Abstract
Growth hormone (GH) replacement therapy currently requires daily injections. Somapacitan is a long-acting GH-derivative being developed for once-weekly (OW) use in children and adults with GH deficiency (GHD). A phase 2, multinational, randomized, open-label, controlled trial (ClinicalTrials.gov: NCT02616562) investigated the efficacy and safety of OW somapacitan compared with daily GH (Norditropin® FlexPro®). GH-treatment-naïve prepubertal children with GH deficiency received 0.04 (n=16), 0.08 (n=15) or 0.16 mg/kg/wk (n=14) subcutaneous (sc) OW somapacitan, or sc GH 0.034 mg/kg/day (0.24 mg/kg/wk; n=14) for 52 wks, followed by a 104-wk safety extension with all patients on somapacitan receiving 0.16 mg/kg/wk while GH dose was unaltered. Safety endpoints included frequency of adverse events (AEs), including injection-site reactions, and occurrence of anti-somapacitan/anti-human growth hormone (hGH) antibodies. The 52-wk efficacy and safety results have been reported. We report here safety results at 104 wks’ total treatment. Number of AEs (% of patients) was as follows: OW somapacitan 0.04/0.16 mg/kg/wk, 51 (75%); 0.08/0.16 mg/kg/wk, 89 (80%); 0.16/0.16 mg/kg/wk, 89 (100%); and for daily GH, 82 (100%). Nasopharyngitis, influenza, allergic rhinitis and gastroenteritis were the most common AEs across all treatment groups. Pyrexia was more common in the OW somapacitan 0.04/0.16 mg/kg/wk (43.8%) and 0.08/0.16 mg/kg/wk (26.7%) groups vs the higher-dose OW somapacitan and daily GH groups (7.1% each). Most AEs were mild to moderate and unlikely related to treatment. Ten serious AEs were reported in five (8.5%) children and unlikely related to treatment, except two AEs of moderate severity during the first 26 wks: generalized edema and vomiting in one child on 0.16 mg/kg/wk OW somapacitan, rated as probably related to treatment although she was also given intravenous antibiotics for suspected infection. Injection-site reactions were reported in the 0.04/0.16 mg/kg/wk (n=2) and 0.16/0.16 mg/kg/wk (n=1) OW somapacitan groups and in the daily GH group (n=1). Four children (0.04/0.16 mg/kg/wk) and one child (0.16/0.16 mg/kg/wk) had transient anti-somapacitan antibodies; one child (0.16/0.16 mg/kg/wk) had low-titer anti-somapacitan antibodies at two consecutive visits; in one child (daily GH group) with persistent low-titer anti-hGH antibodies, treatment was discontinued at wk 52. All antibodies were non-neutralizing. In conclusion, OW somapacitan was well tolerated at all doses, with no new safety or tolerability issues identified after up to 104 wks of treatment. The frequency, severity and type of AEs were similar in the OW somapacitan and daily GH treatment groups except for pyrexia, which was unlikely related to treatment and more frequently reported in the lowest dose somapacitan group.
Long-Term Effect of Growth Hormone (GH) Treatment on Body Composition in Children with GH Deficiency
