Investigational Study of Delayed Release Metformin

The study is a multicenter, international study with a 28 week randomized, double blind parallel group, placebo and active comparator controlled period and a 24 week open label extension period in patients with T2DM who are treated with metformin at the time of study screening. Approximately 675 patients will be randomly assigned to 1 of 3 treatment groups. The study will assess change in HbA1c through 28 weeks for Metformin DR compared to placebo as a primary endpoint. In addition, assessments of change in HbA1c for Metformin DR compared to Metformin IR and assessment of absolute change in HbA1c will be evaluated in the study. Screening and Run-in Period: The study will include an up to 10-day screening period, an 4 to 8-week metformin washout period, and a 2-week single blind (patient blinded) placebo run-in period. Treatment Period: Patients that are determined eligible based upon the screening and run-in criteria will enter the 28-week double-blind treatment period. During the double-blind treatment period, patients will be randomly assigned to 1 of 3 treatment groups (Group A, B, or C) in a 1:1:1 ratio. The 3 treatments are Metformin DR (1800 mg Metformin DR with matching placebo for Metformin IR), Metformin IR (1500 mg Metformin IR with matching placebo for Metformin DR), and placebo (matching placebo for Metformin IR with matching placebo for Metformin DR). For those patients randomized to Metformin IR, their Metformin IR dose will be titrated to prevent gastrointestinal intolerability: Open Label Extension Period: Upon completion of the 28 week treatment patients will be eligible for an additional 24 weeks of open label extension period where assigned study treatment will continue and additional efficacy, safety and tolerability data will be collected and analyzed.