The PK/PD, Efficacy, Safety and Tolerability Study of SHR3824 in Combination With Metformin in Type 2 Diabetes Mellitus Patients

Inclusion Criteria: * Patients must have a diagnosis of type 2 diabetes mellitus; * Hemoglobin A1c levels \>=7.5% and \<=10.5%; * Body mass index (BMI) 25 to 45 kg/m2; * Patient either has been treated with metformin for more than 8 weeks with dose more than 1500mg/day. Exclusion Criteria: * Type I diabetes mellitus, diabetes mellitus resulting from pancreatic disorder, or secondary diabetes mellitus (acromegaly, Cushing's syndrome, etc.); * Past or current history of severe diabetic complications (proliferative diabetic retinopathy, stage III or later stage overt nephropathy, diabetic ketoacidosis, or serious diabetic neuropathy); * Systolic blood pressure of ≥160 mmHg or diastolic blood pressure of ≥100 mmHg on the start or end day of the run-in period; * History of myocardial infarction, unstable angina, or cerebrovascular disorder within 6 months before the start of the run-in period; * Past or current history of malignant tumor; * Past or current history of drug hypersensitivity such as shock and anaphylactoid symptoms; * Pregnant women, lactating mothers, or women of childbearing potential; * Any condition that subjects are assessed to be ineligible by the investigator (sub investigator).