Amgen entered an agreement to acquire Five Prime Therapeutics for approximately $1.9 billion in cash. This acquisition adds Five Prime's innovative pipeline of immuno-oncology and targeted cancer therapies to Amgen's oncology portfolio.

Five Prime's lead asset, bemarituzumab, is a first-in-class, Phase 3 ready anti-FGFR2b antibody with positive data from a Phase 2 study in frontline advanced gastric or gastroesophageal junction (GEJ) cancer. Bemarituzumab targets FGFR2b, which has been found to be overexpressed in approximately 30% of patients with non-HER2 positive gastric cancer, as well as other solid tumors.

The bemarituzumab Phase 2 FIGHT trial demonstrated clinically meaningful improvements in progression-free survival (PFS), overall survival (OS) and overall response rate (ORR) in the frontline treatment of patients with advanced gastric or GEJ cancer.

Additional analysis showed a positive correlation between efficacy and expression of FGFR2b on tumor cells, confirming both the importance of the FGFR2b target and the activity of bemarituzumab against this target. This correlation suggests that FGFR2b could play a role in other epithelial cancers, including lung, breast, ovarian and other cancers.

The acquisition also supports Amgen's expansion strategy in gastric cancer, which is particularly prevalent in the Asia-Pacific region, where Amgen expects to leverage its presence in Japan and other Asia-Pacific markets to maximize bemarituzumab's potential. As part of this transaction, Amgen will receive a royalties on future sales in Greater China from a pre-existing co-development and commercialization agreement between Five Prime and Zai Lab (Shanghai) Co., Ltd.