A multicomponent intervention incorporating CYP2C19 genotype-guided therapy and integrated pharmaceutical care reduces hospitalizations and improves adherence in ischemic stroke.

Clopidogrel bioactivation depends on CYP2C19 activity: intermediate and poor metabolizer phenotypes reduce conversion of the prodrug and blunt platelet inhibition, prompting therapy adjustment.

This single-center, prospective, parallel-group, open-label, assessor-blinded randomized trial enrolled 300 ischemic stroke patients, allocated to a complex pharmacist-led intervention combining CYP2C19 genotype-guided antiplatelet therapy with integrated pharmaceutical care (n = 150) or to routine care (n = 150). In the individualized arm, intermediate and poor metabolizers were far more often switched or adjusted (48.72% and 77.27% vs 10.00%, p < 0.001), and genotype correlated with treatment modification (ρ = 0.476, p < 0.001). At one year, hospitalization frequency was lower in the individualized arm (IRR = 0.700, 95% CI 0.491-0.999, p = 0.049) and medication adherence higher (adjusted mean difference = 0.533, 95% CI 0.250-0.815, p < 0.001). The benefit on hospitalizations was more pronounced in patients at high recurrence risk (ESRS ≥ 3: IRR = 0.640, 95% CI 0.425-0.965, p = 0.033), with no significant between-group difference in adverse reactions after adjustment (OR = 0.543, 95% CI 0.279-1.057, p = 0.072). The authors acknowledge that the specific contribution of genotyping cannot be separated from the overall care package.

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

This is a randomized trial with a hard clinical endpoint, still uncommon in applied pharmacogenetics, but the intervention is a bundle: genotyping, therapeutic education and pharmacist follow-up are delivered together, so the effect attributable to CYP2C19 alone cannot be estimated. The upper confidence bound for hospitalizations reaches 0.999, which argues for describing a signal rather than a demonstration, in a single-center open-label setting. It is a useful argument for funding a pharmacist-genotype pathway, provided it is not presented as proof of a benefit from genotyping itself.

Analysis by Dr Thibaut Benquey