SAN ANTONIO ? The drug Herceptin, already viewed as promising for women with both early and late-stage breast cancer, got another boost Thursday with new research showing the heart damage it sometimes causes might be avoidable.

It also might still be effective when given for a shorter time, a finding that could drastically lower the cost of the pricey treatment.

At a meeting of more than 7,000 breast cancer experts on Thursday, Finnish doctors said nine weeks of Herceptin instead of the usual year prevented recurrences and didn’t raise the risk of heart failure. A second study found that pairing it with novel chemotherapy gave good results and avoided much of the risk of heart damage.

They make a convincing case for using Herceptin earlier in breast cancer treatment, said Dr. Robert Carlson, a Stanford University breast cancer expert who had no role in the studies.

“The jury is in and the jury has a very strong verdict” – that virtually all women whose tumors are the type targeted by Herceptin should get the drug, he said.

Herceptin works against a gene that’s overactive in about one-fourth of breast cancers. About 50,000 women in the United States and 250,000 worldwide are diagnosed with this type each year. Herceptin targets cancer cells, avoiding the side effects of most other treatments.

It was approved in 1998 for advanced breast cancer, but its maker, Genentech, wants to sell it for women with early-stage disease, which is when most women are diagnosed. Recent studies on such women found it cuts the risk of recurrence and one analysis suggests it improves survival.

But it also can raise the risk of heart failure, especially in women also taking older chemotherapy drugs called anthracyclines.

Dr. Dennis Slamon, a scientist at UCLA’s Jonsson Cancer Center who led Herceptin’s development, tested its effectiveness in 3,222 women around the world on various chemotherapy drugs.

Slamon’s test results suggest the benefits of Herceptin could be obtained without the risk of the anthracycline.

“Herceptin is very safe” except when taken with an anthracycline, Slamon said.

The study was paid by Sanofi-Aventis, makers of Taxotere, and Genentech.

“The big problem is, it costs too much” – more than $40,000 for a year of the drug alone, said Dr. Linda Vahdat, director of breast cancer research at Weill Cornell Medical College.

To attack that problem, Dr. Heikki Joensuu of the University Central Hospital in Helsinki, Finland, tested nine weeks of Herceptin plus chemo or chemo alone in 232 women.

Three years later, disease-free survival was 89 percent in those who got Herceptin versus 78 percent of the others.