A43 - Effectiveness of Bevacizumab maintenance therapy associated with metronomic chemotherapy and hormone therapy after treatment with taxanes in patients with HER-2 negative metastatic breast cancer (mBC)

Abstract

Background: it is known that the continuation of Bevacizumab after therapy with taxanes is a strategy recommended in HER-2 negative metastatic breast cancer. Currently, it is not well defined yet if and which treatment bind to the anti-VEGF antibody. However, considering the undoubted antiangiogenic effect of metronomic chemotherapy, we evaluated if the triple combination Bevacizumab, hormone therapy and chemotherapy may be an option for maintenance therapy in these type of patients. Material and methods: Our study aims to evaluate the effectiveness of the association between Bevacizumab, metronomic chemotherapy and hormone therapy, by measuring the PFS, as primary endpoint and OS and RR as secondary endpoints. We enrolled 22 patients with HER2-negative mBC, who received at least six cycles of treatment with Bevacizumab + taxanes. Progression-free patients, at the suspension of the taxane, continued treatment with the antibody, combined with oral metronomic chemotherapy and hormone therapy if receptor-positive. Results: From April 2009 to January 2015 were evaluated 22 patients who received treatment with taxanes + Bevacizumab, followed by maintenance Bevacizumab, associated to Capecitabine (45.5%), Cyclophosphamide (45.5%) or Etoposide (9%) in metronomic schedule. 17 patients (77.3%) also received hormone therapy. At a median follow-up of 19 months, 5 patients have not relapsed yet. The median PFS from beginning of maintenance was 22 months (95% CI: 6.9-37.1). The median OS was 51 months (95% CI 7.1-94.9), whereas at the time of data analysis, only 10 patients have died. CR and PR were achieved/maintained in 2 (9.1%) and 5 (22.7%) patients, respectively, for an overall response rate of 31.8%; 11 (50%) women experienced SD and 4 (18.2%) patients had a PD at first control. The treatment appears to be well tolerated. Conclusions: From our study results, the continuation of Bevacizumab, combined with chemotherapy and hormone therapy, appears to improve the chance of disease control.