A Study Assessing Saxagliptin Treatment in Type 2 Diabetic Subjects Who Are Not Controlled With TZD Therapy Alone

The purpose of this clinical research study is to learn whether Saxagliptin added to thiazolidinedione (TZD) therapy is more effective than TZD alone as a treatment for Type 2 diabetic subjects who are not sufficiently controlled with TZD alone

All subjects will participate in a lead-in period, and qualifying subjects will continue into a short-term randomized treatment period. Subjects who complete the short-term period will be eligible to enter the long term extension period. Also, subjects in the short-term period who have an elevated blood sugar that requires additional medication for blood sugar control will be eligible to enter the long-term treatment extension period where they will receive metformin (defined as rescue medication) added onto their blinded study medication