Efficacy and safety of re-induction therapy with bevacizumab and paclitaxel for metastatic breast cancer

In many trials (including E2100), bevacizumab (Bmab) monotherapy has been continued if toxicity of paclitaxel (PTX) becomes unacceptable during combined treatment with Bmab and PTX. When progression occurs on Bmab monotherapy, one possible option is re-induction with the combination of Bmab and PTX (rBP therapy), because PTX was previously stopped due to toxicity rather than progression. However, we have no data about rBP therapy. Therefore, we investigated the efficacy and safety of rBP therapy in this study. We retrospectively investigated 46 patients who started Bmab and PTX between October 2011 and April 2013 at our institution. After induction with Bmab and PTX, 19 patients subsequently received Bmab monotherapy and 12 patients received rBP therapy. The overall response rate and clinical benefit rate of rBP therapy was 25 % (3/12) and 58 % (7/12), respectively, while the median time to failure of rBP therapy was 174 days (95 % CI 49-273). The median overall survival time of the 46 patients was 777 days (95 % CI 543-NA). Adverse events of grade 3 or worse associated with rBP therapy were neutropenia (25 %), fatigue (8 %), and gastrointestinal bleeding (8 %). This is the first report about rBP therapy, which was found to be both safe and effective. The OS of all 46 patients in this study (including 12 patients given rBP therapy) was better than in past reports. Selecting rBP therapy for patients with progression on Bmab monotherapy might have contributed to better overall survival, but a randomized controlled trial will be needed to confirm these findings.