Company: RCUS
Filing Date: 2025-10-31
Form Type: 424B5
Source: 0001193125-25-260836
Chunk: 5

Company: Arcus Biosciences, Inc.
Filing Date: 2025-10-31
Form: 424B5
Chunk 5
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: mPFS was not reached, the 18-month landmark PFS was not reached; the 12-month landmark PFS was 
 60% and the cORR was 35%.                                                                                                       |

| • |     | No unexpected safety signals were observed at the time of data cut off, and casdatifan had an acceptable and                                                               
 manageable safety profile across all doses. Across all four cohorts, one patient discontinued treatment due to anemia, and four patients (3%) discontinued due to hypoxia. |

In October 2025, we announced eVOLVE-RCC02, a Phase 1b/3 study sponsored and operationalized by AstraZeneca, evaluating casdatifan plus volrustomig, AstraZeneca’s investigational anti-PD-1/CTLA-4bispecific antibody, in first-line, metastatic clear cell renal cell carcinoma (“ccRCC”), has paused recruitment.

| • |     | The Phase 1b portion of the study has recruited rapidly and in the context of this rapid enrollment, following                                                                                                                               
 observations of potentially immune-mediated adverse events (“AEs”), none of which exceeded Grade 3, a decision was made to temporarily pause recruitment, while continuing to treat participants already enrolled into the study. No grade 4 
 or 5 events were observed and the majority of AEs were grade 1 or 2.                                                                                                                                                                         |

| • |     | We and AstraZeneca will continue to monitor these participants to further characterize the safety profile of the                         
 combination with longer follow-up. These data, along with any discussions with health authorities, will inform next steps for the study. |

TIGIT Program (domvanalimab) In October 2025, we presented the first overall survival results from Arm A1 of the Phase 2 EDGE-Gastric study in patients with locally advanced unresectable or metastatic gastric, gastroesophageal junction or esophageal adenocarcinoma. At data cutoff (March 3, 2025), safety and efficacy were evaluated in all patients enrolled and treated (n=41) and median study follow-upwas 26.4 months.

| • |     | Median overall survival (“mOS”) was 26.7 months in the overall patient population, 26.7 months in                                  
 patients with PD-L1 expression ≥1% as measured by TAP scoring (SP263 assay) and not reached in patients with PD-L1 expression ≥5