Acute myocardial infarction occurring while on chronic clopidogrel therapy ('clopidogrel failure') is associated with high incidence of clopidogrel poor responsiveness and stent thrombosis

Prior Myocardial Infarction and Treatment Effect of Ticagrelor Versus Prasugrel in Patients With Acute Coronary Syndromes - A Post-hoc Analysis of the ISAR-REACT 5 Trial

Background The efficacy and safety of ticagrelor versus prasugrel in patients with acute coronary syndrome and prior myocardial infarction (MI) remain unstudied. We aimed to assess the treatment effect of ticagrelor versus prasugrel according to prior MI status in patients with ACS. Methods and Results Patients with acute coronary syndrome planned for an invasive strategy and randomized to ticagrelor or prasugrel in the ISAR-REACT (Intracoronary Stenting and Antithrombotic Regimen: Rapid Early Action for Coronary Treatment) 5 trial were included. The primary end point was the composite of 1-year all-cause death, MI, or stroke; the secondary safety end point was the composite of 1-year Bleeding Academic Research Consortium type 3 to 5 bleeding. The study included 4015 patients (prior MI=631 patients; no prior MI=3384 patients). As compared with patients without prior MI, the primary end point occurred more frequently in patients with prior MI (12.6% versus 7.2%; hazard ratio [HR], 1.78 [95% CI, 1.38-2.29]); the secondary safety end point appears to differ little between patients with and without prior MI (5.8% versus 5.7%, respectively; HR, 1.02 [95% CI, 0.71-1.45]). With regard to the primary end point, ticagrelor versus prasugrel was associated with an HR of 1.62 (95% CI, 1.03-2.55) in patients with prior MI and an HR of 1.28 (95% CI, 0.99-1.65) in patients without prior MI (P_int=0.37). With regard to the secondary safety end point, ticagrelor versus prasugrel was associated with an HR of 1.28 (95% CI, 0.56-2.91) in patients with prior MI and an HR of 1.13 (95% CI, 0.82-1.55) in patients without prior MI (P_int=0.79). Conclusions Patients with acute coronary syndrome and prior MI are at higher risk for recurrent ischemic but not bleeding events. Prasugrel is superior to ticagrelor in reducing the risk of ischemic events without a tradeoff in bleeding regardless of prior MI status. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT01944800.

Pre-admission antiplatelet therapy and treatment effect of ticagrelor vs. prasugrel in patients with acute coronary syndromes-a subgroup analysis of the ISAR-REACT 5 trial

AIMS

To assess whether the efficacy and safety of ticagrelor vs. prasugrel in patients with acute coronary syndromes (ACSs) are influenced by pre-admission treatment with aspirin and/or clopidogrel.

METHODS AND RESULTS

Patients (n = 4018) were categorized into two groups: pre-admission aspirin and/or clopidogrel group (n = 1455) and no pre-admission aspirin or clopidogrel group (n = 2563). The primary endpoint was the composite of all-cause death, myocardial infarction, or stroke; the secondary safety endpoint was Bleeding Academic Research Consortium (BARC) type 3-5 bleeding, both at 1 year. Patients in the pre-admission aspirin and/or clopidogrel group had a higher risk of ischaemic events, but a similar risk of bleeding to patients in the no pre-admission aspirin or clopidogrel group (cumulative incidences 10.5% vs. 6.7%, and 5.7% vs. 5.7%, respectively). The primary endpoint occurred in 81/717 patients assigned to ticagrelor and 69/738 patients assigned to prasugrel in the pre-admission aspirin and/or clopidogrel group [11.5% vs. 9.5%; hazard ratio (HR) = 1.23; 95% confidence interval (CI) 0.89-1.69], and in 103/1295 patients assigned to ticagrelor and 68/1268 patients assigned to prasugrel in the no pre-admission aspirin or clopidogrel group [8.0% vs. 5.4%; HR = 1.50 (1.10-2.03); Pint = 0.38]. BARC type 3-5 bleeding events did not differ between ticagrelor and prasugrel in patients in the pre-admission aspirin and/or clopidogrel (6.2% vs. 4.5%) or no pre-admission aspirin or clopidogrel (5.3% vs. 5.1%) group (Pint = 0.54).

CONCLUSION

In patients with ACS, pre-admission therapy with aspirin and/or clopidogrel has no influence on the relative efficacy and safety of ticagrelor and prasugrel.