- Diagnosis of type 2 diabetes mellitus currently treated with a thiazolidinedione either alone or in combination with metformin or a sulfonylurea but who are experiencing inadequate glycemic control. The subject should have received the thiazolidinedione therapy (rosiglitazone or pioglitazone) either alone or in combination with metformin or a sulfonylurea for at least the 3 months prior to Screening and must have been on a stable dose for all their antidiabetic treatments for at least the month prior to Screening.