Liraglutide and Βeta‐Cell Function in Young Adults With Long‐Standing Type 1 Diabetes and Residual C‐Peptide: A Blinded, Randomized Controlled Trial

Aims To evaluate the effect of liraglutide on residual beta‐cell function in adults with long‐standing type 1 diabetes (T1D) and detectable C‐peptide. Materials and Methods In this randomized, blinded, placebo‐controlled trial, 18 adults with T1D duration ≥ 5 years and detectable fasting C‐peptide were assigned to liraglutide or placebo for 52 weeks. Mixed‐meal tolerance tests were performed at baseline and weeks 6, 52, and 65. The primary endpoint was change in stimulated C‐peptide area under the curve from baseline to week 52. Results Liraglutide did not improve stimulated C‐peptide compared with placebo at week 52. In exploratory post hoc longitudinal analyses including the post‐treatment period (weeks 0–65), stimulated C‐peptide declined more steeply in the liraglutide group than in the placebo group, accompanied by increasing insulin requirements over time. Conclusions In adults with long‐standing T1D, liraglutide did not preserve stimulated C‐peptide after 52 weeks. Exploratory post hoc longitudinal analyses suggested a steeper decline in stimulated C‐peptide with liraglutide than with placebo.