SAL067 Treatment in Patients With Type 2 Diabetes Who Are Not Controlled by Metformin

Inclusion Criteria: 1. Type 2 diabetes patients who meet the diagnostic criteria for diabetes issued by the World Health Organization (WHO) in 1999; 2. Men or women aged 18 to 75 years old at the day of signing the informed consent; 3. Body mass index: BMI 19kg/m2 to 35kg/m2, \[BMI=weight (kg)/height 2 (m2)\]; 4. Subjects treated with metformin≥ 1500mg/day constantly for at least 8 consecutive weeks before screnning; 5. Glycated hemoglobin (HbA1c): Screening period: HbA1c 7.5% to 10.5% (tested by the research center), when randomly enrolled: HbA1c 7.0% to 10.0% (central laboratory test) Measurement); 6. Screening period and random time fasting blood glucose \<=13.9mmol/L. Exclusion Criteria: 1. Drug compliance during the introduction period \<80% or \>120%; 2. Use other hypoglycemic drugs other than test drugs during the introduction period; 3. The patient may have any contraindications, allergies or hypersensitivity to fuglitagliptin (including study drug and placebo) or its excipients, DPP4 drugs, metformin; 4. Before screening, have any of the following endocrine-related medical history or evidence: * Diabetes other than type 2 diabetes, such as type 1 diabetes, single-gene mutation diabetes, diabetes caused by pancreatic injury or secondary diabetes, such as diabetes caused by Cushing's syndrome or acromegaly; * diabetic ketoacidosis, hyperglycemia and hyperosmolarity, lacticacidosis and other acute complications of diabetes within 6 months before screening; * severe hypoglycemia episodes (such as sleepiness caused by hypoglycemia, unconsciousness, nonsense, and even coma), or a serious history of unconscious hypoglycemia; 5. Before screening, there is a history or evidence of any of the following diseases: * Unstable angina, stroke or transient ischemic attack, myocardial infarction, coronary artery bypass graft or percutaneous coronary intervention (diagnostic angiography is allowed of); * Decompensated heart failure before screening (New York Heart Association NYHA heart function grades III and IV, persistent and clinically significant arrhythmia; * A history of acute and chronic pancreatitis, symptomatic gallbladder disease or history of pancreatic injury, etc. may lead to high risk factors for pancreatitis.