A panel of experts that advises the US Food and Drug Administration (FDA) concluded on Wednesday that the cancer drug Avastin, generic name bevacizumab, is not a suitable treatment for breast cancer and recommended the FDA withdraw its approval of the drug for such use. The FDA does not have to follow the recommendations of its advisory committees, but it usually does. The agency’s Commissioner Margaret Hamburg will make the final decision, although they have not said when that will be.

The public hearing received two days of testimony from breast cancer patients, doctors and advocacy groups. Some of the patients who spoke gave tearful accounts of their experiences, saying they were living proof that the drug works and asked for it to be kept on the market.

But the 6 voting members of the 7 member panel voted unanimously for the withdrawal of Avastin’s approval as a suitable treatment for breast cancer, saying studies have failed to show Avastin is effective for such.

Although they acknowledged that emotions were high, the panel said they had to go with the science. Their patient representative, Natalie Compagni-Portis, said: “I think we all wanted Avastin to succeed,” but the studies “didn’t bear out that hope,” reports the Los Angeles Times.

This was the second time the same panel, the FDA’s Oncologic Drugs Advisory Committee (ODAC) has come to the conclusion that the agency should withdraw its approval of Avastin (bevacizumab) in combination with paclitaxel chemotherapy for previously untreated (first-line) HER2-negative metastatic breast cancer.

The last time was less than 12 months ago, but the drug maker, Genentech, a member of the Roche Group, took the unusual step of filing an appeal, and lobbied the agency and Congress for a second hearing, reports the Boston Globe.

Avastin received FDA endorsement under an “accelerated approval” program that was set up in 1992 so that patients could have access to new promising treatments more quickly. The condition was that the drug maker continue to carry out research on the drug’s safety and effectiveness.

A spokeswoman for the FDA’s Center for Drug Evaluation and Research (CDER), Erica Jefferson, told CNN that since 2005, four cancer drugs approved under the “accelerated” program have been withdrawn by the companies who make them. In all four cases, the drug companies accepted evidence that promising early results from trials did not bear fruit in the long run.

Avastin works by starving tumors of their blood supply. It was first approved as a cancer drug in 2004, and received accelerated approval in 2008 for use in patients with previously untreated (first-line) HER2-negative metastatic breast cancer, in combination with copaclitaxel chemotherapy. The provisional approval was granted on the strength of early trial data that showed an increase in the length of time patients went without worsening of symptoms.

Under the conditions of accelerated approval, Genentech had to continue to research the drug’s safety and effectiveness and report the results. But the early data did not bear out in the long run: the delay in symptoms was not as good as it had appeared at first, and the final results of the research showed no overall improvement in survival.

Subsequent evidence also shows the drug carries the risk of high blood pressure, heart attacks and bleeding.

But some experts say that the overall data masks cases of dramatic improvement in individual patients, perhaps explaining why some of the witnesses at the hearing were able to relate such remarkable success stories.

However, it appears that the final decision rested on the lack of evidence that the benefits outweigh the risks, and that Avastin does not on average, appear to help patients live longer.

Dr. Richard Pazdur, director of CDER’s cancer drug division, told CNN there was no argument:

“Five clinical trials of breast cancer have failed to demonstrate an overall survival benefit.”

In the meantime Avastin plus paclitaxel is still approved in the US for women with HER2-negative metastatic breast cancer.

Genentech said in a statement that the proceedings and the panel recommendation has “no impact” on the drug’s approved used for other types of cancer (the blockbuster drug is also approved for the treatment of colon, lung, kidney and brain cancers), and neither does it affect the use of Avastin for metastatic breast cancer in other countries.

“We are very disappointed by the committee’s recommendation,” said Genentech’s Dr Hal Barron, chief medical officer and head of their Global Product Development arm, “and hope the Commissioner does not decide to remove this important medicine for women with an incurable disease who already have too few treatment options”.

Sources: Boston Globe, LA Times, CNN, FDA, Genentech.

Written by: Catharine Paddock, PhD