Last Updated: 2007-12-26 17:00:21 -0400 (Reuters Health)

NEW YORK (Reuters Health) - In women with advanced breast cancer, progression-free survival (that is, a patient remaining alive without the disease getting worse) is improved with the addition of Avastin to the commonly-used drug paclitaxel, but overall survival is not affected, according to a study reported in The New England Journal of Medicine this week.

Known generically as bevacizumab, Avastin is a monoclonal antibody that binds to endothelial growth factor (VEGF), which in turn inhibits the formation of new blood vessels, cutting off oxygen and nutrients cancer cells need to survive.

Dr. Kathy Miller, from Indiana University Cancer Center in Indianapolis, and colleagues assessed the outcomes of 722 women with metastatic breast cancer who were randomized to receive paclitaxel alone or in combination with Avastin. Paclitaxel was given on days 1, 8, and 15 every 4 weeks, while Avastin was given on days 1 and 15.

The median progression-free survival period with the drug combination was 11.8 months, twice as long as the 5.9 months achieved with paclitaxel alone. The objective response rate was also higher when both drugs were given: 37 percent versus 21 percent.

As noted, however, no significant difference in overall survival was seen between the groups, with a median survival period for each of about 26 months.

High blood pressure, blood clots, heart attacks, and infection were seen more often in the combination arm than the single-drug arm.

In early December, a U.S. advisory panel recommended against approval of Avastin to treat women with breast cancer. The panel decided by a vote of 5-4 that Avastin maker Genentech Inc failed to establish a favorable balance of risks and benefits in the data it presented for Avastin's use in advanced breast cancer patients.

Avastin currently is approved by the U.S. Food and Drug Administration (FDA) for treating lung and colon cancer, but many doctors use it to treat breast cancer.

SOURCE: The New England Journal of Medicine, December 27, 2007.