A Study of Efficacy and Safety of Supaglutide in Type 2 Diabetes Patients On Metformin Treatment(SUPER-2)

1. Male or female patients aged from 18 to 75;

2. Clinical diagnosed of Type 2 diabetes for at least 8 weeks ，receive metformin single treatment ；

3. During screening, HbA1c: 7.5% ≤ HbA1c ≤ 11% ，and before randomization 7.5% ≤ HbA1c ≤ 10.5%;

4. During screening and before randomization: FPG< 13.9 mmol/L； 5.18.5 kg/m2 ≤ BMI ≤ 35 kg/m2;

6. without birth plan and voluntarily take effective contraceptive measures; 7. fully understood the study, signed the informed consent；

1. Diabetes other than Type 2;

2. Any dipeptidyl peptidase IV and / or glucagon-like peptide-1 （GLP-1）analogues were used within 3 months before screening;

3. Continuous use of insulin for more than 14 days in the previous year;

4. C-Peptide <0.3 nmol/L;

5. Diabetic ketoacidosis, diabetic lactic acidosis or hyperosmolar non ketonic diabetic coma occurred within 6 months before screening;

6. Unstable proliferative retinopathy or macular lesion, severe diabetic neuropathy, intermittent claudication or diabetic foot occurred within 6 months before screening;

7. Severe hypoglycemia occurred within 6 months before screening

8. Severe trauma infection or operation within one month before screening;

9. Blood donation or massive blood loss or transfusion within 3 months ;

10. Suspected active infection ;

11. Growth hormone therapy was performed within 6 months before screening;

12. Patients having received corticosteroid continuous ≥ 7 days through within 2 months ;

13. use any drugs or surgery with weight control effect within 2 months;

14. weight change of more than 5% within 3 months;

15. mean systolic pressure (SBP) ≥ 160mmhg and / or diastolic pressure （DBP） ≥ 90 mmHg at screening, or new/changed antihypertensive drugs or adjusted dosage of antihypertensive drugs within 4 weeks before screening or before induction period

16. with a history of severe cardiovascular disease, high risk of stroke/stroke within 6 months before screening;

17. with a history of acute or chronic pancreatitis, symptomatic gallbladder , pancreatic injury and other risk factors for pancreatitis, or with blood amylase and/or blood lipase ≥1.5 times the upper limit of normal (ULN) at the time of screening or before randomization;

18. Calcitonin level ≥50 ng/L (pg/mL) during screening;

19. with a history of medullary thyroid cancer, multiple endocrine neoplasm (Men) 2A or 2B syndrome, or related family history;

20. with clinically significant abnormal gastric emptying , severe chronic gastrointestinal diseases , long-term use of drugs that have a direct impact on gastrointestinal peristalsis , or having undergone gastrointestinal surgery within 6 months before screening, are not suitable to participate in this clinical study according to the evaluation of the researchers;

21. suffering from hematological diseases or any disease causing hemolysis or erythrocyte instability ;

22. Uncontrolled hyperthyroidism or hypothyroidism;

23. with hemoglobinopathy that may affect the determination of HbA1c levels;

24. HBsAg, Hepatitis C antibody, HIV-Ab, Treponema pallidum antibody or Corona Virus Disease 2019 nucleic acid tested positive;

25. serious mental illness;

26. drinking more than 14 standard units weekly within 6 months before screening ;

27. a history of organ transplantation or other acquired or congenital immune system diseases;

28. allergic to the active ingredients (GLP-1 and GLP-1 analogues) of the study drug;

29. clear contraindications for the use of metformin;

30. clear contraindications for Empagliflozin；

31. Any of the following conditions: the pacemaker was installed when screened; no pacemaker was installed, but 12 lead ECG showed degree II or III atrioventricular block, long QT syndrome or QTc interval ≥ 450ms ; Patients with New York Heart Function Classification III or IV; Or other abnormal cardiac function with clinical significance that is not suitable for clinical research judged by researchers;

32. acute or chronic hepatitis, or whose laboratory examination indexes meet one of the following criteria at the time of screening or before randomization : alanine aminotransferase (ALT) level ≥ 2.5 fold ULN, aspartate aminotransferase (AST) ≥ 2.5 fold ULN, fasting triglyceride (TG) > 5.7 mmol/L or 500 mg/dl; the glomerular filtration rate (EGFR) < 60 ml/min/1.73 square meters was calculated by CKD-EPI (epi - (SCR)) formula;

33. participated in clinical trials of other drugs or devices within 3 months before screening;

34. Medication compliance in the metformin dosage stable period was < 80% or > 120%;

35. Supaglutide placebo injection compliance during the induction period was <75% or>125%, or metformin compliance <80% or >120%;

36. Any other situation that researchers think may affect the patients' informed consent or compliance with the trial protocol;