A Randomised, Double-blind, Placebo-controlled, Five Parallel Groups Study Investigating the Efficacy and Safety of BI 1356 BS (1 mg, 5 mg and 10 mg Administered Orally Once Daily) Over 12 Weeks as add-on Therapy in Patients With Type 2 Diabetes and Insufficient Glycaemic Control Despite Metformin Therapy, Including an Open-label Glimepiride Treatment Arm.

The objective of the study is to test the efficacy, safety and tolerability of several doses of BI 1356 BS (1, 5, or 10 mg taken once daily) compared to placebo given for 12 weeks together with metformin in patients with type 2 diabetes mellitus who are not at goal with their HbA1c levels. In addition, there will be an unblinded treatment arm with glimepiride as add-on therapy to metformin for comparison. The influence of several factors (gender, age, weight, race, etc.) on the bioavailability and efficacy of BI 1356 BS will also be tested in this study.