Pharmacogenetic profiling in patients with advanced colorectal cancer treated with first-line FOLFOX-4 chemotherapy

The objective is to investigate whether polymorphisms with putative influence on fluorouracil/oxaliplatin activity are associated with clinical outcomes of patients with advanced colorectal cancer treated with first-line oxaliplatin, folinic acid, and fluorouracil palliative chemotherapy.

Consecutive patients were prospectively enrolled onto medical oncology units in Central Italy. Patients were required to have cytologically/histologically confirmed metastatic disease with at least one measurable lesion. Peripheral blood samples were used for genotyping 12 polymorphisms in thymidylate synthase, methylenetetrahydrofolate reductase, xeroderma pigmentosum group D (XPD), excision repair cross complementing group 1 (ERCC1), x-ray cross complementing group 1, x-ray cross complementing protein 3, glutathione S-transferases (GSTs) genes. The primary end point of the study was to investigate the association between genotypes and progression-free survival (PFS).

In 166 patients, ERCC1-118 T/T, XPD-751 A/C, and XPD-751 C/C genotypes were independently associated with adverse PFS. The presence of two risk genotypes (ERCC1-118 T/T combined with either XPD-751 A/C or XPD-751 C/C) occurred in 50 patients (31%). This profiling showed an independent role for unfavorable PFS with a hazard ratio of 2.84% and 95% CI of 1.47 to 5.45 (P = .002). Neurotoxicity was significantly associated with GSTP1-105 A/G. Carriers of the GSTP1-105 G/G genotype were more prone to suffer from grade 3 neurotoxicity than carriers of GSTP1-105 A/G and GSTP1-105 A/A genotypes.

A pharmacogenetic approach may be an innovative strategy for optimizing palliative chemotherapy in patients with advanced colorectal cancer. These findings deserve confirmation in additional prospective studies.