Meta-Analysis of Noncompartmental Pharmacokinetic Parameters to Evaluate the Impact of CYP2C19 and CYP2C9 Genetic Polymorphisms on Abrocitinib Exposure

Abrocitinib is a selective Janus kinase 1 inhibitor approved for the treatment of atopic dermatitis. It is metabolized primarily by cytochrome P450 (CYP) 2C19 (approximately 53%) and CYP2C9 (approximately 30%), which form 2 active metabolites. The pharmacologic activity of abrocitinib is attributable to the unbound exposures of abrocitinib and those metabolites with active moiety area under the plasma concentration–time curve (AUC) considered the best measure of the total pharmacological effect. The effect of CYP2C19 and/or CYP2C9 genotypes on abrocitinib and active moiety exposures were evaluated using a meta-analysis of the noncompartmental estimates of exposure pooled from 10 clinical studies. A linear mixed-effects model was developed on the basis of the power model to evaluate the effect of CYP2C19 and/or CYP2C9 genotypes on exposure (i.e., abrocitinib AUC and peak plasma concentration, active moiety AUC and peak plasma concentration). The genotypes were evaluated individually and as a combined phenotype effect. When evaluating the poor metabolizers of CYP2C19 or CYP2C9 individually, the estimated increases were 44.9% and 42.0% in active moiety AUC, respectively. The combined phenotype models showed a 0.6% decrease, and 25.1% and 10.5% increases in the active moiety AUC for “elevated,” “mixed,” and “reduced” metabolizers, respectively. Overall, the active moiety exposures did not appear to be affected to a clinically meaningful extent by different genotypes of CYP2C19 and/or CYP2C9.