The primary aim of this study is to evaluate the safety and tolerability of AZD1656 in T2DM patients treated with metformin and sulfonylurea.

Inclusion Criteria:

• Male or females of non-childbearing potential
• Patients treated with a combination of Metformin and SU (glyburide, glimepiride, glibenclamide, glipizide or gliclazide) in stable doses for at least 2 months prior to enrolment visit
• Patients should have FPG in the range of 6,0 to 14 mmol/L (108 to 250 mg/dL) at enrolment and on the morning of randomisation

Exclusion Criteria:

• History of ischemic heart disease, symptomatic heart failure, stroke, transitory ischemic attack or symptomatic peripheral vascular disease
• Impaired renal function in terms of GFR<60 ml/min
• Use of insulin, glitazones, gemfibrozil, warfarin, amiodarone within 3 months prior to enrolment (screening) and use of potent CYP450 inhibitors, e.g., ketoconazole within 14 days before randomisation