ESPE Abstracts

Introduction: Recombinant growth hormone (rhGH) treatment has been used for growth hormone (GH) induced short stature since 1985, usually with transient adverse events, while lipoatrophy involves irreversible damage to subcutaneous fatty tissue. Biopsies show mast cells and eosinophils, suggesting destructive inflammation. GH directly increases lipolysis, reduces lipoprotein lipase activity, and decreases mature adipocyte number and volume, inhibiting adipose tissue expansion and reducing body fat. Long-acting rhGH preparations, such as somatrogon, enable once-weekly injections. This is the first case report on localized lipoatrophy in the right upper arm of a 5-year-old girl with isolated GH deficiency and mild intrauterine growth retardation treated with somatrogon, a nonpegylated, long-acting GH.

Case Report: A 5-year-old girl, born weighing 2300 grams and growing at the 5th percentile, was followed at the pediatric endocrinology clinic of Demiroglu Bilim University. Her height was 99 cm and her weight was 15.5 kg (below 3rd percentile and at 10th percentile, respectively according to Turkish standards). After growing only 3 cm in a year, a clonidine test showed a peak value of 8.6 ng/ml, with an IGF-1 low normal level for her age (75 ng/ml). Thyroid levels were normal. She began receiving 0.66 mg of somatrogon weekly. At her first follow-up visit 11 weeks later, localized lipoatrophy developed in her right upper arm, where all injections had been given. Despite this, her height increased by 3.5 cm, indicating a positive response to somatrogon. Thyroid and IGF-1 levels at the first visit were normal. Her treatment was switched to daily rhGH.

Discussion: The first reported case of lipoatrophy due to a daily rhGH treatment occurred in 1999 in a child with a gene deletion causing GH deficiency, after six years of high-dose rhGH at injection sites, attributed to antibody formation. In 2021, Chhiba and Segal found localized lipoatrophy in 14.5% of patients on daily rhGH, unrelated to age, indication, or dose, but linked to repeated injections at the same sites. A phase 3 study by Touraine on a long-acting pegylated rhGH (non-antigenic polyethylene glycol additive) found five cases of lipoatrophy, resulting in the study's termination. Our case with somatrogon shows that lipoatrophy can also occur with a non-pegylated rhGH treatment rapidly within 11 weeks, likely due to repeated injections at the same site. Our findings highlight the importance of close monitoring and rotating injection sites during non-pegylated rhGH treatment, specifically with somatrogon, to reduce the risk of lipoatrophy.