Paclitaxel plus bevacizumab or paclitaxel as first-line treatment for HER2-negative metastatic breast cancer in a multicenter national observational study

In the large observational multicenter Unicancer-ESME database, adjusted OS was longer in first line metastatic breast cancer patients receiving paclitaxel and bevacizumab than in those receiving paclitaxel alone (HR 0.672, 95%CI 0.601-0.752; median OS 27.7 vs 19.8 months). Despite robust methodology, real-life data are exposed to potential biases and interpretation requires caution.Bevacizumab combined with paclitaxel as first-line chemotherapy for patients with HER2-negative metastatic breast cancer (MBC) has led to mixed results in randomized trials, with an improvement in progression-free survival (PFS) but no statistically significant overall survival (OS) benefit. Real-life data could help in assessing the value of this combination. This study aimed to describe the outcome following first-line paclitaxel with or without bevacizumab in the French Epidemiological Strategy and Medical Economics (ESME) database of MBC patients, established in 2014 by Unicancer. The primary and secondary end points were OS and PFS, respectively. From 2008 to 2013, 14 014 MBC patient files were identified, including 10 605 patients with a HER2-negative status. Of these, 3426 received paclitaxel and bevacizumab (2127) or paclitaxel (1299) as first-line chemotherapy. OS adjusted for major prognostic factors was significantly longer in the paclitaxel and bevacizumab group compared with paclitaxel [hazard ratio (HR) 0.672, 95% confidence interval (CI) 0.601-0.752; median survival time 27.7 versus 19.8 months]. Results were consistent in all supportive analyses (using a propensity score for adjustment and as a matching factor for nested case-control analyses) and sensitivity analyses. Similar results were observed for the adjusted PFS, favoring the combination (HR 0.739, 95% CI 0.672-0.813; 8.1 versus 6.4 months). In this large-scale, real-life setting, patients with HER2-negative MBC who received paclitaxel plus bevacizumab as first-line chemotherapy had a significantly better OS and PFS than those receiving paclitaxel. Despite robust methodology, real-life data are exposed to important potential biases, and therefore, results need to be treated with caution. Our data cannot therefore support extension of current use of bevacizumab in MBC.