Aim of the randomized, open-label, multicenter ISAR-REACT 5 trial is to assess whether ticagrelor is superior to prasugrel in patients with acute coronary syndrome and planned invasive strategy in terms of clinical outcomes.

Major Inclusion Criteria:

Hospitalization for an acute coronary syndrome (ST-segment elevation myocardial infarction, non-ST-segment elevation myocardial infarction or unstable angina pectoris) with planned invasive strategy

Major Exclusion Criteria:

1. intolerance of or allergy to ticagrelor or prasugrel
2. history of any stroke, transient ischemic attack or intracranial bleeding
3. known intracranial neoplasm, intracranial arteriovenous malformation or intracranial aneurysm
4. active bleeding, clinical findings, that in the judgement of the investigator are associated with an increased risk of bleeding
5. fibrin-specific fibrinolytic therapy less than 24 h before randomization, non-fibrin-specific fibrinolytic therapy less than 48 h before randomization
6. known platelet count < 100.000/μL at the time of screening
7. known anemia (hemoglobin <10 g/dL) at the time of screening
8. oral anticoagulation that cannot be safely discontinued for the duration of the study
9. INR known to be greater than 1.5 at the time of screening
10. chronic renal insufficiency requiring dialysis
11. moderate or severe hepatic dysfunction (Child Pugh B or C)
12. increased risk of bradycardia events (Sick Sinus, AV block grade II or III, bradycardia-induced syncope)
13. index event is an acute complication (< 30 days) of PCI
14. concomitant medical illness that in the opinion of the investigator is associated with a life expectancy < 1 year
15. concomitant oral or i.v. therapy with strong CYP3A Inhibitors (e.g. ketoconazole, itraconazole, voriconazole, telithromycin, clarithromycin, nefazodone, ritonavir, saquinavir, nelfinavir, indinavir, atazanavir, grapefruit juice > 1 L/d), CYP3A substrates with narrow therapeutic indices (e.g. cyclosporine, quinidine), or strong CYP3A inducers (e.g. rifampin/rifampicin, phenytoin, carbamazepine, dexamethason, phenobarbital ) that cannot be safely discontinued
16. ≥1 doses of ticagrelor or prasugrel within 5 days before randomisation
17. no written informed consent
18. participation in another investigational drug study
19. previous enrolment in this study
20. for women of childbearing potential no negative pregnancy test and no agree to use reliable method of birth control during the study
21. Pregnancy, giving birth within the last 90 days, or lactation
22. inability to cooperate with protocol requirements