Once-Weekly Somapacitan Matches Daily Growth Hormone in Turner Syndrome: Study

A new study published in The Journal of Clinical Endocrinology & Metabolism showed that once-weekly somapacitan, a long-acting growth hormone medication, promoted development in Turner syndrome girls as efficiently as daily growth hormone injections, with comparable safety.

Turner syndrome is a hereditary disorder that mostly affects girls and women, resulting in small height due to delayed development. Growth hormone therapy can increase height, but daily injections may impose a significant strain on children and families. Somapacitan is a long-acting growth hormone that is injected once a week. Thus, this study evaluated the efficacy and safety of once-weekly somapacitan to traditional daily growth hormone administration in girls with Turner syndrome.

49 clinics in 18 countries participated in the randomized, open-label, phase 3 REAL8 research. 105 prepubertal girls with Turner syndrome, ages 2.5 to 10, who had not previously received treatment, were randomized in a 2:1 ratio to receive either daily growth hormone (0.050 mg/kg/day) or somapacitan (0.24 mg/kg/week) once a week. After 52 weeks, height velocity was the main result. IGF-I levels, bone maturation, body mass index, treatment load, and safety were all evaluated.

Girls receiving once-weekly somapacitan grew at an average rate of 9.0 cm/year after 52 weeks, while girls receiving daily growth hormone grew at a rate of 9.5 cm/year. The results of the study demonstrated that weekly somapacitan was just as effective in promoting development as daily therapy.

Bone maturation and BMI were equivalent in both groups, although IGF-I levels rose in a similar manner. Additionally, safety profiles were mostly comparable. The majority of adverse effects were mild or moderate, and pediatric diseases were often recorded. According to patient-reported evaluations, weekly somapacitan was considered by parents as having a considerably reduced treatment load.

Overall, over 52 weeks, once-weekly somapacitan appears to give growth-promoting benefits comparable to daily growth hormone in previously untreated Turner syndrome girls, while retaining a similar safety and tolerability profile. The primary potential benefit is a reduction in injection frequency, which may make long-term growth hormone administration more convenient for children and families. The trial also included a 104-week extension, which might give further information regarding long-term development, safety, and treatment outcomes.

Source:

Mauras, N., Boettcher, C., Højby, M., Soltysik, K., Jorge, A. A. L., Kashimada, K., Linglart, A., Luo, X., Murray, P. G., & Backeljauw, P. (2026). Once-weekly somapacitan enhances linear growth in girls with Turner syndrome: a randomized controlled phase 3 study. The Journal of Clinical Endocrinology and Metabolism, dgag309. https://doi.org/10.1210/clinem/dgag309