF Agreement. These estimates are considered Level 3 fair value inputs. See Note 7 for further discussion of the liability and related estimates.

The Company's investments are classified as (with contractual maturities):


	Year Ended December 31,
	2021		2020
Cash and cash equivalents	$	147,914	$	173,415
Short-term investments (due within one year)		351,394		555,231
Long-term investments (due between one and three years)		181,990		6,440
	$	681,298	$	735,086

All the Company's investments in marketable securities are classified as available-for-sale. At December 31, 2021 and 2020, the balance in the Company’s accumulated other comprehensive income (loss) related to the Company’s available-for-sale marketable securities. There were no realized gains recognized on the sale of available-for-sale marketable securities during the years ended December 31, 2021, 2020 and 2019 and as a result, the Company did not reclassify any amounts out of accumulated other comprehensive income (loss) for the periods then ended. The Company has not recognized any allowances for credit losses given the nature of its receivables and investment portfolio and the immaterial amount of unrealized losses on available for sale securities. No credit related losses have been recognized for any of the periods presented. The fair value and amortized cost of investments in marketable securities by major security type as of December 31, 2021 and 2020 are presented in the tables that follow (in thousands):


	Amortized Cost		Unrealized Gain		Unrealized Loss			Fair Value
As of December 31, 2021:
Money market funds	$	147,914	$	-	$	-		$	147,914
U.S. treasury securities		112,473		1		(304	)		112,170
Corporate securities and commercial paper		422,172		3		(961	)		421,214
Total	$	682,559	$	4	$	(1,265	)	$	681,298


	Amortized Cost		Unrealized Gain		Unrealized Loss			Fair Value
As of December 31, 2020:
Money market funds	$	146,468	$	-	$	-		$	146,468
U.S. treasury securities		301,075		38		(1	)		301,112
U.S. government agency obligations		24,997		4		-			25,001
Corporate securities and commercial paper		262,502		15		(12	)		262,505
Total	$	735,042	$	57	$	(13	)	$	735,086

Note 6. Leases

The Company leases its corporate headquarters, which includes approximately 136,293 square feet of executive offices and research and development and business operations, in an office park in Hayward, California under a non-cancelable operating lease with terms that expire in 2031. The Company also leases space in Brisbane, California under a non-cancelable operating lease that expires in 2031. Both leases are subject to options by the Company to extend the lease terms.

In April 2021, the Company amended the non-cancelable operating lease for its corporate headquarters, which includes approximately 136,293 square feet of executive offices and research and development and business operations, in an office park in Hayward, California. The amended lease added 14,460 square feet of additional space in a new lease expected to commence in 2022, and extended the term of the existing leases through at least December 31, 2031. Once the lease of additional space commences, the Company’s leased space in Hayward will total 150,753 square feet. Any extension periods defined under previous amendments were cancelled under the lease amendment and replaced by two options to extend the lease term for the entire 150,753 square feet then under lease in the Hayward premises for a period of eight years each.

The Company's lease of its space in an office park in Brisbane, California commenced in November 2021. Under this lease, the Company received 109,237 square feet of space in an office building in Brisbane, California. The lease granted the Company certain incentives such as a three-month rent abatement period, a tenant improvement allowance dedicated for the building's initial construction, and an additional tenant improvement allowance to be used at the Company's option. The Company utilized a portion of the additional tenant improvement allowance during the building's construction, which will be repaid with interest through adjustments to base rent during the lease term. The term of the lease will extend through December 31, 2031. The Company has two options to extend the lease term for the space for a period of eight years each.

At December 31, 2021 the Company’s lease portfolio had a weighted average remaining term of 10.0 years. The leases require monthly lease payments that are subject to annual increases throughout the lease term. The optional period has not been considered in the determination of the right-of-use assets or lease liabilities associated with this lease as the Company did not consider it reasonably certain it would exercise the option.

The weighted average discount rate for the Company’s lease portfolio at December 31, 2021 was 5.1%.

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Lease expense is included in operating expenses in the consolidated statements of operations and comprehensive income (loss). For the years ended December 31, 2021 and 2020, the Company incurred lease expense of $7.1 million and $2.7 million, respectively. Lease costs include variable rent expense, which consists primarily of the Company's proportionate share of operating expenses, property taxes, and insurance and is classified as lease expense due to the Company’s election to not separate lease and non-lease components. Short-term lease costs were $0.3 million and $0.2 million for the years ended December 31, 2021 and 2020, respectively.

At December 31, 2021, the Company’s operating lease right-of-use asset totaled $105.0 million, and the operating lease liability totaled $113.6 million. The difference between the amount of the right-of-use asset and the lease liabilities relates to the incentives the Company received upon signing the original leases and its most recent amendment, of which approximately $8.4 million is expected to be received within one year and is recorded in prepaid expenses and other current assets, net of the $5.1 million short-term portion of the operating lease liability. The long term portion of the lease liability was $116.9 million at December 31, 2021 and is reported on the consolidated balance sheet as operating lease liability, noncurrent.

Rent expense was $1.6 million for the year ended December 31, 2019.

The following table summarizes supplemental cash flow disclosures and non-cash financing activities related to our operating leases (in thousands):


	Year Ended December 31,
	2021		2020
Cash paid for amounts included in measurement of lease liabilities	$	4,890	$	2,105
Cash received from tenant improvement allowances	$	2,967	$	-
Right-of-use assets obtained in exchange for new operating lease liabilities	$	95,401	$	8,019
Recognition of tenant improvement allowance receivable included in other current assets	$	10,598	$	979

As of December 31, 2021, the Company’s future minimum lease payments were as follows (in thousands):



Year Ending December 31,	Operating Leases
2022	$	11,198
2023		14,281
2024		14,759
2025		15,255
2026		15,769
Thereafter		87,236
Total undiscounted future minimum lease payments		158,498
Less: Imputed interest		(36,562	)
Less: Tenant improvement allowance receivable		(8,381	)
Total operating lease liabilities		113,555
Tenant improvement allowance expected to be received in less than one year, net of current portion of lease liability (included in prepaid expenses and other current assets)		3,332
Operating lease liabilities, noncurrent	$	116,887

Total undiscounted future minimum lease payments do not include approximately $5.3 million related to the Company’s lease of additional space lease in Hayward that has not yet commenced. This lease is expected to commence during 2022 with a lease term through at least December 31, 2031.

The Company has provided deposits for letters of credit totaling $3.0 million to secure its obligations under its lease, which have been classified as long-term assets on the Company’s consolidated balance sheet as of December 31, 2021.

Note 8. License and Collaboration Agreements

The following table summarizes the revenues recognized from the Company’s collaboration agreements with Gilead Sciences, Inc. (Gilead) and Taiho Pharmaceutical Co., Ltd. (Taiho) (in thousands):


	Year Ended December 31,
	2021		2020		2019
License revenue	$	343,838	$	55,096	$	8,000
License and development services revenue		1,135		-		-
Other collaboration revenue		37,909		22,421		7,000
Total collaboration and license revenues	$	382,882	$	77,517	$	15,000

The following table summarizes revenues by collaboration, category of revenue, and the method of recognition (in thousands):


			Year Ended December 31,
Revenues recognized:	Over time	Point in time	2021		2020		2019
Gilead license to domvanalimab		*	$	328,838	$	-	$	-
Gilead license to zimberelimab		*		-		55,096		-
Development services for all Gilead programs	*			1,135		-		-
Gilead access rights related to the Company's research and development pipeline	*			30,909		15,421		-
Taiho license to domvanalimab		*		15,000		-		-
Taiho license to zimberelimab		*		-		-		8,000
Taiho access rights	*			7,000		7,000		7,000
Total collaboration and license revenues			$	382,882	$	77,517	$	15,000

The Company recognized the following revenue as a result of changes in the deferred revenue balance during the period below (in thousands):


	Year Ended December 31,
Revenue recognized in the period from:	2021		2020		2019
Amounts included in deferred revenue at the beginning of the period	$	202,082	$	7,000	$	7,000
Performance obligations satisfied in a previous period		-		-		-

Gilead Sciences, Inc.

Summary

In May 2020, the Company entered into an Option, License and Collaboration Agreement (Gilead Collaboration Agreement), Common Stock Purchase Agreement (the Stock Purchase Agreement), and Investor Rights Agreement, (collectively, the Gilead Agreements), each with Gilead Sciences, Inc. (Gilead). Upon closing in July 2020, Gilead made an upfront payment of $175 million pursuant to the Gilead Collaboration Agreement and made an equity investment of approximately $200 million in the Company by purchasing 5,963,029 shares of Arcus common stock at a per share price of $33.54 pursuant to the Stock Purchase Agreement.

In November 2021, the Company and Gilead entered into an amendment to the Gilead Collaboration Agreement (the Amended Gilead Collaboration Agreement), under which Gilead exercised its options to three programs for a total option payment of $725 million that was received in January 2022. In connection with Gilead’s exercise of its options to the three programs, the parties agreed to (i) slightly reduce the royalties for these programs, such that Gilead will pay the Company tiered royalties as a percentage of revenues ranging from the mid-teens to the low twenties and (ii) remove the $100 million option continuation payment that was otherwise due on the second anniversary of the Gilead Collaboration Agreement.

As of December 31, 2021, Gilead had obtained licenses to the following investigational products: zimberelimab (in 2020), domvanalimab, AB308, etrumadenant, and quemliclustat (the latter four in 2021).

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Pursuant to the terms of the Gilead Collaboration Agreement, as amended, Gilead obtained exclusive licenses to zimberelimab, domvanalimab, AB308, etrumadenant, and quemliclustat, and time-limited exclusive options to all of the Company’s current and future clinical programs during the 10-year collaboration term and, for those programs that enter clinical development prior to the end of the collaboration term, for up to an additional three years thereafter. Gilead's option rights to future programs are contingent upon Gilead’s payments of up to $300 million in option continuation payments, consisting of a $100 million payment due at Gilead's option on each of the fourth, sixth, and eighth anniversaries of the agreement. Gilead's option, on a program-by-program basis, will expire after a prescribed period, following the achievement of a clinical development milestone in such program and the Company's delivery to Gilead of the requisite data package. Gilead may exercise its option to any program at any time prior to expiration of the option, and will pay the Company an option fee of $150 million per program. Gilead has exercised its option to all of the clinical programs in existence at the date of the 2020 agreement, and the Company may not exercise its opt-out rights for any of these programs. With respect to domvanalimab, the Company is also eligible to receive up to $500 million in potential U.S. regulatory approval milestones.

Gilead was also granted option rights to two research programs for which the Company will lead discovery and early development activities. With respect to these two research programs, Gilead has the right to exercise its option, on a program-by-program basis, either (i) upon the Company's completion of certain IND-enabling activities for an option payment of $60 million or (ii) following the achievement of a clinical development milestone for an option payment of $150 million. These research programs were not determined to be performance obligations at contract inception, due to the very early stages of the programs and the amounts of the option payments.

The Company’s assessment of the transaction price upon the signing of the Amended Gilead Collaboration Agreement included an analysis of amounts it expected to receive, which at contract inception consisted of the upfront cash payment of $725 million committed upon contract closing following expiration of the antitrust waiting period in December 2021, as well as amounts totaling $165.1 million deferred from the original Gilead transaction, which excludes the $100 million option continuation payment that would otherwise have been due on the second anniversary of the Gilead Collaboration Agreement. The Company considers the entire $890.1 million to be the allocable transaction price as of the amendment closing date, due to the Company's history of timely payments from Gilead and receipt of the full $725 million in January 2022 per the terms of the amendment.

The Company determined that the Amended Gilead Collaboration Agreement represented a contract modification under the application of ASC 606. At the amendment closing date, the Company allocated the transaction price to the new and remaining performance obligations identified as follows:


			Amount
Allocation of transaction price
Deferred revenues as of 12/21/2021			$	165,086
Option payment for Domvanalimab				275,000
Option payment for Etrumadenant				250,000
Option payment for Quemliclustat				200,000
Total transaction price allocated to performance obligations			$	890,086

Allocation to performance obligations	Distinct	Combined	Amount
Domvanalimab license	*		$	328,838
Etrumadenant license and R&D activities		*		218,722
Quemliclustat license and R&D activities		*		175,618
Domvanalimab R&D activities	*			34,528
Zimberelimab R&D and commercial services	*			11,243
Access rights related to the Company's research and development pipeline	*			84,076
Material rights to option continuation periods	*			37,061
Total			$	890,086

Upon closing of Gilead’s exercise of its option to a program, the two companies will co-develop and equally share global development costs for the joint development program, subject to opt-out rights of the Company applicable to certain programs, and expense caps on the Company’s spending and related subsequent adjustments. For each

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optioned program, provided the Company has not exercised its opt-out rights (if applicable), the Company has an option to co-promote in the United States with equal sharing of related profits and losses. Gilead has the right to exclusively commercialize any optioned programs outside of the U.S., subject to the rights of the Company’s existing partners to any territories, and Gilead will pay to the Company tiered royalties as a percentage of revenues ranging from (i) the mid-teens to the low twenties for the three 2021 optioned programs, (ii) high single digits to low double digits for research programs if Gilead exercises its option rights at the IND stage, and (iii) the high teens to the low twenties for all other programs.

Stock Purchase Agreement and Investor Rights Agreement

Pursuant to the Stock Purchase Agreement, Gilead has the right, at its option, to purchase additional shares from the Company, up to a maximum of 35% of the Company’s then-outstanding voting common stock, from time to time over five years from closing of the initial transaction, at a purchase price equal to the greater of a 20% premium to market (based on a trailing five-day average closing price) at the time Gilead exercises such option, and the $33.54 initial purchase price. The Investor Rights Agreement also includes a three-year standstill and a two-year lockup and provides Gilead with registration rights commencing at the end of the lockup period, pro rata participation rights in certain future financings and the right to designate two individuals to be appointed to the Company’s Board of Directors.

In the year ended December 31, 2020, Gilead made an equity investment of approximately $200 million in the Company by purchasing 5,963,029 shares of the Company's common stock at a per share price of $33.54 pursuant to the Stock Purchase Agreement. Of the $200 million equity investment, approximately $90.6 million was determined to be a premium on the purchase of common stock and allocated to the performance obligations created by the Gilead Collaboration Agreement. Gilead made an additional equity investment in the Company of approximately $56.7 million, net of offering costs, by purchasing 2,200,000 shares of its common stock at a per share price of $27.50 in the May 2020 public offering. In January 2021, the Company and Gilead entered into an Amended and Restated Common Stock Purchase Agreement, which amended and restated in its entirety the Common Stock Purchase Agreement, pursuant to which Gilead purchased from the Company 5,650,000 shares of its common stock at a purchase price of $39.00 per share, for a total of $220.3 million, net of offering costs. All other terms of the original Common Stock Purchase Agreement, including Gilead's option to purchase additional shares from the Company, up to a maximum ownership of 35% of its then-outstanding common stock, remain unchanged.

Pursuant to the Investor Rights Agreement, the Company appointed Gilead's two designees to the Company’s Board of Directors. Based on the value of the Company’s common stock at the contract closing, the right to purchase additional shares had no value. See Note 14 for further discussion of the agreements with Gilead.

The Company evaluated the agreements with Gilead under ASC 808 and ASC 606 and determined that the licenses to zimberelimab and domvanalimab, and access rights related to the Company's research and development pipeline, were within the scope of ASC 606 because Gilead meets the definition of a customer with respect to those performance obligations.

The Company accounted for each performance obligation as follows:

Zimberelimab license

Effective on the July 2020 closing of the Gilead Collaboration Agreement, Gilead obtained an exclusive license to zimberelimab. The standalone selling price of this license was determined using a discounted cash flow method. The Company recognized the full amount associated with this distinct performance obligation in license revenue on the date the transaction closed.

Domvanalimab option and license

Gilead obtained the right in the Gilead Collaboration Agreement to exercise an option for exclusive rights to the Company’s anti-TIGIT monoclonal antibody program, including domvanalimab and AB308, in exchange for an option payment of $275 million. Prior to the closing of the Amended Gilead Collaboration Agreement, the Company had $36.7 million of deferred revenue on its consolidated balance sheets related to this performance obligation.

Effective on the December 2021 closing of the Amended Gilead Collaboration Agreement, Gilead obtained an exclusive license to domvanalimab. The standalone selling price of this license was determined using a discounted cash flow method. The Company further evaluated the delivery of the license, noting that the program was in later

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stages of development and it met the criteria for being distinct from the research and development services required under the Gilead Collaboration Agreement (as amended). As the license had been made available in the fourth quarter of 2021, the Company recognized the full $328.8 million of transaction price allocated to this performance obligation as license revenue in December 2021.

Etrumadenant option, license and R&D activities

Gilead obtained the right in the Gilead Collaboration Agreement to exercise an option for exclusive rights to the Company’s adenosine receptor program, etrumadenant, in exchange for an option payment of $250 million. Prior to the closing of the Amended Gilead Collaboration Agreement, the Company had $127.0 million of deferred revenue on its consolidated balance sheets related to this performance obligation.

Effective on the December 2021 closing of the Amended Gilead Collaboration Agreement, Gilead obtained an exclusive license to etrumadenant. The standalone selling price of this license was determined using a discounted cash flow method. The Company further evaluated the delivery of the license, noting that it was combined with the research and development services required under the agreements due to the early stage of the technology and the specialized nature of the Company's know-how. The Company determined that it retains obligations to perform further development services for Gilead related to etrumadenant. The standalone selling price of this obligation was determined using an expected cost-plus margin approach. The Company will recognize the amounts allocated to the combined license and services as the performance obligation is satisfied, calculated as an estimated percentage of completion based on management's estimated full-time employee expense for the program.

Due to the combined nature of the performance obligation, the Company determined that the revenue from the license would be recognized at the same rate and using the same input-driven methodology as the revenue from the research and development services. As performance of the R&D activities had not commenced, the Company recognized no license and development services revenue associated with this combined obligation in December 2021. At December 31, 2021, the Company had $218.7 million of deferred revenue remaining on its consolidated balance sheets related to this performance obligation, allocated between current and noncurrent based on the expected timing of future recognition.

Quemliclustat option, license and R&D activities

Gilead obtained the right in the Gilead Collaboration Agreement to exercise an option for exclusive rights to the Company's CD73 program, quemliclustat, in exchange for an option payment of $200 million. Prior to the closing of the Amended Gilead Collaboration Agreement, the Company had no deferred revenue on its consolidated balance sheets related to this performance obligation. The Company determined that it retains obligations to perform further development services for Gilead related to quemliclustat. The standalone selling price of this obligation was determined using an expected cost-plus margin approach. The Company will recognize the amounts allocated to these services as the performance obligation is satisfied, calculated as an estimated percentage of completion based on management's estimated full-time employee expense for the program.

Effective on the December 2021 closing of the Amended Gilead Collaboration Agreement, Gilead obtained an exclusive license to quemliclustat. The standalone selling price of this license was determined using a discounted cash flow method. The Company further evaluated the delivery of the license, noting that it was combined with the research and development services required under the agreements due to the expertise and the know-how developed by the Company.

Due to the combined nature of the performance obligation, the Company determined that the revenue from the license would be recognized at the same rate and using the same input-driven methodology as the revenue from the research and development services. As performance of the R&D activities had not commenced, the Company recognized no license and development services revenue associated with this obligation in December 2021. At December 31, 2021, the Company had $175.6 million of deferred revenue remaining on its consolidated balance sheets related to this performance obligation, allocated between current and noncurrent based on the expected timing of future recognition.

R&D activities for domvanalimab

The Company determined that it retains separate obligations to perform further development services for Gilead related to domvanalimab. The standalone selling price of this obligation was determined using an expected cost-plus margin approach. The Company will recognize the amounts allocated to these services as the performance

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obligation is satisfied, calculated as an estimated percentage of completion based on management's estimated full-time employee expense for the program. As performance of the R&D activities had not commenced, the Company recognized no license and development services revenue associated with these obligations in December 2021. At December 31, 2021, the Company had $34.5 million of deferred revenue remaining on its consolidated balance sheets related to this performance obligation, allocated between current and noncurrent based on the expected timing of future recognition.

R&D and commercialization activities for zimberelimab monotherapy

The Company determined that it retains an obligation to perform further development and commercialization services for Gilead related to zimberelimab monotherapy. Prior to the closing of the Amended Gilead Collaboration Agreement, the Company had $9.7 million deferred revenue on its consolidated balance sheets, related to the two performance obligations. The standalone selling price of this obligation was determined using an expected cost-plus margin approach. The Company will recognize the amounts allocated to these services as the performance obligation is satisfied, calculated as an estimated percentage of completion based on management's estimated full-time employee expense for the program.

The Company determined that its performance of the R&D activities had commenced as of December 31, 2021 and accordingly the Company recognized $1.1 million in license and development services revenue associated with these obligations. At December 31, 2021, the Company had $10.1 million deferred revenue remaining on its consolidated balance sheets related to this performance obligation, allocated between current and noncurrent based on the expected timing of future recognition.

Access rights related to the Company’s research and development pipeline and material rights to option continuation periods

Gilead receives exclusive access to the Company’s current programs as well as the future programs for a period of ten years, contingent upon Gilead’s payment of $300 million, consisting of three $100 million option continuation payments due at Gilead’s option on each of the fourth, sixth, and eighth anniversaries of the agreement. The standalone selling price of this ongoing research and development pipeline access was determined using an expected cost-plus margin approach. The Company uses a time-elapsed input method to measure progress toward satisfying this obligation, which is the method the Company believes most faithfully depicts the Company’s performance in transferring the promised services during the time period in which Gilead has access to the Company’s research and development pipeline. Accordingly, the revenue allocated to the performance obligation is being recognized using this input method over the minimum four-year period. The Company determined that Gilead is not obligated to pay the remaining $300 million due over the remainder of the term. Failure to pay the non-obligatory option continuation payments will result in Gilead’s loss of certain rights to access and obtain licenses to the programs arising from the Company’s research and development pipeline. Prior to the closing of the Amended Gilead Collaboration Agreement, the Company had $91.7 million deferred revenue on its consolidated balance sheets related to this performance obligation.

The Company recognized $30.9 million and $15.4 million in other collaboration revenues associated with these obligations in the years ended December 31, 2021 and 2020, respectively. At December 31, 2021, the Company had $120.2 million of deferred revenue on its consolidated balance sheets related to this performance obligation, classified between current and noncurrent based on the amortization of the revenue.

Cost-sharing reimbursements

The Company's research and development obligations under the Gilead Collaboration Agreement includes a 50/50 share of the joint development costs associated with optioned programs. Payments received from Gilead for their share of costs incurred will be recognized as a reduction of R&D expense. Payments made to Gilead for the Company's share of costs incurred will be recognized as an increase to R&D expense. The Company recognized

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reductions of R&D expense totaling $24.9 million and $3.4 million during the years ended December 31, 2021 and 2020, respectively, as a result of this cost-sharing provision.

Capitalized costs to obtain contract

The Company incurred $7.3 million in costs to obtain the contract in 2020, which consisted of consultant and legal fees that were directly connected to the successful completion of the Gilead Agreements. The Company determined that $1.9 million of these expenses were related to the Stock Purchase Agreement which were recognized as offering costs. The Company allocated the remaining costs between the various performance obligations, to be recognized when the underlying revenue is recognized. The Company incurred an additional $4.5 million in fees to a third party as part of entering into the Amended Gilead Collaboration Agreement in 2021. These fees were combined with the $3.8 million of capitalized fees that remained from the original agreement at the date of closing, and the total $8.3 million was allocated among the performance obligations identified under the Amended Gilead Collaboration Agreement and deferred or recognized accordingly.

The Company recognized $3.8 million and $1.2 million in expense related to these capitalized costs during the years ended December 31, 2021 and 2020, respectively. As of December 31, 2021, the Company had $4.9 million in capitalized costs to obtain the contract, of which $0.9 million was recorded in prepaid expenses and other current assets and $4.0 million was recorded in other long-term assets.

Taiho Pharmaceutical Co., Ltd

In September 2017, the Company and Taiho entered into an option and license agreement (the Taiho Agreement) under which Taiho obtained exclusive options to Arcus programs arising over a five-year period ending September 2022 (the Option Period). If Taiho timely exercises its option, Taiho obtains exclusive development and commercialization rights to investigational products from such Arcus Program for Japan and certain other territories in Asia (excluding China) (the Taiho Territory). In consideration for the exclusive options and other rights contained in the Taiho Agreement, Taiho paid non-refundable, non-creditable cash payments to the Company totaling $35.0 million.

For each option that Taiho elects to exercise, it will be obligated to make an option exercise payment of between $3.0 million to $15.0 million, depending on the development stage of the applicable Arcus Program for which the option is exercised. Upon exercise Taiho is solely responsible for continued development and commercialization in the Taiho Territory. In addition, the Taiho Agreement provides that the Company is eligible to receive additional clinical and regulatory milestones totaling up to $130.0 million per Arcus Program, and it will be eligible to receive contingent payments of up to $145.0 million per Arcus Program associated with the achievement of specified levels of Taiho net sales in the Taiho Territory.

In addition, the Company will receive royalties ranging from high single-digits to mid-teens on net sales of licensed products in the Taiho Territory. Royalties will be payable on a licensed product-by-licensed product and country-by-country basis during the period of time commencing on the first commercial sale of a licensed product in a country and ending upon the later of: (a) ten (10) years from the date of first commercial sale of such licensed product in such country; and (b) expiration of the last-to-expire valid claim of the Company’s patents covering the manufacture, use or sale or exploitation of such licensed product in such country (the Royalty Term).

The Company determined that the identified performance obligations for the Taiho Agreement, which include the combined performance obligation of the research and development services and the obligation to participate on the joint steering committee, are satisfied over time. The Company uses a time-elapsed input method to measure progress toward satisfying its performance obligation, which is the method the Company believes most faithfully depicts the Company’s performance in transferring the promised services during the time period in which Taiho has access to the Company’s research and development activities. Accordingly, the transaction price of $35.0 million is being recognized in other collaboration revenues using this input method over the estimated performance period of five years.

From the inception of the Taiho Agreement through December 31, 2021, Taiho has exercised its option to the Company's adenosine receptor antagonist program (including etrumadenant), its anti-PD-1 program (including zimberelimab), and its anti-TIGIT program (including domvanalimab and AB308) for option payments totaling $26.0 million. The Taiho Agreement will remain in effect until the expiry of all royalty terms for the licensed products. As of December 31, 2021, no clinical or regulatory milestones had been achieved under the Taiho Agreement. As of December 31, 2021, no sales milestone or royalty revenue has been recognized.

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In November 2021, Taiho exercised its option under the Taiho Agreement to the Company's anti-TIGIT program, including domvanalimab and AB308, in exchange for a $15.0 million option exercise fee. In November 2019, Taiho exercised its option to the Company's anti-PD-1 antibody program, including zimberelimab, for a fee of $8.0 million. For each of these exercises, the Company identified one performance obligation comprised of the delivery of the license, which was recognized by the Company as license revenue during the years ended December 31, 2021 and 2019, respectively. Upon the option exercises, Taiho gained sole responsibility for the development and commercialization of the licensed products within the Taiho Territory.

As of December 31, 2021, the Company recorded deferred revenue, current of $5.0 million on its consolidated balance sheet. As of December 31, 2020, the Company recorded deferred revenue, current and deferred revenue, noncurrent of $7.0 million and $5.0 million, respectively, on its consolidated balance sheet.

WuXi Biologics License Agreements

The Company entered into a license agreement (the WuXi PD-1 Agreement) with WuXi Biologics in August 2017, as subsequently amended, in which it obtained an exclusive license to develop, use, manufacture, and commercialize products including an anti-PD-1 antibody worldwide except for Greater China.

From the inception of the WuXi PD-1 Agreement through December 31, 2021, the Company has made upfront and milestone payments of $41.0 million and incurred sub-license fees of $11.3 million. These milestone payments and sub-license fees were recorded as research and development expense, as the products had not reached technological feasibility and did not have alternative future use. During the years ended December 31, 2021, 2020 and 2019, the Company made milestone payments of $10.0 million, $5.0 million and $7.5 million, respectively, and incurred sub-license fees of zero, $10.1 million and $1.2 million, respectively, under the WuXi PD-1 Agreement. The WuXi PD-1 Agreement also provides for clinical and regulatory milestone payments, commercialization milestone payments of up to $375.0 million and tiered royalty payments to be made to WuXi Biologics that range from the high single-digits to low teens of net sales by the Company of licensed products.

In December 2020, the Company entered into a separate license agreement (the WuXi CD39 Agreement) with WuXi Biologics to develop anti-CD39 antibodies. Under the agreement, the Company was granted exclusive worldwide rights to anti-CD39 antibodies discovered under the collaboration and will be responsible for the further development and commercialization of those antibodies. The WuXi CD39 Agreement provides for clinical and regulatory milestone payments totaling $16.5 million, and royalty payments in the low single digits of net sales by the Company of licensed products. From the inception of the WuXi CD39 Agreement through December 31, 2021, the Company paid $0.5 million in upfront payments which was recorded in research and development expense, as the products are still in research stage. The Company incurred no development milestone expense during the years ended December 31, 2021 and 2020. The Company incurred a $1.5 million development milestone in the first quarter of 2022.

Abmuno License Agreement

In December 2016, the Company entered into a license agreement (the Abmuno Agreement) with Abmuno Therapeutics LLC (Abmuno) in which it obtained a worldwide exclusive license to develop, use, manufacture, and commercialize products that include an anti-TIGIT antibody, including domvanalimab. Under the Abmuno Agreement, the Company has made upfront and milestone payments totaling $14.6 million as of December 31, 2021. The Abmuno Agreement also provides for additional clinical, regulatory and commercialization milestone remaining payments of up to $93.0 million as of December 31, 2021.

The Company incurred $5.0 million, $3.0 million, and no development milestone expense for the years ended December 31, 2021, 2020, and 2019, respectively.

AstraZeneca Agreement

On October 29, 2020 the Company announced a collaboration with AstraZeneca to evaluate domvanalimab, the Company’s investigational anti-TIGIT antibody, in combination with AstraZeneca’s Imfinzi (durvalumab) in a registrational Phase 3 clinical trial in patients with unresectable Stage III non-small cell lung cancer (NSCLC), which study the parties refer to as PACIFIC-8. Under the terms of the agreement, each company will retain existing rights to their respective molecules and any future commercial economics. AstraZeneca will conduct the trial, and each company will supply its respective anti-cancer agent to support the trial. Under the terms of the agreement and

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subject to the parties’ approval of a final budget for the clinical trial, the Company may be obligated to reimburse AstraZeneca for a portion of the costs incurred.

This PACIFIC-8 trial forms part of the Arcus and Gilead joint development program for domvanalimab and Arcus’s portion of the trial costs will be shared with Gilead.

For the years ended December 31, 2021 and 2020, the Company incurred expenses pursuant to the AstraZeneca Agreement of $1.0 million and zero, respectively. Expenses from this co-development agreement are recorded within research and development expenses.

Genentech Collaboration Agreement

In December 2019, the Company and Genentech, through F. Hoffmann-La Roche Ltd (collectively, Genentech) entered into a Master Clinical Collaboration Agreement (the Genentech Agreement) pursuant to which the parties may conduct combination clinical studies involving Genentech’s monoclonal antibody, atezolizumab and the Company’s investigational products. Pursuant to the Genentech Agreement, the parties entered into Trial Supplements for the evaluation of etrumadenant and atezolizumab utilizing the MORPHEUS platform in two separate study indications: second and third line metastatic colorectal cancer and first line metastatic pancreatic cancer.

The Company and Genentech will each supply their respective investigational products for use in the collaboration studies and will share a portion of the development costs under specific terms as set forth in the agreement. The Company incurred $1.0 million, $0.5 million and no expense, respectively, under the collaboration for the years ended December 31, 2021, 2020, and 2019, respectively.

Note 10: Stock Plans and Stock-Based Compensation

Stock Plans

The Company grants awards to employees and nonemployees under a series of equity incentive plans, (collectively, the Stock Plans).

In May 2015, the Company adopted the 2015 Stock Plan, which was amended and restated in November 2015 (as amended from time to time, the 2015 Plan).

The terms of the 2015 Plan permitted option holders to exercise stock options before they vest, subject to certain limitations. Such unvested shares are subject to repurchase by the Company at the original exercise price in the

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event the option holder’s service to the Company is terminated either voluntarily or involuntarily. As a result of early exercises under the 2015 Plan, approximately 9,946 shares and 165,133 shares had not vested and were subject to repurchase as of December 31, 2021 and 2020, respectively. The Company treats cash received from the exercise of unvested options as a refundable deposit and classifies such amounts as a liability in its consolidated balance sheets. As of December 31, 2021 and 2020, the Company included cash received for the early exercise of unvested options of $0.1 million and $0.7 million, respectively, allocated to other current liabilities. Amounts included in liabilities are transferred into common stock and additional paid-in capital as the shares vest, which is generally over a period of 48 months.

In March 2018, the Company adopted the 2018 Equity Incentive Plan (2018 Plan), which replaced the 2015 Plan upon completion of the IPO. 3,570,000 shares were reserved under the 2018 Plan plus 709,558 shares remaining available for issuance under the Company’s 2015 Plan and outstanding awards under its 2015 Plan that subsequently expire, lapse unexercised or are forfeited to or repurchased by the Company. In addition, the number of shares reserved for issuance under the Company's 2018 Plan will automatically increase on January 1 of each year by a number equal to the smallest of (i) 3,570,000 shares, (ii) 4% of the shares of common stock outstanding on the last business day of the prior fiscal year or (iii) the number of shares determined by the Company's board of directors. As of December 31, 2021, there were 2,226,271 shares available for grant under the 2018 plan.

In accordance with the provisions of the 2018 Plan, the number of shares available for issuance under the Plan automatically increased by 2,831,269 shares on January 1, 2022.

In January 2020, the Company’s Board of Directors adopted the 2020 Inducement Plan (2020 Plan), pursuant to which it reserved and authorized 3,000,000 shares of the Company’s common stock in order to award non-statutory stock options and other equity-based awards as a material inducement to eligible individuals to enter into employment with the Company. During the years ended December 31, 2021 and 2020, the Company’s Board of Directors authorized an increase of 5,000,000 shares and 1,000,000 shares, respectively, reserved for issuance under the 2020 Plan. As of December 31, 2021, 2,288,000 shares have been issued, and there were 3,743,219 shares available for grant under the 2020 Plan.

The following table, which includes options granted under the Company’s Stock Plans, summarizes option activity:


	Shares Subject to Outstanding Options			Weighted Average Exercise Price Per Share		Weighted Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 2020		9,892,697		$	13.88
Options granted		3,758,769		$	33.03
Options exercised		(680,755	)	$	13.68
Options forfeited or canceled		(950,799	)	$	19.08
Outstanding at December 31, 2021		12,019,912		$	19.46		8.02	$	253,620
Options vested and expected to vest as of December 31, 2021		12,019,912		$	19.46		8.02	$	253,620
Options exercisable as of December 31, 2021		5,158,246		$	14.55		7.15	$	133,742

The weighted-average grant date fair value of the stock options granted was $22.05 per share for 2021, $11.57 per share for 2020, and $6.33 per share for 2019. During the years ended December 31, 2021, 2020 and 2019, the intrinsic value of shares exercised was $17.4 million, $6.8 million, and $0.2 million, respectively, and the fair value of shares vested during the same period was $52.4 million, $16.8 million, and $7.8 million, respectively.

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Restricted Stock Units

The Company grants restricted stock units (RSUs) to its employees and directors under the 2018 Plan. The shares subject to the RSUs vest annually or quarterly over four years for employees and annually for directors.


	Total Restricted Stock Units			Weighted Average Grant Date Fair Value
Nonvested at December 31, 2020		738,650		$	27.84
RSUs granted		932,362			34.05
RSUs vested		(382,183	)		31.60
RSUs forfeited or canceled		(212,741	)		26.06
Nonvested at December 31, 2021		1,076,088		$	32.23

The weighted-average grant date fair value of the RSUs granted was $34.05 per share for 2021 and $27.77 per share for 2020. The total grant date fair value of shares vested during the same periods was $12.1 million and $0.1 million, respectively. There were no RSUs granted or vested during the year ended December 31, 2019.

Employee Stock Purchase Plan

In March 2018, the Company adopted the 2018 Employee Stock Purchase Plan (2018 ESPP). The 2018 ESPP provides eligible employees with the opportunity to purchase shares of common stock through payroll deductions at a price equal to 85% of the lower of the fair market value per share on the first trading day of the applicable 24-month offering period or the fair market value per share on the applicable purchase date, provided that no more than 3,000 shares of common stock may be purchased by an employee on any purchase date. Also, the value of the shares purchased in any calendar year may not exceed $25,000. The 2018 ESPP is intended to constitute an “employee stock purchase plan” under Section 423(b) of the Internal Revenue Code of 1986, as amended. The 2018 ESPP may be terminated by the Company’s board of directors at any time. A total of 714,000 shares of common stock were initially reserved for issuance under the 2018 ESPP, and the number of shares reserved for issuance under the 2018 ESPP will automatically increase on January 1 of each year beginning on January 1, 2019 by a number of shares equal to the least of (i) 1% of the Company's outstanding shares of common stock on the last day of the prior fiscal year, (ii) 1,071,000 shares or (iii) a number of shares determined by the Company's board of directors.

As of December 31, 2021, there were 1,610,979 shares available for purchase under the 2018 ESPP. In accordance with the provisions of the 2018 ESPP, the number of shares available for purchase under the Plan automatically increased by 707,817 shares on January 1, 2022.

Non-employee stock-based compensation

As of December 31, 2021, 2020 and 2019, 37,250, 31,986, and 372,774, respectively, of vested stock options and 1,291, 21,165, and 308,596, respectively, of unvested stock options were held by non-employees. The amount of stock-based compensation expense related to non-employees recognized in the consolidated financial statements for the years ended December 31, 2021, 2020 and 2019 was $0.2 million, $0.7 million and $0.9 million, respectively.

Stock-based compensation expense

The following table summarizes employee and non-employee stock-based compensation expense for the years ended December 31, 2021, 2020 and 2019, and also the allocation within the consolidated statements of operations and comprehensive loss (in thousands):


	Year Ended December 31,
	2021		2020		2019
Research and development	$	28,302	$	11,195	$	4,152
General and administrative		26,226		10,630		4,829
Total stock-based compensation	$	54,528	$	21,825	$	8,981

As of December 31, 2021, unrecognized employee and nonemployee compensation costs related to non-vested stock option awards and RSUs totaled $102.9 million and $31.6 million, respectively, and is expected to be recognized over a weighted average period of 2.5 years and 2.7 years, respectively.

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Valuation Assumptions

Prior to the Company’s IPO, the fair value of the shares of common stock underlying stock-based awards was determined by the board of directors, with input from management. Because there was no public market for the Company’s common stock, the board of directors determined the fair value of the common stock on the grant-date of the stock-based award by considering a number of objective and subjective factors, including enterprise valuations of the Company’s common stock performed by an unrelated third-party specialist, valuations of comparable companies, sales of the Company’s convertible preferred stock to unrelated third parties, operating and financial performance, the lack of liquidity of the Company’s capital stock, and general and industry-specific economic outlook. The board of directors intended all options granted to be exercisable at a price per share not less than the estimated per share fair value of common stock underlying those options on the date of grant.

Following the Company’s IPO, the market traded price of the shares of common stock underlying the stock-based awards is the fair value of the Company's stock as reported on the New York Stock Exchange on the grant date.

Company estimates the fair value of options and ESPP shares utilizing the Black-Scholes option pricing model, which is dependent upon several variables, such as expected term, volatility, risk-free interest rate, and expected dividends. Each of these inputs is subjective and generally requires significant judgment to determine. The following assumptions were used to calculate the fair value of stock-based compensation for the years ended December 31, 2021, 2020, and 2019:


	Stock Options
	Year Ended December 31,
	2021	2020	2019
Risk-free interest rate	1.0% - 1.4%	0.4% - 0.5%	1.6% - 2.3%
Expected term (in years)	6.02	6.02	6.02
Volatility	75.3% - 77.6%	76.5% - 78.5%	71.8% - 74.6%
Dividend yield	0%	0%	0%


	ESPP
	Year Ended December 31,
	2021	2020	2019
Risk-free interest rate	0.0% - 0.6%	0.1% - 0.2%	1.6% - 2.3%
Expected term (in years)	0.5-2.0	0.5-2.0	0.5-2.0
Volatility	61.2% - 95.7%	66.6% - 136.0%	64.8% - 77.1%
Dividend yield	0%	0%	0%

Expected Term — The Company has opted to use the “simplified method” for estimating the expected term of options, whereby the expected term equals the arithmetic average of the vesting term and the original contractual term of the option (generally 10 years).

Expected Volatility — Due to the Company’s limited operating history and a lack of company specific historical and implied volatility data, the Company has based its estimate of expected volatility on the historical volatility of a group of similar companies that are publicly traded. The historical volatility data was computed using the daily closing prices for the selected companies’ shares during the equivalent period of the calculated expected term of the stock-based awards.

Risk-Free Interest Rate — The risk-free rate assumption is based on the U.S. treasury yield in effect at the time of grant for instruments with maturities similar to the expected term of the Company’s stock options.

Expected Dividend — The Company has not issued any dividends in its history and does not expect to issue dividends over the life of the options and therefore has estimated the dividend yield to be zero.

Note 11. Net Income (Loss) per Share

Basic net income (loss) per share is calculated based on the weighted-average number of shares of the Company's common stock during the period. Diluted net income (loss) per share is calculated based on the weighted-average number of shares of the Company's common stock and other dilutive securities outstanding during the period. The

113

potentially dilutive shares of the Company's common stock resulting from the assumed exercise of outstanding stock options and equivalents were determined under the treasury stock method.

The following table sets forth the computation of basic and diluted net income (loss) per share (in thousands, except share and per share data):


	Year Ended December 31,
	2021			2020			2019
Numerator:
Net income (loss)	$	52,830		$	(122,858	)	$	(84,710	)
Denominator:
Weighted-average common shares outstanding		70,328,234			56,354,059			45,385,489
Less: weighted-average common shares subject to vesting		(982,744	)		(1,566,941	)		(1,559,498	)
Weighted-average common shares used to compute basic net income (loss) per share		69,345,490			54,787,118			43,825,991
Dilutive effect of stock options		4,054,142			-			-
Dilutive effect of restricted stock units		566,635			-			-
Weighted-average common shares used to compute diluted net income (loss) per share		73,966,267			54,787,118			43,825,991
Net income (loss) per share, basic	$	0.76		$	(2.24	)	$	(1.93	)
Net income (loss) per share, diluted	$	0.71		$	(2.24	)	$	(1.93	)

The following outstanding potentially dilutive securities were excluded from the computation of diluted net income (loss) per share for the periods presented because including them would have been antidilutive:


	At December 31,
	2021		2020		2019
Common stock options issued and outstanding		4,512,973		9,892,697		4,738,004
Restricted stock units issued		-		738,650		-
Unvested early exercised common stock options		-		165,133		455,158
Employee Stock Purchase Plan shares		103,046		18,219		-
Unvested restricted stock issued as part of collaboration agreement		-		1,257,651		1,257,651
Total		4,616,019		12,072,350		6,450,813

The Company also excluded the effect of Gilead's right to purchase additional shares of the Company's common stock from its calculation as these rights had no intrinsic value at December 31, 2021.

Note 12: Provision for Income Taxes

The Company's loss before provision for income taxes includes the following components (in thousands):


	Year Ended December 31,
	2021		2020			2019
Domestic	$	53,898	$	(123,318	)	$	(85,141	)
Foreign		747		460			431
Income (loss) before income tax	$	54,645	$	(122,858	)	$	(84,710	)

The components of the provision for income taxes are as follows (in thousands):


	Year Ended December 31,
	2021		2020		2019
Current
Federal	$	1,252	$	-	$	-
State		563		-		-
Total income tax expense	$	1,815	$	-	$	-

114

The effective tax rate of the Company's provision for income taxes differs from the federal statutory rate as follows:


	Year Ended December 31,
	2021			2020			2019
Federal statutory income tax rate		21.00	%		21.00	%		21.00	%
State taxes, net of federal benefit		0.81	%		0.00	%		0.00	%
Equity investment		-4.07	%		4.15	%		0.00	%
Research and development credits		-11.91	%		3.10	%		0.00	%
Change in valuation allowance		-2.55	%		-27.35	%		-19.65	%
Stock based compensation		-0.75	%		-0.18	%		-1.28	%
Non-deductible expenses and other		0.79	%		-0.72	%		-0.07	%
Provision for income taxes		3.32	%		0.00	%		0.00	%

Deferred income taxes reflect the net tax effects of loss and credit carryforwards and temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Significant components of the Company’s deferred tax assets for federal and state income taxes are as follows as of December 31 (in thousands):


	Year Ended December 31,
	2021			2020
Deferred tax assets:
Federal and state net operating loss carryforwards	$	24,183		$	54,526
Research and development credits carryforwards		13,288			11,209
Stock-based compensation		9,857			3,828
Depreciation		6,140			9,068
Deferred Revenue		23,557			2,407
Lease liability		25,389			3,831
Other		3,478			2,062
Total deferred tax assets		105,892			86,931
Deferred tax liabilities:
Right-of-use assets		(22,800	)		(2,704	)
Total deferred tax liabilities		(22,800	)		(2,704	)
Less valuation allowance		(83,092	)		(84,227	)
Net deferred tax assets	$	-		$	-

Deferred income taxes reflect the net tax effects of (a) temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes, and (b) operating losses and tax credit carryforwards.

The Company’s accounting for deferred taxes involves the evaluation of a number of factors concerning the realizability of its net deferred tax assets. The Company considered factors such as its history of operating losses, the nature of the Company’s deferred tax assets, and the timing, likelihood and amount, if any, of future taxable income during the periods in which those temporary differences and carryforwards become deductible, including amounts that may arise under the collaboration agreement with Gilead entered into in 2020 and the 2021 program opt-ins. As a result of the Company's evaluation of these factors, including the uncertainty that exists with respect to the option fees and milestone payments, the Company does not believe that it is more likely than not that the deferred tax assets will be realized. Accordingly, a full valuation allowance has been established and no deferred tax asset is shown in the accompanying consolidated balance sheets. The valuation allowance decreased by approximately $1.1 million for the year ended December 31, 2021. The valuation allowance increased by approximately $33.8 million and $19.7 million, respectively, for the years ended December 31, 2020 and 2019.

At December 31, 2021, the Company has total net operating loss carryforwards (NOLs) of $110.5 million that have no expiration date and federal research tax credits of approximately $11.7 million that begin to expire in 2035. The Company also has state NOLs of approximately $13.0 million that begin to expire in 2035, and state research tax credits of approximately $8.3 million that have no expiration date. Use of the NOLs and credit carryforwards may be subject to a substantial annual limitation due to the ownership change provisions of U.S. tax law, as defined in Section 382 and 383 of the Internal Revenue Code of 1986, as amended, and similar state provisions. The annual limitation may result in the expiration of NOLs and credits before use. The Company determined that an ownership change, as defined under IRC Section 382, occurred in the current and previous years. While the Company does not expect these ownership changes to result in the expiration of net operating loss and credit carryforwards prior to

115

utilization, the Company is subject to an annual limitation on the use of its tax attributes. The limitation on the Company's use of net operating loss and credit carryforwards could reduce the Company's ability to use a portion of the tax attributes to offset future taxable income.

The Company has not been audited by the Internal Revenue Service, any state or foreign tax authority. The Company is subject to taxation in the United States and also beginning in 2017, in Australia. Because of the net operating loss and research credit carryforwards, all of the Company’s tax years, from 2015 to 2020, remain open to U.S. federal and California state tax examinations. In addition, the Company’s tax years from 2017 to 2020 are open to examination in Australia. There were no interest or penalties accrued at December 31, 2021 or 2020.

Uncertain Tax Positions

The Company follows the provisions of FASB Accounting Standards Codification (ASC 740-10), Accounting for Uncertainty in Income Taxes. ASC 740-10 prescribes a comprehensive model for the recognition, measurement, presentation and disclosure in financial statements of uncertain tax positions that have been taken or expected to be taken on a tax return. No liability related to uncertain tax positions is recorded in the consolidated financial statements. The Company’s reserve for unrecognized tax benefits was approximately $5.4 million and $3.2 million at December 31, 2021, 2020, respectively.

Due to the full valuation allowance at December 31, 2021 and 2020, current adjustments to the unrecognized tax benefit will have no impact on the Company’s effective income tax rate; any adjustments made after the valuation allowance is released will have an impact on the tax rate.

The following table summarizes the activity related to the Company's unrecognized tax benefits (in thousands):


	Year Ended December 31,
	2021			2020
Beginning balance	$	3,153		$	2,165
Additions (decreases) for tax positions taken in a prior year		(50	)		(258	)
Additions for tax positions taken in current year		2,325			1,246
Ending balance	$	5,428		$	3,153

As of December 31, 2021, the total amount of gross unrecognized tax benefits was $5.4 million, of which, if recognized, none would impact the Company's effective tax rate. The Company does not anticipate material changes to its uncertain tax positions through the next 12 months.

Item 9. Changes in and Disagreements With Accountants on Accounting and Financial Disclosure

We maintain disclosure controls and procedures that are designed to ensure that information required to be disclosed in our Securities Exchange Act of 1934 (Exchange Act) reports is recorded, processed, summarized, and reported within the time periods specified in the rules and forms of the Securities and Exchange Commission, and that such information is accumulated and communicated to management, including our Chief Executive Officer and Chief Financial Officer, as appropriate, to allow timely decisions regarding required disclosure.

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. Because of inherent limitations in all control systems, no evaluation of controls can provide absolute assurance that all control issues, if any, within an organization have been detected. Accordingly, our disclosure controls and procedures are designed to provide reasonable, not absolute, assurance that the objectives of our disclosure control system are met.

As of the end of the period covered by this report, we carried out an evaluation, under the supervision and with the participation of our management, including our Chief Executive Officer and Chief Financial Officer, of the effectiveness of our disclosure controls and procedures pursuant to Exchange Act Rule 13a-15. Based upon, and as of the date of, this evaluation, our Chief Executive Officer and Chief Financial Officer concluded that our disclosure controls and procedures were effective at the reasonable assurance level.

Management is responsible for establishing and maintaining adequate internal control over our financial reporting, as such term is defined in Exchange Act Rules 13a-15(f) and 15(d)-15(f). Our management, with the participation of our principal executive officer and principal financial officer, conducted an evaluation of the effectiveness of our internal control over financial reporting as of December 31, 2021. Our assessment was based on criteria set forth by the Committee of Sponsoring Organizations of the Treadway Commission in Internal Control Integrated − Framework (2013).

Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. Also, projections of any evaluation of effectiveness to future periods are subject to the risk that controls may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.

Based on our evaluation under the framework in Internal Control − Integrated Framework, management concluded that our internal control over financial reporting was effective as of December 31, 2021.

Our independent registered public accounting firm, Ernst & Young LLP, has audited our Consolidated Financial Statements included in Item 8 of this Annual Report on Form 10-K and have issued a report on our internal control over financial reporting as of December 31, 2021. Their report on the audit of internal control over financial reporting appears below.

There were no changes in our internal control over financial reporting during the quarter ended December 31, 2021 that have materially affected, or are reasonably likely to materially affect, our internal control over financial reporting.

We have audited Arcus Biosciences, Inc.’s internal control over financial reporting as of December 31, 2021, based on criteria established in Internal Control—Integrated Framework issued by the Committee of Sponsoring Organizations of the Treadway Commission (2013 framework) (the COSO criteria). In our opinion, Arcus Biosciences, Inc. (the Company) maintained, in all material respects, effective internal control over financial reporting as of December 31, 2021, based on the COSO criteria.

We also have audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States) (PCAOB), the 2021 consolidated financial statements of the Company and our report dated February 23, 2022 expressed an unqualified opinion thereon.

The Company’s management is responsible for maintaining effective internal control over financial reporting and for its assessment of the effectiveness of internal control over financial reporting included in the accompanying Management’s Annual Report on Internal Control over Financial Reporting. Our responsibility is to express an opinion on the Company’s internal control over financial reporting based on our audit. We are a public accounting firm registered with the PCAOB and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audit in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether effective internal control over financial reporting was maintained in all material respects.

Our audit included obtaining an understanding of internal control over financial reporting, assessing the risk that a material weakness exists, testing and evaluating the design and operating effectiveness of internal control based on the assessed risk, and performing such other procedures as we considered necessary in the circumstances. We believe that our audit provides a reasonable basis for our opinion.

A company’s internal control over financial reporting is a process designed to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles. A company’s internal control over financial reporting includes those policies and procedures that (1) pertain to the maintenance of records that, in reasonable detail, accurately and fairly reflect the transactions and dispositions of the assets of the company; (2) provide reasonable assurance that transactions are recorded as necessary to permit preparation of financial statements in accordance with generally accepted accounting principles, and that receipts and expenditures of the company are being made only in accordance with authorizations of management and directors of the company; and (3) provide reasonable assurance regarding prevention or timely detection of unauthorized acquisition, use, or disposition of the company’s assets that could have a material effect on the financial statements.

The information required by this Item will be set forth in our proxy statement to be filed with the Securities and Exchange Commission within 120 days after the end of our fiscal year ended December 31, 2021 (our “Proxy Statement”) and is incorporated into this Annual Report on Form 10-K by reference, specifically:

We have adopted a Code of Conduct and Ethics that applies to all directors, officers and employees of the Company, which is available on our website at www.arcusbio.com. If we make any substantive amendments to our Code of Conduct and Ethics or grant any waivers to our directors or executive officers, we will disclose it on our website or in a Current Report on Form 8-K.

The information required by this Item will be set forth in our Proxy Statement under the captions “Executive Compensation,” “Compensation of Directors” and “Compensation Committee Interlocks and Insider Participation” and is incorporated into this Annual Report on Form 10-K by reference.

Item 12. Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters

The information required by this Item will be set forth in our Proxy Statement under the caption “Security Ownership of Certain Beneficial Owners and Management” and “Equity Compensation Plan Information” and is incorporated into this Annual Report on Form 10-K by reference.

Item 13. Certain Relationships and Related Transactions, and Director Independence

The information required by this Item will be set forth in our Proxy Statement under the captions “Related Person Transactions” and “Corporate Governance” and is incorporated into this Annual Report on Form 10-K by reference.

The information required by this Item will be set forth in our Proxy Statement under the Proposal with the caption “Ratification of Appointment of Independent Registered Public Accounting Firm” and is incorporated into this Annual Report on Form 10-K by reference.

All schedules are omitted because they are not applicable or the required information is shown in the financial statements or notes thereto.

B The Company has been granted confidential treatment for certain portions of this exhibit. The omitted portions have been filed separately with the Securities and Exchange Commission.

† This certification is deemed not filed for purposes of section 18 of the Exchange Act, or otherwise subject to the liability of that section, nor shall it be deemed incorporated by reference into any filing under the Securities Act or the Exchange Act.

Pursuant to the requirements of Section 13 or 15(d) 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.

KNOW ALL PERSONS BY THESE PRESENTS that each person whose signature appears below constitutes and appoints Terry Rosen, Ph.D. and Juan Carlos Jaen, Ph.D., and each of them, his or her true and lawful attorneys-in-fact and agents, each with full power of substitution and resubstitution, for him or her and in his or her name, place and stead, in any and all capacities, to sign any and all amendments to this Annual Report on Form 10-K and to file the same, with exhibits thereto and other documents in connection therewith, with the Securities and Exchange Commission, granting unto said attorneys-in fact and agents, and each of them, full power and authority to do and perform each and every act and thing requisite and necessary to be done, as fully to all intents and purposes as he or she might or could do in person, hereby ratifying and confirming all that each of said attorneys-in-fact and agents or their substitute or substitutes may lawfully do or cause to be done by virtue hereof. Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, this Annual Report on Form 10-K has been signed below by the following persons on behalf of the Registrant in the capacities and on the dates indicated.


Delaware	47-3898435
(State or other jurisdiction of incorporation or organization)	(I.R.S. Employer Identification No.)
3928 Point Eden Way Hayward, CA 94545 (Address of principal executive offices)


Titles of Each Class	Trading Symbol(s)	Name of Each Exchange on which Registered
Common Stock, Par Value $0.0001 Per Share	RCUS	The New York Stock Exchange


Auditor Firm ID:	42	Auditor Name:	Ernst & Young, LLP	Auditor Location:	Redwood City, California, USA


		Page
PART I
Item 1.	Business	5
Item 1A.	Risk Factors	34
Item 1B.	Unresolved Staff Comments	68
Item 2.	Properties	68
Item 3.	Legal Proceedings	69
Item 4.	Mine Safety Disclosures	69

PART II
Item 5.	Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities	70
Item 6.	[Reserved]	71
Item 7.	Management’s Discussion and Analysis of Financial Condition and Results of Operations	72
Item 7A.	Quantitative and Qualitative Disclosures About Market Risk	82
Item 8.	Financial Statements and Supplementary Data	84
Item 9.	Changes in and Disagreements With Accountants on Accounting and Financial Disclosure	117
Item 9A.	Controls and Procedures	117
Item 9B.	Other Information	120
Item 9C.	Disclosure Regarding Foreign Jurisdictions that Prevent Inspections	120

PART III
Item 10.	Directors, Executive Officers and Corporate Governance	121
Item 11.	Executive Compensation	121
Item 12.	Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters	121
Item 13.	Certain Relationships and Related Transactions, and Director Independence	121
Item 14.	Principal Accounting Fees and Services	121

PART IV
Item 15.	Exhibits and Financial Statement Schedules	122
Item 16	Form 10-K Summary	122


Period	Total Number of Shares Purchased		Average Price Paid Per Share		Total Number of Shares Purchased as Part of Publicly Announced Plans or Programs		Maximum Number of Shares that May Yet be Repurchased Under the Plans or Programs
October 1, 2021 to October 31, 2021		-	$	-		-		-
November 1, 2021 to November 30, 2021		-		-		-		-
December 1, 2021 to December 31, 2021		79	$	5.39		-		-
Total		79				-		-


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


☐	TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to


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


$100 investment in stock or index	Ticker	3/15/2018		12/31/2018		12/31/2019		12/31/2020		12/31/2021
Arcus Biosciences, Inc.	RCUS	$	100	$	63	$	59	$	153	$	238
S&P Biotechnology Index	^SPSIBI	$	100	$	77	$	101	$	150	$	119
S&P 500 Index	S&P 500	$	100	$	91	$	118	$	137	$	173


	Year Ended December 31,						$ Change			% Change
	2021			2020
Revenues:
License revenue	$	343,838		$	55,096		$	288,742		*
License and development services revenue		1,135			-			1,135		*
Other collaboration revenue		37,909			22,421			15,488			69	%
Total collaboration and license revenues		382,882			77,517			305,365		*
Operating expenses:
Research and development		256,348			159,348			97,000			61	%
General and administrative		72,286			42,404			29,882			70	%
Total operating expenses		328,634			201,752			126,882			63	%
Income (loss) from operations		54,248			(124,235	)		178,483			-144	%
Non-operating income, net		397			1,377			(980	)		-71	%
Income (loss) before income taxes		54,645			(122,858	)		177,503			-144	%
Income tax expense		(1,815	)		-			(1,815	)	*
Net income (loss)	$	52,830		$	(122,858	)	$	175,688			-143	%


	Total		Current		Noncurrent
Operating lease obligations (1)	$	158,498	$	11,198	$	147,300
Liability for sale of future royalties (2)		5,260		-		5,260
Total (3)	$	163,758	$	11,198	$	152,560


		Page
Report of Independent Registered Public Accounting Firm (PCAOB ID No. 42)		85
Audited Consolidated Financial Statements
Consolidated Balance Sheets		87
Consolidated Statements of Operations and Comprehensive Income (Loss)		88
Consolidated Statements of Stockholders’ Equity		89
Consolidated Statements of Cash Flows		90
Notes to Consolidated Financial Statements		91


Accounting for license and collaboration agreements with Gilead Sciences, Inc.
Description of the Matter	As described in Notes 8 and 14 to the consolidated financial statements, during 2021 the Company entered into an amendment to its Option, License and Collaboration Agreement with Gilead Sciences, Inc., a related party, referred to as the “Amended Gilead Collaboration Agreement”, which resulted in the recognition of $360.9 million of revenue for the year ended December 31, 2021 and $559.2 million of deferred revenue at December 31, 2021. Auditing the Company’s accounting for the Amended Gilead Collaboration Agreement was complex and required the Company to apply significant judgement, including the determination of performance obligations and transaction price, and the estimation of standalone selling price for each identified performance obligation. Estimates of standalone selling price require management judgements and assumptions, which may include forecasted revenues, development timelines, discount rates, and probabilities of technical and regulatory success. Changes to these assumptions can have a material effect on the allocation of transaction price to performance obligations and can impact the amount and timing of revenue recognized.
How We Addressed the Matter in Our Audit	We obtained an understanding, evaluated the design, and tested the operating effectiveness of controls addressing the risks of material misstatement relating to the Company’s accounting for license and collaboration agreements with multiple performance obligations. For example, we tested management’s controls over the identification of performance obligations and the determination of significant assumptions used in the estimation of standalone selling price. We also tested the completeness and accuracy of data used in estimating standalone selling price. Our audit procedures included, among others, obtaining and reading the Amended Gilead Collaboration Agreement and evaluating the completeness of the performance obligations identified by management. We also evaluated management’s estimates of the standalone selling price of the performance obligations. For example, we evaluated the discounted cash flow assumptions used by the Company in developing estimates of standalone selling price by comparing the significant assumptions described above to current industry trends using available information from other similar companies within the same industry and other relevant factors. We also performed a sensitivity analysis to evaluate the impact that changes in significant assumptions would have on estimated standalone selling price and the resulting impact on the allocation of transaction price to performance obligations, as well as revenue recognized during the period. We involved our valuation professionals to assist in the assessment of the estimation methodology and the significant assumptions used in determining estimated standalone selling price.


	As of December 31,
	2021			2020
ASSETS
Current assets:
Cash and cash equivalents	$	147,914		$	173,415
Short-term investments		351,394			555,231
Receivable from collaboration partners ($744,535 and $943 from a related party)		744,595			1,049
Accrued interest receivable		2,227			649
Prepaid expenses and other current assets		15,620			5,471
Total current assets		1,261,750			735,815
Long-term investments		181,990			6,440
Property and equipment, net		32,455			10,807
Right-of-use assets		104,968			12,781
Restricted cash		3,005			203
Other long-term assets		7,730			6,246
Total assets	$	1,591,898		$	772,292
LIABILITIES
Current liabilities:
Accounts payable	$	10,261		$	15,682
Accrued research and development		29,587			18,307
Other accrued liabilities		24,181			9,543
Deferred revenue, current ($96,981 and $67,571 to a related party)		102,003			74,571
Other current liabilities		52			3,566
Total current liabilities		166,084			121,669
Deferred revenue, noncurrent ($462,217 and $127,511 to a related party)		462,217			132,533
Operating lease liabilities, noncurrent		116,887			15,243
Other long-term liabilities		5,260			543
Total liabilities		750,448			269,988
Commitments (Note 13)
Stockholders’ equity:
Preferred stock, $0.0001 par value, 10,000,000 shares authorized as of December 31, 2021 and 2020; no shares issued and outstanding as of December 31, 2021 and 2020		-			-
Common stock, $0.0001 par value, 400,000,000 shares authorized as of December 31, 2021 and 2020; 70,781,736 and 65,114,685 shares issued and outstanding as of December 31, 2021 and 2020, respectively. Shares outstanding incudes 9,946 and 1,422,784 shares issued but subject to vesting as of December 31, 2021 and 2020, respectively.		7			6
Additional paid-in capital		1,118,058			830,438
Accumulated deficit		(275,354	)		(328,184	)
Accumulated other comprehensive income (loss)		(1,261	)		44
Total stockholders’ equity		841,450			502,304
Total liabilities and stockholders’ equity	$	1,591,898		$	772,292


	Years Ended December 31,
	2021			2020			2019
Revenues:
License revenue ($328,838, $55,096 and $0 from a related party)	$	343,838		$	55,096		$	8,000
License and development services revenue ($1,135 from a related party)		1,135			-			-
Other collaboration revenue ($30,909, $15,421 and $0 from a related party)		37,909			22,421			7,000
Total collaboration and license revenues		382,882			77,517			15,000
Operating expenses:
Research and development (($24,891), ($3,446) and $0 from a related party)		256,348			159,348			78,481
General and administrative		72,286			42,404			25,228
Total operating expenses		328,634			201,752			103,709
Income (loss) from operations		54,248			(124,235	)		(88,709	)
Non-operating income (expense):
Interest and other income, net		657			1,377			5,201
Effective interest on liability for sale of future royalties		(260	)		-			-
Gain on deemed sale from equity method investee		-			613			-
Share of loss from equity method investee		-			(613	)		(1,202	)
Total non-operating income, net		397			1,377			3,999
Income (loss) before income taxes		54,645			(122,858	)		(84,710	)
Income tax expense		(1,815	)		-			-
Net income (loss)		52,830			(122,858	)		(84,710	)
Other comprehensive income (loss)		(1,305	)		(20	)		171
Comprehensive income (loss)	$	51,525		$	(122,878	)	$	(84,539	)
Net income (loss) per share, basic	$	0.76		$	(2.24	)	$	(1.93	)
Weighted-average number of shares used to compute basic net income (loss) per share		69,345,490			54,787,118			43,825,991
Net income (loss) per share, diluted	$	0.71		$	(2.24	)	$	(1.93	)
Weighted-average number of shares used to compute diluted net income (loss) per share		73,966,267			54,787,118			43,825,991


	Common stock				Additional Paid-In		Accumulated			Accumulated Other Comprehensive			Total Stockholders’
	Shares		Amount		Capital		Deficit			Income (Loss)			Equity
Balance at December 31, 2018		43,610,823	$	4	$	357,873	$	(122,828	)	$	(107	)	$	234,942
Cumulative effect adjustment upon adoption of ASC 606		-		-		-		2,212			-			2,212
Issuance of common stock upon exercise of stock options		34,780		-		188		-			-			188
Vesting of early exercised stock options and restricted stock		417,883		-		1,029		-			-			1,029
Issuance of common stock under Employee Stock Purchase Plan		148,709		-		1,029		-			-			1,029
Stock-based compensation		-		-		8,981		-			-			8,981
Other comprehensive income		-		-		-		-			171			171
Net loss		-		-		-		(84,710	)		-			(84,710	)
Balance at December 31, 2019		44,212,195		4		369,100		(205,326	)		64			163,842
Issuance of common stock in public offering, net of $21,629 offering costs (2,200,000 shares and $56,738, net of $3,762 offering costs, from a related party)		12,650,000		2		326,244		-			-			326,246
Issuance of common stock and rights to purchase additional shares in accordance with Gilead Stock Purchase Agreement, net of $1,931 offering costs		5,963,029		-		107,468		-			-			107,468
Issuance of common stock upon exercise of stock options and vesting of restricted stock		405,752		-		3,366		-			-			3,366
Vesting of early exercised stock options		258,824		-		848		-			-			848
Issuance of common stock under Employee Stock Purchase Plan		202,101		-		1,587		-			-			1,587
Stock-based compensation		-		-		21,825		-			-			21,825
Other comprehensive loss		-		-		-		-			(20	)		(20	)
Net loss		-		-		-		(122,858	)		-			(122,858	)
Balance at December 31, 2020		63,691,901		6		830,438		(328,184	)		44			502,304
Issuance of common stock and rights to purchase additional shares in accordance with Amended and Restated Gilead Purchase Agreement, net of $55 offering costs		5,650,000		1		220,295		-			-			220,296
Issuance of common stock upon exercise of stock options and vesting of restricted stock		1,045,423		-		9,089		-			-			9,089
Vesting of early exercised stock options		153,877		-		686		-			-			686
Issuance of common stock under Employee Stock Purchase Plan		230,589		-		3,022		-			-			3,022
Stock-based compensation		-		-		54,528		-			-			54,528
Other comprehensive loss		-		-		-		-			(1,305	)		(1,305	)
Net income		-		-		-		52,830			-			52,830
Balance at December 31, 2021		70,771,790	$	7	$	1,118,058	$	(275,354	)	$	(1,261	)	$	841,450


	2021
Beginning balance, January 1	$	-
Cash received from BVF		5,000
Interest accretion		260
Ending balance, December 31	$	5,260


Exhibit Number	Exhibit Description	Incorporated by Reference
Exhibit Number	Exhibit Description	Form	File No	Exhibit	Filing Date

3.1	Amended and Restated Certificate of Incorporation.	10-Q	001-38419	3.1	May 9, 2018
3.2	Amended and Restated Bylaws.	8-K	001-38419	3.1	May 26, 2020
4.1	Reference is made to Exhibits 3.1 and 3.2
4.2	Description of Common Stock.	10-K	001-38419	4.3	February 25, 2021
10.1A	Compensation Program for Non-Employee Directors (for use from June 4, 2020 to June 2, 2021).	8-K	001-38419	10.1	June 5, 2020
10.2A	Compensation Program for Non-Employee Directors (for use from June 3, 2021)	8-K	001-38419	10.1	June 7, 2021
10.3A	Form of Indemnification Agreement between the Registrant and each of its directors and executive officers.	S-1	333-223086	10.1	February 16, 2018
10.4A	Arcus Biosciences, Inc. Management Cash Incentive Plan.	S-1	333-223086	10.13	February 16, 2018
10.5A	Form of Severance and Change in Control Agreement (for use before September 24, 2018).	S-1	333-223086	10.14	February 16, 2018
10.6A	Form of Severance and Change in Control Agreement (for use from September 24, 2018).	10-Q	001-38419	10.2	November 8, 2018
10.7A	Amended and Restated Letter Agreement, dated February 14, 2018, between the Registrant and Terry Rosen, Ph.D.	S-1	333-223086	10.5	February 16, 2018
10.8A	Amended and Restated Letter Agreement, dated February 14, 2018, between the Registrant and Juan Carlos Jaen, Ph.D.	S-1	333-223086	10.6	February 16, 2018
10.9A	Offer letter by and between Arcus Biosciences, Inc. and Jennifer Jarrett dated September 10, 2020.	10-Q	001-38419	10.2	November 5, 2020
10.10A	Offer Letter, dated March 16, 2019, between the Company and William Grossman.	10-Q	001-38419	10.1	August 6, 2019
10.11A	Separation and Consulting Agreement by and between the Company and William Grossman dated July 16, 2021.	10-Q	001-38419	10.3	August 5, 2021
10.12A	Offer letter by and between Arcus Biosciences, Inc. and Robert C. Goeltz II dated June 30, 2020.	10-Q	001-38419	10.1	November 5, 2020
10.13A	Arcus Biosciences, Inc. 2015 Stock Plan and forms of agreements thereunder.	S-1/A	333-223086	10.2	March 5, 2018
10.14A	Arcus Biosciences, Inc. 2018 Equity Incentive Plan (including form agreements for use before January 1, 2021).	S-1/A	333-223086	10.3	March 5, 2018


10.15A	Form of Stock Option Notice and Agreement under 2018 Equity Incentive Plan (for use from January 1, 2021).	10-K	001-38419	10.36	February 25, 2021
10.16A	Form of RSU Notice and Agreement under 2018 Equity Incentive Plan (for use from January 1, 2021).	10-K	001-38419	10.37	February 25, 2021
10.17A	Arcus Biosciences, Inc. 2018 Employee Stock Purchase Plan.	S-1/A	001-38419	10.4	March 5, 2018
10.18*A	Arcus Biosciences, Inc. Amended and Restated 2020 Inducement Plan.
10.19A	Form of Stock Option Grant Notice (2020 Inducement Plan).	10-K	001-38419	10.26	March 5, 2020
10.20A	Form of Restricted Stock Unit Grant Notice (2020 Inducement Plan).	10-K	001-38419	10.27	March 5, 2020
10.21	Lease, dated September 30, 2015, between the Registrant and Hayward Point Eden I Limited Partnership, as amended on July 22, 2016 and October 12, 2017.	S-1	333-223086	10.8	February 16, 2018
10.22	Third Amendment dated June 26, 2020 to the Lease agreement dated September 30, 2015 between Arcus Biosciences, Inc. and Hayward Point Eden I Limited Partnership.	10-Q	001-38419	10.4	August 6, 2020
10.23	Fourth Amendment dated October 16, 2020 to the Lease agreement dated September 30, 2015 between Arcus Biosciences, Inc. and Hayward Point Eden I Limited Partnership.	10-Q	001-38419	10.3	November 5, 2020
10.24	Fifth Amendment Dated April 1, 2021 to the Lease agreement dated September 30, 2015 between Arcus Biosciences, Inc. and Hayward Point Eden I Limited Partnership.	10-Q	001-38419	10.2	May 5, 2021
10.25B	License Agreement, dated December 8, 2016, between Arcus Biosciences, Inc. and Abmuno Therapeutics LLC.	S-1	333-223086	10.10	February 16, 2018
10.26B	License Agreement, dated August 16, 2017, between Arcus Biosciences, Inc. and WuXi Biologics (Cayman) Inc.	S-1	333-223086	10.11	February 16, 2018
10.27C	Amendment No. 1 dated June 27, 2019 to the License Agreement dated August 16, 2017 between Arcus Biosciences, Inc. and WuXi Biologics (Cayman) Inc.	10-Q	001-38419	10.2	August 6, 2019
10.28C	Amendment No. 2 dated March 2, 2020 to the License Agreement dated August 16, 2017 between Arcus Biosciences, Inc. and WuXi Biologics (Cayman) Inc.	10-K	001-38419	10.28	March 5, 2020
10.29	Assignment Agreement dated November 10, 2020 by and among Arcus Biosciences, Inc., WuXi Biologics (Cayman) Inc. and WuXi Biologics Ireland Limited to the License Agreement dated August 16, 2017.	10-K	001-38419	10.35	February 25, 2021


10.30C	Third Amendment dated May 10, 2021 to the License Agreement dated August 16, 2017 between Arcus Biosciences, Inc. and WuXi Biologics Ireland Limited.	10-Q	001-38419	10.2	August 5, 2021
10.31B	Option and License Agreement, dated September 19, 2017, between Arcus Biosciences, Inc. and Taiho Pharmaceutical Co., Ltd.	S-1	333-223086	10.12	February 16, 2018
10.32B	Amendment No. 1 to Option and License Agreement, dated September 19, 2017, between Arcus Biosciences, Inc. and Taiho Pharmaceutical Co, Ltd.	10-Q	001-38419	10.1	November 8, 2018
10.33C	Option, License and Collaboration Agreement dated May 27, 2020 between Arcus Biosciences, Inc. and Gilead Sciences, Inc.	10-Q	001-38419	10.1	August 6, 2020
10.34*C	Amendment No. 1 dated November 17, 2021 to the Option, License and Collaboration Agreement dated May 27, 2020 between Arcus Biosciences, Inc. and Gilead Sciences, Inc.
10.35C	Common Stock Purchase Agreement dated May 27, 2020 between Arcus Biosciences, Inc. and Gilead Sciences, Inc.	8-K	001-38419	99.1	July 13, 2020
10.36C	Amended and Restated Common Stock Purchase Agreement dated January 31, 2021 between Arcus Biosciences, Inc. and Gilead Sciences, Inc.	SC 13D/A	005-90423	99.1	February 2, 2021
10.37C	Investor Rights Agreement dated May 27, 2020 between Arcus Biosciences, Inc. and Gilead Sciences, Inc.	8-K	001-38419	99.2	July 13, 2020
21.1*	List of subsidiaries of the registrant.
23.1*	Consent of independent registered public accounting firm.
24.1*	Power of Attorney (included on signature page to this Annual Report).
31.1*	Certification of Principal Executive Officer Pursuant to Rules 13a-14(a) and 15d-14(a) under the Securities Exchange Act of 1934, as Adopted Pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.
31.2*	Certification of Principal Financial Officer Pursuant to Rules 13a-14(a) and 15d-14(a) under the Securities Exchange Act of 1934, as Adopted Pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.
32.1†	Certification of Principal Executive Officer Pursuant to 18 U.S.C. Section 1350, as Adopted Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002.
32.2†	Certification of Principal Financial Officer Pursuant to 18 U.S.C. Section 1350, as Adopted Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002.


101.INS		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 and contained in exhibit 101)


	ARCUS BIOSCIENCES, INC.

Date: February 23, 2022	By:	/s/ Terry Rosen
		Terry Rosen, Ph.D.
		Chief Executive Officer (Principal Executive Officer and Duly Authorized Officer)


Name	Title	Date

/s/ Terry Rosen	Chief Executive Officer and Director	February 23, 2022
Terry Rosen, Ph.D.	(Principal Executive Officer)

/s/ Juan Carlos Jaen	President and Director	February 23, 2022
Juan Carlos Jaen, Ph.D.

/s/ Jennifer Jarrett	Chief Operating Officer and Director	February 23, 2022
Jennifer Jarrett

/s/ Robert C. Goeltz II	Chief Financial Officer	February 23, 2022
Robert C. Goeltz II	(Principal Financial and Accounting Officer)

/s/ Kathryn Falberg	Director	February 23, 2022
Kathryn Falberg

/s/ Linda Higgins	Director	February 23, 2022
Linda Higgins, Ph.D.

/s/ Yasunori Kaneko	Director	February 23, 2022
Yasunori Kaneko, M.D.

/s/ David Lacey	Director	February 23, 2022
David Lacey, M.D.

/s/ Nicole Lambert	Director	February 23, 2022
Nicole Lambert

/s/ Patrick Machado	Director	February 23, 2022
Patrick Machado, J.D.

/s/ Merdad Parsey	Director	February 23, 2022
Merdad Parsey, M.D., Ph.D.

/s/ Andrew Perlman	Director	February 23, 2022
Andrew Perlman, M.D., Ph.D.

/s/ Antoni Ribas	Director	February 23, 2022
Antoni Ribas, M.D., Ph.D.