Endocrine Abstracts

JOINT2365

Background: The Long-Acting Growth Hormone (LAGH) therapy, Somatrogon, has been available in Turkey since October 2023 for children with growth hormone deficiency (GHD). LAGH demonstrates equal efficacy compared with daily GH, with the added advantage of reduced injection frequency. Although clinical studies have highlighted the efficacy and safety of Somatrogon, the standard initial dose for each child may present difficulties in dose titration.

Objective: The aim of this study was to evaluate dose titrations based on insulin-like growth factor 1 (IGF-1) levels in children initiated on Somatrogon therapy for pediatric growth hormone deficiency (PGHD)

Methods: A single-center, retrospective study was conducted including children initiated on Somatrogon therapy with a diagnosis of PGHD between April 1, 2024, and October 31, 2024. A total of 56 children with GHD (37 males), mean age 12. 42±2. 88 years were commenced on LAGH therapy (initial dose 0. 66 mg/kg/week). 20 patients were GH naïve, and 36 were switched from daily GH to LAGH. Auxology, pubertal stage, laboratory findings including IGF-1 levels (measured 96th hours post-weekly injection) were obtained retrospectively from medical records.

Results: The mean duration of Somatrogon therapy was 0. 46±0. 13 years. Dose reduction was achieved in 55. 5% of individuals due to high IGF-1 SDS, and this rate was similar to patients who were GH naïve and switched from daily GH to LAGH. Dose reductions were made in 33. 3% of 21 prepubertal individuals, 76. 9% of 13 with pubertal stage Tanner 2, 50% of 16 with Tanner 3, and 100% of individuals with Tanner 4/5 (6 patients). Children with Tanner stage 4/5 had a mean dose of 0. 51±0. 02 mg/kg/week and a mean dose reduction of 22. 47±3. 51 %. Children were divided into 4 groups according to their peak growth hormone response to stimulation tests. Dose reduction was made in 56. 5% of those with hormone levels between 7 and 10 ng/mL, 54. 4% of those with levels between 5 and 7 ng/mL, 41. 7% of those with levels between 3 and 5 ng/mL, and 80% of those with levels < 3 ng/mL (severe GHD). The children with severe GHD had a mean dose of 0. 56±0. 08 mg/kg/week and a mean dose reduction of 14. 54±12. 33 %.

Conclusion: Somatrogon may be a suitable option in PGHD patients, but the recommended initial dose of 0. 66 mg/kg/week may need to be individualized, particularly in children with severe GHD and in Tanner stage 4/5 of puberty. Careful monitoring and dose adjustment based on IGF-1 levels are necessary to maintain safety and efficacy.