Custom Gene Panel Analysis Identifies Novel Polymorphisms Associated with Clopidogrel Response in Patients Undergoing...

Clopidogrel is widely used as an antiplatelet therapy for acute coronary syndrome (ACS) patients undergoing percutaneous coronary intervention (PCI). Genetic factors influence variability in clopidogrel response, with non-functional CYP2C19 alleles increasing the risk of major adverse cardiovascular events (MACEs). While CYP2C19 genotype-guided therapy after PCI improves outcomes, MACEs persist at variable rates. Pharmacogenomics (PGx) has primarily focused on genes related to drug metabolism, but therapeutic failure may stem from individual disease predisposition. This study aims to identify novel genetic variants underlying adverse events after PCI despite PGx-guided therapy. A custom sequencing panel was analyzed in 244 ACS-PCI-stent patients and 99 controls without cardiovascular (CV) disease. Association analysis was performed independent of treatment and by prescribed treatment (clopidogrel or prasugrel), complemented by random forest models to predict risk during antiplatelet therapy. No polymorphism reached genomic significance, but in clopidogrel-treated patients, rs2472434 in ABCA1, related to altered lipid metabolism, was strongly associated with secondary CV events (p = 1.7 × 10^-3). Variants in the clopidogrel pathway, including CYP2C19, ABCB1, and UGT2B7, were also identified and may influence clopidogrel response. Predictive models incorporating these variants effectively discriminated patients with and without events (p = 0.02445). Our findings support combined genotyping of CYP2C19 loss-of-function and ABCB1 C3435T variants to guide antiplatelet therapy and suggest additional targets, such as rs2472434 (ABCA1) and rs7439366 (UGT2B7), to improve risk prediction of adverse CV events. Therefore, the unexplained variability in clopidogrel response may be due to disease pathogenesis itself, highlighting the need for a paradigm shift in PGx studies.