The new registration trial follows positive data from the company’s completed Phase Ib/IIa VERTICAL trial as well as the ongoing long-term Extension Study.
The randomized, open-label, Phase III registration VELOCITY trial is carried out in the US, Western Europe and Canada.
Around 136 naive to treatment, pre-pubertal children with GHD are expected to be enrolled in the trial, which will include 3:1 randomization of 3.5 mg/kg VRS-317 semi-monthly to daily rhGH at the highest approved dose on the labels of Genotropin and Norditropin 34 ug/kg/day.
The trial’s primary endpoint is non-inferiority between the two treatment groups for 12 month height velocity.
Following completion of the trial, all patients will be offered the opportunity to continue treatment with VRS-317 in the ongoing pediatric Extension Study.
Versartis chief executive officer Jeffrey Cleland said: "The initiation of our global Phase 3 study in pediatric GHD patients is a significant milestone in our goal of commercializing VRS-317.
"After 12 months of continuous dosing with VRS-317 in our Phase Ib/IIa and Extension Study, we are confident in our trial design and look forward to furthering the development of our lead product candidate as a semi-monthly treatment."
According to the company, six month interim results from the trial are expected to be reported in mid-2016 and final data in early 2017.