This is a 24 week study comparing the efficacy of four dose levels of INT131 besylate with pioglitazone HCl in patients with type 2 diabetes. Eligible patients will be men and women (of non-childbearing potential or using dual barrier methods of contraception) between 30 and 75 years of age who are minimally responsive to treatment with sulfonylurea monotherapy or sulfonylurea plus metformin combination therapy.

Inclusion Criteria:

• Diagnosis of Type 2 diabetes and on either sulfonylurea monotherapy or sulfonylurea plus metformin combination therapy for at least 3 months at stable dose
• Males and Females (of non-childbearing potential or who are using dual barrier methods of contraception) between 30 and 75 years of age
• HbA1c must be ≥7.5% and ≤10% at screening
• Fasting Plasma Glucose must be <240 mg/dL at screening

Exclusion Criteria:

• History of type 1 diabetes
• History of diabetic ketoacidosis
• NYHA Class III or IV cardiac status or hospitalization for congestive heart failure within 6 weeks prior to Visit 1
• Treatment with any non-peroxisome proliferator-activated receptor (non-PPAR) antidiabetic agent, investigational or approved, other than metformin or permitted sulfonylureas within 3 months prior to screening
• Treatment with rosiglitazone, pioglitazone, or any PPAR investigational antidiabetic agent within 6 month prior to screening
• Body mass index >45 kg/m2
• Fasting triglycerides >500 mg/dL
• Uncontrolled hypertension (sitting systolic blood pressure >160 mmHg and/or sitting diastolic blood pressure >100 mmHg
• Presence of diabetic complications, which in the opinion of the investigator, would complicate the subject's participation in the study (i.e., require initiation of new medication)