Press Release

Amunix Announces Licensing Agreement for its Proprietary XTEN Technology

Mountain View, CA – [January 21, 2013] – Amunix, Inc., today announced that it has entered into a worldwide research collaboration and licensing agreement with Janssen Biotech, Inc. and its affiliates (“Janssen”). Amunix will combine its XTEN half-life extension technology with protein and/or peptide therapeutics selected by Janssen.

Under the terms of the agreement, Amunix will assist Janssen in the engineering of up to three XTEN fusion proteins. Janssen will be responsible for all preclinical and clinical development as well as for manufacturing and commercialization of the resulting products. Amunix will receive an initial upfront payment in addition to R&D funding and will be eligible for future milestone and royalty payments. Additional financial terms will not be disclosed.

“We are pleased to be collaborating with Janssen,” said Volker Schellenberger, Ph.D., President of Amunix. “Amunix’s XTEN polymer can be combined with a wide range of proteins and peptides. Collaborations such as this are a central element of our strategy to facilitate the use of XTEN in a wide range of therapeutic applications.”

About Amunix

Amunix, Inc., based in Mountain View, CA, is a privately held biotechnology company focused on the discovery and development of novel therapeutics with improved in vivo half-lives. Amunix’s half-life extension technology is based on XTEN, a unique, biodegradable polymer. XTEN is a hydrophilic, unstructured polypeptide that imparts a number of favorable properties upon the molecules to which it is attached. XTEN can be recombinantly fused to protein-based pharmaceuticals or chemically conjugated to peptides, proteins, and other molecules. Besides the advantages of a lower dosing frequency, XTENylation also stabilizes plasma drug concentrations, which can result in increased potency as well as reduced side effects.