Endocrine Abstracts

Somapacitan is a long-acting, reversible albumin-binding growth hormone (GH) derivative. The objective of this trial was to evaluate the safety, efficacy and treatment satisfaction of onceweekly somapacitan versus daily GH (Norditropin) over 52 weeks in Japanese patients with adult GH deficiency (AGHD). This was a phase 3, multicentre, randomised, open-label, parallel-group, active-controlled trial (NCT03075644). Patients previously treated with GH were randomised 1:3 to daily GH or somapacitan, to undergo 20 weeks of dose titration and 32 weeks of fixed-dose treatment. The primary endpoint was the incidence of adverse events (AEs) from baseline to week 53. Secondary endpoints included change from baseline in visceral, subcutaneous and total adipose tissue (VAT, SAT and TAT, respectively) assessed with computerised tomography scans; change from baseline in treatment satisfaction, evaluated using Treatment Satisfaction Questionnaire for Medication (TSQM-9) scores; andoccurrence of anti-somapacitan antibodies. In total, 62 patients were randomised (daily GH n = 16; somapacitan n = 46); 60 patients completed the trial. Baseline characteristics for daily GH versus somapacitan groups, respectively, were: female, 43.8% vs 47.8%; adult-onset GHD, 87.5% vs 80.4%; mean (s.d.) age, 49.3 (11.5) vs 54.1 (12.1) years; weight 67.9 (12.0) vs 69.4 (22.7) kg; body mass index 24.8 (3.7) vs 26.4 (6.7) kg/m²; and GH dose at screening 0.29 (0.14) vs 0.31 (0.17) mg. Rate of AEs per 100 patient-years was similar between treatment arms (daily GH, 309.8; once-weekly somapacitan, 312.7). Most AEs were mild (97.9% and 93.1%, respectively); none were severe. Four AEs in the somapacitan arm were serious; all were considered unlikely related to treatment. No anti-somapacitan antibodies were detected during treatment. Mean insulin-like growth factor-I standard deviation score (IGF-I SDS) at baseline was maintained with both treatments. Most patients had IGF-I SDS values <+2. No significant differences in VAT, SAT and TAT were seen in either treatment group after 52 weeks (estimated difference, somapacitan – daily GH [95% CI]): –1.74 [–18.13; 14.66], –11.53 [–35.54; 12.48], and –12.85 [–47.31; 21.62] cm², respectively. TSQM-9 scores were not significantly different between treatments, but showed a tendency in favour of somapacitan (estimated difference [95% CI]): 4.87 [–3.46; 13.20] for effectiveness, 6.79 [–1.04; 14.61] for convenience, and 6.88 [–1.08; 14.85] for overall satisfaction. No new safety concerns were identified. Improvements in body composition were similar in both cohorts. The safety and tolerability of somapacitan in Japanese patients with AGHD were consistent with results from the global phase 3 trial (REAL 1).