Phase 2/3 PF-08634404 PD-1×VEGF bispecific antibody + chemo in 1L PD-L1+ HER2− GE cancers

Pfizer’s Phase 2/3, multicenter, interventional study tests PF-08634404—an investigational bispecific antibody that targets PD-1 (immune checkpoint) and VEGF (angiogenesis signaling)—given with standard first-line chemotherapy in treatment-naïve, locally advanced or metastatic gastric, gastroesophageal junction, or esophageal adenocarcinoma that is HER2-negative and PD-L1 positive by local testing. The Phase 2 portion focuses on safety/tolerability plus early antitumor activity to support dose/regimen selection, then the Phase 3 portion randomizes participants to PF-08634404 + chemotherapy versus nivolumab (Bristol Myers Squibb) + chemotherapy to compare clinical benefit in a head-to-head, contemporary immunotherapy control. The scientific/commercial angle is whether dual PD-1 blockade plus VEGF-pathway inhibition in a single molecule can outperform PD-1 + chemo alone without needing a separate anti-VEGF drug, potentially shifting a very high-incidence front-line setting. Today’s care for 1L, HER2−, PD-L1+ metastatic gastric/GEJ/esophageal adenocarcinoma commonly uses a fluoropyrimidine/platinum chemotherapy backbone plus a PD-1 inhibitor (e.g., nivolumab), with later lines moving to additional systemic options.