News Release

Amunix presents XTEN half-life extension technology at Next Generation Protein Therapeutics Summit

Peer-Reviewed Publication

Debra Bannister

Mountain View, CA – June 5, 2014 – Amunix Operating Inc. said today it is presenting unpublished data from its XTEN half-life extension technology development programs during two sessions this week at IBC's 9th Annual Next Generation Protein Therapeutics Summit in San Francisco, CA. Amunix is a biotechnology company developing hydrophilic, unstructured polypeptides which can be recombinantly fused or chemically conjugated to other peptides, proteins and small molecules.

Vladimir N. Podust, PhD, Director of Analytical Chemistry, Amunix Operating Inc., will present "Extension of in vivo Half-Life of Biologically Active Molecules via Chemical Conjugation to XTEN Protein Polymer" today at 11 am during the section titled "Alternative Scaffolds and Delivery Strategies."

XTEN (unstructured biodegradable polypeptides) have been used to extend the half-life of genetically fused therapeutic proteins and peptides. To expand the applications of XTEN technology to half-life extension of other classes of molecules, XTEN protein polymers and methods for chemical XTENylation were developed. Monovalent, multivalent and bispecific XTEN conjugates with various payloads have been synthesized and tested for their biological activities.

The presentation will show an efficient method of synthesis of targeted XTEN-drug conjugates, exemplified by folate as a targeting moiety and DM1 as a chemical toxin. The modular synthetic approach allows investigation of the effects of valency and polymer length, as well as the nature of the toxic payload to select the most potent product format for each indication.

Volker Schellenberger, PhD, Amunix President and Chief Executive Officer, will present "XTEN – A Biodegradable Alternative to PEG Enabling Biopharmaceuticals with Precisely Controlled Structure and Valency" tomorrow, June 6 at 9:15 am during the section titled "Alternatives to PEG for Plasma Half-Life Extension."

Amunix has developed XTEN, a protein-based polymer that mimics the biophysical properties of PEG. XTEN is easily metabolized, thereby eliminating the risk of tissue accumulation. Single or multiple payloads can be conjugated or genetically fused to XTEN which allows the generation of monospecific, bispecific, as well as multivalent biopharmaceuticals.

This presentation will focus on the ability to customize XTEN for each application to enable discovery of long-acting biologics with best-in-class product attributes. Amunix's technology allows one to include multiple XTEN polymers into a single product while maintaining precise positional control of each insertion site. Each insertion site and the length of inserted XTEN can be optimized to maintain or enhance biological activity while achieving increased duration of action of the resulting product. Examples of XTENylated biologics with class-leading duration of action will be shown.


About Amunix

Amunix Operating Inc., a biotechnology company headquartered in Mountain View, CA, has developed a novel half-life extension technology based on XTEN; hydrophilic, unstructured polypeptides which can be recombinantly fused or chemically conjugated to other peptides, proteins and small molecules. Through this proprietary XTEN technology, the company creates and develops novel versions of clinically-proven pharmaceutical products that may offer better efficacy, safety and dosing frequency by extension of the half-life. Two XTEN products – Exenatide-XTEN (VRS-859) and hGH-XTEN (VRS-317) – have completed Phase 1 studies through Amunix partners Diartis and Versartis, respectively. Versartis is currently conducting a Phase 2a study with VRS-317 in pediatric growth hormone deficient patients. In addition, through its partnership with Biogen Idec, Amunix is developing Factor VIII and is working with Janssen Biotech, Inc. and its affiliates to apply the XTEN half-life extension technology with protein and/or peptide therapeutics selected by Janssen. Amunix has several other undisclosed partners in various therapeutic areas. Founded in 2006, Amunix is a profitable, independent biotechnology company with no external investors. Amunix is actively seeking partnerships for application of its XTEN technology. For additional information about the company, please visit

Amunix Media Contact:
Debra Catz Bannister
530 676-7373

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