Arcus Biosciences(US:RCUS) Benzinga·2025-12-12 18:35Core Insights - Arcus Biosciences has announced the discontinuation of the Phase 3 STAR-221 study due to futility, following a recommendation from the Independent Data Monitoring Committee after an interim analysis of overall survival [1][2]. Study Discontinuation - The STAR-221 study evaluated the combination of anti-TIGIT antibody domvanalimab and anti-PD-1 antibody zimberelimab with chemotherapy against nivolumab plus chemotherapy for untreated patients with advanced gastric and esophageal cancers [2]. - The interim analysis revealed that the domvanalimab-based combination did not improve overall survival compared to nivolumab plus chemotherapy, with a similar safety profile and no new safety findings [3]. Future Directions - Arcus will focus its R&D efforts on casdatifan, a potential best-in-class HIF-2α inhibitor, which has shown strong single-agent activity in over 120 late-line clear cell renal cell carcinoma (ccRCC) patients in the ARC-20 Phase 1/1b study [5]. - Key milestones for casdatifan include additional analyses in early 2026, more mature combination data by mid-2026, and potential initiation of a Phase 3 trial in late 2026 [6][7]. Oncology Pipeline - Arcus is advancing quemliclustat, a small-molecule CD73 inhibitor, with the Phase 3 PRISM-1 trial in first-line metastatic pancreatic ductal adenocarcinoma having completed enrollment earlier this year, with results expected in 2027 [8]. Immunology and Inflammation Pipeline - The immunology and inflammation portfolio includes several oral small-molecule programs, with two candidates expected to enter clinical trials in the near future [10][11].