Combo of taxane + bevacizumab + capecitabine is not recommended in metastatic breast cancer

The authors studied the efficacy of taxanes (class of drugs including paclitaxel [Taxol] and docetaxel [Taxotere]) plus bevacizumab (Avastin) with or without capecitabine (Xeloda) in treating metastatic breast cancer. 

Bevacizumab has been studied for the treatment of breast cancer that is metastatic (that has spread to other parts of the body) and is HER2 negative (absent human epidermal growth factor receptor 2, a protein that can be found on cells). In a previous study, bevacizumab improved progression-free survival (time without disease worsening) and decreases in tumor size. Adding taxanes or capecitabine also improved survival. Thus it was suggested that a combination of a taxane, capecitabine and bevacizumab would further improve outcomes. 

116 patients were randomly assigned to receive a taxane plus bevacizumab. 111 patients were randomly assigned to receive taxane, bevacizumab and capecitabine. The taxane they received was either paclitaxel or docetaxel. Patients continued to receive treatment until either their tumors decreased in size or it became too toxic.

The average follow-up period was 26.1 months. The average  progression-free survival was 9.9 months for patients receiving capecitabine and 11.3 months for patients not receiving capecitabine. The overall survival was not different whether patients did or did not receive capecitabine.

86.5% of patients receiving capecitabine and 37.9% of patients not receiving capecitabine had to change their dosage. This was mostly due to toxic effects on the body. 77% of patients treated with capecitabine and 62.1% of patients not receiving capecitabine had a severe or life threatening adverse event (undesired effect of treatment). 6 patients receiving capecitabine and 1 patient not receiving capecitabine died due to an adverse event. Of these patients, 4 had pneumonia, 2 had bowel perforation (hole through bowel) and 1 patient fell due to fainting. 

The authors concluded that adding capecitabine to bevacizumab and a taxane treatment is not recommended for metastatic breast cancer patients due to the toxic nature of the addition.