han that of ibrutinib. The range of the mean metabolite to parent ratio for PCI-45227 at steady-state is 1 to 2.8.
Elimination
Apparent clearance (CL/F) is approximately 1000 L/h. The half-life of ibrutinib is 4 to 6 hours.
Ibrutinib, mainly in the form of metabolites, is eliminated primarily via feces. After a single oral administration of radiolabeled [14C]-ibrutinib in healthy subjects, approximately 90% of radioactivity was excreted within 168 hours, with the majority (80%) excreted in the feces and less than 10% accounted for in urine. Unchanged ibrutinib accounted for approximately 1% of the radiolabeled excretion product in feces and none in urine, with the remainder of the dose being metabolites.
Age
Age (37 to 84 years) does not alter ibrutinib systemic clearance.
Gender
Gender does not alter ibrutinib systemic clearance.
Renal Impairment
Ibrutinib is not significantly cleared renally; urinary excretion of metabolites is < 10% of the dose. Creatinine clearance > 25 mL/min had no influence on the exposure to IMBRUVICA. There are no data in patients with severe renal impairment (CLcr < 25 mL/min) or in patients on dialysis.
Hepatic Impairment
Ibrutinib is metabolized in the liver. No clinical trials have been completed in subjects with impaired hepatic function. Preliminary PK data from an ongoing trial in subjects with hepatic impairment indicate that ibrutinib exposure is approximately 6-fold higher in subjects (N=3) with moderate hepatic impairment (Child-Pugh B) compared with mean exposures observed in healthy volunteer trials.
Drug Interactions
Coadministration of Ibrutinib with CYP3A Inhibitors
In a sequential design trial of 18 healthy volunteers, a single dose of 120 mg of IMBRUVICA was administered alone on Day 1 and a single dose of 40 mg of IMBRUVICA was administered on Day 7 in combination with 400 mg of ketoconazole (given daily on Days 4 – 9). Ketoconazole increased ibrutinib dose-normalized Cmax and AUC 29-fold and 24-fold, respectively. Simulations using physiologically-based pharmacokinetic (PBPK) models suggested that moderate CYP3A inhibitors (diltiazem and erythromycin) may increase the AUC of ibrutinib 6 to 9-fold in fasted condition.
Coadministration of Ibrutinib with CYP3A Inducers
Preliminary PK data from an ongoing dedicated drug interaction trial and simulations using PBPK indicate that rifampin (a strong CYP3A inducer) can decrease ibrutinib Cmax and AUC by more than 10-fold. Simulations using PBPK suggested that a moderate CYP3A inducer (efavirenz) may decrease the AUC of ibrutinib up to 3-fold.
Coadministration of Ibrutinib with CYP Substrates
In vitro studies indicated that ibrutinib (I/Ki < 0.07 using mean Cmax at 560 mg) and PCI-45227 (I/Ki < 0.03) are unlikely to be inhibitors of any major CYPs at clinical doses. Both ibrutinib and the PCI-45227 are weak inducers of CYP450 isoenzymes in vitro.
Coadministration of Ibrutinib with Substrates of Transporters
In vitro studies indicated that ibrutinib is not a substrate of p-glycoprotein (P-gp). Systemic ibrutinib is unlikely to be an inhibitor of P-gp at clinical doses ([I]1/Ki < 0.1). However, it may have an effect on P-gp substrates in the GI tract due to higher local concentrations after an oral dose. Co-administration of oral narrow therapeutic index P-gp substrates (e.g., digoxin) with IMBRUVICA may increase their blood concentration.
13 NONCLINICAL TOXICOLOGY
13.1 Carcinogenesis, Mutagenesis, Impairmen |
