The Journal of Clinical Endocrinology and Metabolism Journal Article

Efficacy of Once-Weekly Somapacitan in Adult GHD

February 05, 2020

Gudmundur Johannsson, Murray B Gordon, Michael Højby Rasmussen, Ida Holme Håkonsson, Wolfram Karges, Claus Sværke, Shigeyuki Tahara, Koji Takano, Beverly M K Biller
The Journal of Clinical Endocrinology & Metabolism, Volume 105, Issue 4, April 2020, dgaa049
https://doi.org/10.1210/clinem/dgaa049

Abstract

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).