A Study of Aleglitazar in Combination With Metformin in Patients With Type 2 Diabetes Mellitus Who Are Inadequately Controlled With Metformin Alone

150 mcg aleglitazar given orally once a day for 26 weeks. Patients will continue on their existing dose and regimen of metformin (≥ 1500 mg/day or individual maximally tolerated dose)

Oral doses of matching placebo once a day for 26 weeks. Patients will continue on their existing dose and regimen of metformin (≥ 1500 mg/day or individual maximally tolerated dose)