Abstract
Endocrine therapy plus bevacizumab improved the time to treatment failure vs. paclitaxel plus bevacizumab.
Major Finding: Endocrine therapy plus bevacizumab improved the time to treatment failure vs. paclitaxel plus bevacizumab.
Concept: Occurrence of adverse events was significantly reduced with a better reported side effect profile.
Impact: A switch to endocrine therapy may be an efficacious and tolerable maintenance therapy in advanced breast cancer.
Standard treatment for breast cancer typically involves systemic therapies that have a multitude of side effects, and chemotherapy continuation as maintenance therapy has shown conflicting survival outcomes. Recent trials have indicated switch maintenance chemotherapy, specifically capecitabine plus bevacizumab, improves progression free survival (PFS) and overall survival (OS) compared with bevacizumab alone after bevacizumab plus docetaxel first-line treatment. However, additional studies showed frequent discontinuation of paclitaxel plus bevacizumab treatment despite durable responses due to paclitaxel-induced toxicities. To investigate potential improvements to side effects and quality of life, Saji and colleagues conducted a phase II clinical trial evaluating a paclitaxel break with a switch to maintenance endocrine therapy plus bevacizumab in 160 patients with ER-positive, HER2-negative advanced or metastatic breast cancer. The primary endpoint of the study was time to failure of strategy (TFS) with secondary endpoints of OS, 2-year OS rates, PFS, safety, patient-reported outcomes (QOL), and adverse events (AE) related to efficacy. Of the 160 patients enrolled, 35 were excluded due to disease progression, AEs, death, or consent withdrawal. Half of the remaining 125 patients received switch maintenance endocrine therapy plus bevacizumab with the other half continuing weekly paclitaxel plus bevacizumab. TFS was increased in the endocrine therapy plus bevacizumab group as compared to the weekly paclitaxel plus bevacizumab group (16.8 vs 8.9 months), but OS was similar between both groups with the 2-year OS being 66.9% and 62.3% respectively. The endocrine therapy plus bevacizumab group also reported fewer grade 3 to 5 AEs (38% vs 48%) with proteinuria, hypertension, low neutrophil count, and peripheral neuropathy being the most common grade 3 to 4 AEs among both groups. Patient-reported outcomes on quality of life also favored the endocrine therapy plus bevacizumab group. Overall, the results of this trial demonstrate the feasibility of a chemotherapy break in maintenance therapy by switching to endocrine therapy and supports this switch as the preferable option in advanced breast due to a longer time to failure of strategy and a more manageable adverse event profile.
Note:Research Watch is written by Cancer Discovery editorial staff. Readers are encouraged to consult the original articles for full details. For more Research Watch, visit Cancer Discovery online at http://cancerdiscovery.aacrjournals.org/CDNews.
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