Next-generation sequencing (NGS) for personalized therapy in metastatic breast cancer: Selection of therapy and outcomes.

e23166 Background: Treatment for metastatic breast cancer (MBC) has been driven by hormone receptors, HER2 expressions or their absence. Resistance to therapy and progressive disease will occur and empirical chemotherapy lines usually are the next steps. We aim to analyze the role of next-generation sequencing (NGS) for a personalized therapy in metastatic breast cancer and its potential clinical benefit. Methods: We included patients diagnosed with MBC treated at Centro Oncologico Antonio Ermirio de Moraes – Brazil from April 2013 to December 2016. All patients had metastasis accessible for biopsy. The tumor tissue was stored in paraffin and then analyzed by NGS-based assay that identifies genomic alterations within 236 genes. Results: 19 patients with MBC were evaluated (10 triple-negative; 4 HER2-positive; 5 hormonal receptor positive/HER2-negative). The most frequent and relevant genomic alterations identified by NGS assay were in the following genes: 13 TP53 (68.4%); 4 ERBB2 (21%); 4 PTEN (21%); 4 FGFR (21%); 3 PIK3CA (15.8%); 2 BRCA (10.5%); 2 ATM (10.5%); 2 AKT (10.5%); 2 MYC (10.5%); 1 CCND1 (5.3%); and 1 KRAS (5.3%). The NGS assay was able to suggest further therapy in 16/19 patients (84%). The suggested therapies would not be an empirical option according to the cancer’s subtype in 12/16 patients (75%). Therapy could be personalized in nine patients, across multiple lines of therapies (median of 5th line, with a range of 1-14). Median PFS was 6 months, and 8/9 patients (90%) achieved an objective response with the treatment indicated by NGS. Therefore, the assay provided clinical benefit in 42% of patients. Conclusions: NGS panel identified potentially actionable alterations in the majority of patients with MBC (84%). The overall clinical benefit with use of NGS-based assay was 42%. Further studies are necessary to better evaluate the role of NGS for a personalized therapy in MBC.