Amgen's promising gastric cancer drug makes good on Five Prime potential with FDA's breakthrough nod
When Five Prime — now part of Amgen — rolled out mid-stage data for gastric cancer candidate bemarituzumab late last year, it looked like a big win with one major catch: The drug missed its OS primary endpoint. Even still, there was enough promise for Amgen to jump aboard, and apparently, the FDA is interested, too.
On Tuesday, the FDA granted bemarituzumab, an anti-FGFR2b antibody, a Breakthrough Therapy Designation for gastric cancer. The drug would be the first of its kind to target FGFR2b, which is overexpressed in about 20% of HER2-negative tumors.
In November, Five Prime unveiled top-line data from the Phase II FIGHT trial showing a combination of bemarituzumab and chemotherapy beat out chemo alone in terms of significantly extending patients’ progression-free survival and spurring an objective response. For progression-free survival, outcomes improved from 7.4 months to 9.5 months — a p-value of 0.073 —while overall response rate improved by 13.1%, good for a p-value of 0.106.
Meanwhile, the drug couldn’t hit its OS endpoint, posting a p-value of 0.027, just above the 0.02 significance mark. That’s a high bar to hit and might not matter much in a Phase III test where the p-value target is higher.
Amgen sees bemarituzumab as not only a frontline gastric cancer breakthrough but potentially a springboard into a broad range of indications, including lung, breast and ovarian. If that comes to pass, it would add a lot of weight to the company’s decision to buy out Five Prime for $1.9 billion — a decision that wasn’t exactly par for the course for CEO Bob Bradway.
Last month, SVB Leerink’s Geoff Porges said that while the purchase is a “fairly small transaction,” there could be more to come to build out the pipeline. The deal was finalized April 16.
In November, news of a plan to launch the Phase III trial excited investors, as Five Prime’s $FPRX stock nearly quadrupled within an hour. That was positive news for a company that was forced to cut 41 jobs in research, pathology and manufacturing to save $10 million in January 2019.