A Four-Year, Open-Label, Multi-Center, Randomized, Two-Arm Study of Genotropin® in Patients with Idiopathic Short Stature: Comparison of an Individualized, Target-Driven Treatment Regimen to Standard Dosing of Genotropin® - Analysis of Two-Year Data

Abstract

Background: Several models have been developed to predict growth response to growth hormone (GH) based on auxological and biochemical parameters for children with non-GH-deficient, idiopathic short stature (ISS). Objective: To demonstrate if an individualized, formula-based, target-driven GH regimen for children with ISS would lead to a height (Ht) gain to -1.3 SDS during the first 24 months of treatment of this 4-year study, with less variability than with standard weight-based dosing. Methods: A 4-year, open-label, multi-center, randomized, two-arm study comparing formula-based dosing of Genotropin® GH from 0.18 to 0.7 mg/kg/week versus standard FDA-approved ISS dosing of Genotropin® (0.37 mg/kg/week). Subjects (n = 316, 89 females) were prepubertal, 3-14 years of age, bone age 3-10 years (m) and 3-9 years (f), naive to GH treatment, Ht SDS -3 to -2.25, Ht velocity <25th percentile for bone age, and peak GH >10 ng/ml. Results: The majority (83%) of subjects had Ht SDS within the normal range by 2 years. All subjects displayed catch-up growth consistent with other studies of GH treatment of ISS. Conclusion: The formula-based therapy did not meet the primary endpoint achieving targeted gain with lower variability. No new safety concerns were found.