This is a placebo-controlled, randomized, double-blind, parallel arm, multicenter, dose-ranging phase IIb trial to assess glycemic and weight loss efficacy and safety of BMS-646256 in overweight and obese patients with type 2 diabetes who have been treated with diet and exercise only or with half-maximal or greater metformin (≥1500mg/day) or sulfonylurea monotherapy (stable dose for at least three months), but who remained inadequately controlled (HbA1c >7% and HbA1c<10%).

Inclusion Criteria:

• Patients aged 18-70 years and BMI ≥27 with type 2 diabetes who have been treated with diet and exercise only or with half maximal or greater metformin or sulfonylurea monotherapy (stable dose for at least three months), but who remained inadequately controlled (HbA1c >7% and HbA1c<10%).

Exclusion Criteria:

• Pregnancy
• Anti-diabetic medications other than baseline metformin or sulfonylurea monotherapy
• History of myocardial infarction in the prior six months/ History of heart failure defined as New York Heart Association Functional Class I, II, III or IV/ History of symptomatic arrhythmia
• Active hepatic disease/ Any documented muscle disease
• History of multiple sclerosis/ Baseline history of tremors, ataxia, anxiety or dizziness
• Seizures within the last year, stroke, and transient ischemic attack/ Known history of schizophrenia, dementia, or bipolar disorder as defined by DSM IV criteria.
• Currently depressed subjects or a CES-D score greater or equal to 16 at the screening visit or at baseline (Day 1)/ History of suicide attempt or ideation
• Previous history of surgical procedures for weight loss (e.g. stomach stapling, bypass)/ Weight loss greater than 5 kg in the prior 3 months