A long-acting form of rhGH in development for GHD

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Addressing the need for long-acting

Somavaratan: an investigational, novel, long-acting form of recombinant human growth hormone (rhGH) in development for the treatment of growth hormone deficiency (GHD)1

Somavaratan is designed to have an increased half-life

Long-acting forms of rhGH may improve adherence to treatment regimens in patients with GHD. Somavaratan is a fusion protein consisting of unmodified rhGH and 2 domains constructed with XTEN® technology intended to prolong rhGH treatment effect.1,2

XTEN regions in somavaratan result in significantly prolonged drug exposure1,3

Through 2 distinct mechanisms, XTEN extends the time that somavaratan remains in the body

  • The XTEN1 domain adds bulk to the molecule by increasing the hydrodynamic size of the rhGH, which may result in reduced kidney clearance
  • The XTEN2 domain modulates binding to the growth hormone receptor, potentially reducing receptor-mediated clearance

Somavaratan is produced as a single soluble molecule

  • XTEN sequences consist of genetically encoded amino acids that are recombinantly fused to the rhGH sequence
  • These genetic fusion constructs can be expressed, purified, and characterized conveniently as a single molecule

Somavaratan is an investigational new drug that has not been approved for sale in any country.

See how somavaratan works

The extended half-life of somavaratan prolongs biological activity and the duration of treatment effect.1,3

XTEN is a registered trademark of Amunix Operating, Inc.

1. Podust VN, Balan S, Sim BC, et al. Extension of in vivo half-life of biologically active molecules by XTEN protein polymers. J Control Release. 2015;240:52-66. doi:10.1016/j.jconrel.2015.10.038.
2. Moore WV, Nguyen HJ, Kletter GB, et al. A randomized safety and efficacy study of somavaratan (VRS-317), a long-acting rhGH, in pediatric growth hormone deficiency. J Clin Endocrinol Metab. 2016;101(3):1091-1097. doi:10.1210/jc.2015-3279.
3. Cleland JL, Geething NC, Moore JA, et al. A novel long-acting human growth hormone fusion protein (VRS-317): enhanced in vivo potency and half-life. J Pharm Sci. 2012;101(8):2744–2754. doi:10.1002/jps.23229.