A Study of Saxagliptin in subjects with Type 2 diabetes who have inadequate blood sugar control with sulfonylureas

The purpose of this trial is to understand if adding saxagliptin to a sulfonylurea is safe and works better than increasing the amount of sulfonylurea a patient takes

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 (defined as rescue) will be eligible to enter the long-term treatment extension period where they will receive metformin.Rescue treatment with metformin is also available during the long-term extension period for subjects who meet glycemic criteria.