Somapacitan safe, effective in children with growth hormone deficiency

Use of somapacitan, a long-acting growth hormone (GH) derivative, for 2 years is efficacious and well tolerated in prepubertal children with GH deficiency (GHD), reports a study.

In addition, patients and their caregivers prefer treatment with somapacitan once weekly over daily GH. They have indicated as well that they would be more adherent to the weekly rather than the daily treatment regimen.

“Somapacitan in children with GHD showed sustained efficacy and tolerability for 2 years, and after switching from daily GH,” the investigators said. “Patients/caregivers switching from daily GH expressed a preference for somapacitan.”

This randomized, multinational, open-label, controlled parallel group phase III trial was conducted in 85 sites across 20 countries and comprised a 52-week main phase and a 3-year safety-extension. A total of 200 treatment-naïve prepubertal patients were randomly assigned 2:1 to somapacitan (0.16 mg/kg/wk) or daily GH (0.034 mg/kg/d) during the first year, after which all received somapacitan.

Of the participants, 194 completed the 2-year study. Height velocity (HV) was sustained in both groups between weeks 52 and 104, with a mean HV of 8.4 cm/year after continuous somapacitan treatment and 8.7 cm/year after 1 year of somapacitan treatment after switch from daily GH. [J Clin Endocrinol Metab 2023;108:3090-3099]

Other height-related endpoints also demonstrated sustained growth. Over 2 years, the mean IGF-I SD score was within normal range (‒2 to 2) and comparable between the two groups. In addition, somapacitan showed good tolerability, with no safety issues arising.

Finally, most patients and caregivers (90 percent) who switched treatment at year 2 expressed preference for somapacitan once weekly over daily GH treatment.

“The preference for once-weekly somapacitan over daily GH reported here by caregivers is due to a variety of different reasons,” the investigators said. “These include the child being less worried or less annoyed by injections as well as experiencing less pain and once-weekly injections infringing less on the plans of the patient and/or parents/caregivers.”

These findings are consistent with treatment burden questionnaires reported at 52 weeks in REAL4 and in REAL3 studies, in which patient/caregiver responses were in favour of 0.16 mg/kg/wk somapacitan over daily GH treatment in terms of impact on physical functioning and emotional and social well-being. [J Clin Endocrinol Metab 2022;107:3378‐3388; J Clin Endocrinol Metab 2020;105:e1847‐e1861]

“One of the main objectives for developing a long-acting GH to treat GHD in children is to establish a less burdensome dosing regimen that is as efficacious and safe as existing daily GH replacement therapy,” the investigators said.

Several randomized clinical studies in children had previously reported that once-weekly somapacitan had similar efficacy and safety profiles to those of daily GH. [J Clin Endocrinol Metab 2021;107:1357‐1367; Eur J Endocrinol 2023;188:lvac008; J Clin Endocrinol Metab 2023;108:2569-2578]

“Although adherence in controlled clinical trials is high, reducing the number of injections required with somapacitan will potentially improve adherence and decrease barriers to initiating and maintaining replacement therapy in a real-world setting and thereby improve treatment outcomes,” according to the investigators.