Pharmacokinetics of the co-administration of boceprevir and St John's wort to male and female healthy volunteers.

BACKGROUND

St John's wort (SJW; Hypericum perforatum) induces CYP3A4 that is involved in the metabolism of the hepatitis C virus (HCV) protease inhibitor boceprevir. Reduced boceprevir exposure and efficacy would contribute to therapeutic failure and increase the risk for resistance development. Boceprevir is co-administered with interferon/ribavirin, and depression has been described frequently in patients undergoing HCV treatment. Patients may purchase over-the-counter herbals to manage depression, and knowing the interaction between SJW and boceprevir is desirable.

METHODS

This Phase I, open-label, three-period, cross-over pharmacokinetic study enrolled healthy males and females who, following consent and screening procedures, were randomized to receive SJW on days 1-14, SJW plus boceprevir (SJW on days 22-35 and together on days 31-35) and boceprevir on days 52-56, separated by 7 day washout periods, or the same treatment in the opposite order. Pharmacokinetic sampling was performed at the end of each phase.

RESULTS

Seventeen (11 female) subjects completed the study and no serious adverse events were reported. Geometric mean ratios (GMRs) and 90% CIs for boceprevir (with SJW versus alone) AUC(0-8), C(max) and C8 were 0.91 (0.87-0.96), 0.94 (0.82-1.07) and 1.00 (0.79-1.27), respectively. GMRs and 90% CIs for hypericin, the active component of SJW, (with boceprevir versus alone) AUC(0-8), C(max) and C(8) were 1.23 (1.10-1.38), 1.32 (1.16-1.52) and 1.37 (1.19-1.58), respectively.

CONCLUSIONS

SJW did not have a clinically significant effect on boceprevir plasma concentrations (or those of its metabolite), suggesting that SJW and boceprevir can be safely co-administered.