Biogen exercises option to enter into exclusive, worldwide License Agreement for Factor IX utilizing Amunix’ XTEN® half-life extension technology

MOUNTAIN VIEW, CA–(Marketwired – January 05, 2017) –Amunix Operating Inc. announced today that Biogen (NASDAQ: BIIB)has exercised its option to enter into an exclusive, worldwide license agreement to develop and commercialize a novel, recombinant Factor IX product candidate that incorporates Amunix’ XTEN technology to provide extended half-life.The agreement is part of Biogen’s hemophilia business, which is expected to launch as Bioverativ on February 1, 2017 as an independent, public company focused on the discovery, research, development and commercialization of treatments for hemophilia and other rare blood disorders.

Under the terms of the agreement, Amunix will receive an upfront $1.25 million payment and will also be eligible to receive up to $17.25 million in clinical and commercial milestone payments. In addition, royalties will be paid on commercial sales from Factor IX products incorporating Amunix’ proprietary XTEN technology.

In March 2011, Amunix and Biogen initiated a Research and Option Agreement under which both companies would collaborate to combine Amunix’ expertise in protein half-life extension and its proprietary XTEN technology with Biogen’s expertise in both hemophilia and engineering long-lasting coagulation factors. Biogen, or its planned spin-out company Bioverativ, will be responsible for developing, manufacturing and commercializing therapeutic product candidates resulting from the collaboration.

“The ongoing research collaboration with Biogen has resulted in the discovery of molecules that retain procoagulant activity while exhibiting significantly improved half-life in animal models,” said Volker Schellenberger, PhD, Amunix President and Chief Executive Officer. “Fruitful collaborations such as the one with Biogen, which will now continue with Bioverativ, are a central element of Amunix’ strategy to facilitate the use of XTEN in a wide range of therapeutic applications.”

About Amunix

Amunix, based in Mountain View, CA, is a privately held biotechnology company focused on the discovery and development of biologics with improved in vivo half-lives. Amunix’ half-life extension technology is based on XTEN — hydrophilic, unstructured, biodegradable proteins that impart a number of favorable properties upon the molecules to which they are attached. XTEN can be recombinantly fused or chemically conjugated to peptides, proteins, and other pharmaceuticals. In addition to the advantages of reduced dosing frequency, XTENylation also stabilizes plasma drug concentrations, which often results in increased efficacy as well as reduced side effects. Two genetically fused XTENylated products have been tested clinically. VRS-859 (exenatide-XTEN) has been tested through Phase I in the treatment of diabetes and VRS-317 (human growth hormone-XTEN) is currently in Phase IIItesting. Amunix is also working with additional partners, including Eli Lilly, Bioverativ, Roche, Janssen, Naia and other undisclosed companies in a wide range of therapeutic areas.

Amunix is developing an internal pipeline of ProTIA (Protease Triggered Immune Activator) immuno-oncology therapeutics. ProTIAs are bispecific molecules that bind tumor antigens and T cells. ProTIAs are administered as long-acting prodrugs that can be activated in the tumor environment by tumor-associated proteases. Amunix is actively seeking partnerships for applications of its XTEN technology and its ProTIA platform. For additional information about the company, please visit

Volker Schellenberger, Ph.D.
President and CEO
Tel: 650-889-5095