Pfizer launches bold challenge to Keytruda with PD-1xVEGF bispecific push

Pfizer is initiating seven clinical trials, including two Phase 3 studies, for its PD-1xVEGF bispecific antibody PF-08634404, aiming to unseat Merck’s Keytruda as the leader in immuno-oncology.

Why it matters: This aggressive development plan signals Pfizer’s intent to build a new foundational cancer therapy platform. If successful, PF-08634404 could disrupt standards in lung, colorectal, and other cancers, reshaping oncology treatment norms.

Backstory: Pfizer acquired the drug from China’s 3SBio for up to $6B in July 2025. In Phase 2 trials, PF-08634404 showed higher overall response rates (ORR) than Tevimbra in NSCLC patients, 69.2% in squamous and 58.6% in nonsquamous disease. Pfizer is positioning it as a dual replacement for both PD-1/L1 checkpoint inhibitors and VEGF-targeted therapies.

Big picture: Pfizer enters a crowded field with Summit/Akeso’s ivonescimab and BMS/BioNTech’s pumitamig already in Phase 3. This next-gen class of bispecifics aims to improve efficacy through dual immune and anti-angiogenic targeting. Pfizer’s global reach and trial infrastructure may offer competitive advantages.

What’s next: Pfizer plans a second wave of up to 10 more indications and novel combinations by the end of 2026.