One-Year Outcomes of Early Therapy With Ticagrelor vs Clopidogrel in CYP2C19 Loss-of-Function Carriers With Stroke or TIA Trial

Background and Objectives The Ticagrelor or Clopidogrel with Aspirin in High-Risk Patients with Acute Nondisabling Cerebrovascular Events II (CHANCE-2) trial showed that among Chinese patients with minor ischemic stroke or transient ischemic attack (TIA) who were carriers of CYP2C19 loss-of-function alleles, dual-antiplatelet therapy with ticagrelor-aspirin reduced the 90-day risk of stroke without increased severe or moderate bleeding compared with clopidogrel-aspirin. However, whether dual-antiplatelet therapy with ticagrelor was superior to clopidogrel beyond the 90 days of follow-up remained unclear. In this study, we reported 1-year follow-up outcomes of the CHANCE-2 trial. Methods The CHANCE-2 trial is a randomized, double-blind, placebo-controlled trial at 202 centers in China. Patients with a minor stroke or TIA who carried CYP2C19 loss-of-function alleles were randomized within 24 hours after symptom onset, in a 1:1 ratio, to receive ticagrelor and placebo clopidogrel or to receive clopidogrel and placebo ticagrelor for 90 days; both groups received aspirin for the first 21 days. After day 90, treatment was as per the choice of the clinician and the patient. Results Among 6,412 patients, the proportion of patients on ticagrelor plus aspirin, clopidogrel plus aspirin, ticagrelor alone, clopidogrel alone, aspirin alone, other antiplatelet, and no antiplatelet beyond month 3 to 1 year was 0.09%, 1.56%, 0.13%, 2.66%, 73.65%, 0.78%, and 21.13% in the ticagrelor-aspirin group and 0.03%, 1.63%, 0.19%, 2.60%, 72.83%, 0.66%, and 22.06% in the clopidogrel-aspirin group, respectively. The primary outcome of new stroke occurred in 252 patients (7.91%) in the ticagrelor-aspirin group and 310 patients (9.73%) in the clopidogrel-aspirin group by 1 year of follow-up (hazard ratio 0.80; 95% CI 0.68-0.95; p = 0.007); new stroke beyond 3 months to 1 year occurred in 61 patients (2.07%) and 67 patients (2.32%) (p = 0.48), respectively. Primary safety outcome of severe or moderate bleeding occurred in 17 patients (0.53%) in the ticagrelor-aspirin group and 20 patients (0.63%) in the clopidogrel-aspirin group (p = 0.61). Discussion For CYP2C19 loss-of-function allele carriers, early dual-antiplatelet therapy with ticagrelor is superior to clopidogrel at 1 year in reducing recurrent stroke.