Safety and Effectiveness of Glargine 300 U/ml After Switching from Basal Insulins in Patients with Type 1 Diabetes: COMET-T Study

Introduction: Appropriate glycemic control is paramount for people with type 1 diabetes (PwT1D) by the effective delivery of exogenous insulin. However, glycemic variability and the risk of severe hypoglycemia must be reliably controlled.

Methods: COMET-T is a prospective, multicenter, observational study conducted in Germany, Austria, and Switzerland during 2021-2022 to assess the effectiveness and safety of insulin glargine 300 U/ml (Gla-300) after switching from other basal insulins. Out of 135 PwT1D, data of 94 patients were analyzed. The primary endpoint was the change in time in range (TIR) approximately 12 and 24 weeks after switching to Gla-300. Secondary endpoints were: change in HbA_1c, fasting plasma glucose (FPG), coefficient of variation (CV%) of plasma glucose, body weight (BW) and insulin dose.

Results: Patients had mean age of 48.6 ± 16.5 years, included 39.4% males and had 18.2 ± 15.5 years T1D duration. From baseline (54.3%), TIR changed at week 12 (mean change 0.3% [± 14.3]; p = 0.8383) and at week 24 (+ 4.5% [± 14.9], p = 0.078). At week 24, TIR significantly increased in patients with body mass index > 30 kg/m² (8.4% [± 12.8] p = 0.0057) and patients who previously received insulin detemir (10.5%; [± 12.93]; p = 0.0005). At week 24, there was a significant reduction in the HbA_1c value (8.1 ± 0.6% vs. 7.7 ± 0.9%; p < 0.001), a reduction in the CV% of plasma glucose (36.1 ± 12.4% vs. 32.8 ± 9.6%, p = 0.056), and increase in bolus insulin dose (26.5 ± 16.3 vs. 27.9 ± 16.6 U/day; p = 0.042). FPG, BW, and basal insulin doses were not significantly changed.

Conclusions: Although switching to Gla-300 in poorly controlled PwT1D did not significantly reduce TIR, it significantly decreased HbA_1c values and glycemic variability without changes in BW and basal insulin dose.