Randomized, Double-Blind Trial of Triple Therapy With Saxagliptin Add-on to Dapagliflozin Plus Metformin in Patients With Type 2 Diabetes

OBJECTIVE The objective of this study was to assess the efficacy and safety of triple therapy with saxagliptin add-on versus placebo add-on to dapagliflozin plus metformin in adults with type 2 diabetes. RESEARCH DESIGN AND METHODS Patients on stable metformin (≥1,500 mg/day) for ≥8 weeks with glycated hemoglobin (HbA1c) 8.0–11.5% (64–102 mmol/mol) at screening received open-label dapagliflozin (10 mg/day) plus metformin immediate release (IR) for 16 weeks. Patients with inadequate glycemic control (HbA1c 7–10.5% [53–91 mmol/mol]) were then randomized to receive placebo (n = 153) or saxagliptin 5 mg/day (n = 162) in addition to background dapagliflozin plus metformin IR. The primary efficacy end point was change in HbA1c from baseline to week 24. RESULTS There was a significantly greater reduction in HbA1c at 24 weeks with saxagliptin add-on (–0.51% [–5.6 mmol/mol]) versus placebo (–0.16% [–1.7 mmol/mol]) add-on to dapagliflozin plus metformin (difference, –0.35% [95% CI –0.52% to –0.18%] and –3.8 [–5.7 to –2.0 mmol/mol], respectively; P < 0.0001). Reductions in fasting plasma glucose and 2-h postprandial glucose were similar between treatment arms. A larger proportion of patients achieved HbA1c <7% (53 mmol/mol) with saxagliptin add-on (35.3%) versus placebo add-on (23.1%) to dapagliflozin plus metformin. Adverse events were similar between treatment groups. Episodes of hypoglycemia were infrequent in both treatment arms, and there were no episodes of major hypoglycemia. CONCLUSIONS Triple therapy with the addition of saxagliptin to dapagliflozin plus metformin was well tolerated and produced significant improvements in HbA1c in patients with type 2 diabetes inadequately controlled with dapagliflozin plus metformin.