Canagliflozin is a drug that is being tested to see if it may be useful in treating patients diagnosed with type 2 diabetes mellitus (T2DM). This is a randomized (study drug assigned by chance), double-blind (neither the patient or the study doctor will know the name of the assigned treatment), multicenter study to determine the efficacy, safety, and tolerability of canagliflozin 300 mg compared to sitagliptin 100 mg (an antihyperglycemic drug) in patients with T2DM who are not achieving an adequate response from current antihyperglycemic therapy with metformin and sulphonylurea to control their diabetes. Approximately 720 patients with T2DM who are receiving combination therapy with metformin and sulphonylurea will receive the addition of once-daily treatment with canagliflozin 300 mg or sitagliptin 100 mg capsules for 52 weeks. Patients will participate in the study for approximately 59 to 72 weeks. During treatment, patients will be monitored for safety by review of adverse events, results from laboratory tests, 12-lead electrocardiograms (ECGs), vital signs measurements, body weight, physical examinations, and self monitored blood glucose (SMBG) measurements. The primary outcome measure in the study is the effect of canagliflozin compared to sitagliptin on hemoglobin A1c (HbA1c) after 52 weeks of treatment. Study drug will be taken orally (by mouth) once daily before the first meal each day unless otherwise specified. Patients will take single-blind placebo for 2 weeks before randomization. After randomization, patients in the study will take double-blind canagliflozin 300 mg or matching sitagliptin 100 mg for 52 weeks.
