Bemarituzumab plus mFOLFOX6 as first-line treatment in East Asian patients with FGFR2b-overexpressing locally advanced or metastatic gastric/gastroesophageal junction cancer: subgroup of FIGHT final analysis.

Background: In the FIGHT study (NCT03694522) bemarituzumab, a humanized monoclonal antibody selective for fibroblast growth factor receptor 2b (FGFR2b), plus mFOLFOX6 showed clinically meaningful efficacy in patients with FGFR2b-positive (2+/3+ membranous staining by immunohistochemistry) locally advanced unresectable/metastatic gastric/gastroesophageal cancer (G/GEJC). A meaningful proportion of patients in FIGHT were enrolled in East Asia, reflecting global epidemiology of G/GEJC.

Methods: This subgroup analysis of the global, phase 2, double-blind FIGHT study included all patients enrolled in East Asian sites. Patients were randomized 1:1 to bemarituzumab-mFOLFOX6 (15 mg/kg and one 7.5 mg/kg dose on cycle 1, day 8) or matching placebo-mFOLFOX6. The primary endpoint was investigator-assessed progression-free survival (PFS). Secondary endpoints included overall survival (OS), objective response rate, and safety. Efficacy was evaluated after a minimum follow-up of 24 months.

Results: The East Asian subgroup comprised 89 patients (57% of overall study population); 45 were randomized to bemarituzumab-mFOLFOX6 and 44 to placebo-mFOLFOX6. Median PFS (95% confidence interval [CI]) was 12.9 months (8.8-17.9) with bemarituzumab-mFOLFOX6 and 8.2 months (5.6-10.3) with placebo-mFOLFOX6 (HR 0.50, 95% CI 0.29-0.87); median OS (95% CI) was 24.7 months (13.8-33.1) vs 12.9 months (9.3-21.4), respectively (HR 0.56, 95% CI 0.32-0.96). Treatment benefit was more pronounced in patients with FGFR2b-positive G/GEJC in ≥ 10% of tumor cells. No new safety signals were reported.

Conclusion: In East Asian patients with FGFR2b-positive advanced/metastatic G/GEJC enrolled in the global FIGHT study, bemarituzumab-mFOLFOX6 showed clinically meaningful outcomes over placebo-mFOLFOX6.