Genentech Cancer Drug Ineffective in Trial

Genentech Inc. said that an experimental cancer drug failed to extend the lives of breast cancer patients in a large clinical trial, a setback for the South San Francisco-based biotechnology company.

In a news release issued after the markets closed, Genentech said that Avastin slowed the growth of tumors in a trial of 462 women, but that benefit did not translate into increased survival, the gold standard for government approval.

The results raise questions about the market potential of Avastin, which Genentech is continuing to test in colon cancer. Analysts had expected the drug to launch in 2004 and fuel Genentech’s growth, with sales as high as $1 billion.

Avastin is an antibody that restricts growth of blood vessels that feed tumors. It works by blocking a protein that causes vessels to proliferate.

Genentech did not release details of the breast cancer study, which the company said would be released at a medical conference in December. Genentech closed at $32, up 30 cents, on the New York Stock Exchange before the news was announced.