Itraconazole increases ibrutinib exposure ten-fold and reduces inter-individual variation – A potentially beneficial drug-drug interaction.
Clin Transl Sci. 2019 Oct 30;:
Authors: Tapaninen T, Olkkola AM, Tornio A, Neuvonen M, Elonen E, Neuvonen PJ, Niemi M, Backman JT
The oral bioavailability of ibrutinib is low and variable, mainly due to extensive first-pass metabolism by CYP3A4. The unpredictable exposure can compromise its safe and effective dosing. We examined the impact of itraconazole on ibrutinib pharmacokinetics. In a randomized crossover study, 11 healthy subjects were administered itraconazole 200 mg or placebo twice on day 1, and once on days 2-4. On day 3, 1 hour after itraconazole (placebo) and breakfast, ibrutinib (140 mg during placebo; 15 mg during itraconazole) was administered. Itraconazole increased the dose-adjusted geometric mean AUC0-∞ of ibrutinib 10.0-fold (90% CI 7.2-13.9; P < 0.001) and Cmax 8.8-fold (90% CI 6.3-12.1; P < 0.001). During itraconazole, the inter-subject variation for the AUC0-∞ (55%) and Cmax (53%) was around half of that during placebo (104%; 99%). In conclusion, itraconazole markedly increases ibrutinib bioavailability and decreases its inter-individual variability, offering a possibility to improved dosing accuracy and cost savings.
PMID: 31664782 [PubMed – as supplied by publisher]