Amgen said on Monday its experimental therapy helped patients with advanced gastric cancer live longer when combined with chemotherapy, according to interim data from a late-stage study.
The antibody drug, bemarituzumab, was acquired as part of Amgen's $1.9 billion purchase of Five Prime Therapeutics in 2021, aiming to gain a foothold in the Asian market where gastric cancer is more prevalent than the US
Amgen did not disclose how much the therapy when provided with chemotherapy helped improve overall survival in patients compared with those who received chemotherapy alone.
The company said the most common side effects linked to bemarituzumab included vision problems, eye irritation, anemia and nausea. Eye-related problems occurred more frequently and were more severe in patients taking the drug, it said.
The data is "clearly good news" for bemarituzumab given the cancer's difficult-to-treat nature, Guggenheim analyst Vamil Divan said, adding that further details on the magnitude of the benefits and side effects will be keenly watched.
Eye-related problems and related discontinuations will be important data points to evaluate the potential market opportunity, William Blair analyst Matt Phipps said.
Amgen said it plans to present further details from the study at a future medical meeting.
The study enrolled 547 patients with a type of gastric or gastroesophageal junction cancer that had spread to other parts of the body and had excessive amounts of the FGFR2b protein.
The drug targets FGFR2b, which is associated with tumour growth in about 38% of patients with the cancer, according to Amgen.
Treatment options for advanced gastric cancer include chemotherapy alone or with immunotherapy drugs such as Bristol Myers Squibb's Opdivo for some patient groups or Roche's Herceptin for tumours with specific genetic markers.
Divan projects potential US peak sales of about $550 million for the drug, when adjusted for a 60% probability of success.
Amgen partners with Zai Lab to develop and commercialise bemarituzumab in mainland China, Hong Kong, Macau and Taiwan.
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