RESUMO
This study investigated the impact of ABCB5, ABCC5 and RLIP76 polymorphisms on doxorubicin pharmacokinetics in Asian breast cancer patients (N=62). Direct sequencing was performed to screen for previously identified ABCC5 polymorphisms as well as polymorphisms in the exons and exon-intron boundaries of ABCB5 and RLIP76 genes. Genotype-phenotype correlations were analyzed using Mann-Whitney U-test. The homozygous variant allele at the ABCC5 g.+7161G>A (rs1533682) locus was significantly associated with higher doxorubicin clearance (g.+7161AA vs g.+7161GG, CL/BSA (Lh-1m-2): 30.34 (25.41-33.60) vs 22.46 (15.04-49.4), P=0.04). Homozygosity for the reference allele at the ABCC5 g.-1679T>A locus was associated with significantly higher doxorubicinol exposure (g.-1679TT vs g.-1679TA, AUC0-∞/dose/BSA (hm-5): 15.48 (6.18-67.17) vs 8.88 (3.68-21.71), P=0.0001). No significant influence of the three newly identified ABCB5 polymorphisms (c.2T>C, c.343A>G and c.1573G>A) on doxorubicin pharmacokinetics was observed. No polymorphisms were identified in the RLIP76 gene. These findings suggest that ABCC5 polymorphisms may explain partially the interpatient variability in doxorubicin disposition.
Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP/genética , Transportadores de Cassetes de Ligação de ATP/genética , Povo Asiático/genética , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/genética , Doxorrubicina/farmacocinética , Proteínas Ativadoras de GTPase/genética , Proteínas Associadas à Resistência a Múltiplos Medicamentos/genética , Subfamília B de Transportador de Cassetes de Ligação de ATP , Adulto , Idoso , Alelos , Antibióticos Antineoplásicos/farmacocinética , Antibióticos Antineoplásicos/uso terapêutico , Doxorrubicina/uso terapêutico , Éxons/genética , Feminino , Frequência do Gene/genética , Estudos de Associação Genética , Genótipo , Haplótipos/genética , Humanos , Pessoa de Meia-Idade , Farmacogenética/métodos , Polimorfismo Genético/genéticaRESUMO
BACKGROUND: The aim of this study was to determine the maximum tolerated dose (MTD) and the pharmacokinetic profile of Genexol-PM in Asian cancer patients. MATERIALS AND METHODS: Patients (N = 24) refractory to previous chemotherapy received Genexol-PM as an 1-h infusion on a weekly basis for 3 weeks followed by a resting week. The starting dose was 80 mg/m(2) and the maximum administered dose was 200 mg/m(2). RESULTS: The majority of patients had lung, nasopharyngeal and breast cancers and in eleven patients (46%), taxane-based chemotherapy had previously failed. The MTD was defined at 180 mg/m(2). The most common grade 3 non-hematologic adverse events in cycle 1 were fatigue (4%) and neuropathy (4%) occurring mainly at 200 mg/m(2). Five (21%) patients had partial response, nine (38%) had stable disease and seven (29%) had disease progression. Five of 11 previously taxane-refractory patients showed clinical benefit to Genexol-PM. The pharmacokinetics of Genexol-PM displayed dose-proportionality, with both the maximum concentration (C(max)) and the area under the concentration-time curve from zero to infinity (AUC(0-infinity)) increasing by approximately four- and threefold, respectively, as the dose of Genexol-PM was escalated from 80 to 200 mg/m(2). The median total-body clearance of Genexol-PM for all patients was 43.9 l/h. CONCLUSION: The weekly regimen of Genexol-PM was well tolerated and responses were observed in patients with refractory tumors, including patients who had failed taxane-based chemotherapy previously.