Efficacy/Safety Study of Amaryl®M 1/500 mg Twice Daily Versus Amaryl® 4 mg Both in Combination With Lantus® in Type 2 Diabetes Mellitus

Inclusion Criteria: * Patients over 20 years old with type 2 DM * Patients with inadequate glycemic control despite continuous use of tolerable or maximal doses of one or more OADs for 3months or more. * 7%\<HbA1c\<11 % at screening * 21 kg/m2 ≤ BMI ≤ 30 kg/m2 * Patents who need insulin add-on therapy based on investigator's discretion * Patients who would give the informed consent * Patients who can perform SMBG and record the data on the patient's diary Exclusion Criteria: * History of acute metabolic complications such as diabetic ketoacidosis or hyperosmolar nonketotic coma within 3 months before screening * Pregnant or lactating females * History of drug or alcohol abuse * Patients with known hypersensitivity to glimepiride, metformin HCL or insulin * Night-shift workers * Patients who are under insulin therapy at screening * Treatment with any investigational products in the last 3 months before screening * Clinically significant laboratory abnormality on screening labs or any medical condition that would affect the completion or outcome of the study based on investigator's decision * Patients with serum creatinine level \> 1.5 mg/dl in male and \> 1.4 mg/dl in female * Patients with ALT or AST \> 3x ULN