The c.480C>G polymorphism of hOCT1 influences imatinib clearance in patients affected by chronic myeloid leukemia.

The aim of the study was to investigate any possible influence of polymorphisms of transmembrane transporters human organic cation transporter 1 (hOCT1), ABCB1, ABCG2 on imatinib pharmacokinetics in 33 men and 27 women (median age and range, 56 and 27-79 years, respectively) affected by chronic myeloid leukemia. A population pharmacokinetic analysis was performed to investigate imatinib disposition in every patient and the role of transporter polymorphisms. Results showed that the α1-acid glycoprotein and the c.480C>G genotype of hOCT1 had a significant effect on apparent drug clearance (CL/F) being responsible, respectively, for a 20% and 10% decrease in interindividual variability (IIV) of CL/F (from 50.1 up to 19.6%). Interestingly, 25 patients carrying at least one polymorphic c.480 G allele had a significant lower CL/F value with respect to the 35 c.480CC individuals (mean±s.d., 9.6±1.6 vs 12.1±2.3 l h(-1), respectively; P<0.001). In conclusion, the hOCT1 c.480C>G SNP may significantly influence imatinib pharmacokinetics, supporting further analyses in larger groups of patients.