Amunix hooks Janssen with its XTEN delivery technology

In a worldwide agreement, Janssen Biotech has connected with privately held Amunix to gain access to XTEN, which prolongs the life of proteins and peptides in the bloodstream.

The long, biodegradable XTEN polypeptide is fused to a protein drug, using recombinant technology, or to a peptide, protein or other molecule using chemical conjugation, which lengthens the therapeutic's half-life, by slowing the rate at which it is cleared from the body. This has potential to increase the drug's duration of action and efficacy, and reduce the frequency of dosing and side effects. XTEN can also improve the solubility of drugs, allowing them to be given in a liquid formulation.

Mountain View, CA-based Amunix will work with Janssen to create up to three of its XTEN fusion proteins based on therapeutics of Janssen's choice. Janssen will then carry out preclinical and clinical development, taking any successful drugs right through to the market. The value of the deal hasn't been disclosed, but Amunix will get an upfront payment and R&D funding, as well as milestone and royalty payments.

"We are pleased to be collaborating with Janssen," said Volker Schellenberger, Amunix's president. "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."

Janssen isn't the only company to be working on XTEN-based drugs. In 2008, Amunix created a joint venture with Index Ventures, known as Versartis. After raising money in a Series B round of funding, Versartis moved VRS-317, an XTEN formulation of human growth hormone, into Phase I trials. Diartis Pharmaceuticals, another startup created by Amunix and Index, is developing an XTEN formulation of exenatide (VRS-859), Amylin Pharmaceuticals' diabetes drug Byetta, as a monthly treatment of Type 2 diabetes. This is also in a Phase I trial.

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