TUESDAY, May 17, 2005 (HealthDay News) -- A study involving two chemotherapy drugs used in combination to treat breast cancer was halted after two patients died and one suffered a serious complication, French investigators report.
All three women had febrile neutropenia, a complication of chemotherapy involving a reduction in immune white blood cells accompanied by fever.
The study authors warn of the possible risks of the drug combo in a report published in the May 18 issue of the Journal of the American Medical Association.
"Clinicians should be aware of the potential toxicity of the doxorubicin-docetaxel regimen," the authors wrote. This combination should not be used outside of carefully designed clinical trials, they added.
Certain drug combos have been shown to be superior to single chemotherapy agents in treating advanced or metastatic breast cancer, according to the report. However, questions remain about the optimal administration of these combination regimens, their safety and cost, the authors added.
Dr. Etienne G. C. Brain, of the Rene Huguenin Cancer Centre in Saint-Cloud, France, set out to compare the effectiveness of two chemotherapy regimens in women treated at 11 French cancer centers from June 1999 through January 2003.
A total of 627 women, aged 18 to 70, participated in the study. All of them had early-stage breast cancer, with either a moderate number of lymph nodes involved or no positive lymph nodes, but a high risk of relapse.
The women were randomly assigned to receive one of the two regimens: doxorubicin plus docetaxel or doxorubicin plus cyclophosphamide. The drugs were administered in four courses after surgery.
According to the National Cancer Institute, doxorubicin is a type of antibiotic used to treat cancer. Cyclophosphamide, another anti-cancer drug, belongs to the family of drugs called alkylating agents that interfere with a cell's DNA and inhibit cancer cell growth. Docetaxel inhibits cell growth by stopping cell division.
Investigators had intended to examine the safety and overall survival of patients at five years, but were only able to collect 24 months of data. The trial was terminated after two women died, apparently due to drug toxicity, and a third suffered bowel perforation with peritonitis, an inflammation of the membrane of the abdomen.
The authors said they observed a much higher rate of toxic death with the doxorubicin-docetaxel regimen than has been seen in recent trials involving various chemotherapy regimens.
Febrile neutropenia, the potentially deadly chemo complication, occurred at a much higher rate (40.8 percent), among patients on the doxorubicin-docetaxel regimen, than in women on the other drug combo (7.1 percent). The authors suspect that doxorubicin plus docetaxel may have severely suppressed patients' immune systems, contributing to the high rate of toxic death.
The National Cancer Institute has more information on chemotherapy treatments.