Background Dapagliflozin, a selective inhibitor of sodium-glucose cotransporter 2, may improve glycemic control with a lower dose of insulin and attenuate the associated weight gain in patients with inadequate control despite high doses of insulin. Objective To evaluate the efficacy and safety of adding dapagliflozin therapy in patients whose type 2 diabetes mellitus is inadequately controlled with insulin with or without oral antidiabetic drugs. Design A 24-week, randomized, placebo-controlled, multicenter trial followed by a 24-week extension period. An additional 56-week extension period is ongoing. (ClinicalTrials.gov registration number: NCT00673231) Setting 126 centers in Europe and North America from 30 April 2008 to 19 November 2009. Patients 808 patients with inadequately controlled type 2 diabetes mellitus receiving at least 30 U of insulin daily, with or without up to 2 oral antidiabetic drugs. Intervention Patients were randomly assigned in a 1:1:1:1 ratio and allocated with a computer-generated scheme to receive placebo or 2.5, 5, or 10 mg of dapagliflozin, once daily, for 48 weeks. Measurements The primary outcome was change in hemoglobin A(1c) from baseline to 24 weeks. Secondary outcomes included changes in body weight, insulin dose, and fasting plasma glucose level at 24 weeks and during the 24-week extension period. Adverse events were evaluated throughout both 24-week periods. Results 800 patients were analyzed. After 24 weeks, mean hemoglobin A(1c) decreased by 0.79% to 0.96% with dapagliflozin compared with 0.39% with placebo (mean difference, -0.40% [95% CI, -0.54% to -0.25%] in the 2.5-mg group, -0.49% [CI, -0.65% to -0.34%] in the 5-mg group, and -0.57% [CI, -0.72% to -0.42%] in the 10-mg group). Daily insulin dose decreased by 0.63 to 1.95 U with dapagliflozin and increased by 5.65 U with placebo (mean difference, -7.60 U [CI, -10.32 to -4.87 U] in the 2.5-mg group, -6.28 U [CI, -8.99 to -3.58 U] in the 5-mg group, and -6.82 U [CI, -9.56 to -4.09 U] in the 10-mg group). Body weight decreased by 0.92 to 1.61 kg with dapagliflozin and increased by 0.43 kg with placebo (mean differences, -1.35 kg [CI, -1.90 to -0.80 kg] in the 2.5-mg group, -1.42 kg [CI, -1.97 to -0.88 kg] in the 5-mg group, and -2.04 kg [CI, -2.59 to -1.48 kg] in the 10-mg group). These effects were maintained at 48 weeks. Compared with the placebo group, patients in the pooled dapagliflozin groups had a higher rate of hypoglycemic episodes (56.6% vs. 51.8%), events suggesting genital infection (9.0% vs. 2.5%), and events suggesting urinary tract infection (9.7% vs. 5.1%). Limitation Insulin doses were not titrated to target, and the study was not designed to evaluate long-term safety. Conclusion Dapagliflozin improves glycemic control, stabilizes insulin dosing, and reduces weight without increasing major hypoglycemic episodes in patients with inadequately controlled type 2 diabetes mellitus. Primary funding source AstraZeneca and Bristol-Myers Squibb.
