The addition of onartuzumab to paclitaxel with or without bevacizumab did not provide clinical benefit to patients with predominantly MET-negative metastatic triple-negative breast cancer, a new study published in the journal Annals of Oncology has shown.

For the phase 2 trial, researchers sought to evaluate the impact of adding onartuzumab, a monoclonal anti-MET antibody, to paclitaxel with or without bevacizumab for the treatment of patients with triple-negative breast cancer.

Researchers enrolled 185 women with triple-negative breast cancer and randomly assigned them 1:1:1 to receive onartuzumab plus placebo plus weekly paclitaxel, onartuzumab plus bevacizumab plus paclitaxel, or placebo plus bevacizumab plus paclitaxel. The majority of patients had MET-negative tumors.

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Results showed no improvement in progression-free survival with the addition of onartuzumab to bevacizumab plus paclitaxel.

Researchers found that risk of progression-free events was higher with onartuzumab plus paclitaxel than bevacizumab plus paclitaxel.

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In addition, objective response rate was higher in the bevacizumab groups versus onartuzumab plus paclitaxel. Median overall survival was longer with bevacizumab plus paclitaxel than the other two groups.

In regard to safety, peripheral edema occurred 34% to 41% more frequently in the onartuzumab treatment arms than the bevacizumab plus paclitaxel arm.


  1. Dieras V, Campone M, Yardley DA, et al. Randomized, phase II, placebo-controlled trial of onartuzumab and/or bevacizumab in combination with weekly paclitaxel in patients with metastatic triple-negative breast cancer.Ann Oncol. 2015. [epub ahead of print]. doi: 10.1093/annonc/mdv263.