BACKGROUND: Gilbert's syndrome is characterized by a functional promoter single nucleotide polymorphism (SNP) of the UDP-glucuronosyltransferase (UGT) 1A1 gene and represents a pharmacogenetic risk factor for irinotecan toxicity, but study data remain controversial. The active CPT-11 metabolite 7-ethyl-10-hydroxycamptothecin is detoxified by several UGT1A proteins, which include UGT1A7 with a high specific activity that may contribute to the risk of irinotecan toxicity in Gilbert's syndrome patients. METHODS: Genotyping of the UGT1A1*28, UGT1A7 N129K/R131K, and UGT1A7-57T/G variants was done in 105 irinotecan-treated patients with metastatic colorectal cancer; adverse events were documented during all 297 treatment cycles and analyzed by Cochran-Mantel-Haenszel, Mann-Whitney, and chi2 tests. RESULTS: The presence of UGT1A7 but not UGT1A1 variants was associated with at least one adverse event. In patients combining all three variants, thrombocytopenia and leukopenia were significantly more frequent. The overall incidence of adverse events was significantly higher (P = 0.0035) in carriers of the UGT1A risk alleles, who also had significantly higher rate of dose reductions. CONCLUSIONS: Irinotecan toxicity is more likely in patients with Gilbert's syndrome carrying the UGT1A1*28 allele combined with reduced function UGT1A7 N129K/R131K and UGT1A7-57T/G SNP. Based on the ability of UGT1A7 to metabolize and eliminate the active irinotecan metabolite 7-ethyl-10-hydroxycamptothecin, the UGT1A1/UGT1A7 SNP combination haplotype appears to be a superior risk predictor than Gilbert's syndrome alone.
BACKGROUND:Gilbert's syndrome is characterized by a functional promoter single nucleotide polymorphism (SNP) of the UDP-glucuronosyltransferase (UGT) 1A1 gene and represents a pharmacogenetic risk factor for irinotecantoxicity, but study data remain controversial. The active CPT-11 metabolite 7-ethyl-10-hydroxycamptothecin is detoxified by several UGT1A proteins, which include UGT1A7 with a high specific activity that may contribute to the risk of irinotecantoxicity in Gilbert's syndromepatients. METHODS: Genotyping of the UGT1A1*28, UGT1A7 N129K/R131K, and UGT1A7-57T/G variants was done in 105 irinotecan-treated patients with metastatic colorectal cancer; adverse events were documented during all 297 treatment cycles and analyzed by Cochran-Mantel-Haenszel, Mann-Whitney, and chi2 tests. RESULTS: The presence of UGT1A7 but not UGT1A1 variants was associated with at least one adverse event. In patients combining all three variants, thrombocytopenia and leukopenia were significantly more frequent. The overall incidence of adverse events was significantly higher (P = 0.0035) in carriers of the UGT1A risk alleles, who also had significantly higher rate of dose reductions. CONCLUSIONS:Irinotecantoxicity is more likely in patients with Gilbert's syndrome carrying the UGT1A1*28 allele combined with reduced function UGT1A7 N129K/R131K and UGT1A7-57T/G SNP. Based on the ability of UGT1A7 to metabolize and eliminate the active irinotecan metabolite 7-ethyl-10-hydroxycamptothecin, the UGT1A1/UGT1A7 SNP combination haplotype appears to be a superior risk predictor than Gilbert's syndrome alone.
Authors: So-Youn Shin; Ann-Kristin Petersen; Nicole Soranzo; Christian Gieger; Karsten Suhre; Robert P Mohney; David Meredith; Brigitte Wägele; Elisabeth Altmaier; Panos Deloukas; Jeanette Erdmann; Elin Grundberg; Christopher J Hammond; Martin Hrabé de Angelis; Gabi Kastenmüller; Anna Köttgen; Florian Kronenberg; Massimo Mangino; Christa Meisinger; Thomas Meitinger; Hans-Werner Mewes; Michael V Milburn; Cornelia Prehn; Johannes Raffler; Janina S Ried; Werner Römisch-Margl; Nilesh J Samani; Kerrin S Small; H-Erich Wichmann; Guangju Zhai; Thomas Illig; Tim D Spector; Jerzy Adamski Journal: Nature Date: 2011-08-31 Impact factor: 49.962
Authors: Celia N Sanchez-Dominguez; Hugo L Gallardo-Blanco; Mauricio A Salinas-Santander; Rocio Ortiz-Lopez Journal: Exp Ther Med Date: 2018-05-18 Impact factor: 2.447