A glimmer of hope for bemarituzumab?

Amgen’s fourth-quarter call on Tuesday marked the company’s formal abandonment of the anti-FGFR2b MAb bemarituzumab in first-line gastric cancer, with confirmation that the phase 1/2 Fortitude-103 study had been stopped. Though the negative outcome of Fortitude-103, an uncontrolled study in combination with chemo with or without Opdivo, was new it hardly came as a surprise given the earlier stopping for inadequate efficacy of the similar but controlled phase 3 Fortitude-102 trial, and the hero-to-zero outcome of the chemo combo study Fortitude-101. What’s more surprising is that Amgen still apparently sees hope in bemarituzumab, with the company telling analysts: “We observed an emerging signal of putative survival benefit in a subset of biomarker-defined patients.” However, it’s not clear what biomarkers are being referred to; presumably this isn’t to do with FGFR2b, as all four key bemarituzumab studies mandated FGFR2b expression. The waning result of Fortitude-101 was put down to potential “biomarker heterogeneity”, but nothing more was specified, so perhaps a conference presentation will shed more light on this. In the second line the solid tumour Fortitude-301 trial has been completed, Amgen said, without disclosing data. The company gained Zai Lab-partnered bemarituzumab through the $1.9bn acquisition of Five Prime Therapeutics.