A Randomized, Double-Blind, Placebo-Controlled, 3-Arm, Parallel-Group, Multicenter Study to Evaluate the Efficacy, Safety, and Tolerability of Canagliflozin in the Treatment of Subjects With Type 2 Diabetes Mellitus With Inadequate Glycemic Control on Metformin and Pioglitazone Therapy

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), parallel-group, 3-arm (3 treatment groups) multicenter study to determine the efficacy, safety, and tolerability of canagliflozin (100 mg and 300 mg) compared to placebo (a capsule that looks like all the other treatments but has no real medicine) in patients with T2DM who are not achieving an adequate response from current antihyperglycemic therapy with metformin and pioglitazone to control their diabetes. Approximately 360 patients with T2DM who are receiving combination therapy with metformin and pioglitazone will receive the addition of once-daily treatment with canagliflozin (100 mg or 300 mg) or placebo capsules for 26 weeks followed by a 26-week extension period where patients treated with canagliflozin (100 mg or 300 mg) will continue treatment for an additional 26 weeks and patients treated with placebo will be switched to active double-blind treatment with sitagliptin 100 mg, an antihyperglycemic agent administered once-daily for 26 weeks. In addition, all patients will take protocol specified stable doses of metformin and pioglitazone along with assigned study drug for the duration of the study. Patients will participate in the study for approximately 59 to 78 weeks. During the study, if a patient's fasting blood sugar remains high despite treatment with study drug, the patient will receive treatment with glimepiride (rescue therapy) in accordance with local prescribing information. 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 (SMGB) measurements. The primary outcome measure in the study is the effect of canagliflozin relative to placebo on hemoglobin A1c (HbA1c) after 26 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 capsules for 2 weeks before randomization. After randomization, patients will take double-blind canagliflozin (100 mg or 300 mg) for 52 weeks OR placebo for 26 weeks switched to double-blind sitagliptin 100 mg for 26 weeks.