Five Prime Therapeutics Provides an Update on Its Strategic Discovery Collaborations With Pfizer and GlaxoSmithKline

FivePrime Concludes Strategic Collaboration With Pfizer to
Discover Innovative Biologics for Oncology and Diabetes

FivePrime and GlaxoSmithKline Expand Strategic Collaboration to
Discover Innovative Biologics for Skeletal Muscle Disorders

SOUTH SAN FRANCISCO, California, June 16, 2011 (GLOBE NEWSWIRE) -- Five Prime Therapeutics, Inc. (FivePrime), a leader in the discovery and development of innovative biologics, announced today the completion of the three-year funded research program with Pfizer Inc. PFE, that began in 2008 and focused on the discovery of antibody targets and novel therapeutic protein products to treat multiple cancer indications and diabetes. During the three-year research program, FivePrime designed and conducted cell-based and primary in vivo screens against FivePrime's comprehensive library of extracellular proteins and successfully identified numerous targets that may lead to future protein or antibody candidates. FivePrime screened more than 1,000 extra-cellular domains of receptor proteins in vivo in animal models of disease as part of the research program. FivePrime also conducted target validation work and advanced studies of leads and targets identified in the research program. 

The numerous oncology and diabetes targets identified by FivePrime in the course of the research program provide a pool of potential opportunities for Pfizer's and FivePrime's drug research and development activities. FivePrime continues to work independently on several of the targets from the collaboration with the goal of advancing protein or antibody therapeutics against these targets into preclinical development.

Additionally, GlaxoSmithKline GSK and FivePrime have agreed to expand the scope of their discovery collaboration to include FivePrime's Rapid In vivo Protein Production System (RIPPS^SM) technology for a large-scale in vivo screen for potential drug targets or drug candidates that modulate muscle wasting. As part of the expansion of the collaboration, FivePrime is eligible to receive from GSK additional research payments, milestone payments and potential option exercise fees, as well as royalties on global net sales for each product resulting from a selected drug target or drug candidate that results from the research program.

FivePrime entered into its Research Collaboration and License Agreement with GSK in July 2010. Under the collaboration agreement, FivePrime is responsible for conducting high-throughput in vitro and in vivo assays against its comprehensive library of extracellular proteins to identify potential drug targets and drug candidates for treating skeletal muscle diseases. GSK has the option to exclusively license each drug target or drug candidate discovered by FivePrime from the collaboration and take on sole responsibility for additional preclinical studies, clinical development, manufacturing and worldwide commercialization.

About FivePrime

Five Prime Therapeutics, Inc. is a clinical-stage, privately held, biotechnology company discovering and developing innovative protein and antibody therapeutics. Using its integrated discovery platform, FivePrime is building a strong pipeline of oncology and immunology drug candidates. FivePrime mines its comprehensive library of secreted and extracellular human proteins to screen for medically relevant new therapeutic proteins and antibody targets. FivePrime has entered into a collaboration agreement to develop and commercialize its lead product, FP1039, with Human Genome Sciences, Inc. in the United States, Canada and the EU. FivePrime has also established significant collaborations for the discovery of innovative biologics in specific therapeutic areas with several leading pharmaceutical companies, including Pfizer, Centocor and GlaxoSmithKline. For more information about FivePrime, please visit FivePrime's web site at www.fiveprime.com.