Safety and Efficacy of BGP-15 in Patients With Type 2 Diabetes Mellitus

This is a randomized, double-blind, placebo-controlled, parallel group, multiple dose, multicenter study with 5 treatment arms and 1 placebo arm. Patients should be treated with both metformin and SU or metformin alone. Patients will be randomized to 100,100 + 100, 200, 200 + 200, and 400 mg/day or placebo, as an add-on to their current treatment. The study consists of 2 periods: * A 14-day screening period for ascertaining the inclusion/exclusion criteria; and, * A 13-week treatment period with different doses of BGP-15 or placebo as an add-on therapy to metformin and SU treatment or metformin treatment alone.