First-Line Bevacizumab More Effective in MBC Not Previously Treated with Taxanes

Among long-term responders, first-line bevacizumab-based therapy is more effective in patients with HER2-negative metastatic breast cancer (MBC) who were not previously treated with taxanes, a recent Spanish study suggests. The study, LORENA, also found that maintenance hormonal therapy (MHT) provides additional therapeutic benefits by extending progression-free survival (PFS) and overall survival (OS). The study was published in OncoTargets and Therapy.

Researchers, led by Andres Redondo, MD, and colleagues, conducted an ambispective, observational study that consisted of both a retrospective and prospective phase. During the retrospective phase, patients with HER2-negative MBC who were treated with bevacizumab-based first-line therapy were included. During the prospective phase, patients with PFS of 12 or more months were treated according to routine clinical practice procedures. OS and OFS were estimated using the Kaplan-Meier method; univariate and multivariate analyses of prognostic factors were also performed. A total of 148 women were included in the study (median age, 50 years; range, 29-81 years), and mean duration of exposure to bevacizumab was 18 months.

The majority of patients experienced objective response (complete, 23%; partial, 57%). Median PFS was 22.7 months and median OS was 58.2 months. In multivariate analyses, patients receiving MHT had longer PFS (P=.002; hazard ratio [HR], 1.8) and OS (P=.009; HR, 2.0), while patients not previously treated with taxanes had longer OS (P <.001; HR, 3.3). No unexpected adverse events were observed.

Although first-line combination therapy with bevacizumab and chemotherapy has shown some efficacy in the treatment of patients with MBC in phase 3 clinical trials, it has failed to significantly improve OS. In addition, the use of bevacizumab in this indication is controversial because the FDA has proposed withdrawal of marketing approval for MBC after deciding there is not enough evidence that the drug is safe and effective for this one indication.

“Identification of factors that predict long-term response to bevacizumab would provide patients with a valuable therapeutic option,” the authors say, and the LORENA study was conducted to describe the clinical characteristics of patients with MBC who have experienced long-term response to bevacizumab.

“The results suggest that long-term responders are relatively young (50 years of age), more often premenopausal, have stage IV disease at diagnosis, and have [fewer than] 3 sites of metastases,” they conclude. “The benefit of bevacizumab may be greater in patients who have not received prior treatment with taxanes and in those who received MHT.”

In 2017 the FDA approved the first biosimilar bevacizumab, Mvasi.

Redondo disclosed serving as an advisor for, and received honoraria and research funding from Roche, as did other coauthors.

Reference

Redondo A, Vazquez MR, Manso L, et al. Long-term response to first-line bevacizumab-based therapy in patients with metastatic breast cancer: results of the observational “LORENA” study. Onco Targets Ther. 2018;11:5845-5852. Doi: 10.2147/OTT.S170303.