Somapacitan, A Once-Weekly Reversible Albumin-Binding Gh Derivative, In Children With Gh Deficiency: A Randomized Dose-Escalation Trial

ObjectiveTo evaluate the safety, local tolerability, pharmacodynamics and pharmacokinetics of escalating single doses of once-weekly somapacitan, a reversible, albumin-binding GH derivative, vs once-daily GH in children with GH deficiency (GHD).DesignPhase 1, randomized, open-label, active-controlled, dose-escalation trial (NCT01973244).PatientsThirty-two prepubertal GH-treated children with GHD were sequentially randomized 3:1 within each of four cohorts to a single dose of somapacitan (0.02, 0.04, 0.08 and 0.16mg/kg; n=6 each), or once-daily Norditropin((R)) SimpleXx((R)) (0.03mg/kg; n=2 each) for 7days.MeasurementsPharmacokinetic and pharmacodynamic profiles were assessed.ResultsAdverse events were all mild, and there were no apparent treatment-dependent patterns in type or frequency. Four mild transient injection site reactions were reported in three of 24 children treated with somapacitan. No antisomapacitan/anti-human growth hormone (hGH) antibodies were detected. Mean serum concentrations of somapacitan increased in a dose-dependent but nonlinear manner: maximum concentration ranged from 21.8ng/mL (0.02mg/kg dose) to 458.4ng/mL (0.16mg/kg dose). IGF-I and IGFBP-3, and change from baseline in IGF-I standard deviation score (SDS) and IGFBP-3 SDS, increased dose dependently; greatest changes in SDS values were seen for 0.16mg/kg. IGF-I SDS values were between -2 and +2 SDS, except for peak IGF-I SDS with 0.08mg/kg somapacitan. Postdosing, IGF-I SDS remained above baseline levels for at least 1week.ConclusionsSingle doses of once-weekly somapacitan (0.02-0.16mg/kg) were well tolerated in children with GHD, with IGF-I profiles supporting a once-weekly treatment profile. No clinically significant safety/tolerability signals or immunogenicity concerns were identified.