Five Prime Therapeutics Receives FDA Orphan Drug Designation for FPA144 for the Treatment of Gastric Cancer

SOUTH SAN FRANCISCO, Calif., July 05, 2016 (GLOBE NEWSWIRE) — Five Prime Therapeutics, Inc. (Nasdaq:FPRX), a clinical-stage biotechnology company focused on discovering and developing innovative immuno-oncology protein therapeutics, announced that the U.S. Food and Drug Administration (FDA) has granted Orphan Drug Designation to FPA144 for the treatment of gastric cancer, including cancer of the gastroesophageal junction in patients whose tumors overexpress FGFR2b. FPA144 is an anti-FGF receptor 2b (FGFR2b) humanized monoclonal antibody in clinical development as a targeted immune therapy.

“Patients with advanced gastric cancer whose tumors overexpress FGFR2b have a significant unmet medical need, and the literature suggests that they have an especially poor prognosis,” said Robert Sikorski, M.D., Ph.D., senior vice president and chief medical officer. “The initial single-agent efficacy and safety data seen so far during the ongoing FPA144 Phase 1 study is encouraging, and we look forward to further exploring FPA144 as a potential treatment for patients with gastric cancer.”

Orphan Drug Designation is granted by the FDA Office of Orphan Drug Products to products that treat rare diseases. The FDA defines rare diseases as those affecting fewer than 200,000 people in the United States. Orphan Drug Designation provides the sponsor certain benefits and incentives, including a period of marketing exclusivity if regulatory approval is received for the designated indication, as well as potential tax credits and waiver of certain administrative fees.

About Gastric Cancer
Globally, gastric cancer is the sixth most common malignancy with the third highest mortality. The prevalence of gastric cancer worldwide is approximately 1.5 million patients, of which an estimated 5%, or approximately 80,000 patients, have FGFR2 gene-amplified tumors that overexpress FGFR2b. There are an estimated 76,000 gastric cancer patients in the United States, but the prevalence of gastric cancer is much higher in Asia and other regions of the world.

About FPA144
FPA144 is an anti-FGF receptor 2b (FGFR2b) humanized monoclonal antibody in clinical development as a targeted immune therapy for tumors that over-express FGFR2b, as determined by a proprietary immunohistochemistry (IHC) diagnostic assay. FGFR2 gene amplification (as identified by FISH) is found in a number of tumors, including in approximately 5% of gastric cancer patients, and is associated with poor prognosis.

FPA144 is designed to block tumor growth through two distinct mechanisms. First, it has been engineered to drive immune-based killing of tumor cells by antibody-dependent cell-mediated cytotoxicity (ADCC) and the recruitment of natural killer (NK) cells and T cells. Second, it binds specifically to FGFR2b and prevents the binding of certain fibroblast growth factors that promote tumor growth. When combined with PD-1 blockade, FPA144 has shown an additive effect in tumor growth inhibition in preclinical models. Five Prime retains global development and commercialization rights to FPA144.

About Five Prime
Five Prime Therapeutics, Inc. discovers and develops innovative therapeutics to improve the lives of patients with serious diseases. Five Prime’s comprehensive discovery platform, which encompasses virtually every medically relevant extracellular protein, positions it to explore pathways in cancer, inflammation and their intersection in immuno-oncology, an area with significant therapeutic potential and a growing focus of the company’s R&D activities. Five Prime has entered into strategic collaborations with leading global pharmaceutical companies and has promising product candidates in clinical and preclinical development. For more information, please visit

Cautionary Note on Forward-looking Statements
This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Words such as “may,” “will,” “expect,” “plan,” “anticipate,” “estimate,” “intend” and similar expressions (as well as other words or expressions referencing future events, conditions or circumstances) are intended to identify forward-looking statements. These forward-looking statements are based on Five Prime’s expectations and assumptions as of the date of this press release. Each of these forward-looking statements involves risks and uncertainties. Actual results may differ materially from these forward-looking statements. Factors that may cause actual results to differ from those expressed or implied in the forward-looking statements in this press release are discussed in Five Prime’s filings with the U.S. Securities and Exchange Commission, including the “Risk Factors” contained therein. Except as required by law, Five Prime assumes no obligation to update any forward-looking statements contained herein to reflect any change in expectations, even as new information becomes available.

CONTACT: Heather Rowe
Investor Relations

Amy Kendall
Corporate Communications