Amgen Halts Gastric Cancer Trial as Bemarituzumab Fails to Meet Efficacy Standards

Amgen has announced the termination of its phase 1b/3 Fortitude-102 trial for bemarituzumab, a monoclonal antibody being studied for gastric and gastroesophageal junction cancer. The decision, revealed during the company's third-quarter earnings call on November 4, 2025, marks a significant setback in Amgen's oncology pipeline.

Trial Termination and Efficacy Concerns

The Fortitude-102 trial was evaluating bemarituzumab in combination with chemotherapy and Bristol Myers Squibb's Opdivo in 515 patients with untreated advanced gastric and gastroesophageal junction cancer exhibiting FGFR2b overexpression. Jay Bradner, M.D., Amgen's executive vice president of R&D, cited inadequate efficacy as the reason for halting the study.

"The magnitude of observed efficacy did not meet our standard for an Amgen medicine," Bradner stated during the investor call. This decision followed an ad hoc analysis requested by an internal data monitoring committee.

Previous Trial Results and Ongoing Studies

The termination of Fortitude-102 comes in the wake of disappointing results from another phase 3 trial, Fortitude-101. In September, Amgen and its partner Zai Lab reported that the final analysis of Fortitude-101 showed a weak survival benefit that had "attenuated" compared to earlier interim results.

Despite these setbacks, Amgen continues to pursue bemarituzumab's potential in other studies. Two trials remain ongoing: Fortitude-103, a phase 1b/2 gastric cancer study, and Fortitude-301, a phase 1b/2 solid tumor study.

Strategic Implications and Industry Outlook

Amgen acquired bemarituzumab through its $1.9 billion purchase of Five Prime Therapeutics in 2021. The recent trial terminations raise questions about the value of this acquisition and Amgen's broader gastric cancer strategy.

While Amgen reaffirms its commitment to developing treatments for challenging cancers with significant unmet needs, the company's standards for efficacy appear to be driving strategic decisions. The pharmaceutical industry will be watching closely to see how Amgen navigates this setback and whether bemarituzumab can demonstrate value in its remaining clinical programs.