Cancer drug Avastin

A U.S. Food and Drug Administration advisory panel recommended Wednesday Dec. 5, that the cancer drug Avastin should not be used to treat women with advanced breast cancer.

In a close vote the advisers decided the drug’s ability to slow down the growth of tumors did not outweigh the increased risk of blood clots and other cardiovascular troubles among users, the Associated Press reported. In rare cases, patients taking Avastin with standard chemotherapy have died.

Avastin was approved to treat colon cancer in 2004, and lung cancer in 2006. It works by cutting off the tumor’s blood supply.

In trial results submitted to the FDA by the drug’s U.S. maker, Genentech Inc., use of Avastin (bevacizumab) did boost the progression-free survival of women with advanced breast cancer by an average of 5.5 months, when combined with the chemotherapy drug paclitaxel. Progression-free survival refers to survival without any advancement of the malignancy.

Avastin is not traditional chemotherapy, but instead is a monoclonal antibody that robs tumors of their blood supply. It has been found to boost the survival of patients with metastatic colorectal cancer and non-small-cell lung cancer when added to chemotherapy and used as a first-line treatment.

But the drug has its downside. In an analysis of pooled data from five randomized controlled trials involving more than 1,700 patients with metastatic colon, breast or lung cancers, Genetech researchers found that 3.8 percent of patients experienced blood clots while on the drug, compared to 1.7 percent of those who took standard chemotherapy alone.

Patients who were 65 or older appeared to be at special risk for clots while taking Avastin, according to the study, which was published in August in the Journal of the National Cancer Institute.

The exact link between Avastin and cardiovascular risk remains unclear, although the Genentech team speculated that a vascular endothelial growth factor (VEGF), a natural compound that boosts blood vessel growth, may play a role.