SUN-207 - Real-World Safety of A Biosimilar Recombinant Human Growth Hormone in Pediatric Patients: Interim Results from A Multicenter Registry in Argentina

Recombinant human growth hormone (rhGH) has been widely used for pediatric growth disorders treatment for decades, with a well-established safety profile in clinical trials and real-world studies. Biosimilar rhGH is a treatment option based on comparable safety and efficacy to the reference medicine. In Argentina, a biosimilar recombinant human somatropin (Somactive LF®) was approved for clinical use in 2022; however, to date, no real-world studies have been published describing its safety and tolerability in routine clinical practice. The GEMSOM002 registry was designed to address this evidence gap.
GEMSOM002 is an ongoing, multicenter, observational, retrospective and prospective real-world registry. Eligible patients are children and adolescents younger than 18 years who received at least one dose of the biosimilar rhGH as part of standard clinical care and provided informed consent and assent when applicable. Primary outcomes included adverse drug reactions (ADRs), serious adverse events (SAEs), and treatment discontinuation, while secondary outcomes assessed local tolerability at the injection site.
At the interim data cut-off, 44 pediatric patients were registered. One of the subjects was excluded due to lack of reliable data and two patients were excluded due to lack of follow up data by interim analysis date, therefore, 41 patients were included in this analysis. Median age was 10.4 years (1.9–15.5), and 53.5% were female. Prior growth hormone therapy was reported in 51.2% of patients. The most frequent diagnoses were growth hormone deficiency and small for gestational age without catch-up growth, followed by Turner syndrome, Prader–Willi syndrome (PWS), chronic kidney disease, short stature at pubertal onset, and Silver–Russell syndrome. The median follow-up time was 13.5 (0.6-38) months. No ADRs or SAEs were reported, and no permanent treatment discontinuations due to safety concerns occurred. Local injection-site reactions were observed in 4 patients (9.8%), accounting for 8 events, most commonly mild pain and local erythema. One moderate injection-site pain event was reported; no reactions required medical intervention. Occurred in both treatment-naïve and previously treated patients and did not impact treatment continuation. A PWS patient experienced a temporary 5-day treatment interruption due to nocturnal respiratory symptoms. Polysomnography confirmed mild obstructive sleep apnea consistent with pre-existing condition, and treatment was successfully subsequently resumed.
Interim real-world data from the GEMSOM002 registry support a favorable safety profile of this biosimilar recombinant human growth hormone in pediatric patients treated under routine clinical practice conditions. Continued follow-up will allow further characterization of long-term safety outcomes in a real-world setting.

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