Bemarituzumab Plus mFOLFOX6 Improves PFS, OS Rates in Gastric Cancers

Bemarituzumab is a humanized monoclonal antibody that is selective for fibroblast growth factor receptor 2b (FGFR2b). In 2017, researchers began the FIGHT trial to determine the efficacy of bemarituzumab in combination with modified FOLFOX6 (mFOLFOX6) for the treatment of gastric and gastroesophageal cancers.

Zev A. Wainberg, MD, MSc, and colleagues provided an update on the phase 2 FIGHT trial, which included the study’s final results.

A total of 155 patients with FGFR2b-positive HER2-negative gastric or gastroesophageal junction cancer (GC) received bemarituzumab 15.0 mg/kg (n=77) or placebo (n=78) once every 2 weeks, with an additional dose of bemarituzumab 7.5 mg/kg or placebo on day 8 of cycle 1. All patients received mFOLFOX6.

The study’s primary end point was progression-free survival (PFS), while secondary end points included overall survival (OS), objective response rate, and safety. Efficacy was evaluated after a minimum follow-up of 24 months.

In the bemarituzumab and placebo arms, 59.7% and 66.7% of patients, respectively, were FGFR2b-positive in ≥10% of tumor cells. In the bemarituzumab arm, the median PFS (95% CI) was 9.5 months (range, 7.3-13.7 months) and the median OS (95% CI) was 19.2 months (range, 13.6-24.2 months). In the placebo arm, the median PFS and OS rates were 7.4 months (range, 5.7-8.4 months) and 13.5 months (range, 9.3-15.9 months), respectively.

Observed efficacy in patients with FGFR2b-positive GC in ≥10% of tumor cells included a PFS hazard ratio (HR) of 0.43 (95% CI, 0.26-0.73) and an OS HR of 0.52 (95% CI, 0.31-0.85). No new safety findings were reported.

In patients with FGFR2b-positive advanced GC, the addition of bemarituzumab to mFOLFOX6 can result in longer PFS and OS rates compared with treatment with mFOLFOX6 alone. Efficacy was also more pronounced in patients with FGFR2b overexpression in ≥10% of tumor cells. FIGHT phase 3 confirmatory trials are ongoing.