Nilotinib preclinical pharmacokinetics and practical application toward clinical projections of oral absorption and systemic availability
Nilotinib is a highly potent and selective bcr-abl tyrosine kinase inhibitor used for the treatment of patients who are in the chronic and accelerated phases of Philadelphia chromosome-positive (Ph+) chronic myeloid leukemia (CML). Nilotinib preclinical data and its use for practical predictions of systemic exposure profiles and oral absorption are described. The systemic clearance (CL) of nilotinib was relatively low in rodents with a value of less than 25% of hepatic blood flow (QH), while it was moderate in monkeys and dogs (CL /QH = 32–35%). The steady state volume of distribution (Vss) ranged from 0.55 to 3.9 l/kg across the species tested. The maximum concentration (Cmax) of nilotinib occurred at 0.5–4 h and the bioavailability was moderate (17–44%). The plasma protein binding was high (> 97.5%) in preclinical species and humans. The human CL (~ 0.1 l/h/kg) and Vss (~2.0 l/kg) were best predicted by the rat–dog–human proportionality method and allometric scaling method, respectively. The human intravenous pharmacokinetic profile was projected by the Wajima ‘Css–MRT’ method. The predicted micro-constants from human intravenous profiles were incorporated into the advanced compartmental absorption and transit model within the GastroPlus program to simulate the oral concentration–time curves in humans. Overall, the simulated oral human pharmacokinetic profiles showed good agreement with observed clinical data, and the model predicted that the Cmax, AUC, t1/2, Vz/F and CL/F values were within 1.3-fold of the observed values. The absolute oral bioavailability of nilotinib in healthy humans was predicted to be low (< 25%). Copyright © 2012 John Wiley & Sons, Ltd.