Background: Sodium-glucose cotransporter 2 (SGLT2) inhibitors improve glycaemia in patients with type 2 diabetes by enhancing urinary glucose excretion. We compared the efficacy and safety of canagliflozin, an SGLT2 inhibitor, with glimepiride in patients with type 2 diabetes inadequately controlled with metformin.
Methods: We undertook this 52 week, randomised, double-blind, active-controlled, phase 3 non-inferiority trial at 157 centres in 19 countries between Aug 28, 2009, and Dec 21, 2011. Patients aged 18-80 years with type 2 diabetes and glycated haemoglobin A1c (HbA1c) of 7·0-9·5% on stable metformin were randomly assigned (1:1:1) by computer-generated random sequence via an interactive voice or web response system to receive canagliflozin 100 mg or 300 mg, or glimepiride (up-titrated to 6 mg or 8 mg per day) orally once daily. Patients, study investigators, and local sponsor personnel were masked to treatment. The primary endpoint was change in HbA1c from baseline to week 52, with a non-inferiority margin of 0·3% for the comparison of each canagliflozin dose with glimepiride. If non-inferiority was shown, we assessed superiority on the basis of an upper bound of the 95% CI for the difference of each canagliflozin dose versus glimepiride of less than 0·0%. Analysis was done in a modified intention-to-treat population, including all randomised patients who received at least one dose of study drug. This study is registered with ClinicalTrials.gov, number NCT00968812.
Findings: 1450 of 1452 randomised patients received at least one dose of glimepiride (n=482), canagliflozin 100 mg (n=483), or canagliflozin 300 mg (n=485). For lowering of HbA1c at 52 weeks, canagliflozin 100 mg was non-inferior to glimepiride (least-squares mean difference -0·01% [95% CI -0·11 to 0·09]), and canagliflozin 300 mg was superior to glimepiride (-0·12% [-0·22 to -0·02]). 39 (8%) patients had serious adverse events in the glimepiride group versus 24 (5%) in the canagliflozin 100 mg group and 26 (5%) in the 300 mg group. In the canagliflozin 100 mg and 300 mg groups versus the glimepiride group, we recorded a greater number of genital mycotic infections (women: 26 [11%] and 34 [14%] vs five [2%]; men: 17 [7%] and 20 [8%] vs three [1%]), urinary tract infections (31 [6%] for both canagliflozin doses vs 22 [5%]), and osmotic diuresis-related events (pollakiuria: 12 [3%] for both doses vs one [<1%]; polyuria: four [<1%] for both doses vs two [<1%]).
Interpretation: Canagliflozin provides greater HbA1c reduction than does glimepiride, and is well tolerated in patients with type 2 diabetes receiving metformin. These findings support the use of canagliflozin as a viable treatment option for patients who do not achieve sufficient glycaemic control with metformin therapy.
Funding: Janssen Research & Development, LLC.
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