Five Prime to Present Phase 2 FIGHT Trial Results of Bemarituzumab at American Society of Clinical Oncology (ASCO) Gastrointestinal (GI) Cancers Virtual Annual Symposium

Five Prime Therapeutics, Inc. (NASDAQ: FPRX), a clinical-stage biotechnology company focused on developing immune modulators and precision therapies for solid tumor cancers, today announced that detailed results from the global, randomized, double-blind placebo-controlled Phase 2 FIGHT trial evaluating bemarituzumab plus mFOLFOX6 chemotherapy in patients with fibroblast growth factor receptor 2b-positive (FGFR2b+), non HER2 positive (non HER2+) advanced gastric and gastroesophageal junction (GEJ) cancer will be featured during an oral podium presentation on January 15, 2021, at the ASCO Gastrointestinal Cancers Symposium being held virtually from January 15-17, 2021.

On November 10, 2020, Five Prime announced that the FIGHT trial met all three efficacy endpoints with bemarituzumab in combination with mFOLFOX6 chemotherapy providing statistically significant and clinically meaningful improvements in progression-free survival, overall survival, and objective response rate compared with mFOLFOX6 chemotherapy plus placebo in the front-line setting of patients with FGFR2b+, non HER2+ advanced gastric or GEJ cancer.

Bemarituzumab is the first and only investigational treatment targeting FGFR2b+ tumors. FGFR2b is overexpressed in approximately 30 percent of non HER2+ gastric and GEJ cancers. For these patients, no new front-line therapies have been approved in over a decade and systemic chemotherapy remains the standard of care. Five Prime and Roche Tissue Diagnostics (formerly Ventana Medical Systems) have also found that FGFR2b is overexpressed in numerous other cancers, including squamous non-small cell lung cancer, triple negative breast cancer, ovarian cancer, pancreatic cancer and intrahepatic cholangiocarcinoma. This represents additional potential areas for development of bemarituzumab beyond gastric and GEJ cancer.

The Company will host a conference call and live audio webcast on Friday, January 15, 2021 at 4:30pm (EST) / 1:30pm (PST) to review highlights from the presentation and will feature members of the Five Prime management team and Zev A. Wainberg, M.D., Associate Professor of Medicine at UCLA, Co-director of the Gastrointestinal Oncology Program and Director of Early Phase Clinical Research at the Jonsson Comprehensive Cancer Center, and a principal investigator of the trial.