Genentech today said it is seeking federal permission to have its cancer-fighting drug Avastin given accelerated approval to treat people with an aggressive form of brain cancer.

The U.S. Food and Drug Administration already has approved Avastin for use in combination with chemotherapy to treat colon and breast cancer. In today's announcement, the South San Francisco biotechnology giant said it is seeking approval to have the drug approved to treat glioblastoma, the most common type of brain tumor.

"There has been no substantial improvement in the treatment of glioblastoma in more than 20 years," said Dr. Hal Barron, Genentech's chief medical officer in a prepared statement. "This is a devastating disease and people with glioblastoma desperately need new treatment options."

Usually, companies are required to prove the effectiveness of a drug in three separate stages of studies. But Genentech is seeking to have Avastin approved for brain cancer on the basis of just two stages. The FDA sometimes grants such approval for medicines to treat cancer or other life-threatening diseases if the early stage studies show evidence the drug is effective.

Genentech's request is based on a study of 167 glioblastoma patients. It found that 43 percent of those taking Avastin showed no signs of their cancer worsening after six months. In addition, the company said, the tumors decreased in size by at least half for 28 percent of the patients........