The results were from a study called Avado, which included patients who took Avastin with Taxotere, but the data is too new to be included in the biotech’s application to market Avastin for this use. The benefit was seen among patients on both low and high doses, compared with patients given a placebo along with chemo, according to Genentech. The study also measured whether patients lived longer than those on placebo.

The FDA is expected to decide later this month on whether to approve Avastin - which is already cleared to treat colon and lung tumors - based on a different study. The earlier trial, called ECOG 2100, showed Avastin was able to slow the spread of breast cancer by an additional 5.5 months when used with Taxotere, compared with just chemo. Genentech hopes the latest results will sway the agency, but some analysts are dubious.

In a research report this morning, Jim Reddoch of Friedman Billings Ramsey notes that an FDA advisory panel in December wasn’t convinced of Avastin’s risk-reward profile and voted 5-4 against approval. “They also had issues with (progession-free survival) as an endpoint for approval in first-line breast cancer. The ECOG 2100 trial, the main study in the filing, showed a robust 5.5 month benefit, but no overall survival benefit. Therefore, the PFS results from Avado, absent survival, are unlikely to persuade the FDA to reconsider the recommendation.”

Remember that patients taking Avastin in the ECOG 2100 trial had a 20 percent increase in serious side effects, including high blood pressure, blood clots and heart attack. Avastin didn’t show a statistically significant ability to extend lives in that study, either.

“In our view, the Avado results only modestly improve the odds of FDA approval by the (Feb. 23) PDUFA date,” writes Rodman & Renshaw analyst Michael King in an note this morning. “Based on previous FDA thinking on this issue, Avado may potentially have to show a benefit in the overall survival in addition to the PFS benefit to influence the FDA towards approval.”