License and Collaborations	9 Months Ended
Sep. 30, 2026
License and Collaboration Agreements [Abstract]
License and Collaborations	License and collaborations We enter into licensing agreements, strategic collaborations and other similar arrangements with third parties for the development and commercialization of certain investigational products. These arrangements: may be collaborative and involve two or more parties who are active participants in the operating activities of the collaboration and are exposed to significant risks and rewards depending on the commercial success of the activities; are performed with no guarantee of either technological or commercial success; and are each unique in nature. Such arrangements may include: non-refundable upfront payments; payments for options to acquire certain rights; potential development and regulatory milestone payments and/or sales-based milestone payments; royalty payments; revenue or profit-sharing arrangements; expense reimbursements; and cost-sharing arrangements. Operating expenses for costs incurred pursuant to these arrangements are reported in their respective expense line items in the Condensed Consolidated Statements of Operations, net of any payments due to or reimbursements due from our collaboration partners, with such reimbursements being recognized at the time the party becomes obligated to pay. Our significant arrangements are discussed below. For a more detailed discussion on revenues recognized under these arrangements, see Note 5, Revenues. Gilead Collaboration See Note 3, Related party - Gilead Sciences, Inc., for more information. Taiho Collaboration In 2017, we entered into an agreement with Taiho Pharmaceutical Co., Ltd. ("Taiho" and the "Taiho Agreement") pursuant to which Taiho obtained an exclusive option to in-license development and commercialization rights to programs for Japan and certain other Asian countries, excluding China (the "Taiho Territory") for which IND-enabling studies had begun during a five-year term which ended in September 2022, for an upfront payment of $35 million. For each option to a program that Taiho exercises, except for casdatifan (the HIF-2α program) discussed below, they will be obligated to make a payment of $3 million to $15 million, depending on the development stage of the optioned program. Upon exercise, Taiho is solely responsible for continued development and commercialization in the Taiho Territory, unless they opt to participate in a global study, in which case they would become obligated to reimburse us for their portion of the global study costs. In addition, for each optioned program we would be eligible to receive clinical and regulatory milestones of up to $130 million and commercial milestone payments of up to $145 million with the achievement of certain sales thresholds in the Taiho Territory. We will also receive royalties ranging from high single-digits to mid-teens on net sales of licensed products in the Taiho Territory. Royalties will be payable by product and country commencing on the first commercial sale and ending upon the later of: (a) 10 years; and (b) expiration of the last-to-expire valid claim of our patents covering the manufacture, use or sale. In 2022, Taiho opted to participate in two global Phase 3 trials of domvanalimab and zimberelimab combinations, STAR-121 and STAR-221, and in 2024, Taiho opted to participate in the global Phase 3 trial of quemliclustat, PRISM-1. For each of these trials, Taiho became obligated to reimburse us for their portion of the global trial costs, and to make milestone payments contingent upon successfully satisfying the related clinical milestones. The clinical milestones were met: for domvanalimab and zimberelimab for the STAR-221 trial in 2023, and Taiho became obligated to pay us $28 million; domvanalimab and zimberelimab for the STAR-121 trial in 2024, and Taiho became obligated to pay us $26 million; and for quemliclustat for the PRISM-1 trial in the first-quarter 2025, and Taiho became obligated to make milestone payments totaling $19 million. All the milestone payments due have been fully received. In the fourth-quarter 2025, Taiho exercised its option for HIF-2α inhibitor program (including casdatifan) for the Taiho Territory, for an option payment of $15 million. We and Taiho concurrently entered into an amendment (the "Second Amendment") where we will lead development for two indications for casdatifan in Japan and be responsible for the global study costs and we may also be eligible to receive: (i) clinical and regulatory milestones of up to $172 million of which Taiho became obligated to pay us $30 million in the second-quarter 2026 upon the achievement of a clinical milestone (of which $15 million was received in the third-quarter 2026 and the remaining $15 million is due in the first-quarter 2027); (ii) commercial milestone payments of up to $145 million upon the achievement of certain sales thresholds in the Taiho Territory; and (iii) royalties ranging from high single-digits to mid-teens on net sales of the licensed product in the Taiho Territory. Due to the nature of these arrangements, a portion of these upfront and clinical milestones were determined to be advance cost sharing payments for Taiho's share of the related global study R&D costs under the collaboration and are deferred and recognized as a reduction in R&D expense as the related global studies are performed, calculated as an estimated percentage of completion based on the estimated total effort for the programs. See Note 5, Revenues, for more information. As of September 30, 2026, Taiho has licenses for the Taiho Territory to (i) HIF-2α inhibitor program (including casdatifan); (ii) anti-TIGIT program (including domvanalimab and AB308); (iii) anti-PD-1 program (including zimberelimab); (iv) CD73 program (including quemliclustat); and (v) adenosine receptor antagonist program (including etrumadenant). Taiho holds a time-limited option for the Taiho Territory to our CD39 program (including AB598). We recognized net reimbursements, including amortization of advance cost share payments, under this arrangement for the three and nine months ended September 30, 2026, of $5 million and $16 million, respectively, and for the three and nine months ended September 30, 2025, of $7 million and $24 million, respectively. These net reimbursements are recognized as a reduction of R&D expense in our Condensed Consolidated Statements of Operations. We had net receivables under this arrangement at September 30, 2026 and December 31, 2025, of $18 million and $10 million, respectively, recorded in Receivable from collaboration partners on our Condensed Consolidated Balance Sheets. See Note 5, Revenues for more information. We had liabilities related to certain advance cost sharing payments under this arrangement at September 30, 2026 and December 31, 2025, of $32 million and $44 million, respectively, recorded in Other liabilities, allocated between current and noncurrent based on the expected timing of future recognition. AstraZeneca Collaboration In 2020, we entered into a collaboration with AstraZeneca to evaluate domvanalimab, our investigational anti-TIGIT antibody, in combination with AstraZeneca’s durvalumab in a registrational Phase 3 clinical study in patients with unresectable Stage 3 non-small cell lung cancer ("NSCLC"), known as the PACIFIC-8 study. The terms of this agreement were amended in 2024 and again after the discontinuation of the PACIFIC-8 study in the third-quarter 2026. Under the collaboration agreement, as amended, we are obligated to make milestone payments of $18 million, which we have fully accrued as of September 30, 2026 and recorded in Other noncurrent liabilities. We are also obligated to reimburse AstraZeneca annually for a portion of the trial costs, which are accrued as the costs are incurred. Prior to January 2024, the PACIFIC-8 trial formed part of the Arcus and Gilead joint development program for domvanalimab and our portion of the trial costs was shared with Gilead. Under the Third Gilead Collaboration Agreement Amendment, we agreed to solely fund our share of PACIFIC-8, subject to Gilead's right to reinstate PACIFIC-8 as part of the parties’ joint development activities for the TIGIT Program. We recognized expenses under this arrangement for the three and nine months ended September 30, 2026, of $12 million and $21 million, respectively, and for the three and nine months ended September 30, 2025, of $7 million and $16 million, respectively. These expenses are recognized as R&D expense in our Condensed Consolidated Statements of Operations. We had liabilities under this arrangement, at September 30, 2026 and December 31, 2025, of $33 million and $12 million, respectively, recorded in Other current liabilities and Other noncurrent liabilities on our Condensed Consolidated Balance Sheets based on the expected timing of payment. WuXi Biologics License - anti-PD-1 In 2017, we entered into an agreement with WuXi Biologics Ireland Limited ("WuXi Biologics") which, as amended, provides us with exclusive rights to (i) develop, use and manufacture products that include an anti-PD-1 antibody, including zimberelimab, worldwide and (ii) commercialize any such products worldwide, except in Greater China. As of September 30, 2026, under this arrangement, we may incur (i) additional regulatory milestone payments of up to $50 million and commercialization milestone payments of up to $375 million, (ii) tiered royalties that range from the high single-digits to low teens on net sales of the licensed products and (iii) fees related to any sublicenses. We did not have any milestones or royalties due under this arrangement for the three and nine months ended September 30, 2026 and 2025. WuXi Biologics License - anti-CD39 In 2020, we entered into an agreement with WuXi Biologics, under which we obtained the exclusive worldwide license to develop and commercialize anti-CD39 antibodies discovered under this arrangement. As of September 30, 2026, under this arrangement we may incur additional clinical and regulatory milestone payments of up to $14 million and royalty payments in the low single digits on net sales of the licensed products. We did not have any milestones or royalties due under this arrangement for the three and nine months ended September 30, 2026 and 2025. Abmuno License In 2016, we entered into an agreement (the "Abmuno Agreement") with Abmuno Therapeutics LLC ("Abmuno"), under which we obtained the exclusive worldwide license to develop, use, manufacture, and commercialize products that include an anti-TIGIT antibody, including domvanalimab. As of September 30, 2026, under this arrangement we may incur additional clinical, regulatory and commercialization milestone payments of up to $88 million. We did not have any milestones or royalties due under this arrangement for the three and nine months ended September 30, 2026 and 2025.

License and Collaborations

9 Months Ended

Sep. 30, 2026

License and Collaboration Agreements [Abstract]

License and collaborations

We enter into licensing agreements, strategic collaborations and other similar arrangements with third parties for the development and commercialization of certain investigational products. These arrangements: may be collaborative and involve two or more parties who are active participants in the operating activities of the collaboration and are exposed to significant risks and rewards depending on the commercial success of the activities; are performed with no guarantee of either technological or commercial success; and are each unique in nature. Such arrangements may include: non-refundable upfront payments; payments for options to acquire certain rights; potential development and regulatory milestone payments and/or sales-based milestone payments; royalty payments; revenue or profit-sharing arrangements; expense reimbursements; and cost-sharing arrangements.

Operating expenses for costs incurred pursuant to these arrangements are reported in their respective expense line items in the Condensed Consolidated Statements of Operations, net of any payments due to or reimbursements due from our collaboration partners, with such reimbursements being recognized at the time the party becomes obligated to pay.

Our significant arrangements are discussed below. For a more detailed discussion on revenues recognized under these arrangements, see Note 5, Revenues.

Gilead Collaboration

See Note 3, Related party - Gilead Sciences, Inc., for more information.

Taiho Collaboration

In 2017, we entered into an agreement with Taiho Pharmaceutical Co., Ltd. ("Taiho" and the "Taiho Agreement") pursuant to which Taiho obtained an exclusive option to in-license development and commercialization rights to programs for Japan and certain other Asian countries, excluding China (the "Taiho Territory") for which IND-enabling studies had begun during a five-year term which ended in September 2022, for an upfront payment of $35 million.

For each option to a program that Taiho exercises, except for casdatifan (the HIF-2α program) discussed below, they will be obligated to make a payment of $3 million to $15 million, depending on the development stage of the optioned program. Upon exercise, Taiho is solely responsible for continued development and commercialization in the Taiho Territory, unless they opt to participate in a global study, in which case they would become obligated to reimburse us for their portion of the global study costs. In addition, for each optioned program we would be eligible to receive clinical and regulatory milestones of up to $130 million and commercial milestone payments of up to $145 million with the achievement of certain sales thresholds in the Taiho Territory. We will also receive royalties ranging from high single-digits to mid-teens on net sales of licensed products in the Taiho Territory. Royalties will be payable by product and country commencing on the first commercial sale and ending upon the later of: (a) 10 years; and (b) expiration of the last-to-expire valid claim of our patents covering the manufacture, use or sale.

In 2022, Taiho opted to participate in two global Phase 3 trials of domvanalimab and zimberelimab combinations, STAR-121 and STAR-221, and in 2024, Taiho opted to participate in the global Phase 3 trial of quemliclustat, PRISM-1. For each of these trials, Taiho became obligated to reimburse us for their portion of the global trial costs, and to make milestone payments contingent upon successfully satisfying the related clinical milestones. The clinical milestones were met: for domvanalimab and zimberelimab for the STAR-221 trial in 2023, and Taiho became obligated to pay us $28 million; domvanalimab and zimberelimab for the STAR-121 trial in 2024, and Taiho became obligated to pay us $26 million; and for quemliclustat for the PRISM-1 trial in the first-quarter 2025, and Taiho became obligated to make milestone payments totaling $19 million. All the milestone payments due have been fully received. In the fourth-quarter 2025, Taiho exercised its option for HIF-2α inhibitor program (including casdatifan) for the Taiho Territory, for an option payment of $15 million. We and Taiho concurrently entered into an amendment (the "Second Amendment") where we will lead development for two indications for casdatifan in Japan and be responsible for the global study costs and we may also be eligible to receive: (i) clinical and regulatory milestones of up to $172 million of which Taiho became obligated to pay us $30 million in the second-quarter 2026 upon the achievement of a clinical milestone (of which $15 million was received in the third-quarter 2026 and the remaining $15 million is due in the first-quarter 2027); (ii) commercial milestone payments of up to $145 million upon the achievement of certain sales thresholds in the Taiho Territory; and (iii) royalties ranging from high single-digits to mid-teens on net sales of the licensed product in the Taiho Territory. Due to the nature of these arrangements, a portion of these upfront and clinical milestones were determined to be advance cost sharing payments for Taiho's share of the related global study R&D costs under the collaboration and are deferred and recognized as a reduction in R&D expense as the related global studies are performed, calculated as an estimated percentage of completion based on the estimated total effort for the programs. See Note 5, Revenues, for more information.

As of September 30, 2026, Taiho has licenses for the Taiho Territory to (i) HIF-2α inhibitor program (including casdatifan); (ii) anti-TIGIT program (including domvanalimab and AB308); (iii) anti-PD-1 program (including zimberelimab); (iv) CD73 program (including quemliclustat); and (v) adenosine receptor antagonist program (including etrumadenant). Taiho holds a time-limited option for the Taiho Territory to our CD39 program (including AB598).

We recognized net reimbursements, including amortization of advance cost share payments, under this arrangement for the three and nine months ended September 30, 2026, of $5 million and $16 million, respectively, and for the three and nine months ended September 30, 2025, of $7 million and $24 million, respectively. These net reimbursements are recognized as a reduction of R&D expense in our Condensed Consolidated Statements of Operations.

We had net receivables under this arrangement at September 30, 2026 and December 31, 2025, of $18 million and $10 million, respectively, recorded in Receivable from collaboration partners on our Condensed Consolidated Balance Sheets. See Note 5, Revenues for more information.

We had liabilities related to certain advance cost sharing payments under this arrangement at September 30, 2026 and December 31, 2025, of $32 million and $44 million, respectively, recorded in Other liabilities, allocated between current and noncurrent based on the expected timing of future recognition.

AstraZeneca Collaboration

In 2020, we entered into a collaboration with AstraZeneca to evaluate domvanalimab, our investigational anti-TIGIT antibody, in combination with AstraZeneca’s durvalumab in a registrational Phase 3 clinical study in patients with unresectable Stage 3 non-small cell lung cancer ("NSCLC"), known as the PACIFIC-8 study. The terms of this agreement were amended in 2024 and again after the discontinuation of the PACIFIC-8 study in the third-quarter 2026.

Under the collaboration agreement, as amended, we are obligated to make milestone payments of $18 million, which we have fully accrued as of September 30, 2026 and recorded in Other noncurrent liabilities. We are also obligated to reimburse AstraZeneca annually for a portion of the trial costs, which are accrued as the costs are incurred.

Prior to January 2024, the PACIFIC-8 trial formed part of the Arcus and Gilead joint development program for domvanalimab and our portion of the trial costs was shared with Gilead. Under the Third Gilead Collaboration Agreement Amendment, we agreed to solely fund our share of PACIFIC-8, subject to Gilead's right to reinstate PACIFIC-8 as part of the parties’ joint development activities for the TIGIT Program.

We recognized expenses under this arrangement for the three and nine months ended September 30, 2026, of $12 million and $21 million, respectively, and for the three and nine months ended September 30, 2025, of $7 million and $16 million, respectively. These expenses are recognized as R&D expense in our Condensed Consolidated Statements of Operations.

We had liabilities under this arrangement, at September 30, 2026 and December 31, 2025, of $33 million and $12 million, respectively, recorded in Other current liabilities and Other noncurrent liabilities on our Condensed Consolidated Balance Sheets based on the expected timing of payment.

WuXi Biologics License - anti-PD-1

In 2017, we entered into an agreement with WuXi Biologics Ireland Limited ("WuXi Biologics") which, as amended, provides us with exclusive rights to (i) develop, use and manufacture products that include an anti-PD-1 antibody, including zimberelimab, worldwide and (ii) commercialize any such products worldwide, except in Greater China. As of September 30, 2026, under this arrangement, we may incur (i) additional regulatory milestone payments of up to $50 million and commercialization milestone payments of up to $375 million, (ii) tiered royalties that range from the high single-digits to low teens on net sales of the licensed products and (iii) fees related to any sublicenses.

We did not have any milestones or royalties due under this arrangement for the three and nine months ended September 30, 2026 and 2025.

WuXi Biologics License - anti-CD39

In 2020, we entered into an agreement with WuXi Biologics, under which we obtained the exclusive worldwide license to develop and commercialize anti-CD39 antibodies discovered under this arrangement. As of September 30, 2026, under this arrangement we may incur additional clinical and regulatory milestone payments of up to $14 million and royalty payments in the low single digits on net sales of the licensed products.

We did not have any milestones or royalties due under this arrangement for the three and nine months ended September 30, 2026 and 2025.

Abmuno License

In 2016, we entered into an agreement (the "Abmuno Agreement") with Abmuno Therapeutics LLC ("Abmuno"), under which we obtained the exclusive worldwide license to develop, use, manufacture, and commercialize products that include an anti-TIGIT antibody, including domvanalimab. As of September 30, 2026, under this arrangement we may incur additional clinical, regulatory and commercialization milestone payments of up to $88 million.

We did not have any milestones or royalties due under this arrangement for the three and nine months ended September 30, 2026 and 2025.