ESPE Abstracts

Background: The long-acting growth hormone (LAGH) somatrogon has been found to be as effective and safe as daily somatotropin in the treatment of children with GH deficiency (GHD). Somatrogon administered once weekly has the potential to improve treatment adherence and height prognosis.

Objective: We aimed to evaluate the first real-life data on somatrogon therapy, which was launched in Türkiye in October 2023.

Methods: Clinical characteristics (n:21) and first three-to-six-month treatment responses (n:10) of children who started somatrogon treatment in four different centers were examined retrospectively.

Results: Somatrogon was started for the first time (n:13) or by switching from daily GH to 21 children (12 girls, 8 pubertal), with a median age of 10.1 (range: 3.0–15.8) years. The indications for GH treatment were GHD (n:8), idiopathic short stature (ISS, n:10; 9 familial), SGA/preterm birth (n:2) and Silver-Russel syndrome (SRS, n:1). A GHD patient with homozygous GH1 gene defect who was unresponsive to somatotropin due to neutralizing antibodies was also switched to somatrogon. Dose was 0.66 (0.54-0.77) mg/kg/week. In treatment-naïve children, annual height velocity (HV) increased from 4.9 (2.2–7.4) to 12.3 (8.0–15.7) cm at 3 months (n:5). In one of them, HV was 11.8 cm/year at 6 months. In treatment-switched group, while the average HV was 7.6 (2.0–12.8) cm/year under somatotropin treatment, it increased to 10.6 (7.2–12.4) cm/year at 3 months (n:5) and to 9.8 (9.2–10.4) cm/year at 6 months (n:2). Somatotropin-unresponsive patient grew at a rate of 12.4 cm/year in the first 3 months. IGF-1 SD scores in treatment-naïve and -switched children increased from -1.13 (-2.45–0.3) to -0.26 (-1.84–0.91) and from 0.64 (-2.36–1.12) to 1.28 (-2.13–1.93), respectively. One patient was switched from somatrogon to somatotropin due to an allergic reaction. One patient reported pain at the injection site. No other adverse effect was observed. Families preferred to continue weekly somatrogon treatment due to both ease of use and comfort.

Conclusion: Despite the limited number of patients and short treatment duration, our study provides the first real-life experience in our country showing that somatrogon is effective in the patient group including GHD, ISS, SGA, and SRS. LAGH preparations with modified molecular structure may be a treatment option in isolated GHD cases that develop resistance to somatotropin due to neutralizing antibodies. Further studies are needed to determine the long-term efficacy and safety of somatrogon in real-life settings.