Efficacy and safety of dapagliflozin over 1 year as add-on to insulin therapy in Japanese patients with type 2 diabetes: the DAISY (Dapagliflozin Added to patients under InSulin therapY) trial

Aims To evaluate the efficacy and safety of dapagliflozin as add-on to insulin in Japanese patients with type 2 diabetes. Materials and methods Insulin-treated Japanese patients were randomized to 5 mg dapagliflozin or placebo during a 16-week double-blind treatment period. Both groups then received dapagliflozin 5 or 10 mg (the dose was increased at or after week 24 if glycated haemoglobin [HbA1c] at the previous visit was >7.5%) during a 36-week open-label extension period. The exploratory efficacy endpoint was to assess the maintenance efficacy of 5/10 mg dapagliflozin + insulin over 52 weeks of treatment. Safety was assessed in terms of adverse events, laboratory variables and vital signs. Results The changes in HbA1c from baseline to weeks 16 and 52 were −0.62% and −0.74%, respectively, in the dapagliflozin group, vs −0.08% and −0.83%, respectively, in the placebo–dapagliflozin group. Body weight decreased at both time points in the dapagliflozin group and after switching to open-label dapagliflozin in the placebo–dapagliflozin group. The total insulin dose decreased slightly after starting dapagliflozin. Adverse events occurred in 82.9% and 71.7% of patients in the dapagliflozin and placebo–dapagliflozin groups, respectively. Hypoglycaemia occurred in 35.0% and 41.7% of patients in the dapagliflozin and placebo–dapagliflozin groups, respectively, but the incidence was not increased by use of dapagliflozin in either trial period. Genital/urinary tract infections, renal impairment/failure, volume depletion, fracture and hepatic disorders occurred in ≤5% of patients. Conclusion This trial showed that administration of dapagliflozin as an add-on to insulin therapy was effective, was well tolerated and had insulin-sparing effects in Japanese patients with type 2 diabetes.