Versartis, Inc. Announces Publication of Preclinical Data for Once Monthly Human Growth Hormone Treatment in Journal of Pharmaceutical Sciences

REDWOOD CITY, CA--(Marketwire - June 07, 2012) - Versartis, Inc., an emerging biotechnology company developing novel therapeutics for patients with endocrine disorders, announced today that its manuscript “A Novel Long-Acting Human Growth Hormone Fusion Protein (VRS-317): Enhanced In Vivo Potency and Half-Life” was published in the online edition of The Journal of Pharmaceutical Sciences (7 JUN 2012 | DOI: 10.1002/jps.23229). The peer reviewed publication expands on the extensive preclinical safety and efficacy data for VRS-317, the company’s proprietary once monthly form of recombinant human growth hormone (rhGH). These results, along with preclinical data previously presented, have demonstrated that VRS-317 provides comparable biological activity and safety to daily rhGH with a lower total monthly dose of rhGH and were used as the basis for the company’s Phase 1 clinical trial.

Initial results from the first clinical study of VRS-317 will be discussed in an oral presentation “A Phase 1 Trial of Safety, Pharmacokinetics (PK) and Pharmacodynamics (PD) of a Single Dose of a New Human Growth Hormone Analogue (VRS-317) for Monthly Subcutaneous Administration in Adults with Growth Hormone Deficiency,” on June 25 at ENDO 2012: The 94th Annual Meeting of the Endocrine Society in Houston.

Summary of Published Results

A fundamental limitation of hGH therapies and long acting forms of hGH such as PEGylated hGH products is failure to address the second of two key clearance mechanisms for hGH, glomerular filtration and receptor mediated clearance in the kidneys. In contrast, the novel recombinant human growth hormone (rhGH) fusion protein (VRS-317) was designed to minimize receptor mediated clearance through a reduction in receptor binding without mutations to rhGH by genetically fusing with XTEN amino acid sequences to the N-terminus and the C-terminus of the native hGH sequence. Although in vitro potency of VRS-317 was reduced, in vivo potency was increased due to the greatly prolonged exposure to the target tissues and organs. VRS-317 was 3 fold more potent than daily rhGH in hypophysectomized rats and 5 fold more potent than daily rhGH in juvenile monkeys. In juvenile monkeys, a monthly dose of 1.4 mg/kg VRS-317 (equivalent to 0.26 mg/kg rhGH) caused a sustained pharmacodynamic response for one month equivalent to 0.05 mg/kg/day rhGH (1.4 mg/kg rhGH total over 28 days). In monkeys, VRS-317 had a terminal elimination half-life of approximately 110 hr, was rapidly and near completely absorbed, and was well tolerated with no observed adverse effects after every other week subcutaneous dosing for 14 weeks. VRS-317 also did not cause lipoatrophy in pig and monkey studies. These results indicate that VRS-317 should have a large therapeutic window to ensure selection of a safe and efficacious dose in growth hormone deficient patients.

About Versartis

Versartis, Inc. is a biotechnology company developing therapeutics for the treatment of endocrine disorders. The company’s lead product candidate is VRS-317, a once monthly form of human growth hormone. Versartis is pursuing the development of new therapeutic proteins utilizing the proprietary Amunix half-life extension XTEN technology. XTEN is a novel hydrophilic sequence of natural amino acids and is expressed as a fusion protein with a therapeutically active peptide or protein. New compounds developed by Versartis using the XTEN technology are expected to provide improved therapeutic outcomes such as enhanced efficacy/compliance, fewer side effects, prolonged half-life (up to monthly dosing), as well as low-cost production and enhanced stability. Further information on Versartis can be found at www.versartis.com.