Twice-daily dapagliflozin co-administered with metformin in type 2 diabetes: a 16-week randomized, placebo-controlled clinical trial.

Aims: To evaluate the efficacy and safety of twice-daily dosing of dapagliflozin and metformin, exploring the feasibility of a fixed-dose combination.

Methods: In this 16-week, phase III, randomized, double-blind placebo-controlled study, adults who were receiving metformin administered twice daily (≥1500 mg/day) and had inadequate glycaemic control were randomized 1:1:1:1 to receive dapagliflozin twice daily (2.5 or 5 mg), placebo or dapagliflozin 10 mg once daily (which was included as a benchmark). The primary endpoint was change from baseline glycated haemoglobin (HbA1c) level. Secondary endpoints included changes in fasting plasma glucose (FPG) level and body weight.

Results: Four hundred adults were randomized to dapagliflozin (2.5 mg twice daily, 5 mg twice daily, 10 mg once daily) or placebo co-administered with metformin twice daily. At 16 weeks, the adjusted mean change in HbA1c from baseline was significantly reduced in the dapagliflozin 2.5 mg twice daily and 5 mg twice daily groups versus placebo (-0.52 vs. -0.30%, p = 0.0106 and -0.65% vs. -0.30%, p < 0.0001). There were also significantly greater improvements for dapagliflozin twice daily groups versus placebo in FPG body weight and achievement of HbA1c level of <7%. Efficacy outcomes for dapagliflozin twice daily were numerically similar to those for dapagliflozin once daily. Dapagliflozin twice daily was well tolerated.

Conclusions: Dapagliflozin 2.5 or 5 mg twice daily added to metformin was effective in reducing glycaemic levels in patients with type 2 diabetes inadequately controlled with metformin alone. This study supports the development of a fixed-dose combination regimen.