The Food and Drug Administration (FDA) has approved bevacizumab (Avastin), in combination with paclitaxel chemotherapy, for the treatment of metastatic HER2-negative breast cancer in women who have not previously received chemotherapy.

The drug was given "accelerated approval,' which makes it available to women with this deadly disease based on limited clinical trial results. Full approval is contingent on additional positive results from ongoing clinical trials.

Accelerated approval was based on a phase III study in which bevacizumab plus paclitaxel chemotherapy resulted in a 52-percent reduction in the risk of disease progression or death compared with those treated with paclitaxel alone and a doubling in progression-free survival, according to the drug's maker, Genentech.

The drug has not yet been shown to improve overall survival in this disease. An FDA advisory panel recommended last December against making bevacizumab available for breast cancer in a 5-4 vote. Some experts were concerned that the risk of serious side effects outweighed the potential benefit of the drug's ability to slow the spread of tumors.

Bevacizumab is designed to fight cancer by blocking the growth of blood vessels (angiogenesis) that supply tumors with nutrients. The drug is also approved for the treatment of colorectal and lung cancers.