A Phase 2 Study of Vosoritide in Children With Idiopathic Short Stature

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)(hGH; only in the United States), 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.

Key Inclusion Criteria: 1. Height assessment corresponding to a height Z-score of ≤ -2.25 SDs in reference to the general population of the same age and sex, as calculated using the Centers for Disease Control and Prevention (CDC) growth charts 2. Tanner Stage 1, at time of signing the ICF (unless too young to stage). Key Exclusions: 1. Known chromosomal imbalance or genetic variant causing short stature syndrome, including but not limited to Laron syndrome, Prader-Willi syndrome, Russell-Silver Syndrome, Turner syndrome, disproportionate skeletal dysplasias, abnormal SHOX gene analysis, or Rasopathy (including Noonan syndrome) 2. Previous treatment with a growth promoting agent