Pharmacokinetics of ibrutinib in a patient with chronic lymphocytic leukemia on hemodialysis.

Ibrutinib, an oral Bruton's tyrosine kinase inhibitor, is a key drug for the treatment of chronic lymphocytic leukemia (CLL). It is primarily metabolized by cytochrome P450 3A. However, there are no data on the pharmacokinetics of ibrutinib in patients with severe renal impairment or on hemodialysis (HD). We evaluated the pharmacokinetics of ibrutinib in a patient with CLL undergoing HD. An 84-year-old man on HD was diagnosed with CLL and was started on ibrutinib 140 mg daily. The second day of ibrutinib administration was an HD day, and its plasma concentrations before and 1, 2, 4, and 24 hours after administration were measured and found to be 0, 6.9, 28.4, 57.1, and 0 ng/mL, respectively. The maximum plasma concentration (Cmax) and time taken to reach Cmax (tmax) on days 14 and 15 of ibrutinib treatment were 64.8 ng/mL (4 hours) and 48.1 ng/mL (2 hours), respectively. Thus, we concluded that HD did not have a significant effect on the pharmacokinetics of ibrutinib in this patient. Therefore, dose adjustment of ibrutinib between HD and non-HD days is not recommended. Interestingly, we found that tmax of the drug was prolonged, and Cmax was higher on HD days compared to those on non-HD days.