Aim To investigate the long‐term efficacy and safety of dapagliflozin as an adjunct to adjustable insulin in adults with type 1 diabetes (T1D) and inadequate glycaemic control. Materials and Methods Dapagliflozin Evaluation in Patients with Inadequately Controlled Type 1 Diabetes (DEPICT‐2) was a placebo‐controlled, double‐blind, multicentre, phase III study of adults with T1D (HbA1c 7.5%‐10.5%) randomized (1:1:1) to receive dapagliflozin 5, 10 mg, or placebo. The efficacy and safety of dapagliflozin over 52 weeks were exploratory endpoints in this extension to DEPICT‐2. Results Of 813 participants randomized, 88.2% completed the study. From baseline to 52 weeks, dapagliflozin 5 and 10 mg were associated with reduction in HbA1c (difference [95% CI] vs. placebo: −0.20% [−0.34, −0.06] and −0.25% [−0.38, −0.11], respectively) and adjusted mean percentage change in body weight (difference [95% CI] vs. placebo: −4.42% [−5.19, −3.64] and −4.86% [−5.63, −4.08], respectively). Serious adverse events were reported in the dapagliflozin 5, 10 mg, and placebo groups (32 [11.8%], 19 [7.0%] and 16 [5.9%], respectively). The proportion of hypoglycaemic events was similar across groups; severe hypoglycaemia was uncommon. More participants with events adjudicated as definite diabetic ketoacidosis (DKA) were in the dapagliflozin 5 and 10 mg groups versus placebo (11 [4.1%], 10 [3.7%] and 1 [0.4%], respectively); the majority of events were mild or moderate in severity and all were resolved with treatment. Conclusions Dapagliflozin led to long‐term reductions in HbA1c and body weight in adults with T1D, but increased DKA risk compared with placebo.

Metformin is the first-line oral medication to increase insulin sensitivity in patients with type 2 diabetes (T2D). Our aim was to investigate the pleiotropic effect of metformin using a nontargeted metabolomics approach. We analyzed 353 metabolites in fasting serum samples of the population-based human KORA (Cooperative Health Research in the Region of Augsburg) follow-up survey 4 cohort. To compare T2D patients treated with metformin (mt-T2D, n = 74) and those without antidiabetes medication (ndt-T2D, n = 115), we used multivariable linear regression models in a cross-sectional study. We applied a generalized estimating equation to confirm the initial findings in longitudinal samples of 683 KORA participants. In a translational approach, we used murine plasma, liver, skeletal muscle, and epididymal adipose tissue samples from metformin-treated db/db mice to further corroborate our findings from the human study. We identified two metabolites significantly (P < 1.42E-04) associated with metformin treatment. Citrulline showed lower relative concentrations and an unknown metabolite X-21365 showed higher relative concentrations in human serum when comparing mt-T2D with ndt-T2D. Citrulline was confirmed to be significantly (P < 2.96E-04) decreased at 7-year follow-up in patients who started metformin treatment. In mice, we validated significantly (P < 4.52E-07) lower citrulline values in plasma, skeletal muscle, and adipose tissue of metformin-treated animals but not in their liver. The lowered values of citrulline we observed by using a nontargeted approach most likely resulted from the pleiotropic effect of metformin on the interlocked urea and nitric oxide cycle. The translational data derived from multiple murine tissues corroborated and complemented the findings from the human cohort.