Idiopathic Short Stature 111-210

The purpose of this study is to evaluate i) the effect of multiple doses of vosoritide and ii) the effect of the therapeutic dose of vosoritide compared to human growth hormone (hGH), in children with idiopathic short stature (ISS).

Following a minimum 6 month observational period in which baseline growth is assessed, participants in the vosoritide and placebo groups will complete a minimum of 6 months of randomized treatment (maximum of 6 months of placebo treatment), followed by open-label treatment with vosoritide until they reach near-final adult height, or at least 16 years of age for females or 18 years of age for males, whichever comes later. Participants randomized to the hGH group will receive open-label hGH for a minimum of 4 years.