Panel Recommends FDA Withdraws Approval of Avastin for Breast Cancer

Approval for use of the cancer drug Avastin to treat breast cancer should be withdrawn, according to a panel of experts convened by the FDA. The panel indicated that the potential benefits provided by the drug are outweighed by the risk of potentially serious side effects of Avastin.

An FDA advisory panel voted 12-1 on Tuesday to recommend that the FDA withdraw Avastin’s breast cancer approval. Although the FDA is not required to follow the recommendations of their advisory panels, they often do. If approval is withdrawn for breast cancer treatment, Avastin would still be approved for the treatment of kidney, colon, lung and brain cancer.

The panel said that the drug shows too few actual benefits to rationalize exposing breast cancer patients to the Avastin side effects, which can include a risk of blood clots, hypertension, febrile neutropenia, gastrointestinal bleeding and perforations. There have also been reports of serious eye inflammation from Avastin when used off-label to treat wet macular degeneration.

Avastin (bevacizumab) was approved by the FDA in 2004 for treatment of non-small cell lung cancer and colorectal cancer when combined with chemotherapy. It was then was granted accelerated approval for use with paclitaxel to treat breast cancer patients by FDA in February 2008. The drug prevents the formation of new blood vessels in tumors, starving them and inhibiting their growth.

The approval of Avastin for breast cancer treatment was based on a clinical trial finding that it slowed the growth of breast cancer tumors, at odds with the usual requirement that breast cancer treatment drugs show that they actually extend the lives of patients. As part of the accelerated approval process, Genentech, a subsidiary of Roche, had to continue two more drug trials and then submit their findings to FDA.

However, further studies have failed to show that Avastin extends the lives of breast cancer patients, and it does not appear to actually reduce tumors that are already present. The postmarket clinical trials also seem to indicate that the drug’s ability to slow tumor growth is not as pronounced as the initial trials suggested.

Cancer experts have long been split on whether the delay of tumor growth should be a goal for a cancer drug. Most believe that extending the life of the patient and reduction of tumors are more accurate and beneficial goals for a cancer treatment drug.

If the FDA withdraws the drug’s approval for breast cancer, that does not prevent doctors from prescribing the drug off-label for that purpose. However, it would prevent Genentech from promoting it for such uses. The withdrawal of breast cancer approval is also likely to make doctors think twice about prescribing it for that use, and insurance companies might not agree to pay for Avastin prescribed to treat breast cancer after the panel’s recommendation.