Lately, it seems that for most biopharmaceutical companies, any news is not good news when it's about the Food and Drug Administration. Genentech (NYSE:DNA) proved Monday to be no exception, reporting that the FDA requested additional trial data to review a label expansion for Avastin to treat breast cancer.

Genentech's Herceptin has already been approved to treat a subset of breast cancer sufferers with tumors that might be HER2 positive. Genentech, though, was trying to get Avastin approved to treat a broader group, suffering from first-line metastatic breast cancer, in a front-line setting.

The word from the FDA Monday quashes formal approval for Avastin in this indication until at least early 2008 because Genentech said it would take until the middle of next year at the earliest to gather the necessary data and submit another regulatory filing for Avastin. The market could bring the company well more than a billion dollars.

This hasn't been the first setback for Avastin this year. In June, the drug failed a phase 3 trial in pancreatic cancer. Despite this failure, and now the delay in the breast cancer indication, Avastin offers Genentech the potential for years of revenue growth.

Because it cuts off the blood supply of tumors, Avastin could be used in many different types of cancers. The drug is already approved to treat colorectal cancer, but Genentech is testing it in 130 clinical trials for 25 types of cancer. Even with the delay, Avastin will probably trump Sanofi-Aventis' (NYSE:SNY) broadly used chemotherapy drug, Taxotere, in sales this year.

Partly because of the drug's expected effect on various types of cancer, Avastin sales have been growing at a torrid pace, with no sign of slowing down any time soon.

U.S. Avastin Sales*

Y-O-Y Change

Q2 06



Q1 06



Q4 05



Q3 05



Q2 05



*Sales in millions

Sales for Avastin should continue to grow at a rapid pace until competing drugs with similar mechanisms -- maybe ones in the making from Rule Breakers pick Exelixis (NASDAQ:EXEL) -- enter the market in a few years. Until that time, Genentech investors won't have to worry much about Avastin's sales growth.

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Fool contributor Brian Lawler does not own shares of any company mentioned in this article. He welcomes your feedback . The Fool has a disclosure policy .