WASHINGTON - Federal health authorities recommended Thursday that the blockbuster drug Avastin no longer be used to treat breast cancer, saying recent studies failed to fulfill the drug's original promise to help slow the disease and extend lives.

The rare decision by the Food and Drug Administration is supported by many cancer experts but drew fierce opposition from cancer patients and some doctors who defend the drug and say it should remain available.

The ruling is a significant setback for the world's best-selling cancer drug and will likely cost Swiss drugmaker Roche hundreds of millions of dollars in lost revenue. Avastin is also approved for various types of colon, lung, kidney, and brain cancer.

FDA officials stressed that the recommendation was only a preliminary step toward revoking the drug's approval for breast cancer. Roche has refused to voluntarily withdraw the indication, and the company said in a statement it would request a public meeting on the issue.

Drug companies almost always follow FDA requests, and agency officials said a meeting over the fate of Avastin would be the first of its kind. The agency said it would consider whether to hold the meeting in the months ahead.

"Today's decision was a difficult one for the agency but certainly not unique," said Janet Woodcock, director of the FDA's drug center. Drugs must be "both effective and safe."

The FDA approved Avastin for breast cancer in 2008 based on one study suggesting it halted the spread of breast cancer for more than five months when combined with chemotherapy. But follow-up studies showed that the delay lasted no more than three months, and caused dangerous side effects.

In a separate announcement Thursday, the European Medicines Agency said it would keep the drug available as a combination treatment with the chemotherapy drug paclitaxel - the same use rejected by the FDA.

FDA officials said the split opinion was due to differences in how Avastin was approved in the United States vs. Europe. The FDA cleared the drug under its accelerated approval program, giving the agency the option to rescind approval if follow-up studies did not confirm initial results. European regulators granted the drug full approval based on the same results, making it more difficult to reverse course when faced with weaker follow-up results.

If the FDA ultimately removes Avastin's breast cancer indication, doctors will still have the option to prescribe the drug "off-label," or without a federal approval, but many insurers do not reimburse drugs for such uses. Without coverage, Avastin's high cost would put it out of reach for most patients.

Avastin can run more than $100,000, though Roche caps spending for patients who meet its financial criteria.