SP2086 is a new dipeptidy1 peptidase(DPP)-4 inhibitors. This study aims to evaluate the efficacy and safety of SP2086 as monotherapy in patients with Type 2 Diabetes Mellitus in Metformin monotherapy Who Have Inadequate Glycemic Control treated with diet and exercise for 3 months

Inclusion Criteria:

• Patients diagnosed with type 2 diabetes mellitus
• Patients have treated with diet/exercise at least 3 months
• 7.5% ≤HbA1C ≤11.0% at screening,7.0% ≤HbA1C ≤10.5% after run-in

Exclusion Criteria:

• Patient has history of type 1 diabetes mellitus
• Patient has history of ketoacidosis
• Patient has history of severe unconscious hypoglycemosis
• Patient has history of acute and chronic pancreatitis or pancreatic injury that may lead to high risk of pancreatitis
• Patient has history of decompensated heart failure (NYHA class III and IV), unstable angina, stroke or transient ischemic attack, myocardial infarction, persistence and clinical
• Patient has history of a history of hypertension, and after antihypertensive treatment, systolic blood pressure ≥ 160 mmHg or diastolic blood pressure ≥ 100 mmHg
• Patient has severe liver or kidney disease,alanine aminotransferase >2×UNL, Aspartate Aminotransferase >2×upper normal limit(UNL)；total bilirubin >2×UNL； creatinine>1.5 mg/dL (Male,132.6μmol/L) ，>1.4 mg/dL(Female，123.8μmol/L)
• Patient has severe chronic gastrointestinal disease or therapy that may affect drug absorption, such as gastrointestinal surgery
• Patient has severe haematological diseases or other diseases leading to hemolyze and red blood cell unstable (malaria、haemolytic anaemia eg. )
• Patient has other endocrine diseases, for example hyperthyroidism、hypothyroidism、hypercortisolism、multiple endocrine neoplasia and so on
• Patient has history of malignancy
• Patient has history of alcohol or drug abuse