Abstract 5448: Pharmacogenetics of drug transporters may be useful to identify chronic myeloid leukemia patients who are less likely to achieve molecular responses to imatinib: Implications for treatment optimization in the era of new tyrosine kinase inhibitors

Abstract

Abstract The availability of multiple options for chronic myeloid leukemia (CML) treatment is not paralleled by the availability of biological predictors of outcome allowing to identify patients (pts) who are more likely to benefit from dasatinib or nilotinib rather than imatinib (IM). We thus investigated a panel of 20 SNPs in ABCB1, ABCG2, SLC22A1, OCTN1, CYP3A4 and CYP3A5 genes that can be hypothesized to influence IM transport and metabolism in 189 newly diagnosed CML pts enrolled in the TOPS phase III trial (Cortes et al, J Clin Oncol 2010). Median age was 46 yrs; male to female ratio was 103:86; 156 (83%) pts were Caucasian and 23 (12%) were Asian; low, intermediate and high Sokal risk pts were 84 (44.4%), 65 (34.4%) and 40 (21.2%), respectively. Baseline demographic/clinical features did not differ significantly from those of the entire population enrolled. Treatment outcomes (major molecular response [MMR]; complete molecular response [CMR]) were compared according to i) each candidate genotype ii) summary measures based on combinations of SNPs in the same gene and iii) summary measures based on combinations of SNPs in functionally related genes (uptake; efflux). Additive models, with SNPs represented as number of major alleles, were used. Significant results are summarized in the Table below and will be presented in detail. Cumulative incidence plots were also analysed, with similar results. Our data suggest that in CML pts, genotyping should be taken into account in an attempt to further individualize treatment, with the aim of enhancing efficacy in terms of MMR and CMR achievement. On the basis of our findings, stratification of pts according to genotypes may be proposed for selection between IM and second generation TKIs, and represents an attractive opportunity for new clinical trials. Supported by Novartis, TOPS Correlative Studies Network Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5448. doi:10.1158/1538-7445.AM2011-5448