Efficacy and Safety of Continuing Sitagliptin when Initiating Insulin Therapy in Subjects with Type 2 Diabetes Mellitus

DPP-4 inhibitors (DPP-4is) are often discontinued with initiation of insulin therapy but the impact of this discontinuation on efficacy and hypoglycemia has not been studied. In this double-blind trial the safety and efficacy of initiating insulin while continuing sitagliptin (SITA) was evaluated. Eligible patients had inadequately controlled T2DM on metformin (MET, ≥ 1500 mg/day) in dual or triple combination therapy with a DPP-4i and/or sulfonylurea. Those on MET + SITA (100 mg/day) directly entered the trial; all others were switched to MET + SITA and stabilized during a run-in period. Subjects were randomized to continuing SITA or discontinuing SITA and switching to matching placebo, with both groups initiating insulin (LANTUS®), which was titrated based on fasting glucose. 746 subjects (mean A1C 8.8%, disease duration 10.6 years) were randomized. After 30 weeks, continuing SITA was superior to discontinuing SITA in reducing A1C (p