Real life long-term efficacy and safety of rhGH therapy in children with SHOX deficiency

Objective: This Italian survey aims to evaluate real-life long-term efficacy and safety of rhGH therapy in children with short stature homeobox-containing gene deficiency disorders (SHOX-D) and to identify potential predictive factors influencing response to rhGH therapy. Design and methods: This is a national retrospective observational study collecting anamnestic, anthropometric, clinical, instrumental and therapeutic data in children and adolescents with a genetic confirmation of SHOX-D treated on rhGH. Data were collected at the beginning of rhGH therapy (T0), yearly during the first 4 years of rhGH therapy (T1, T2, T3, T4) and at near-final height (nFH) (T5), when available. Results: 117 SHOX-D children started rhGH therapy (initial dose 0.23 ± 0.04 mg/kg/week) at a mean age of 8.67 ± 3.33years (74% prepubertal), 99 completed the 1st year of treatment, and 46 reached nFH. During rhGH therapy, growth velocity (GV) SDS and height (H) SDS improved significantly. Mean H SDS gain from T0 was +1.14±0.58 at T4 and +0.80 ± 0.98 at T5. Both patients carrying mutations involving intragenic SHOX region (group A) and ones with regulatory region defects (group B) experienced a similar beneficial therapeutic effect. The multiple regression analysis identified the age at the start of rhGH treatment (β -0.31, p = 0.030) and the GV during the first year of rhGH treatment (β 0.45, p = 0.008) as main independent predictor factors of height gain. During rhGH therapy, no adverse event of concern was reported. Conclusions: Our data confirm the efficacy and safety of rhGH therapy in SHOX-D children, regardless the wide variety of genotype.