P4.A013: Sustained Efficacy of Weekly Somapacitan in Children With GHD: 3-year Results From Phase 3 REAL4 Study

Background: Growth hormone (GH) replacement therapy for children with GH deficiency (GHD) traditionally required daily subcutaneous injections. Somapacitan (Novo Nordisk A/S) is a reversible albumin-binding GH derivative administered once-weekly and the only long-acting GH (LAGH) approved for the treatment of both adults and children with GHD.

Methods: REAL4 is a randomized, open-label, multi-national, phase 3 trial, consisting of a 52-week main phase and a three-year (week 52 to 208) extension period (NCT03811535). The trial included 200 GH-treatment-naïve, prepubertal children with GHD. Participants received either once-weekly somapacitan (0.16 mg/kg; n=132) or once-daily GH (Norditropin® 0.034 mg/kg; n=68) for 52 weeks. Afterwards, participants receiving daily GH switched to 0.16 mg/kg/week somapacitan (switch group), while those receiving somapacitan continued treatment (soma/soma group). Growth-related endpoints included height velocity (HV), HV standard deviation score (SDS), height SDS, and bone age. The 3-year (156-week) results are presented here.

Results: A total of 188 participants (125 in the soma/soma group and 63 in the switch group) completed 3 years of treatment. Improvements in HV, HV SDS, height SDS, and bone age were similar between the groups. In year 3 (week 104 to 156), mean (SD) HV was 7.4 (1.5) cm/year in the soma/soma group and 7.8 (1.4) cm/year in the switch group. The mean (SD) change in height SDS from baseline to week 156 was 2.04 (0.85) in the soma/soma group and 2.38 (1.14) in the switch group, with mean (SD) height SDS at week 156 of -0.95 (0.98) and -1.08 (0.93) in the soma/soma and switch groups, respectively. Mean BMI SDS remained within normal range in both groups at week 156. No safety or tolerability issues were identified. During the extension period (week 52 to 156), a low proportion of the participants reported injection site reactions. No neutralizing antibodies were detected at any of the visits.

Conclusion: Once-weekly somapacitan showed sustained efficacy and tolerability for three years, as well as for two years following the switching from daily GH treatment in this pivotal phase 3 REAL4 trial. The safety profile of somapacitan was similar to the well-known safety profile of daily GH.