[Correlation between nUGT1A1 gene polymorphisms and adverse events of irinotecan plus S-1 for patients with recurrent or metastatic esophageal squamous cell carcinoma: a prospective, open-label, randomized controlled trial (ESWN 01)].

ABSTRACT

Objective: To investigate the correlation between UGT1A1 polymorphisms and the irinotecan plus S-1 regimen-induced toxicities in Chinese advanced esophageal squamous cell carcinoma (ESCC) patients. Methods: A total of 46 recurrent or metastatic ESCC patients selected from ESWN 01 trial were randomly assigned to irinotecan plus S-1 group [intravenous infusion of irinotecan (160 mg/m(2)) on day 1 and oral S-1 (80-120 mg) on days 1-10, repeated every 14 days]. Peripheral venous blood at baseline was collected and genomic DNA was extracted. The genetic polymorphisms of UGT1A1*6 and UGT1A1*28 were analyzed by polymerase chain reaction (PCR) amplification. Irinotecan plus S-1 regimen-induced toxicities of patients with different UGT1A1 polymorphisms were observed. The correlation between UGT1A1 polymorphisms and the adverse effects was analyzed. Results: Among the 46 patients, the numbers of UGT1A1*6 wild type genotype (GG), mutant heterozygote (GA) and mutant homozygote (AA) were 30, 15 and 1, while those with UGT1A1*28 wild type genotype (TA6/6), mutant heterozygote (TA6/7) and mutant homozygote (TA7/7) were 36, 8 and 2, respectively. Only one patient with UGT1A1*6 AA genotype occurred grade 3 diarrhea, while one of the 2 patients with UGT1A1*28 TA7/7 genotype occurred grade 4 diarrhea. No neutropenia was observed in the patient with UGT1A1*6 AA genotype, however, both of the two patients with UGT1A1*28 TA7/7 genotype occurred grade 3-4 neutropenia. Patients with UGT1A1*28 genetic polymorphism (TA 6/7 or TA7/7) had a higher response rate compared with wild-type TA6/6 carriers. (55.6% versus 26.5%). Conclusions: The homozygous genotype of UGT1A1*6 AA and UGT1A1*28 TA7/7 are rare (<5%) in Chinese ESCC population. Not all homozygous AA and TA7/7 carriers occur severe dose limited toxicities (DLT) when treated with irinotecan (160 mg/m(2)) plus S-1 regimen for 2 weeks. However, it's still necessary torigorously observe the occurrence of severe diarrhea and neutropenia in patients with UGT1A1*6 AA and UGT1A1*28 TA7/7 and adjust the dose timely.