Five Prime Therapeutics Advances FPA008 Into Phase 2 Dose Expansion in Patients with Pigmented Villonodular Synovitis (PVNS)

SOUTH SAN FRANCISCO, Calif., May 12, 2016 (GLOBE NEWSWIRE) -- Five Prime Therapeutics, Inc. (Nasdaq:FPRX) a clinical-stage biotechnology company focused on discovering and developing novel protein therapeutics for cancer and inflammatory diseases, today announced the advancement of FPA008 into the Phase 2 dose expansion portion of the ongoing Phase 1/2 trial in PVNS.

“We are very pleased to progress to the Phase 2 portion of this trial evaluating FPA008 as a treatment for patients with PVNS, an orphan joint disease associated with significant morbidity,” said Robert Sikorski, M.D., Ph.D., Senior Vice President of Global Clinical Development at Five Prime. “Macrophages make up the bulk of PVNS tumors due to local over-expression of CSF-1, and we believe FPA008, a CSF-1 inhibitor, has the potential to impact the tumor by blocking the activation and survival of these cells. In the Phase 2 portion of the trial, we will evaluate clinical measures such as response rate, pain and mobility in patients with PVNS, for whom there are currently few options beyond surgery.”

Five Prime initiated patient dosing in this Phase 1/2 clinical trial of FPA008 in July 2015. During the Phase 1 dose escalation part of the trial, Five Prime assessed the safety and pharmacodynamics of multiple ascending doses of FPA008 to determine the dose for expansion. During the Phase 2 expansion, the company will evaluate response rate and duration, as well as measures of pain and range of motion, in approximately 30 patients.

In January 2016, the U.S. Food and Drug Administration (FDA) granted Orphan Drug Designation for FPA008 for the treatment of PVNS, which is estimated to have a prevalence of 25,000 patients in the U.S.

About PVNS
PVNS is a rare, locally aggressive tumor of the synovium. It is characterized by local over-expression of CSF-1, which recruits macrophages into the joints, forming the non-malignant tumor mass. It is associated with high morbidity, and there are no approved therapies for the condition. FPA008 blocks the binding of CSF-1 and inhibits the activity and survival of the macrophages that form the bulk of the tumor. Five Prime is currently in a Phase 2 clinical trial studying FPA008 as a treatment for PVNS.

About FPA008
FPA008 is an investigational antibody that inhibits the CSF-1 receptor and has been shown in preclinical models to block the activation and survival of monocytes and macrophages. Inhibition of CSF1R in preclinical models of several cancers reduces the number of immunosuppressive tumor-associated macrophages (TAMs) in the tumor microenvironment, thereby facilitating an immune response against tumors. FPA008 is currently in a Phase 2 clinical trial in PVNS and a Phase 1 clinical trial in oncology indications. FPA008 is being developed under an exclusive worldwide license and collaboration agreement with Bristol-Myers Squibb (BMS).

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.