Five Prime Therapeutics Announces Option Exercise by GlaxoSmithKline For A Commercial License To A Novel Muscle Disease Target

Five Prime Therapeutics, Inc.

(Five Prime), a clinical-stage biotechnology company focused on discovering and developing novel protein therapeutics for cancer and inflammatory diseases, announced today that GlaxoSmithKline (GSK) has exercised its option to obtain an exclusive, worldwide license to products containing or directed to an undisclosed muscle disease target that Five Prime discovered using its proprietary library of human extracellular proteins and target screening and discovery capabilities. Five Prime and GSK established the collaboration in 2010 to enable the potential discovery, development and commercialization of drug targets for skeletal muscle diseases using Five Prime's protein target discovery platform. By exercising its option, GSK will receive exclusive rights to develop and commercialize products globally, at its own cost and expense, that incorporate or are directed to the selected target. Five Prime will receive a payment of $1.5 million in connection with the option exercise and is entitled to receive up to $122.5 million in preclinical, development and commercial-related milestone payments and royalties in the low- to mid-single-digit range on net sales of products related to the target. "GSK has thoroughly evaluated this muscle disease target and their decision to obtain an exclusive license further validates the strength of our protein discovery platform to identify novel targets in conditions beyond our internal focal areas of cancer and inflammatory diseases," said Lewis T. "Rusty" Williams, M.D., Ph.D., president and chief executive officer of Five Prime. "This novel target has the potential to result in new treatments for patients suffering from skeletal muscle disorders, many of which are not adequately treated by current therapies."