Treatment Differences Between Canagliflozin and Placebo in Insulin Secretion in Subjects With Type 2 Diabetes Mellitus (T2DM)

This is a double-blind (neither physician nor participants knows the treatment that the participant receives), randomized (the study medication is assigned by chance), placebo-controlled (an inactive substance is compared with a medication to test whether the medication has a real effect in a clinical study), parallel-groups study which will be conducted at 2 clinical research centers (CRC) in the US. Approximately 56 participants, ages 25-70 years, with T2DM inadequately controlled on either metformin monotherapy or combination therapy with metformin and a DPP-4 inhibitor, will be enrolled. The study has 3 phases: pre-treatment, double-blind treatment, and post-treatment. Pre-Treatment Phase will consist of a screening visit (Week -5), 14 days Single- Blind Placebo Run-in period, followed by 14 days of Single-Blind Placebo Baseline Period, during which participants will be randomized (1:1) to one of 2 treatment groups, either canagliflozin or placebo. Double-Blind Treatment Phase begins on Day 1, and ends at approximately Week 25, during which participants will be assessed at least biweekly at outpatient visits or by telephone contact. Canagliflozin treatment will be initiated at 100 mg/day, with up-titration to 300 mg/day, consistent with the approved INVOKANA® US Prescribing Information 2013. During post-treatment phase, a follow-up visit will occur within approximately 28 days after the last dose of study drug. At baseline and after 24 weeks of treatment with canagliflozin, hepatic and peripheral insulin sensitivity will be assessed using tracer labeled euglycemic clamp technique; hepatic fat content will be determined using 1H nuclear magnetic resonance spectroscopy (MRS); beta cell function (insulin secretion rate and beta cell glucose sensitivity) will be assessed during mixed meal tolerance test (MMTT); substrate oxidation and energy production rates will be measured using indirect calorimetry during euglycemic clamp and MMTT. During the study, participants will remain on their stable dose regimens of metformin or combination metformin DPP-4 inhibitor therapy, unless the investigator considers dose modification to be medically necessary. The total study duration for each participant participating in this study will be up to approximately 34 weeks.