The pH-altering agent omeprazole affects rate but not the extent of ibrutinib exposure

Abstract

Purpose

This drug-interaction study evaluated the effect of omeprazole, a proton-pump inhibitor, on ibrutinib's pharmacokinetics (PK) in healthy participants.

Methods

This open-label, sequential-design study included 20 healthy adults aged 18–55 years. Ibrutinib (560 mg, single dose) was administered after an overnight fast alone on day 1 and with omeprazole on day 7. Omeprazole (40 mg) alone was administered on days 3–6, 1 h before breakfast; and after an overnight fast on day 7, followed by ibrutinib 2 h later. Blood was sampled on days 1 and 7 for up to 48 h postdose, and the standard PK parameters for ibrutinib and PCI-45227 were summarized using descriptive statistics. The effect of omeprazole on ibrutinib's PK was determined by assessing geometric mean ratios (GMRs) and 90% CIs. Mechanistic modeling was performed using the BTK-receptor occupancy (RO) model.

Results

AUC_48h and AUC_last of ibrutinib plus omeprazole versus ibrutinib alone showed a modest decrease (GMR [90% CI] 98.3% [83.1–116.3] and 92.5% [77.8–109.9], respectively); C_max decreased by 62.5% (GMR [90% CI] 37.5% [26.4–53.4]), with delayed t_max (1−2 h) and terminal half-life unaffected. Mean AUC for PCI-45227 (primary metabolite) was ~ 20% lower with ibrutinib plus omeprazole versus ibrutinib alone. Model predictions showed no impact of decreased C_max on BTK target engagement. No new safety signals were identified with the use of ibrutinib in this study.

Conclusions

The decrease in C_max without a corresponding decrease in AUC by omeprazole was not clinically relevant for ibrutinib's bioavailability. No dose adjustments are recommended during ibrutinib's co-administration with omeprazole or other pH-altering agents.

https://ift.tt/2zUVsGw