Company: RCUS
Filing Date: 2025-10-31
Form Type: 424B5
Source: 0001193125-25-260836
Chunk: 4

Company: Arcus Biosciences, Inc.
Filing Date: 2025-10-31
Form: 424B5
Chunk 4
---
 current clinical pipeline: cabo: cabozantinib; cas: casdatifan; chemo: chemotherapy; dom: domvanalimab; gem/nab-pac: gemcitabine/nab-paclitaxel;IO: immuno-oncology; ipi: ipilimumab; nivo: nivolumab; pembro: pembrolizumab; quemli: quemliclustat; volru: volrustomig; zim: zimberelimab

| * | Gilead and Arcus co-develop globally and share co-commercialization rights in the United States for domvanalimab, zimberelimab and quemliclustat. Gilead holds commercialization rights outside of the United States subject to any third-party rights. |

Recent Developments Corporate Developments In October 2025, Taiho exercised its option for an exclusive license to casdatifan, an investigational small molecule HIF-2αinhibitor, in Japan and certain other territories in Asia (excluding mainland China). In exchange, Taiho will make an option exercise payment to us along with milestone payments upon the achievement of clinical, regulatory and commercialization milestones, and, additionally pay royalties on net sales. HIF-2α Program (casdatifan) In October 2025, we presented new data for our HIF-2αinhibitor, casdatifan, across all four monotherapy cohorts (n=121) of the Phase 1/1b ARC-20study in late-line metastatic kidney cancer, most of whom had

S-2

progressed on at least two prior lines of therapy, including both an anti-PD-1and a VEGFR tyrosine kinase inhibitor (“TKI”). At the time of data cut-off(August 15, 2025):

| • |     | For the pooled analysis of all four monotherapy cohorts, with 15.2 months of median follow-up: median progression-free survival (“mPFS”) was 12.2 months, the 18-month landmark progression-free survival (“PFS”) was 43%, the 12-month landmark PFS was 50% and the confirmed overall response rate (“cORR”) was 31%. |

| • |     | For the 100mg QD cohort (the Phase 3 PEAK-1 dose and formulation), with                                                         
 12.4 months of median follow-up