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.
Trial registration: ClinicalTrials.gov NCT01619059.
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