Five Prime Therapeutics Announces Updated Clinical Data on FPA144 and FP-1039 to be Presented during 2016 ASCO Annual Meeting

SOUTH SAN FRANCISCO, Calif., May 18, 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 updated data from the ongoing clinical trials of FPA144 and FP-1039 will be presented during the 2016 American Society of Clinical Oncology (ASCO) Annual Meeting to be held June 3-6, 2016, in Chicago. The presentation abstracts are now available online at the meeting website: Information contained in the abstracts was as of the time of submission in February 2016. Five Prime intends to announce more detailed results at the time of the presentations at the ASCO Annual Meeting.

Further data on safety and activity from the Phase 1 trial evaluating FPA144, an antibody-dependent cell-mediated cytotoxicity (ADCC)-enhanced, FGFR2b isoform-selective monoclonal antibody, as a single agent in patients with FGFR2b+ gastric cancer and advanced solid tumors will be featured in an oral presentation:

Antitumor activity and safety of FPA144, an ADCC-enhanced, FGFR2b isoform-selective monoclonal antibody, in patients with FGFR2b+ gastric cancer and advanced solid tumors
Oral Abstract Session: Developmental Therapeutics—Clinical Pharmacology and Experimental Therapeutics
Date/Time: Monday, June 6, 2016, 8:24 AM - 8:36 AM Central Time
Location: E354b

Preliminary dose escalation data from the FPA144 trial were presented during the ASCO Gastrointestinal Cancers Symposium in January 2016.

Additionally, data on the safety, response rate and duration of response of FP-1039, an FGF ligand trap, combined with standard of care chemotherapy to treat malignant pleural mesothelioma patients in GlaxoSmithKline’s Phase 1b trial will be highlighted in a poster presentation:

Multi-arm, open-label Phase 1b study of FP-1039/GSK3052230 with chemotherapy in malignant pleural mesothelioma (MPM)
Poster Session: Lung Cancer—Non-Small Cell Local-Regional/Small Cell/Other Thoracic Cancers
Date/Time: Saturday, June 4, 2016, 8:00 AM - 11:30 AM Central Time
Location: Hall A

Initial data from the Phase 1b trial of FP-1039 were released during the World Conference on Lung Cancer in September 2015, but the majority of mesothelioma patients enrolled at the time were not yet evaluable.

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 FP-1039

FP-1039 is a protein drug designed to intervene in FGF signaling. As a ligand trap, FP-1039 binds to FGF ligands circulating in the extracellular space (such as FGF2), preventing these signaling proteins from reaching FGFR1 on the surface of tumor cells where they would otherwise stimulate cancer cell division and/or angiogenesis. However, FP-1039 does not bind to certain "hormonal" FGFs, including FGF-23, which regulates phosphate levels in the blood. As a result, treatment with FP-1039 treatment has not been shown to cause hyperphosphatemia, a side effect seen with small molecule inhibitors of FGF receptors, which block the activity of both cancer-associated FGFs and FGF-23.

GlaxoSmithKline is completing the ongoing Phase 1b trial in malignant pleural mesothelioma and will transfer its development and commercialization rights for FP-1039 back to Five Prime during 2016. Five Prime will base decisions on further development of FP-1039 in mesothelioma on the quality and duration of responses from the trial, as well as considerations such as drug supply and manufacturing.

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 415-365-5737 Amy Kendall Corporate Communications 415-365-5776

Source:Five Prime Therapeutics, Inc.