354P - Genetic Interaction Profile May Predict Bevacizumab (BV) Efficacy in Metastatic Breast Cancer (MBC) Patients (PTS): An Exploratory Retrospective Analysis

Abstract

ABSTRACT Background previous retrospective studies have attempted to identify a possible role of VEGF single nucleotide polymorphisms (SNPs) to predict BV efficacy in terms of OS and PFS in MBC pts with conflicting results (Schneider 2008, Grimaldi 2011, Lambrechts 2011). Methods on the basis of these preliminary data, we decided to assess in a MBC population if different VEGF, VEGFR-2, IL-8, IL-6, HIF-1alfa, EPAS-1 and TSP-1 genotypes could predict first line BV + Paclitaxel (P) response in terms both of OS and PFS. Analyses were performed on germline DNA obtained from blood samples. Fourteen polymorphisms were investigated by real-time PCR technique. Both single and combinations of SNPs were investigated. The multifactor dimensionality reduction (MDR) methodology was applied to identify a genetic interaction profile for PFS ( http://sourgeforge.net/projects/mdr/ ). Results 102 pts have been enrolled from 8 Oncology Units. Main pts characteristics are: median age 59 years (range 32-81), ECOG-PS 0/1 in 78%/22%, hormone receptor positive 83%, previous adjuvant chemotherapy 68%, disease free interval (DFI) 12 months (HR= 0.4, 95% CI: 0.2-0.82, p= 0.011) and BV maintenance (HR = 0.63, 95% CI: 0.25.0.71, p = 0.001) were significantly associated with a better PFS. Conclusions genetic interaction between VEGFR-2 rs11133360 and IL-8 rs4073 polymorphisms could predict BV response in terms of PFS. With a longer follow up correlations with OS will be investigated. Prospective study is planned. Study supported by the no-profit foundation F.A.R.O. Disclosure All authors have declared no conflicts of interest.