Real-World Paclitaxel–Bevacizumab Results Reported For HER2-Negative Metastatic Breast Cancer

Analysis of French patients treated for HER2-negative metastatic breast cancer indicates the possibility of a survival benefit for paclitaxel plus bevacizumab over paclitaxel alone

medwireNews: Real-world database results suggest that patients with HER2-negative status at the time of metastatic breast cancer diagnosis might derive a significant overall survival (OS) benefit from the addition of bevacizumab to first-line therapy with paclitaxel.

However, the study authors emphasize that their conclusions are tentative. “Despite robust methodology, real-life data are exposed to important potential biases and interpretation requires caution”, they write.

The investigators compared French Epidemiological Strategy and Medical Economics database information for 2127 patients who received combined first-line therapy and 1299 who were given only paclitaxel.

After adjusting for major prognostic factors, such as metastases type and number, OS was significantly longer for patients given paclitaxel plus bevacizumab than paclitaxel alone, at 27.7 versus 19.8 months and a hazard ratio (HR) of 0.67. And the HR remained significant, at 0.70, after propensity score adjustment, and in sensitivity analyses.

Progression-free survival was also significantly longer for the combined than paclitaxel alone groups, at 8.1 versus 6.4 months and an HR of 0.74, and remained significantly in favour of bevacizumab addition in supportive analyses, the team adds.

But writing in the Annals of Oncology, the researchers highlight significant differences between the treatment groups. Patients using combined therapy were younger than those given only paclitaxel, had a different distribution of metastatic disease sites and a shorter time between metastatic breast cancer diagnosis and beginning treatment.

In addition, they note that patient performance status was not routinely recorded. “Thus, the observed between-group OS difference might just reflect a lower performance status and higher level of co-morbidity in patients assigned to paclitaxel, deliberately chosen in order to minimize the risk of side effects of the combination”, explain Suzette Delaloge, from the Institut Gustave Roussy in Villejuif, France.

The authors therefore conclude: “Whether the observed difference is linked to the treatment itself, to prescription bias, or to a mixed effect of both cannot be ascertained. Based on the present study, data cannot support extension of current use of bevacizumab in [metastatic breast cancer].”

Reference

Delaloge S, Perol D, Courtinard C, et al. Paclitaxel plus bevacizumab or paclitaxel as first-line treatment for HER2-negative metastatic breast cancer in a multicenter national observational study. Ann Oncol 2016; Advance online publication 19 July. doi: 10.1093/annonc/mdw260

medwireNews (www.medwireNews.com) is an independent medical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2016