Alkermes, Inc and Acceleron Pharma, Inc announced that Alkermes has licensed a proprietary long-acting Fc fusion technology platform, called the Medifusion technology, which is designed to extend the circulating half-life of proteins and peptides. The first drug candidate being developed with this technology is a long-acting form of a TNF receptor-Fc fusion protein for the treatment of rheumatoid arthritis (RA) and related autoimmune diseases. The TNF receptor-Fc fusion protein is structurally similar to etanercept, commercially known as Enbrel, which had worldwide sales of nearly US$ 6 billion in 2008.

Under the terms of the agreement, Alkermes will have worldwide rights to the Medifusion technology in return for an upfront payment and equity investment in Acceleron as well as future development, regulatory and sales milestones and royalties on product sales. Acceleron will retain all rights to the technology for products derived from the TGF-beta superfamily. As part of the agreement, Acceleron will develop up to two selected drug compounds using the Medifusion technology through preclinical studies, at which point Alkermes will assume responsibility for all clinical development and commercialization of these two compounds and any other compounds Alkermes elects to develop resulting from the platform.

"We are very pleased to have in-licensed this novel and broadly applicable technology from Acceleron and look forward to applying this new technology to develop a long-acting TNF candidate," commented Richard Pops, chief executive officer of Alkermes. "In addition to this lead product candidate, we believe there are several other important protein therapeutics for which we can use the Medifusion platform to develop long-acting products that may offer valuable new treatment options for patients."

ALKS 6931, the lead candidate from the Medifusion platform, is a fusion protein of a soluble TNF receptor with the Fc component of human immunoglobulin G1. In vivo studies have shown a significantly extended half-life of ALKS 6931 beyond the half-life of etanercept. Alkermes expects to file an Investigational New Drug Application (IND) for ALKS 6931 in 2010.

"We believe this technology platform for fusion protein optimization could have a major impact on people required to take injections on a frequent basis, and that Alkermes is the ideal collaborator as the clear leader in the development of novel long-acting therapeutics," commented John Knopf, chief executive officer and Founder of Acceleron. "Acceleron has advanced three internally discovered fusion proteins into human clinical trials, each of which is based on our knowledge and expertise in fusion protein optimization. We believe Alkermes will be a great partner to generate value from this promising Fc fusion protein platform."

Alkermes is a fully integrated biotechnology company committed to developing innovative medicines to improve patients' lives.

Acceleron is a privately held biopharmaceutical company committed to discover, develop, manufacture and commercialize novel biotherapeutics that modulate the growth of red blood cells, bone, muscle, fat and the vasculature to treat musculoskeletal, metabolic and cancer-related diseases.