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Predictive value of Ile105Val polymorphism of the gluthatione-S-transferase P1 in patients with metastatic colorectal cancer (m CRC) treated with the triplet combination of irinotecan, oxaliplatin, and capecitabine. J Clin Oncol 2009. [DOI: 10.1200/jco.2009.27.15_suppl.2544] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
2544 Background: Several phase I/II trials have shown that the triplet combination of oxaliplatin, irinotecan and capecitabine is a feasible and active in solid tumors. We aimed to investigate whether germline polymorphisms may be predictors of clinical outcome in mCRC pts treated with this combination. Methods: The following genetic polymorphisms were analysed: glutathione S-transferase (GSTP1-Ile105Val, GSTT1 and GSTM1 deletion), TYMS (TS-5´UTR 2R/3R; TS-5´G/C; TS-3´UTR 6-bp deletion), MTHFR 1298A>C, UGT1A1, ERCC1, XPD. Polymorphisms from peripheral lymphocytes were detected using the TaqMan genotyping assays (Applied Biosystems, CA). Univariate analysis (Fisher´s exact test for response; log-rank test for TTP and OS) was performed to examine associations between polymorphisms and clinical outcome. Results: Blood samples for 63 out of 72 prospectively enrolled pts were tested for genomic analysis. Median age was 57 (32–78), median ECOG 1(0–2), median number of cycles administered 6 (1–13), median number of metastatic sites was 1 (1–4). M/F: 50/22. Risk according to Köhne classification was low (52.8% of pts), intermediate (26.4%) and high (8.3%). Overall response rate (ORR) was 62.5%. Median progression-free survival (PFS) was 9.87 months (95% CI; 7.6–12) and median overall survival was 24.6 months (95% CI; 19.5–29.7). A significant association was observed between MTHFR 1298A>C and haematological toxicity, with C/C genotype pts being at higher risk of grade 3–4 neutropenia (50% vs. 28%, p = 0.035) and leucopenia (50% vs. 15%, p = 0.04). Heterozygous and homozygous GSTP-105Val showed a significant superior response rate (80%) compared to only 40% in pts harbouring the GSTP1–105Ile/Ile genotype (p = 0.008, Fisher´s exact test). PFS was also adversely affected in pts with GSTP1–105Ile/Ile (5.2 months vs. 12.3 months in those pts with at least one GSTP1–105Val allele, p = 0.001). In the multivariate analysis, the relative risk for progression was 3.4 (95% CI; 1.3–9.1) for the GSTP1–105Ile/Ile genotype (p = 0.01). Conclusions: The GSTP1-Ile105Val polymorphism is a strong predictor of clinical outcome for XELOXIRI therapy in mCRC pts. No significant financial relationships to disclose.
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