Positive News For Gastric Cancers - Gilead/Arcus Biosciences' Combination Cancer Therapy Shows Encouraging Clinical Activity

Gilead Sciences Inc GILD and Arcus Biosciences Inc RCUS announced that domvanalimab plus zimberelimab and chemotherapy showed encouraging overall response rate (ORR) and six-month progression-free survival (PFS) rate results in a preliminary analysis from Arm A1 of the EDGE-Gastric study. 

This ongoing Phase 2 study is evaluating the safety and efficacy of various combinations of the Fc-silent anti-TIGIT antibody domvanalimab plus the anti-PD-1 antibody zimberelimab and chemotherapy in patients with locally advanced unresectable or metastatic gastric, gastroesophageal junction or esophageal adenocarcinoma. 

At the data cutoff (September 4, 2023), 41 patients were enrolled and treated with a median follow-up of 8.1 months; 24 patients (59%) remained on study treatment at the time of data cutoff. The median time on treatment was 33 weeks (range: <1 to 53 weeks).

The domvanalimab-containing regimen showed an ORR of 80% in patients with PD-L1-high tumors (tumor activity positivity (TAP) ≥5%), 46% in patients with PD-L1-low tumors (TAP <5%), and 59% for patients overall. 

There were two confirmed complete responses. 

The six-month landmark PFS rate was 93% for patients with PD-L1-high tumors (TAP ≥5%), 68% for patients with PD-L1-low tumors (TAP <5%), and 77% for patients overall. Median PFS was not reached, and mature PFS data are expected in the second half of next year.

The domvanalimab-containing regimen was well tolerated, with a similar safety profile to what has been reported for anti-PD-1 plus chemotherapy in this setting.

The companies have three additional ongoing Phase 3 registrational studies of domvanalimab-containing regimens in lung cancer, including STAR-121, ARC-10, and PACIFIC-8.

Price Action: RCUS shares are up 1.54% at $15.81 on the last check Tuesday.