Five Prime Therapeutics Announces The Presentation of Preliminary FPA008 Phase 1 Trial Data in Rheumatoid Arthritis Patients at the 2015 ACR Annual Meeting

Five Prime Therapeutics, Inc.

, a clinical-stage biotechnology company focused on discovering and developing novel protein therapeutics for cancer and inflammatory diseases, today announced that preliminary data from rheumatoid arthritis (RA) patients in part 3 of Five Prime's ongoing Phase 1 trial of FPA008 will be presented during the upcoming 2015 American College of Rheumatology (ACR)/Association of Rheumatology Health Professionals Annual Meeting, to be held November 7-11, 2015 in San Francisco. FPA008 is Five Prime's anti-CSF1R antibody that blocks the binding of CSF1 and IL34 ligands to CSF1R, resulting in inhibition of the activation and survival of inflammatory macrophages and osteoclasts. Abstract #2749 entitled, "A Phase 1 Study of FPA008, an Anti-Colony Stimulating Factor 1 Receptor (anti-CSF1R) Antibody in Patients (pts) with Rheumatoid Arthritis (RA): Preliminary Results," is accessible on the meeting website and includes data as of May 13, 2015. The poster presentation will take place during the session, Rheumatoid Arthritis - Small Molecules, Biologics and Gene Therapy Poster III, scheduled from 9:00-11:00 am Pacific Time on Tuesday, November 10, 2015. The poster is expected to include study data up to October 2015, which will be detailed in a press release during the conference. The Phase 1 clinical trial of FPA008 is being conducted in three parts. Parts 1 and 2 involved dose administration and escalation in healthy volunteers and data on safety, pharmacokinetics, and biomarkers from this portion of the study were presented during the 2014 ACR Annual Meeting. Part 3 of the trial consists of an open-label evaluation of 3 dose levels of FPA008 in combination with methotrexate in RA patients whose disease is not responding to methotrexate therapy. The primary endpoint of the trial is safety, with secondary endpoints including PK, pharmacodynamics (PD) and disease activity as measured by ACR scores and joint MRI.