San Antonio ? Some women with very advanced breast cancer may have a new treatment option. A combination of two drugs that more precisely target tumors significantly extended the lives of women who had stopped responding to other medicines, doctors reported Friday.

It was the first big test of combining Herceptin and Tykerb. In a study of 300 patients, women receiving both drugs lived nearly five months longer than those given Tykerb alone.

Doctors hope for an even bigger benefit in women with less advanced disease, and were elated at this much improvement for very sick women who were facing certain death.

“We don’t see a lot that works in patients who have seen six prior therapies as they did in this trial, so that alone is exciting,” said Dr. Jennifer Litton, a breast cancer specialist at the University of Texas M. D. Anderson Cancer Center.

The good results are in stark contrast to two other studies that found no survival advantage from Avastin, a drug whose approval for breast cancer patients was very controversial. Two infusions of Avastin a month, as needed for this treatment, can run well more than $10,000 with fees for administering the drug. Its maker, Genentech, says the wholesale price it charges for the drug averages $7,700 a month.

Considering Avastin’s potential side effects — blood clots in the lungs, poor wound healing, kidney problems — a survival benefit “would have made the cost of the drug less painful to take,” Litton said.