Yesterday, Genentech (NYSE:DNA) didn't get the holiday cheer that it was expecting from an FDA advisory panel. The panel voted 5-4 to recommend against approval of cancer-fighting drug Avastin as a front-line treatment for metastatic (late-stage) breast cancer.

On Monday, the FDA reviewers of the proposed label change made known their skeptical positions on Avastin's use in breast cancer. Even a 5-4 or 6-3 vote in favor of Avastin likely wouldn't have mattered, since advisory panel votes are nonbonding on the FDA and only an extremely upbeat advisory panel view would be likely to affect the agency's decision.

As expected, the main problem that some members of the advisory committee had with Avastin was that the drug was producing a strong progression-free survival advantage in breast cancer patients. But these effects, like delayed tumor growth, weren't translating into improved overall survival rates for breast cancer patients who were treated with Avastin.

The good news for Genentech investors is that even if Avastin doesn't get approved to treat breast cancer by its Feb. 23 PDUFA date next year, Genentech does have data coming out from two more Avastin breast cancer studies in the first half and third quarter of next year.

Both of these studies used PFS as their primary endpoints as well and had overall survival as a secondary endpoint. There have been many cases -- like ImClone System's (NASDAQ:IMCL) ERBITUX, Amgen's (NASDAQ:AMGN) Aranesp, or AstraZeneca's (NYSE:AZN) Iressa -- of cancer drugs showing ambiguous efficacy results in one study, but then producing much more robust (though not necessarily positive) data in a larger trial or with a different patient group.

In Genentech's favor, there are still plenty of growth opportunities left for Avastin; thousands of patients are enrolled in different clinical trials for numerous cancer indications. The negative advisory panel meeting and probable February FDA rejection of the drug for breast cancer will have some effect on the trajectory of Avastin revenue growth and its off-label sales. But if Genentech reports strong Avastin breast cancer data next year, then everything will be copacetic again.

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Fool contributor Brian Lawler does not own shares of any company mentioned in this article. The Fool has an A+ disclosure policy.