A Study of DBPR108 and Metformin Hydrochloride Combination Therapy in Patients With T2DM

Inclusion Criteria: * Diagnosis of type 2 diabetes according to World Health Organization (1999) diabetes diagnosis standard; * Age 18-75 years, men and women; * BMI 19-35 kg/m2; * HbA1c 7.0%-9.5%; * Before screening, a stable Metformin dose（≥1000mg/day）should be maintained for at least 8 weeks. * Signed informed consent from the patient; * Agree to use contraceptive measures from the date of signing the informed consent to 1 month after the end of the last medication. Exclusion Criteria: * FPG \> 13.9 mmol/L; * Insulin treatment required in the investigator's opinion; * Administration of antidiabetic drugs (except for metformin) including insulin, rosiglitazone, pioglitazone, DPP-4 inhibitor, Glucagon like peptide-1 (GLP-1) receptor agonist for 8 weeks before screening; * Acute complications of diabetes (including diabetic ketosis and ketoacidosis, hyperosmotic nonketotic diabetic coma, lactic acidosis and hypoglycemia coma); * Severe hypoglycemia; * Serious diabetic complications (such as diabetic foot, etc.); * History of acute or chronic pancreatitis, or related diseases that are most common cause of acute pancreatitis (such as recurrent cholelithiasis, etc.); * History of being allergic to DPP-4 inhibitors; * Untreated hyperthyroidism and other diseases which may cause secondary hyperglycemia; * Previous treatment with glucocorticoids (except for external use and inhalation) within 4 weeks before screening or may be used for more than 14 consecutive days during the study; * Inflammatory bowel disease, partial intestinal obstruction or chronic bowel disease related to obvious digestive and absorption disorders; * Aspartate aminotransferase (AST) or Alanine aminotransferase (ALT) \> 3\*upper limit of normal (ULN), or total bilirubin \> 1.5ULN; * Abnormal renal function; * White blood cells (WBC) \< 3.0109/l, neutrophil count of peripheral blood \< 1.5109/l, hemoglobin \< 100g / L, triglyceride \> 5.7 mmol/l; * HBsAg, HBeAg or HBcAb positive, or any one of hepatitis C antibody, anti-HIV antibody and nonspecific antibody of Treponema pallidum positive; * Pregnant or lactating women; * History of alcohol or drug abuse; * Participation in other clinical trials or administration of any other investigational drugs or devices within 3 months before screening; * Significant unstable diseases; * Any condition that in the investigator's opinion might render the patient unable to participate the trial.