Christina Ficara - All Headline News Staff Reporter

The problems developed in women given the standard intravenous drug doxorubicin along with a newer drug called docetaxel. The two drugs are frequently used alone to treat breast cancer. Scientists have been exploring the effects of combining them, with mixed results.

Docetaxel, or Taxotere, belongs to a class of cancer drugs that also includes Taxol. These drugs are derived from the yew tree and have shown promise in improving cancer survival.

French researchers set out to compare five-year, disease-free survival rates in 627 women treated with either doxorubicin plus Taxotere or the more conventional combination of doxorubicin plus cyclophosphamide.

The three-year study was stopped in 2003.

The patients who died had developed low white blood cell counts, fever and severe intestinal problems. A third woman became severely ill with similar symptoms.

Low white-cell counts with fever developed in nearly 41 percent of the doxorubicin-Taxotere women, compared with 7 percent of the other patients. The condition is a potential side effect of chemotherapy and can be life-threatening because it means the drugs have weakened the body's ability to fight infection.

According to the researchers, led by Dr. Etienne Brain of the Rene Huguenin Cancer Center in Saint-Cloud, France, the high rate of complications indicated the two-drug combination was too toxic.

The study appears in Wednesday's Journal of the American Medical Association.

Dr. Carolyn Runowicz, president-elect of the American Cancer Society and an oncologist at the University of Connecticut, said the combination should not be excused because there is still a chance that it could improve survival. Runowicz suggested the combination be used with drugs to boost white-cell counts as a precaution.

In a study presented over the weekend, Dr. Lori Goldstein of Fox Chase Cancer Center in Philadelphia compared the same two-drug combinations for treating early breast cancer.

There were four treatment-related deaths among the nearly 3,000 women studied all in women on the Taxotere combination but Goldstein said that rate was acceptably low. She found no difference in survival rates over nearly five years, but low white-cell counts with fever were more common in patients on the Taxotere combination.

Participants in the French study had a high chance of cancer recurrence because the cancer had reached their lymph nodes or because they had other risk factors.