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RCUS · Current Report (Form 8-K) · Filed April 20, 2026

Arcus Biosciences Inc — Current Report (Form 8-K)

Form
8-K
Filed
April 20, 2026
Period
Apr 20, 2026
Ticker
RCUS
Accession
0001724521-26-000021
Boardroom Alpha · Filing insights

STAR-121 is discontinued due to futility; no new safety issues identified. Gilead’s option rights end July 14, 2026, with limited remaining rights to select programs.

About Arcus Biosciences Inc
Market cap
$3.1B
1Y TSR
+171.4%
3Y TSR
+7.3%
Board grade
B-
Sector
Healthcare
CEO
Terry J Rosen
Last annual meeting: Jun 11, 2026 · View full Arcus Biosciences Inc profile →
rcus-20260420

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549
________________________________________________________
FORM 8-K
________________________________________________________
CURRENT REPORT
Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934
Date of Report (Date of earliest event reported): April 20, 2026
________________________________________________________
Arcus Biosciences, Inc.
(Exact name of Registrant as Specified in Its Charter)
________________________________________________________
Delaware001-3841947-3898435
(State or Other Jurisdiction
of Incorporation)
(Commission File Number)
(IRS Employer
Identification No.)
3928 Point Eden Way
Hayward, California
94545
(Address of Principal Executive Offices)(Zip Code)
Registrant’s Telephone Number, Including Area Code: (510) 694-6200
(Former Name or Former Address, if Changed Since Last Report)
________________________________________________________
Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:
oWritten communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)
oSoliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)
oPre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))
oPre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))
Securities registered pursuant to Section 12(b) of the Act:
Title of each class
Trading
Symbol(s)
Name of each exchange on which registered
Common Stock, Par Value $0.0001 Per ShareRCUSThe New York Stock Exchange
Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter).
Emerging growth company o
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. o



Item 8.01 Other Events.

STAR-121 Update.

On April 20, 2026, Arcus Biosciences, Inc. (the “Company”) announced the discontinuation of the Phase 3 STAR-121 study, which is being conducted in collaboration with Gilead Sciences, Inc. (“Gilead”), due to futility. STAR-121 evaluated the anti-TIGIT antibody domvanalimab plus anti-PD-1 antibody zimberelimab and chemotherapy versus pembrolizumab plus chemotherapy as a first-line treatment for metastatic non-small cell lung cancer. The decision is based on the recommendation from the Independent Data Monitoring Committee (“IDMC”), following its review of data from a pre-planned futility analysis. Safety was not assessed at this futility analysis; however, no new safety issues have been identified during regular reviews by the IDMC.

The STAR-121 study also evaluated zimberelimab and chemotherapy as an exploratory endpoint. Zimberelimab plus chemotherapy performed consistently with respect to overall survival as compared to pembrolizumab plus chemotherapy.

STAR-121, along with the Phase 2 EDGE-Lung study, will be discontinued. Gilead is communicating with investigators to determine appropriate next steps for patients in these studies.

Gilead Collaboration Update.

On April 20, 2026, the Company announced that the period for Gilead’s option rights under the Option, License and Collaboration Agreement entered into between the Company and Gilead in 2020, as amended, will end on July 14, 2026, following Gilead’s decision to not make the option continuation payment to the Company. Accordingly, Gilead will not have option rights to additional programs in the Company’s early-stage pipeline, including the CCR6, CD89 and CD40L programs, but will maintain its existing time-limited options to programs including AB801 (an investigational small molecule AXL inhibitor), AB598 (an investigational anti-CD39 monoclonal antibody), AB102 (an investigational MRGPRX2 antagonist), and an investigational TNF small molecule inhibitor.

The Company has full rights to casdatifan and the casdatifan development program, other than those rights licensed to Taiho in Japan and certain other Asian territories (not including China).



SIGNATURES
Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.
ARCUS BIOSCIENCES, INC.
Date: April 20, 2026By:/s/ Terry Rosen, Ph. D.
Terry Rosen, Ph.D.
Chief Executive Officer
(Principal Executive Officer)

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Reference

Frequently asked questions

When did Arcus Biosciences Inc file this 8-K?
Arcus Biosciences Inc (RCUS) filed this Current Report (Form 8-K) with the SEC on April 20, 2026. The accession number assigned by EDGAR is 0001724521-26-000021.
What does an 8-K disclose?
Form 8-K is the SEC's current-report form, used to disclose material events between periodic reports (10-K / 10-Q). Triggers include CEO/CFO departures, acquisitions, bankruptcies, earnings releases, auditor changes, changes in fiscal year, and amendments to corporate governance. Each 8-K is keyed to one or more Item numbers (1.01 through 9.01).
What is the key takeaway from this filing?
STAR-121 is discontinued due to futility; no new safety issues identified. Gilead’s option rights end July 14, 2026, with limited remaining rights to select programs. This is Boardroom Alpha's one-line summary of the current report; see the full filing text above for the formal disclosure.
What Item codes does an 8-K cover?
An 8-K's Item codes (1.01 through 9.01) specify what kind of event is being disclosed — e.g. Item 1.01 for entering a material agreement, Item 5.02 for departure/election of directors and executive officers, Item 8.01 for other events. The Item codes for this 8-K appear in the filing text above.
Where can I find Arcus Biosciences Inc's prior current reports on EDGAR?
The SEC EDGAR browser lists every 8-K Arcus Biosciences Inc has filed under CIK 1724521, sortable by date. Use the "View on SEC EDGAR" link in the page header, or browse directly via https://www.sec.gov/cgi-bin/browse-edgar.
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