Phase I Results From The Phase 1/3 Fight Study Evaluating Bemarituzumab And Mfolfox6 In Advanced Gastric/Gej Cancer (Gc).

91Background: GC with FGFR2b overexpression or FGFR2 amplification is associated with a poor prognosis. Bemarituzumab (bema, FPA144) is a first-in-class humanized monoclonal IgG1 antibody that selectively blocks FGFR2b and triggers antibody-dependent cell-mediated cytotoxicity. With favorable safety and activity as a single agent in 2L+ patients with FGFR2b+ GC, the global, randomized, double-blind, placebo-controlled FIGHT study (NCT03343301) is evaluating the front-line combination of bema with mFOLFOX6. We report here the results from the phase I evaluation of the combination. Methods: Patients (pts) with unresectable, locally advanced or metastatic gastrointestinal malignancy (irrespective of FGFR2b status) for whom mFOLFOX6 would be appropriate were eligible for enrollment in the phase I. Her2+ disease or prior treatment with FGF-FGFR inhibitors was not allowed. All pts in the Phase 1 received mFOLFOX6 combined with bema in Q2W cycles. Cohort 1 (3+3) began with bema 6 mg/kg and cohort 2 (Rolling-6) b...