Clopidogrel monotherapy associated with better net outcomes relative to aspirin monotherapy 6-18 months after PCI

The open-label HOST-EXAM study showed that clopidogrel monotherapy was associated with better net outcomes relative to aspirin in patients who were event-free for 6–18 months following percutaneous coronary intervention (PCI) with a drug-eluting stent (DES) over a 2-year follow-up period [1,2].

In patients who have undergone PCI, guidelines suggest 6–12 months of dual antiplatelet therapy (DAPT), typically with aspirin plus a P2Y₁₂ inhibitor such as clopidogrel. After the initial 6–12 month period, lifetime aspirin monotherapy is recommended. Prof. Hyo-Soo Kim (Seoul National University Hospital, South Korea) and colleagues aimed to explore whether an alternative monotherapy could achieve superior clinical outcomes compared with aspirin.

The primary endpoint was a composite of all-cause death, acute coronary syndrome including non-fatal MI, stroke, the need for revascularisation while under antiplatelet therapy, or Bleeding Academic Research Consortium (BARC) type ≥3 bleeds. At 2 years, 152 (5.7%) primary endpoint events had occurred in the clopidogrel group compared with 207 (7.7%) in the aspirin group (HR 0.73; 95% CI 0.59–0.70; P=0.0035).

These results demonstrated that clopidogrel monotherapy was associated with better net outcomes, driven by bleeding, to aspirin monotherapy following an event-free 6–18 months period of DAPT after PCI with DES.

The researchers acknowledged several limitations of this trial. It was open-label and conducted only in South Korea.  East Asians tend to have a higher prevalence of loss-of-function mutations of the CYP2C19 gene, yet they tend to have lower rates of thrombosis and higher rates of bleeding events following PCI (the “East Asian paradox”) [1,3]. Furthermore, most of the enrolled patients had followed a DAPT regimen for about 1 year; thus, results may not be generalisable to those who have been on DAPT for a shorter period. The investigators have launched the HOST-EXAM extended study, which will continue to follow these participants for a median of 10 years [1].

1. 
   
   1. Kim HS. Aspirin Vs. Clopidogrel During Chronic Maintenance Monotherapy After Percutaneous Coronary Intervention: The Host Exam Randomised Controlled Trial. Abstract 407-12, ACC 2021 Scientific Session, 15–17 May.
   2. Koo BK, et al. Lancet. 2021;May 16. DOI: 1016/S0140-6736(21)01063-1.
   3. Jeong YH. Curr Cardiol Rep. 2014;16(5):485.

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Posted on 9 July 202122 February 2024