The combination of the anti-cancer drugs Herceptin and Taxotere appears to work better than Taxotere alone in women with advanced breast cancer that has spread beyond the breast, research shows. Moreover, there is little added toxicity when Herceptin is given.

Herceptin (trastuzumab) is a monoclonal antibody, meaning that it binds to one specific protein, HER2, which helps regulate cell growth. Overexpression of HER2, a sign of more aggressive cancer, occurs in about 25 percent to 30 percent of breast tumors. Taxotere (docetaxel) is a chemotherapy drug widely used to treat breast cancer and other cancers as well.

Previous studies indicate “synergy” between the two agents in women with breast cancer. To investigate further, Dr. Michel Marty, from Innovative Therapeutics in Paris, and colleagues treated 186 women with HER2-positive advanced breast cancer with six cycles of Taxotere with or without Herceptin.

Women treated with the combination regimen had a higher response rate (61 percent vs. 34 percent) and survived significantly longer (31.2 vs. 22.7 months) than women given Taxotere alone.

These findings, along with previous findings, support the use of Herceptin with a taxane such as Taxotere as first-line therapy for HER2-positive advanced breast cancer, the researchers conclude in the Journal of Clinical Oncology.

Overall, the number and severity of side effects seen in both groups were similar, aside from a higher incidence of neutropenia in the combination group. Neutropenia is a condition characterized by a drop in infection-fighting white blood cells that can occur with frequent chemotherapy.

Cardiac toxicity with Herceptin and Taxotere combination therapy, a concern in earlier trials, is “manageable,” the authors conclude, based on the low incidence of heart problems seen in women in the study.

In a commentary, Drs. Charles L. Vogel and Elizabeth Tan-Chiu, from the Cancer Research Network in Plantation, Florida, comment that while they “fully endorse” first-line Herceptin in these women, “a lingering question” remains regarding the survival benefit of Herceptin combination therapy compared with a sequential treatment approach.

SOURCE: Journal of Clinical Oncology, July 1, 2005.