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An advisory committee to the Food and Drug Administration voted unanimously on Wednesday that the approval of Avastin as a treatment for breast cancer should be revoked, despite a two-day appeal hearing by Genentech, the drug’s manufacturer.

In four 6-0 votes, the committee said recent studies have not shown that the drug is safe and effective. It unanimously rejected a compromise proposal made by Genentech that the approval be retained while the company conducts another clinical trial to confirm that the drug works.

The votes make it more likely that the F.D.A. will go ahead with its decision, made in December, to rescind the approval. The actual decision will be made by the agency’s commissioner, Dr. Margaret A. Hamburg. It is not clear when the decision will be made but it will not be until after July 28 because the F.D.A. will still accept public comments until then.

The votes came after an emotional two-day hearing at the F.D.A. campus in Silver Spring, Md., in which about a dozen women with breast cancer, many of them saying that Avastin was helping control their disease, pleaded with the agency to make sure the drug remained available.

Even if the breast cancer approval is withdrawn, the drug will remain on the market as a treatment for other cancers, so doctors could use it “off label” to treat breast cancer. But insurers might be less likely to pay for the drug, which can cost $88,000 a year for a typical breast cancer patient.

Avastin received so-called accelerated approval for metastatic breast cancer in 2008 under a program that allows drugs for serious diseases to reach the market more quickly, subject to further study.

The F.D.A. said in December that these subsequent studies had not confirmed the initial findings, so it proposed to rescind the drug’s approval for breast cancer.

Neither of the two new studies showed that the drug prolonged women’s lives or improved the quality of their lives. And in the two new studies, use of the drug delayed the progression of tumors by less than one month to 2.9 months, far less than the 5.5-month delay seen in the initial trial.

Genentech argued that the new trials still showed that the drug had benefits, even if they were not as great as in the initial trial. Certainly, the company said, the new results did not contradict the results of the initial trial.

The company said that the difference in trial results might be explained by the different chemotherapy drugs with which Avastin was used. It is proposing to do another clinical trial combining Avastin with paclitaxel, the chemotherapy drug used in the initial trial that led to approval. In the meantime, it said, Avastin should retain its approval.

“The law provides this flexibility and this middle course best meets the purposes of accelerated approval to facilitate needed treatment options,” Michael S. Labson, a lawyer representing Genentech, said at the hearing.

Genentech said the trial would take several years to complete.

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