Pfizer mimics pumitamig in gastroesophageal cancers

Pfizer hopes to differentiate itself in the PD-(L)1 x VEGF space but, for now, it appears to be closely following competitors, at least judging by a new late-stage trial posted on clinicaltrials.gov.

Last Tuesday, during its fourth-quarter results, Pfizer reaffirmed plans to kick off several pivotal trials in 2026 for the 3SBio-originated PD-1 x VEGF bispecific PF-08634404, including one in endometrial, and another in urothelial cancer, in combination with Padcev. Both are indications where direct competitors have not revealed near-term plans to start pivotal studies.

However, on Friday Pfizer posted a phase 2/3 study on clinicaltrials.gov in an indication not previously disclosed by the company. This will enrol patients with first-line gastric, oesophageal and gastroesophageal cancers, a setting where BioNTech and Bristol Myers Squibb have already revealed their own phase 2/3 trial for their PD-L1 x VEGF bispecific, pumitamig.

Similar designs

The latest PF-08634404 study, known as C6461016, is projected to begin in March, broadly in line with competitors' timelines, and will follow a similar design.

It will test PF-08634404 in combination with chemo, starting with an open-label phase 2 cohort before progressing into a phase 3 head-to-head comparison against Opdivo plus chemotherapy. Overall survival and progression-free survival will serve as primary endpoints for the phase 3 part.

Perhaps most notably, the study will enrol patients regardless of PD-L1 expression; checkpoint inhibitors have been restricted to PD-L1 expressors (≥1%) in upper gastrointestinal cancers.

Pfizer has already begun phase 3 trials of PF-08634404 in first-line colorectal cancer (Symbiotic-GI-03); first-line squamous and non-squamous NSCLC (Symbiotic-Lung-01); and a phase 2/3 in extensive-stage SCLC (Symbiotic-Lung-04). The last was missing from Pfizer's fourth-quarter presentation, but the company confirmed to ApexOnco that it was still taking place.

PD-(L)1 x VEGF phase 2/3 trials in first-line gastroesophageal cancers

Source: OncologyPipeline.