US regulators have extended by three months a review of Roche Holding's blockbuster drug Avastin in breast cancer, the company said.

The Food and Drug Administration has made no decision on whether to revoke Avastin's approval for treating breast cancer patients as an advisory panel has recommended, the FDA and the company said.

Roche unit Genentech said it had submitted additional information to the FDA on two applications to expand Avastin's approved breast cancer uses to include combining the drug with other types of chemotherapy.

The new information prompted the FDA to extend the review of those uses until December 17, a Genentech statement said.

An FDA advisory panel that met in July urged the agency to reject those applications and to remove the drug's current approval for breast cancer. There is no set timeline for an FDA ruling on whether to revoke the breast cancer approval, Genentech spokeswoman Charlotte Arnold said.

Avastin won US clearance for breast cancer in 2008 based on a study showing the drug stalled cancer growth by 5.5 months.

The FDA required Roche to run follow-up studies to confirm the drug worked. Later studies found only a one- to three-month delay in breast cancer growth.

No studies showed Avastin extended the lives of patients with advanced breast cancer. About $1 billion of Avastin's more than $6 billion in yearly sales come from breast cancer uses, analysts estimate.

The product is Roche's top-selling drug, accounting for 13 per cent of 2009 sales.

If the FDA pulls the breast cancer approval, the drug would remain on the market with clearance for colon, lung, brain and kidney cancers.

Doctors still could prescribe Avastin for breast cancer but sales likely would fall. Insurers may refuse to pay Avastin's $8,000-a-month pricetag for breast cancer patients without FDA approval.

Cancer patients and some advocacy groups have lobbied the FDA to keep the breast cancer approval, saying patients need options.

FDA spokeswoman Erica Jefferson said the agency 'will be reviewing the additional data submitted by the company to make a science-based decision with the best interest of patients in mind.'-Reuters