Amgen's $1.9bn looks buried

Things are going from bad to worse for Amgen and Zai Lab’s anti-FGFR2b antibody bemarituzumab, with the make-or-break Fortitude-102 trial just revealed as a failure.

Amgen said during its third-quarter earnings call that the study, which tested bemarituzumab plus Opdivo plus chemo in first-line gastric cancer, had been stopped for “inadequate efficacy” following an ad hoc analysis requested by the data monitoring committee. The US company had paid $1.9bn for bema's originator, Five Prime Therapeutics.

The company highlighted a couple of ongoing early-stage trials, but the future looks bleak for this project, which was already facing serious questions following the presentation of data from another phase 3 first-line gastric cancer study, Fortitude-101, at ESMO.

Fortitude-101 initially found an overall survival benefit with bema plus chemo, versus chemo alone. However, at two years that survival benefit had disappeared. Ocular toxicities led to treatment discontinuation in 28% of patients and might have contributed to the diminishing survival advantage.

At that point, bema’s hopes of being filed and eventually approved switched to Fortitude-102, which added Opdivo into the mix being tested. But with that now also being revealed as a bust, it’s hard to see a way forward for the project.

Amgen didn’t give further details, so it’s unclear if toxicity has reared its head again. Perhaps things will become clearer if and when full data are presented.

While Amgen gained bema through the $1.9bn acquisition of Five Prime in 2021, Zai already had Chinese rights via an earlier deal with Five Prime.

Other FGFR2b-targeting projects in development, according to OncologyPipeline, include ADCs from BeOne Medicines (BG-C137), Allink (ALK201), Jiangsu Simcere (SIM0686) and Huadong Medicine (HDM2020). Chia Tai also has a MAb, TQB2210, in phase 1 in China.

Selected studies of bemarituzumab

Source: OncologyPipeline & company presentation.