...- Fibroblast growth factor receptor 2b (FGFR2b) overexpression as determined by a centrally performed immunohistochemistry tissue test and/or FGFR2 gene amplification as determined by a centrally performed circulating tumor deoxyribonucleic acid (ctDNA) blood based assay...

...Measurable or non-measurable, but evaluable disease using RECIST v1.1 Additional Inclusion Criteria for Phase 3 Only: • Histologically documented gastric or gastroesophageal junction (GEJ) adenocarcinoma (not amenable to curative therapy) • Radiographic imaging of the chest, abdomen and pelvis (computed tomography [CT] preferred, magnetic resonance imaging [MRI] acceptable) performed within 28 days (± 3 days) of treatment (C1D1) • FGFR2b overexpression as determined by a centrally performed IHC tissue test and/or FGFR2 gene amplification as determined by a centrally performed ctDNA blood based assay • Patient must be a candidate for mFOLFOX6 chemotherapy • No prior chemotherapy for metastatic or unresectable disease (except a maximum of 1 dose of mFOLFOX6 administered while waiting for results of FGFR2 testing during the Pre-Screening period) • If prior adjuvant or neo-adjuvant therapy (chemotherapy and/or chemoradiation) has been received, more than 6 months must have elapsed between the end of adjuvant therapy and the confirmation of radiographic disease progression`Phase 1 and Phase 2:1. ...

The combination of bemarituzumab with chemotherapeutic regimens commonly used for treatment of patients with gastric cancer was also evaluated in the OCUM-2M xenograft model. Twice weekly bemarituzumab (5 mg/kg, IP) combined with weekly 5-fluorouracil (5-FU) (30 mg/kg, IP) and oxaliplatin (5 mg/kg, IP) demonstrated greater inhibition of tumor growth in the OCUM-2M xenograft model of gastric cancer....Bemarituzumab inhibited FGFR2 signaling and tumor growth in mice bearing FGFR2-amplified tumors (SNU-16 and OCUM-2M human gastric cancer cells, respectively).

...the efficacy of bemarituzumab monotherapy to inhibit growth of FGFR2-amplified tumors was measured….Bemarituzumab displayed therapeutic efficacy against OCUM-2M gastric tumors at all dose levels tested compared to the negative control (albumin) group….Specifically, tumor growth inhibition and tumor regression were seen starting at the 1 mg/kg dose, with complete tumor regression observed in 1/15 mice at the 1.5 mg/kg and 2 mg/kg doses...Bemarituzumab inhibited FGFR2 signaling and tumor growth in mice bearing FGFR2-amplified tumors (SNU-16 and OCUM-2M human gastric cancer cells, respectively).