Five Prime Therapeutics, Inc. announced that on December 27, 2017, the company initiated dosing in the Phase 1 portion of the FIGHT Phase 1/3 clinical trial (NCT03343301) of FPA144, an isoform-selective anti-FGF receptor 2b antibody, in combination with chemotherapy in patients with previously untreated, advanced gastric or gastroesophageal cancer. Patients with advanced gastric cancer need new treatment options. Progression free survival with mFOLFOX6, a standard front-line therapy for gastric cancer, is typically less than seven months. For patients whose tumors overexpress FGFR2b or have FGFR2 gene amplification, prognosis has been found to be particularly poor, so hopeful that a targeted therapy like FPA144 may provide a clinical benefit in this setting. The open label Phase 1 portion of the trial will evaluate ascending doses of FPA144 in combination with the modified FOLFOX6 regimen (mFOLFOX6) to identify a recommended dose for Phase 3. Endpoints include safety, tolerability, and pharmacokinetic and pharmacodynamics parameters. Approximately 21 patients with unresectable, locally advanced, or metastatic gastrointestinal cancer will be enrolled during the Phase 1 portion of the FIGHT trial. FGFR2 status will be tested retrospectively but is not a requirement for enrollment. This safety lead-in portion of the study is designed to support the Phase 3 portion of the trial, which Five Prime expects to transition to in mid-2018.  Five Prime designed the randomized, controlled Phase 3 portion of the trial to serve as a global registrational study.  The FIGHT trial will evaluate FPA144 plus mFOLFOX6 versus placebo plus mFOLFOX6 in approximately 550 patients with advanced gastric or gastroesophageal cancer whose tumors overexpress FGFR2b or have FGFR2 gene amplification. Five Prime will use immunohistochemistry and circulating tumor DNA tests to identify patients who would be eligible for inclusion in the trial. The primary Phase 3 endpoint is overall survival with progression free survival, objective response rate, and safety as secondary endpoints. The Phase 3 portion of the trial is expected to include sites in the U.S., Europe and Asia, including China and Japan, where the incidence of gastric cancer is high. Efficacy Results: Objective Response Rate (ORR): 19.0%; Disease control rate at 6 weeks: 57.1%; Median duration of response of 15.4 weeks; Median number of prior therapies: 3.