XTEN Technology

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XTEN Technology

Powered By A Novel Half-Life Extension Technology

Versartis’ lead product candidate, somavaratan (VRS-317), is a fusion protein consisting of recombinant human growth hormone (rhGH) and a proprietary half-life extension technology known as XTEN®.

The novel XTEN Technology, developed by Amunix Operating, Inc., is designed to extend the time that somavaratan remains in the body, and has been demonstrated to prolong rhGH treatment effect. This prolonged treatment effect may benefit patients by allowing for twice-monthly dosing of somavaratan. This more convenient dosing schedule may improve treatment adherence, and therefore, long-term outcomes.

The Science Behind XTEN

The XTEN Technology used in somavaratan works by extending the in vivo half-life of the rhGH molecule with two unique XTEN sequences. The long tail of hydrophilic amino acids (XTEN1) helps to reduce kidney filtration and the short tail of amino acids (XTEN2) helps to reduce receptor-mediated clearance of somavaratan. As a result, somavaratan has a much longer half-life than any marketed rhGH while retaining its biological activity.

XTEN® is a registered trademark of Amunix Operating, Inc.

  • Cleland, et al. J Pharma Sci, August 2012, 101(8):2744-2754.
  • Moore, et al. J Clin Endocrinol Metab. 2016;101(3):1091-1097.

3D rendering of Somavaratan (VRS-317)