Five Prime Therapeutics, Inc. announced clinical results from the global, randomized, double-blind placebo-controlled Phase 2 FIGHT trial evaluating first-in-class targeted therapy bemarituzumab in advanced gastric or gastroesophageal junction (GEJ) cancer. Trial results were presented in a late-breaking oral presentation on January 15, 2021 by UCLA Health’s Zev Wainberg, M.D., at the 2021 ASCO Gastrointestinal Cancers Virtual Annual Symposium (ASCO GI). The FIGHT trial evaluated bemarituzumab plus chemotherapy (mFOLFOX6) versus placebo plus chemotherapy in patients with fibroblast growth factor receptor 2b-positive (FGFR2b+), non HER2 positive frontline advanced gastric or GEJ cancer. The trial enrolled 155 patients in 15 countries across Asia, the European Union, and the United States, with 77 patients randomized to the bemarituzumab arm and 78 patients to the placebo arm. The Phase 2 trial met all three efficacy endpoints and demonstrated statistically significant and clinically meaningful improvements in the primary endpoint of progression-free survival (PFS) and secondary endpoints of overall survival (OS) and overall response rate (ORR). Additional analysis showed a positive correlation between benefit and the percentage of FGFR2b+ tumor cells, confirming both the importance of the FGFR2b target and the activity of bemarituzumab against this target. The incidence of all grade adverse events was similar in the bemarituzumab and placebo arms of the study (100% vs 98.7%, respectively). Corneal events were reported more frequently in the bemarituzumab arm (67.1% vs 10.4%), with the most common corneal events in the bemarituzumab arm being dry eye (26.3%), keratitis (15.8%) and punctate keratitis (14.5%). Stomatitis (31.6% vs 13.0%) and elevated transaminases (34.2% vs 19.5%) were also more common in the bemarituzumab arm. Grade 3 and higher adverse events (82.9% vs 74.0%), serious adverse events (31.6% vs 36.4%) and deaths (6.6% vs 5.2%) were comparable across arms. Ocular events are common in therapies targeting FGFR and were also reported in the FIGHT trial. More patients in the FIGHT trial discontinued bemarituzumab compared to placebo due to an adverse event (34.2% vs 5.2%) and the majority of these patients (21 of 26 patients) discontinued due to an ocular event. The discontinuation of bemarituzumab due to an ocular event decreased the median duration of exposure to bemarituzumab by 3.2 weeks; from 25.3 weeks (n=55, range: 2.0 to 71.7 weeks) to 22.1 weeks (n=21, range: 12.0 to 46.7 weeks). In designing the Phase 3 trial, the company plans to incorporate findings from the FIGHT trial including baseline eye exams, prophylactic lubricating eye drops and close monitoring for signs and symptoms of corneal toxicity, including dry eye.