The latest clinical trials have shown that Genentech’s cancer drug, Avastin, proved its effectiveness in slowing the progression of breast cancer tumors when combined with chemotherapy treatment. The drug has already been approved in colon and lung cancer treatment, and Genentech is expecting a green light in breast cancer treatment as well.

The company publicly announced the results of the study, saying Avastin managed to lengthen the time before the cancer spreads, and is now waiting for the Food and Drug Administration to make a decision on February 23. An approval of the cancer drug would mean a significant boost in sales for Genentech, a company whose U.S. sales of Avastin alone reached $2.3 billion in 2007.

Previous discussions in December on whether to approve or reject the use of the cancer drug for treatment of breast cancer reached no agreement, as the FDA advisory panel considered there were no sufficient data from earlier studies to allow an equitable analysis risks-benefits regarding Avastin. The latest study released could be exactly what Genentech could need to swing the balance in its favor.

“We are pleased that a second Phase III study in this population of breast cancer patients showed a significant improvement in progression-free survival,” said Hal Barron, chief medical officer of Genentech, in a statement. “The trial also demonstrated Avastin’s potential with a different chemotherapy in this disease,” Barron added.

So far, the FDA commission analyzing another study said the drug’s toxic side effects outweighed the beneficial effects and at the same time, the fact that it was hard to establish the moment the cancer would start to worsen could also stand in the way of a favorable decision on February 23.

Approximately 170,000 women have been diagnosed with breast cancer in 2007 in the United States, and at least one in 8 women are affected by it during their lives. In the Unites States, breast cancer is responsible for more deaths than any other form of cancer, except lung cancer, with 40,000 deaths last year alone.