The Food and Drug Administration announced in December that Genentech Inc.'s drug Avastin failed to help breast cancer patients live longer and had serious side effects, including deaths. The results of a clinical trial showed that the drug failed to extend overall survival, although it did meet its primary goal of extending "progression-free survival."

However, the company said Friday that FDA has reversed its earlier ruling and approved the drug for treatment for advanced breast cancer. However, the regulator approved Avastin under a mechanism known as accelerated approval, which means that Genentech must submit additional data to gain full approval.

Avastin (active ingredient: bevacizumab), a monoclonal antibody against vascular endothelial growth factor, showed encouraging results in patients with the most aggressive form of brain cancer, Genentech announced in mid-November last year. The announcement came after a successful Phase II trial in which bevacizumab showed clear improvements of the patients' survival rate.

Bevacizumab was developed by Genentech and is marketed in the United States by Genentech and elsewhere by Roche, which is Genentech's parent company, under the brand name Avastin. Bevacizumab, approved by the Food and Drug Administration (FDA) in February 2004 for use in colorectal cancer, was the first commercially available angiogenesis inhibitor. This class of drugs stops tumor growth by preventing the formation of new blood vessels. The main side effects of the drug are hypertension and heightened risk of bleeding.

The cancer drug had sales of $2.3 billion in 2007, with part of that coming from off-label use of Avastin for advanced breast cancer, WSJ reports.