Distinct Glucose Profiles with Daily and Weekly Growth Hormone Therapy Revealed by Continuous Glucose Monitoring

Context Somapacitan, a long-acting growth hormone (GH) derivative, has been used to treat adult GH deficiency (AGHD). Although the distinct pharmacokinetics of somapacitan compared with daily GH administration are presumed to affect daily and weekly glucose profiles, detailed information on the glucose fluctuations remains limited. Objective Glycemic variability in individuals during somapacitan treatment was assessed. Methods A prospective, single-arm, single-center study was conducted in 20 AGHD participants without diabetes. Participants receiving somatropin were switched to somapacitan, with doses titrated over 3 months to maintain insulin-like growth factor-1 (IGF-1) levels within ± 2 SD. Continuous glucose monitoring (CGM) was performed for 14 days before and after the switch. The primary endpoint was the change in glycemic variability indices. Results With IGF-1 levels matched between regimens, no significant differences were observed in glycated hemoglobin A1c, fasting blood glucose, and insulin resistance index before and after switching to somapacitan. The CGM data demonstrated that the mean sensor glucose level (SGL) and continuous overall net glycemic action over 24 hours were significantly increased during somapacitan treatment. Notably, whereas SGLs showed no significant interday fluctuations during somatropin treatment, biphasic glucose fluctuations were observed during somapacitan treatment, with mean SGLs peaking on the second day and reaching their lowest on the fourth day. After switching to somapacitan, the time below range tended to decrease across all days. Conclusion The switch from somatropin to somapacitan resulted in increased interday glucose variability, characterized by biphasic glucose fluctuations, suggesting a unique physiological effect of somapacitan on glucose profiles.