Somapacitan in children with idiopathic short stature: a randomized controlled phase 3 study

OBJECTIVE: Daily growth hormone (GH) injections restore normal growth and improve psychological outcomes in children with idiopathic short stature (ISS) but treatment burden is significant. The objective of this study is to demonstrate efficacy and safety of once-weekly somapacitan, a long-acting GH, in children with ISS. DESIGN: REAL8 (ClinicalTrials.gov: NCT05330325) is a global, randomized, open-labelled, active-comparator, phase 3 basket study including 4 non-GH deficiency indications comprising a 52-week main phase and 104-week extension. Here, we present 52-week results from the REAL8 ISS study. METHODS: Eighty-eight pre-pubertal, treatment-naive children with ISS at clinics in 20 countries were randomized 2:1 to somapacitan .24 mg/kg/week or daily GH 0.050 mg/kg/day, both administered subcutaneously. Eighty-five children completed the main 52-week treatment period. RESULTS: Observed mean height velocity, HV, (SD) at week 52 was 10.2 (1.7) and 10.6 (1.6) cm/year for somapacitan and daily GH groups, respectively (estimated treatment difference [ETD]: -0.3 cm/year [-1.00;0.42]95%CI, non-inferiority confirmed). Safety profiles were similar (somapacitan: 191 events in 47 (79.7%) participants, daily GH: 87 events in 22 (78.6%) participants) with most adverse events (AEs) mild and unlikely related to study product. Disease and treatment burden questionnaires presented favourable results. CONCLUSIONS: Similar efficacy and safety were confirmed for once-weekly somapacitan versus daily GH in treatment-naïve children with ISS, with favourable patient-reported outcome measures, setting the ground for future treatment for ISS with a once-weekly option. CLINICAL STUDY REGISTRATION: NCT05330325.