Preferred Treatment of Type 1.5 Diabetes

Inclusion Criteria: * Age at onset of diabetes - 35-69 years old. * No history of ketonuria or ketoacidosis. * Not requiring insulin to achieve glycemic control. * Not receiving more than two oral hypoglycemic agents. * Not taking a thiazolidinedione agent. * HbA1c in established patients (on an oral hypoglycemia agent for over 4 months) of greater than 6% and under 10%. * Fasting c-peptide greater than or equal to 0.8 ng/ml. * Women must be either post-menopausal or on adequate birth control (i.e. oral contraceptives, tubal ligation, hysterectomy, condoms, or diaphragm) or use abstinence. Exclusion Criteria: * Patients with history of chronic pancreatitis or other secondary causes of diabetes. * Patients receiving systemic corticosteroids. * Patients with severe systemic illness (e.g. recent MI, CHF or cerebral vascular disease). * Creatinine greater than 1.4 or liver enzymes greater than 2 times the upper limits of normal. * Not able to adhere to the protocol.