July 20, 2010 -- Avastin is not helpful in the treatment of metastatic breast cancer, and the drug's approval for this use should be withdrawn.
That's the verdict of an FDA advisory panel, whose 12-1 vote urges the FDA to remove breast cancer from the list of approved uses of the Genentech drug. The vote is specific to breast cancer and does not affect Avastin's approval for the treatment of colon, lung, brain, or kidney cancer.
Against the advice of a previous advisory committee, the FDA in 2008 gave Avastin "accelerated approval" for the treatment of spreading breast cancer, in combination with chemotherapy. As a condition of that approval, Genentech agreed to conduct two new clinical trials.
Those trials showed no evidence that Avastin offered an overall benefit to breast cancer patients. In contrast, the drug added significantly to the side effects of chemotherapy.
Avastin is a man-made antibody that blocks the chemical signals that tumors use to grow new blood vessels. By preventing the growth of new blood vessels, the drug starves tumors.
But clinical trials showed little evidence that breast cancer patients benefit by adding Avastin to chemotherapy. The drug increased the rate at which these patients experienced serious side effects.
Briefing documents prepared for the panel by FDA staff painted a dim picture, suggesting Avastin's risks outweigh its benefits.
But Genentech noted that Avastin did not shorten patient survival, and that the drug should be tried in more patients with metastatic breast cancer in order to find out how it might best be used. Far from withdrawing its earlier approval, Genentech argued, the FDA should grant Avastin full approval for a wider group of patients.
The FDA is not bound by the decisions of its advisory panels, which are made up of experts drawn from outside the FDA. However, it's rare for the federal agency to buck a panel's near-unanimous decision.