Amgen's investigational monoclonal antibody, bemarituzumab, has shown promising results in improving overall survival for patients with advanced gastric cancer when combined with chemotherapy, as indicated by interim findings from the Fortitude-101 phase 3 trial.

In this trial, patients received either bemarituzumab combined with mFOLFOX6 or a placebo with mFOLFOX6, successfully meeting the primary endpoint of overall survival.

While the trial demonstrated a statistically significant survival benefit, detailed efficacy data is expected to be presented at a future medical meeting.

The trial enrolled 547 patients from 37 countries, specifically targeting those with unresectable locally advanced or metastatic gastric or gastroesophageal junction cancer who also exhibit overexpression of fibroblast growth factor receptor 2b (FGFR2b).

Bemarituzumab is particularly relevant as a first-line treatment candidate for tumors overexpressing FGFR2b, which is found in approximately 38% of individuals with advanced G/GEJ cancer.

The U.S. FDA has granted bemarituzumab breakthrough therapy designation for gastric cancer patients whose tumors overexpress FGFR2b in at least 10% of cells.

Following these interim findings, Zai Lab plans to submit a regulatory application for bemarituzumab in China, where it holds co-development rights.

Jay Bradner, M.D., Amgen’s head of R&D, emphasized the significance of these results as a meaningful advancement in targeted therapy for gastric cancer, a disease that typically has a poor prognosis.

However, common treatment-emergent adverse effects observed included reduced visual acuity, corneal inflammation, and anemia, with ocular events being more frequent and severe in the bemarituzumab group.

The trial's exclusion criteria ensured a focused patient population by disallowing prior treatments in the metastatic setting and any significant coexisting conditions.

Amgen announced the trial's findings and plans to provide further detailed data at an upcoming medical meeting.

Amgen acquired bemarituzumab in 2021 through a $1.9 billion purchase of Five Prime Therapeutics, while Zai Lab retains exclusive rights in specific regions.