Comparison of Ticagrelor, the First Reversible Oral P2Y(12) Receptor Antagonist, with Clopidogrel in Patients with Acute Coronary Syndromes: Rationale, Design, and Baseline Characteristics of the PLATelet Inhibition and Patient Outcomes (PLATO) Trial

Background: Antiplatelet therapy is essential treatment for acute coronary syndromes (ACS). Current therapies, however, have important limitations affecting their clinical success. Ticagrelor, the first reversible oral P2Y(12) receptor antagonist, provides faster, greater, and more consistent adenosine diphosphate-receptor inhibition than clopidogrel. The phase III PLATelet inhibition and patient Outcomes (PLATO) trial is designed to test the hypothesis that ticagrelor compared with clopidogrel will result in a lower risk of recurrent thrombotic events in a broad patient population with ACS.

Methods: PLATO is an international, randomized, double-blind, event-driven trial involving >18,000 patients hospitalized for ST-elevation ACS with scheduled primary percutaneous coronary intervention or for non-ST-elevation ACS. After loading doses of ticagrelor 180 mg or clopidogrel 300 mg in a double-blind, double-dummy fashion (with provision for additional 300 mg clopidogrel at percutaneous coronary intervention), patients will receive ticagrelor 90 mg twice daily or clopidogrel 75 mg once daily for 6 to 12 months on top of acetylsalicylic acid. The primary efficacy end point is time to first occurrence of death from vascular causes, myocardial infarction, or stroke. The primary safety variable is PLATO-defined major bleeding. An extensive substudy program will explore the pathophysiology of ACS, indicators of prognosis and response to treatment, mechanisms of effect and safety of the study medications, health economics, and quality of life.

Conclusion: The PLATO study will provide a pivotal comparison of the efficacy and safety of ticagrelor with those of clopidogrel in ACS patients, together with extensive information on treatment outcomes in different subsets of ACS in a broad patient population.