WEDNESDAY, June 29 (HealthDay News) -- The blockbuster cancer drug Avastin got soundly rejected late Wednesday as a treatment for metastatic breast cancer by a U.S. health advisory panel that found the medication was not effective and causes dangerous side effects.

By unanimous vote, the panelists rejected the drug maker's appeal of a U.S. Food and Drug Administration recommendation last December to revoke Avastin's approval for breast cancer. The FDA recommendation cited the medication's poor performance in follow-up studies and its potential for serious side effects.

The drug maker, Genentech, now owned by pharmaceutical giant Roche, was given an unusual two-day hearing this week before the six-member advisory group.

Tuesday's opening-day hearing was dominated by patients and physicians who argued, often emotionally, against the drug's revocation.

"For the patients and their supporters, it was the reality that many of them were alive and well with few symptoms, which they and their physicians attributed to the fact that Avastin had a significant treatment benefit for their breast cancer," blogged Dr. Len Lichtenfeld, Deputy Chief Medical Officer for the American Cancer Society, who attended the hearing.

But later in the day, he added, "the FDA told a different story. The data from clinical trials, after looking at thousands of patients treated with Avastin in addition to more standard chemotherapy, showed no meaningful clinical benefit. At one point, an FDA representative said that they were looking for only one trial that had some sort of benefit ... No such trial emerged, while the side effect risk was considerable."

On Wednesday, according to CNN, Dr. Sandra Horning, one of Genentech's top scientists, cited a February 2008 memo in which the head of the FDA's cancer drugs division made positive comments about the study that he had criticized on Tuesday. Genentech officials also defended E2100, the original study that formed the basis for the FDA's accelerated approval, and said there were no better treatments available for many women, CNN reported.

Lichtenfeld, at the end of the first day of hearings, outlined the dilemma. "Clearly, we are in a place where emotion meets science and the FDA's decision will prove to be a difficult one," he said in his blog.

The advisory panel's vote is non-binding, and FDA commissioner Margaret Hamburg will make a final ruling, the Associated Press reported.

The FDA's unusual step of scheduling another hearing on the drug underscored the difficulty of withdrawing approval of a cancer medication, the AP reported.

"It says to me that either they [the FDA] have gotten a great deal of negative feedback from various quarters, or there's some kind of internal disagreement within the agency," Dr. Gary Lyman, professor at the Duke Cancer Institute in North Carolina, told the news service. Lyman was part of the FDA advisory panel that voted 12-1 last year to revoke Avastin's approval as a breast cancer therapy.

The FDA's December recommendation did not immediately affect breast cancer patients' access to the drug or limit use of Avastin (bevacizumab) for advanced colon, lung, kidney and brain cancer.

Doctors can continue to prescribe Avastin to patients "off-label," as they do other drugs. But it's unlikely that insurance companies would cover off-label use of the drug given its high price tag. Avastin costs more than $8,000 a month, according to published reports.

Avastin was OK'd in 2008 for use in metastatic breast cancer in conjunction with chemotherapy under the FDA's accelerated approval program. Approval was based on a clinical trial of patients with metastatic HER2-negative breast cancer that found a benefit in terms of cancer recurrence -- but not overall survival -- and was contingent on further data to confirm the results.

Three subsequent studies failed to find an overall survival benefit and showed less impressive improvements in survival involving no progression of cancer.

More information

The U.S. National Cancer Institute has more on Avastin.