Domvanalimab Plus Zimberelimab and Chemotherapy Achieve 26.7-Month Median Overall Survival in Advanced Gastroesophageal Adenocarcinomas: Phase 2 EDGE-Gastric Study Results

Arcus Biosciences, Inc. (NYSE: RCUS), a clinical-stage global biopharmaceutical company, has announced promising results from Arm A1 of its Phase 2 EDGE-Gastric study. The study evaluated the combination of domvanalimab, an Fc-silent anti-TIGIT antibody, zimberelimab, an anti-PD-1 monoclonal antibody, and chemotherapy as a first-line treatment for patients with locally advanced unresectable or metastatic gastric, gastroesophageal junction (GEJ), or esophageal adenocarcinoma. These findings will be presented on October 18 at the European Society for Medical Oncology (ESMO) 2025 Congress.

The study revealed a median overall survival (OS) of 26.7 months, with 50% of patients living beyond two years. This result significantly exceeds the threshold for demonstrating clinically meaningful benefits over the current standard of care. Dr. Sun Young Rha, professor of Medical Oncology at Yonsei University Health System in Seoul, Korea, remarked, “A 26.7-month median OS is well beyond what would be required to demonstrate clinically meaningful benefit over standard of care.”

Key Findings from Arm A1 of the EDGE-Gastric Study

The Phase 2 EDGE-Gastric study is a multi-arm, global trial conducted in collaboration with Gilead Sciences. It evaluates the safety and efficacy of domvanalimab and zimberelimab in combination with chemotherapy. At the data cutoff on March 3, 2025, the study included 41 patients with a median follow-up of 26.4 months. The treatment demonstrated sustained efficacy across all PD-L1 subgroups, with a median time on treatment of 49 weeks.

Efficacy Results:

• Median OS: 26.7 months (90% CI: 18.4, NE)
• 24-Month OS Rate: 50.2% (90% CI: 36.3, 62.6)
• Median Progression-Free Survival (PFS): 12.9 months (90% CI: 9.8, 14.6)
• 24-Month PFS Rate: 25.9% (90% CI: 14.8, 38.5)
• Confirmed Objective Response Rate (ORR): 59% (90% CI: 45%, 72%)

The regimen was well-tolerated, with no unexpected safety signals. Immune-mediated treatment-emergent adverse events related to domvanalimab and/or zimberelimab occurred in 22% of patients, and infusion-related reactions were observed in 7%.

Ongoing Development in Phase 3 STAR-221 Study

The positive results from the EDGE-Gastric study support the continued development of domvanalimab and zimberelimab in the Phase 3 STAR-221 trial. This global study is enrolling approximately 1,050 participants with advanced gastric, GEJ, or esophageal adenocarcinoma. The trial aims to evaluate overall survival in PD-L1-high, PD-L1-positive, and all-comer populations, with secondary endpoints including PFS, ORR, and duration of response.

About Domvanalimab and Zimberelimab

Domvanalimab is the first Fc-silent anti-TIGIT monoclonal antibody designed to block TIGIT, a checkpoint receptor that suppresses the immune response against cancer. By targeting TIGIT with Fc-silent properties, domvanalimab activates immune cells without depleting regulatory T cells, potentially reducing immune-related toxicity. Zimberelimab, an anti-PD-1 monoclonal antibody, restores T-cell antitumor activity and is being evaluated as a foundational treatment in combination with other immunotherapies.

About Arcus Biosciences

Founded in 2015, Arcus Biosciences is dedicated to developing innovative cancer therapies. The company’s pipeline includes domvanalimab, zimberelimab, and other investigational medicines targeting well-characterized biological pathways. Arcus collaborates with industry partners, patients, and physicians worldwide to advance treatments that improve survival outcomes for people with cancer.

For more information about Arcus Biosciences and its clinical programs, visit www.arcusbio.com.