Once-weekly Somapacitan is Effective and Well Tolerated in Adults with GH Deficiency: A Randomized Phase 3 Trial.

CONTEXT: Growth hormone (GH) replacement requires daily GH injections, which is burdensome for some adult patients with GH deficiency (AGHD). OBJECTIVE: To demonstrate efficacy and safety of somapacitan, a once-weekly reversible albumin-binding GH derivative, versus placebo in AGHD. DESIGN: Randomized, parallel-group, placebo-controlled (double-blind) and active-controlled (open-label) phase 3 trial, REAL 1 (NCT02229851). SETTING: Clinics in 17 countries. PATIENTS: Treatment-naïve patients with AGHD (n = 301 main study period, 272 extension period); 257 patients completed the trial. INTERVENTIONS: Patients were randomized 2:2:1 to once-weekly somapacitan, daily GH, or once-weekly placebo for 34 weeks (main period). During the 52-week extension period, patients continued treatment with somapacitan or daily GH. MAIN OUTCOME MEASURES: Body composition measured using dual-energy x-ray absorptiometry (DXA). The primary endpoint was change in truncal fat percentage to week 34. Insulin-like growth factor 1 (IGF-I) standard deviation score (SDS) values were used to dose titrate. RESULTS: At 34 weeks, somapacitan significantly reduced truncal fat percentage (estimated difference: -1.53% [-2.68; -0.38]; P = 0.0090), demonstrating superiority compared with placebo, and it improved other body composition parameters (including visceral fat and lean body mass) and IGF-I SDS. At 86 weeks, improvements were maintained with both somapacitan and daily GH. Somapacitan was well tolerated, with similar adverse events (including injection-site reactions) compared with daily GH. CONCLUSIONS: In AGHD patients, somapacitan administered once weekly demonstrated superiority over placebo, and the overall treatment effects and safety of somapacitan were in accordance with known effects and safety of GH replacement for up to 86 weeks of treatment. Somapacitan may provide an effective alternative to daily GH in AGHD. A short visual summary of our work is available (1).

Safety and convenience of once-weekly somapacitan in adult GH deficiency: a 26-week randomized, controlled trial.

OBJECTIVE: Somapacitan is a reversible albumin-binding growth hormone (GH) derivative, developed for once-weekly administration. This study aimed to evaluate the safety of once-weekly somapacitan vs once-daily Norditropin®. Local tolerability and treatment satisfaction were also assessed. DESIGN: 26-week randomized, controlled phase 3 safety and tolerability trial in six countries (Nbib2382939). METHODS: Male or female patients aged 18-79 years with adult GH deficiency (AGHD), treated with once-daily GH for ≥6 months, were randomized to once-weekly somapacitan (n = 61) or once-daily Norditropin (n = 31) administered subcutaneously by pen. Both treatments were dose titrated for 8 weeks to achieve insulin-like growth factor I (IGF-I) standard deviation score (SDS) levels within the normal range, and then administered at a fixed dose. Outcome measures were adverse events (AEs), including injection site reactions; occurrence of anti-somapacitan/anti-GH antibodies and change in treatment satisfaction, assessed using the Treatment Satisfaction Questionnaire for Medication-9 (TSQM-9). RESULTS: Mean IGF-I SDS remained between 0 and 2 SDS throughout the trial in both groups. AEs were mostly mild or moderate and transient in nature. The most common AEs were nasopharyngitis, headache and fatigue in both groups. More than 1500 somapacitan injections were administered and no clinically significant injection site reactions were reported. No anti-somapacitan or anti-GH antibodies were detected. The TSQM-9 score for convenience increased significantly more with somapacitan vs Norditropin (P = 0.0171). CONCLUSIONS: In this 26-week trial in patients with AGHD, somapacitan was well tolerated and no safety issues were identified. Once-weekly somapacitan was reported to be more convenient than once-daily Norditropin.