The Effect of Verapamil, a P-Glycoprotein Inhibitor, on the Pharmacokinetics of Peficitinib, an Orally Administered, Once-Daily JAK Inhibitor.

Peficitinib is an orally administered, once-daily Janus kinase inhibitor currently in development for the treatment of rheumatoid arthritis. It has been shown to be a P-glycoprotein (P-gp) substrate in vitro. The effects of verapamil, an inhibitor of the efflux pump P-gp, on the pharmacokinetic profile of peficitinib were assessed in this open-label, single-center, single-sequence, crossover drug-interaction study. Twenty-four healthy volunteers received a single 150-mg dose of peficitinib on days 1 and 12 of a 14-day treatment period and received verapamil 80 mg 3 times daily on days 5-14. Repeated-dose administration of verapamil increased mean peficitinib AUC , AUC , and C by 27%, 27%, and 39%, respectively, and also increased the mean AUC and C of peficitinib metabolites H1, H2, and H4. Coadministration of verapamil with peficitinib 150 mg was generally well tolerated. Overall, the most commonly reported adverse event was headache, which occurred in 5 subjects (21%); all reported adverse events were grade 1 severity, with the exception of 1 grade 2 incident of vomiting.