• Sin-Chi Chew, Onkar Singh, Xiangai Chen, Rathi Devi Ramasamy, Tejal Kulkarni, Edmund J D Lee, Eng-Huat Tan, Wan-Teck Lim, and Balram Chowbay.
• Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, 10 Medical Drive, Singapore 117597, Singapore.
• Cancer Chemother. Pharmacol. 2011 Jun 1; 67 (6): 1471-8.

PurposeThis exploratory study aimed to explain the interindividual variabilities of docetaxel pharmacokinetics and pharmacodynamics in Asian nasopharyngeal carcinoma patients (n = 54) through the genotyping of CYP3A4, CYP3A5, ABCB1, ABCC2, ABCG2 and SLCO1B3 genes.MethodsDocetaxel was administered over 1 h on days 1, 8, and 15 every 28 days at 30 mg/m(2)/dose. Genomic DNA was isolated from peripheral blood and genotyped for the selected polymorphisms in the candidate genes. Docetaxel pharmacokinetic parameters were estimated by non-compartmental modelling.ResultsPatients homozygous for the variant allele (GG) of SLCO1B3 rs11045585 (IVS12-5676A > G) had significantly higher area under the plasma concentration-time curve of docetaxel (P = 0.026) and lower clearance (P = 0.036) compared to patients with AA/AG genotypes. Patients harbouring the heterozygous genotype (GA + GT + TA) for ABCB1 rs2032582 (2677G > T/A) had the highest percentage decrease in nadir haemoglobin from cycle 1 baseline compared to those with GG/TT genotypes (P = 0.006). Similar trend was observed for ABCB1 rs1045642 (3435C > T) with heterozygotes (CT) having the highest percentage decrease in nadir haemoglobin from cycle 1 baseline compared to those with CC/TT genotypes (P = 0.066).ConclusionsThis study suggests that the cooperative influence of functional polymorphisms in SLCO1B3 and ABCB1 genes may be responsible for the interindividual variability in docetaxel disposition in Asian nasopharyngeal cancer patients.

31 keywords...

hide…