SAT-190 Efficacy And Safety Of Weekly PEGylated Recombinant Human Growth Hormone (Jintrolong) In Prepubertal Children With Turner Syndrome: 3-year Results From A Multicenter, Randomized Study In China

Abstract Disclosure: J. Chen: None. Y. Lv: None. H. Du: None. Y. Ma: None. L. Han: None. F. Luo: None. G. Li: None. L. Chen: None. B. Cao: None. M. Qin: None. C. Su: None. L. Wei: None. Q. Wang: None. P. Li: None. Z. Xu: None. R. Xie: None. X. Chen: None. H. Wu: None. J. Xia: Jing Xia is employee of Changchun GeneScience Pharmaceutical Co., Ltd. D. Pang: Dongqing Pang is employee of Changchun GeneScience Pharmaceutical Co., Ltd.. C. Gong: None. Objective: To evaluate the efficacy and safety of weekly PEGylated recombinant human growth hormone (PEG-rhGH, Jintrolong) over 3-year in prepubertal children with Turner Syndrome (TS). Methods: This multicenter, randomized, negative-controlled phase 2 study (NCT03189160) included a 52-week main phase followed by an ongoing open-label extension. Prepubertal patients with genetically confirmed TS, bone age <12 years, height≤-2.5 SD for age, and no prior GH therapy were randomized 1:1:1 across 8 centers to receive weekly subcutaneous Jintrolong at 0.1 mg/kg, 0.2 mg/kg, or no treatment with monitoring only. Patients completing the main phase entered the open-label extension, during which all received Jintrolong (0.1-0.4 mg/kg/week). Doses were adjusted every 13 weeks based on annualized height velocity (AHV), IGF-1 SDS, and clinical guidelines. Treatment continued until near-adult height, with follow-up every 26 weeks thereafter until final height was attained. The primary endpoint was change in height SDS (HT-SDS) calculated using the LMS method from baseline at Week 52 and every 52 weeks during extension. Other growth-related parameters and safety were also evaluated. Results: A total of 177 patients were included in the main phase analysis, and 170 in the extension phase. The mean (SD) age at baseline was 7.87 (3.01) years, and mean HT-SDS was -3.33 (0.63). At Week 52, mean (SD) changes in HT-SDS from baseline were -0.07 (0.29) in the control group, 0.28 (0.35) in the 0.1 mg/kg/week group, and 0.60 (0.41) in the 0.2 mg/kg/week group. Both treatment groups showed significantly improvement compared with control (p<0.0001 for each), and the 0.2 mg/kg/week group improved significantly than the 0.1 mg/kg/week group (p<0.0001). After two years of extension (Year 3 overall), mean (SD) increases in HT-SDS from baseline were 0.81 (0.68) and 1.15 (0.63) in the 0.1 and 0.2 mg/kg/week groups, respectively, indicating sustained benefit, particularly in patients initially received the higher dose. AHV in both Jintrolong groups peaked at Week 52 and gradually declined over time but remained above baseline at Week 104 and Week 156. During the extension, 84.1% of patients (143/170) underwent dose escalation. The incidence of adverse events (AEs) and treatment adherence were comparable across groups during the main phase. Most AEs during long-term treatment were mild to moderate and consistent with the known GH safety profile. Conclusion: Weekly Jintrolong at 0.1 to 0.4 mg/kg/week provided sustained and clinically meaningful growth improvements over 3 years in girls with TS. Most patients required dose escalation after the first year to achieve optimal growth velocity. This dosing range was appropriate for most patients and associated with a favorable long-term safety profile. Jintrolong offers a convenient long-acting formulation for managing short stature associated with TS. Presentation: Saturday, July 12, 2025