Coherus Tagmokitug Combo Shows 75% Response in Esophageal Cancer; CHRS Falls 9% Premarket

Coherus Oncology (CHRS) reported interim Phase 1b TREGCHECK results Wednesday showing tagmokitug plus toripalimab and chemotherapy produced a confirmed overall response rate of 75% in first-line esophageal squamous cell carcinoma, though shares fell 9.48% to $1.05 premarket after closing Wednesday at $1.16, up 8.41%. Six of eight evaluable patients responded regardless of PD-L1 status as of October 14, 2026, including one complete response; subsequent confirmations raised the rate to 89%, or eight of nine patients. PD-L1-positive patients showed a 100% cORR. In second-line ESCC, the 700-mg cohort of six evaluable patients showed a 16.7% confirmed response rate, 33.3% clinical benefit rate and median progression-free survival of 5.5 months. No new safety signals emerged; Grade 3-5 immune-related adverse events occurred in 20% of patients on the combination, with no treatment-related deaths. Coherus plans expanded enrollment in both ESCC cohorts.