CYP3A4*22 Impairs the Elimination of Ticagrelor, But Has No Significant Effect on the Bioactivation of Clopidogrel or Prasugrel

CYP3A enzymes participate in the elimination of ticagrelor and the bioactivation of clopidogrel and prasugrel. We studied the effects of functional CYP3A genetic variants (CYP3A4*22; rs35599367 and CYP3A5*3; rs776746) on the pharmacokinetics and pharmacodynamics of ticagrelor, clopidogrel, and prasugrel. Six healthy volunteers with the CYP3A4*1/*22 and CYP3A5*3/*3 genotype (CYP3A4*22 carriers), eight with the CYP3A4*1/*1 and CYP3A5*1/*3 genotype (CYP3A5 expressors), and 11-13 with the CYP3A4*1/*1 and CYP3A5*3/*3 genotypes (controls) ingested single doses of ticagrelor, clopidogrel, and prasugrel on separate occasions. Ticagrelor area under the plasma concentration-time curve (AUC) was 89% (P = 0.004) higher in CYP3A4*22 carriers than in controls. CYP3A4*22 carriers also showed more pronounced platelet inhibition at 24 hours after ticagrelor ingestion than the controls (43% vs. 21%; P = 0.029). The CYP3A5 genotype did not affect ticagrelor pharmacokinetics. Neither CYP3A5 nor CYP3A4 genotypes significantly affected prasugrel or clopidogrel. In conclusion, the CYP3A4*22 allele markedly impairs ticagrelor elimination enhancing its antiplatelet effect.