A Phase IIb clinical trial to investigate the safety and efficacy of antiplatelet thrombolysin injection for patients with ST Segment Elevation Myocardial Infarction (STEMI) before receiving PCI therapy, in order to provide evidence for Phase III design.

Anfibatide is a snake venom, and we have investigated it in humans for many years with phase 1&2a studies. A Phase IIb clinical trial to investigate the safety and efficacy of antiplatelet thrombolysin injection for patients with ST Segment Elevation Myocardial Infarction (STEMI) before receiving PCI therapy, in order to provide evidence for Phase III design.

Inclusion Criteria:

1. Aged 18-75 years;
2. Fulfill the standard of direct PCI: ST Segment Elevation Myocardial Infarction occurred < 12 hours (ST Segment Elevation or New Left Bundle Branch Block (LBBB), combined myocardial ischemia chest pain medical history or the dynamic change of cardiac marker (troponin and/or CK-MB);
3. Patients who will receive PCI and suitable for angioplasty and stent placement;
4. Patients, or their family or guardian give signed informed consent forms.

Exclusion Criteria:

1. Patients with weight < 50kg;

2. Patients with severe hepatic or renal dysfunction, alanine aminotransferase (ALT) exceeds 3 times the normal maximum reference level, creatinine clearance level < 30ml/min or serum creatinine ≥ 200μmol/L or ≥2.5mg/dl;

3. Patients with severe hemodynamic instability;

4. Patients who will receive 2 times or more PCI treatment;

5. Patients with heart function in decompensatory phase (Killip grade 3-4) or cardiac shock;

6. Patients with untreated hypertension (SBP > 180mmHg or DBP > 110mmHg) or hypotension shock (SBP < 90mmHg);

7. Patients received GPIIb/IIIa receptor antagonists and/or thrombolytic therapy before randomization;

   1. Used eptifibatide and tirofiban in the past 12 hours before the randomization;
   2. Used abxicimab in the past 7 days before the randomization;
   3. Have received thrombolytic therapy before the randomization;

8. Patients who need a long-term treatment of clopidogrel;

9. Patients who have received enoxaparin sodium injection before the surgery;

10. Patients who have hemorrhage risk:

    1. Suffered from ischemic stroke or transient ischemic attack (TIA) in the past 12 months;
    2. Suffered from hemorrhage stroke, or other life-long neuronal dysfunction;
    3. Suffered from tumor, arteriovenous malformation in brain and aneurysms;
    4. Suffered from traumatic brain injury in the past 3 months, or received major surgery;
    5. Received percutaneous coronary intervention (PCI) in the past 6 months;
    6. Have received coronary artery bypass graft therapy (CABG);
    7. Receiving long-term oral anticoagulants therapy;
    8. Suffered from active peptic ulcer, urinary and reproductive tract hemorrhage, or other active hemorrhage.

11. Patients with coagulation disorder:

    1. Known as international normalized ratio > 2*;
    2. Patients with coagulation abnormalities or other hemorrhagic tendency (including inherited hemorrhagic diseases, e.g. Von Willebrand disease or hemophilia; acquired hemorrhagic diseases; and other clinically identified hemorrhagic diseases with unsolved rationale);
    3. Hematology test shows platelet count < 100x109mm3/L, or hemoglobin < 100g/L;
    4. Recorded clopidogrel-related thrombocytopenia or agranulocytosis;

12. Life expectancy < 1 year;

13. Patients who have implemented with pacemaker, and contraindicated to MRI examination;

14. Patients who are allergic constitution or allergic to any component of aspirin, clopidogrel, creatinine, antiplatelet thrombolysin and investigational product;

15. Women in pregnant or lactation period, or women of child-bearing age do not take efficient contraception measures;

16. Patients who are participating or will be participating in other clinical trials;

17. Patients who have participated in clinical trials of antiplatelet thrombolysin or other related trials;

18. Patients who are not suitable for participating in this clinical trial according to the investigator's judgment, including who are unable or unwilling to follow the protocol;

19. Patients who participated in other clinical trials in the past 3 months.