Reviwer: Dr. Betül Balaban Koçaş

Name of the Study : Harmonizing Optimal Strategy for Treatment of coronary artery diseases-EXtended Antiplatelet Monotherapy- HOST-EXAM

Published in Congress: ACC 2021

Full Text Link: https://www.clinicalkey.com/service/content/pdf/watermarked/1-s2.0-S0140673621010631.pdf?locale=en_US&searchIndex=

Background: In patients who have completed the required period of dual antiplatelet therapy after percutaneous coronary interventions (PCI), indefinite single antiplatelet therapy is recommended for secondary prevention of atherosclerotic cardiovascular events, but the question of optimal agent is unclear.

Objective: The aim of the HOST-EXAM study was to evaluate the safety and efficacy of clopidogrel and aspirin monotherapy in patients who have completed the required dual antiplatelet therapy period after PCI with drug-eluting stent (DES).

Method: Patients were randomized 1:1 to receive clopidogrel monotherapy (n = 2710) and aspirin monotherapy (n = 2728). The follow-up period of the study was 24 months, the mean patient age was 63.5%, 75% of the patients were male and the diabetes rate was 34%. Patients aged 20 years and older, who completed 12±6 months of dual antiplatelet therapy following PCI with DES, and who did not experience any clinical events after PCI were included in the study. Of the study population, 16% had previous myocardial infarction, 18% had three-vessel disease, 5% had main coronary disease, and 9% had chronic total occlusion.

Results: At 24-month follow-up, the primary endpoint of all-cause death, myocardial infarction, stroke, re-admission due to acute coronary syndrome, and major bleeding occurred in 152 (5.7%) patients in the clopidogrel group and in 207 (7.7%) patients in the aspirin group. (HR 0.73, [95% CI 0.59–0.90]; p=0.0035). The secondary outcomes were thrombotic composite outcome 3.7% versus 5.5% (p=0.003), and bleeding from any cause 2.3% versus 3.3% (p=0003).

Conclusion: Clopidogrel monotherapy significantly reduced the combined risk of all-cause death, non-fatal myocardial infarction, stroke, rehospitalization for acute coronary syndrome, and BARC 3 or more bleeding types in the chronic maintenance period after PCI with DES compared to aspirin monotherapy. Clopidogrel monotherapy was found to be superior to aspirin monotherapy in the chronic maintenance treatment in patients who completed the required dual antiplatelet therapy period after PCI with DES.

Interpretation: The HOST-EXAM trial is the first large randomized controlled trial to demonstrate the superiority of clopidogrel in chronic maintenance therapy in patients undergoing PCI with DES. As clopidogrel has higher antiplatelet efficacy than aspirin, the risk of thrombotic events and other adverse outcomes favor clopidogrel, as expected in the results. However, the most remarkable point is that the risk of bleeding was also reduced in the clopidogrel group, which is a more potent antiplatelet agent. This makes clopidogrel a more reasonable option in patients requiring long-term maintenance therapy.