ABCB1, CYP3A5*3, and CYP3A4*1B SNPs and risk of toxicity with sunitinib treatment for mRCC.

485Background: Currently there are no biomarkers to predict either toxicity or activity of targeted therapy in mRCC. The aim of this study was to correlate single nucleotide polymorphisms (SNPs) of genes encoding for efflux transporters and metabolizing enzymes with sunitinib toxicity in metastatic renal cell carcinoma (mRCC) patients (pts). Methods: We conducted an observational, retrospective analysis of 60 Caucasian pts who received sunitinib for mRCC from 2 Italian institutions. Correlation between adverse events (AE, according to CTCAE v.4.0) and 4 polymorphisms in 3 genes (ABCB1 [1236C>T, 3435C>T], CYP3A5*3 6986A>G, CYP3A4*1B-392A>G) was analyzed. SNPs were detected in blood samples using pyrosequencing technique. Association between SNPs and toxicities was evaluated using the Chi Square test. Results: 60pts (median age: 61 years; male: 63.3%) with mRCC (clear cell: 85%, other histologies: 15%) were treated with sunitinib (83.3% as first-line). The most common AE (any-grade) reported were: hypertens...