In this 16-week , phase III , randomized , double-blind placebo-controlled study , adults who were receiving metformin administered twice daily ( 1500mg/day ) and had inadequate glycaemic control were randomized 1:1:1:1 to receive dapagliflozin twice daily ( 2.5 or 5mg ) , placebo or dapagliflozin 10mg once daily ( which was included as a benchmark ) .