- Type 2 Diabetes Mellitus subjects on a stable anti-diabetes regimen of diet and/or metformin alone therapy or on metformin plus an insulin secretion enhancer (sulfonylureas, dipeptidyl peptidase 4 (DPP4) Inhibitors, Glucagon-like peptide (GLP-1) analogs) therapy for a 60 day period prior to randomization. Subjects with diabetes duration of ≥ 4 years must be using an insulin secretion enhancer (e.g. sulphonylureas (SU), DPP4, GLP-1 analog). Subjects must have a documented C-peptide level (either fasting or random) of >2 ng/ml from the screening visit.