---
schema_version: "secwatch.filing_event.v1"
accession: "0001724521-25-000120"
form_type: "8-K"
ticker: "RCUS"
cik: "0001724521"
company_name: "Arcus Biosciences, Inc."
filed_at: "2025-12-12T23:59:59+00:00"
generated_at: "2026-05-16T13:22:16.612237+00:00"
event_type: "other_material"
sentiment: "negative"
materiality_score: 0.75
calibrated_materiality_score: 0.75
confidence: "high"
source: SEC EDGAR
---

# Arcus ends Phase 3 STAR-221 domvanalimab study on futility; no OS benefit

## Summary
- Phase 3 STAR-221 of domvanalimab + zimberelimab + chemo vs nivolumab + chemo stopped for futility after IDMC review.
- Domvanalimab combo did not improve overall survival vs nivolumab + chemo; safety profile similar.
- Phase 2 EDGE-Gastric also discontinued; company and Gilead communicating with investigators.
- R&D focus shifts to HIF-2a inhibitor casdatifan and small molecule inflammation programs; MRGPRX2 inhibitor clinical entry expected 2026.
- Cash runway expected to fund operations until at least second half 2028.

## SEC filing metadata
- accession: 0001724521-25-000120
- form_type: 8-K
- ticker: RCUS
- cik: 0001724521
- company_name: Arcus Biosciences, Inc.
- filed_at: 2025-12-12T23:59:59+00:00
- event_type: other_material
- sentiment: negative
- materiality_score: 0.75
- calibrated_materiality_score: 0.75
- confidence: high
- sec_items: 8.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1724521/000172452125000120/0001724521-25-000120-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1724521/000172452125000120/rcus-20251212.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001724521-25-000120
- JSON: https://secwatch.observer/filing/0001724521-25-000120.json
- Plain text: https://secwatch.observer/filing/0001724521-25-000120.txt

This AI-assisted summary is a reading aid. Review the linked SEC EDGAR filing before relying on any specific claim.