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Targeted Therapies Hit Breast Cancer Hard

Herceptin and other drugs look promising, studies show

FRIDAY, May 13, 2005 (HealthDay News) -- Evidence is mounting that so-called targeted therapies, including Herceptin, work well against breast cancer.

In two North American trials of Herceptin, women with aggressive breast cancer who took the drug after surgery and chemotherapy had a 52 percent reduction in the risk of a recurrence, compared with women who did not take the drug. Because of the positive results, the trials were halted early.

Researchers at the American Society of Clinical Oncology annual meeting in Orlando, Fla., delivered more good news: A third trial of Herceptin showed a 46 percent reduction in risk among women who took the drug simultaneously with chemotherapy.

In more good news for breast cancer patients, the colorectal cancer drug Avastin is also showing promise against breast cancer.

"Targeted therapy is really a clinical reality," Dr. Roy Herbst, an associate professor of medicine and cancer biology at the University of Texas M. D. Anderson Cancer Center in Houston, said at a press conference Friday. "Hardly anyone who is treating cancer patients doesn't think about targeted therapy."

Targeted therapy refers to drug treatments that attack tumors without harming healthy tissue.

The HER2 gene is present in about 20 percent to 30 percent of breast cancers, and indicates a more aggressive disease and an increased risk for relapse, explained Dr. Gabriel N. Hortobagyi, a professor of medicine and director of the breast cancer research program at the University of Texas M.D. Anderson Cancer Center.

All three Herceptin trials together showed about one-third fewer deaths. "It's unusual to show a survival difference in the first five years," Hortobagyi said.

Dr. Len Lichtenfeld, deputy chief medical officer of the American Cancer Society, called the results "spectacular."

The studies do not give enough information to determine whether giving Herceptin sequentially or simultaneously is better, Hortogagyi noted.

Additionally, Herceptin carries a risk of heart complications, which need to be watched, he said.

Avastin, a drug already used for colorectal cancer, conferred a 50 percent reduction in breast cancer recurrence, prolonging progression-free survival from 6.11 months to almost 11 months after about 30 months of follow-up. "This is a substantial addition to what chemotherapy can do alone," Hortobagyi said.

Avastin also prolonged survival for patients with advanced non-small-cell lung cancer, from 10.2 months to 12.5 months after a follow-up of almost 10 months. This is the first time that adding such a targeted agent to chemotherapy has been shown to improve survival, researchers said.

"This is really a proof of concept, Lichtenfeld said.

The drug, however, is not approved for these new indications and is not yet reimbursable by insurance. "I certainly would expect the FDA to review favorably on this, but that may have to wait," said study author Dr. Alan Sandler, an associate professor of medicine at Vanderbilt University Medical Center.

More information

The National Cancer Institute has more on Herceptin.

SOURCES: Roy S. Herbst, M.D, Ph.D., associate professor, medicine and cancer biology, University of Texas M.D. Anderson Cancer Center, Houston; Alan B. Sandler, M.D., associate professor, medicine, Vanderbilt University Medical Center, Nashville, Tenn.; Gabriel N. Hortobagyi, M.D., professor, medicine and director, breast cancer research program, University of Texas M.D. Anderson Cancer Center; May 13, 2005, study presentations, American Society of Clinical Oncology annual meeting, Orlando, Fla.
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