Genentech's

(DNA)

cancer drug Avastin has been approved by U.S. regulators to help treat cases of colorectal cancer that have spread to other parts of the body and that haven't responded to prior medications.

The approval by the Food and Drug Administration was based on a study of 829 patients with advanced or metastatic colorectal cancer. The patients had received treatment with a type of chemotherapy regimen called 5-FU plus the drug irinotecan as an initial therapy, in some cases in addition to surgery.

Patients who received Avastin plus chemo saw a 25% reduction in the risk of death, which is equivalent to a 33% improvement in overall survival, compared with who received chemotherapy alone, the company said late Tuesday. Colorectal cancer is the second-leading cause of cancer death in the U.S.

"Avastin used in combination with chemotherapy has become an important component of care for patients with metastatic colorectal cancer," said Dr. Hal Barron, Genentech's chief medical officer, who adds that the "new indication offers CRC patients who have received a previous treatment regimen a new option to help fight their disease."

The median survival time for those who received Avastin was 13 months, compared with 10.8 months for patients getting only chemo. Among cancer therapies, extending a life for two months is considered significant. Since the figure is a median, some patients see little or no benefit to therapies with Avastin, while others see significant gains.

Genentech's shares were up 89 cents, or 1.2%, to $77.79.

Genentech is also studying the drug's effectiveness in a number of phase III trials for kidney, breast, pancreatic, nonsmall-cell lung, prostate and ovarian cancers. Phase III is the stage of trials conducted immediately before a drug is submitted to the FDA for marketing approval.

Avastin was first cleared in 2004 as a first-choice treatment for colorectal cancer in combination with chemotherapy. Since that initial approval, Avastin has been widely used, off-label, against a number of cancers, including types of lung and breast cancer.

The drug has received what's called a compendia listing for both cancers, a measure that often indicates to doctors and insurers that it's an acceptable and effective treatment for a specific disease for which it may not be FDA-approved. The South San Francisco, Calif.-based company expects to hear from the FDA on whether it can officially market the drug for those cancers by the end of the year.

The compendia listing for lung cancer was given in September 2005, and Genentech received the listing for breast cancer last month, but the company doesn't break out sales data on unapproved uses, according to a spokeswoman.