Prognostic implication of CYP2C19 genotype during chronic clopidogrel monotherapy after percutaneous coronary intervention

CYP2C19

CYP2C19 metaboliser status (intermediate or poor vs rapid or normal) applied to clopidogrel monotherapy after the standard dual antiplatelet period

Drawing on the SMART-CHOICE 3 trial and the nationwide PTRG-DES consortium, the authors analysed 1,352 patients genotyped for CYP2C19 who had completed the standard duration of dual antiplatelet therapy without a cardiovascular event. Of these, 807 carried a loss-of-function allele and were classified as intermediate or poor metabolisers. The composite primary outcome (all-cause death, myocardial infarction, stroke) at three years after switching to clopidogrel monotherapy did not differ between groups (1.2% vs 2.2%; adjusted HR 0.53; 95% CI 0.20-1.44). Major bleeding risk was comparable (1.1% vs 2.0%) and subgroup analyses showed no significant interaction.

Synthesis written by Geno'X. For the full original abstract, please refer to the source publication.

A negative result that delimits where the test belongs: the value of CYP2C19 genotyping concentrates on the acute post-intervention phase, not on long-term maintenance once the high-risk period has passed. The reasoning holds largely because the population is selected on freedom from events during dual antiplatelet therapy, which effectively removes the patients in whom genotype would have weighed. Very low event rates in both arms leave genuine uncertainty about power, and extrapolation beyond an East Asian population, where loss-of-function alleles are far more frequent, needs checking.

Analysis by Dr Thibaut Benquey