=Versartis (VSAR) Phase 3 VELOCITY trial of somavaratan did not meet primary endpoint

• Versartis (VSAR) plunged late Thursday after its pediatric growth-hormone deficiency drug failed in a late-stage trial, sending shares of rival Ascendis Pharma (ASND) soaring.
• Ascendis also has a late-stage drug for the same hormone deficiency.

Versartis Phase 3 VELOCITY trial of somavaratan did not meet primary endpoint; plan to provide a corporate update later this year  

Co announced that the VELOCITY Phase 3 clinical trial of somavaratan in pediatric growth hormone deficiency (GHD) did not meet its primary endpoint of non-inferiority.

• Non-inferiority versus daily growth hormone was not demonstrated in the intent to treat (ITT) population for the primary efficacy variable, height velocity (HV) at 12 months. The 12-month HV for ITT patients receiving somavaratan twice monthly was 9.44 cm, versus 10.70 cm for those receiving Genotropin 1 daily. Non-inferiority was defined as the lower bound of the two-sided 95% confidence interval of the difference between somavaratan and Genotropin HV greater than or equal to -2.0 cm/year. In the ITT study population the lower bound of this confidence interval was -2.3 cm/year. In the per protocol population (PP), non-inferiority was demonstrated. The 12-month HV for PP patients receiving somavaratan twice monthly was 9.71 cm, versus 10.63 cm for those receiving Genotropin daily. Somavaratan was well tolerated with treatment discontinuation rate lower than for the Genotropin arm. No new emergent safety signals were observed.

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Versartis' drug, known as somavaratan, missed its key goal in the trial dubbed Velocity. Over the course of 12 months, patients treated with somavaratan grew 9.44 centimeters in height vs. 10.7 centimeters for patients who received Pfizer's (PFE) growth hormone drug, Genotropin.

Chief Executive Jay Shepard said Versartis is reviewing the results and will provide a corporate update later this year.

Ascendis is also working on pediatric and adult growth-hormone deficiency drugs. The pediatric iteration has begun a Phase 3 trial while the adult version has wrapped up Phase 2 testing. The firm sees these hormone deficiencies as a $3 billion combined market.