The US Food and Drug Administration (FDA) recently approved the use of capecitabine(Drug information on capecitabine) (Xeloda) in combination with docetaxel(Drug information on docetaxel) (Taxotere) for the treatment of metastatic breast cancer in patients who failed anthracycline therapy. This regimen is the first chemotherapy combination to significantly extend survival (by 3 months) in these patients compared to docetaxel alone.
Previously, docetaxel monotherapy (100 mg/m² on day 1 of each 21-day cycle) was the only regimen to demonstrate improved survival over that achieved with the standard combination regimen of mitomycin (Mutamycin) and vinblastine(Drug information on vinblastine). Recent findings indicate that patients treated with the combination of capecitabine and docetaxel had a superior survival and a 22.5% reduced risk of mortality (hazard ratio: 0.775, P = .013) compared to those treated with docetaxel alone. In addition, the combination produced significantly superior tumor response rates (32% vs 22% for docetaxel alone) and longer time to disease progression (6.1 months vs 4.2 months).
"Xeloda combined with Taxotere is an important treatment improvement for women with metastatic breast cancer," said Joyce O’Shaughnessy, md, codirector of breast cancer research at Baylor-Sammons Cancer Center and US Oncology. "The clinical data showed significant improvements in survival, tumor response, and time to disease progression for the combination compared to Taxotere alone in patients after failure of anthracycline treatment. This represents a major advance in the management of women with metastatic breast cancer, as improvements in survival are the bottom line."
Clinical Trial Results
The FDA decision was based on the results of a large phase III trial in 511 patients that compared capecitabine in combination with docetaxel to docetaxel alone and looked at survival, time to disease progression, and tumor response rate. Women with metastatic breast cancer who had failed treatment with an anthracycline were randomized to either the combination (oral capecitabine, 1,250 mg/m² twice daily, days 1 to 14 with 1 week of rest, plus IV docetaxel, 75 mg/m², day 1 of each 21-day treatment cycle) or monotherapy (IV docetaxel 100 mg/m², day 1 of each 21-day cycle).
The combination produced significantly better outcomes than docetaxel alone. Median survival among women in the combination group compared to the monotherapy group was 14.5 vs 11.5 months (P = .013), median time to disease progression was 6.1 vs 4.2 months (P = .001), and the tumor response rate was 32% vs 22% (P = .009). The trial was conducted in the United States, Canada, and Australia, as well as countries in Europe, Asia, and Latin America.
Adverse events, including diarrhea, stomatitis, hand-foot syndrome, and nausea and vomiting, were observed more commonly in the combination therapy group. These effects, however, proved to be manageable with appropriate medical intervention and dose interruptions. Dose reductions decreased the overall incidence of these events in subsequent cycles. Patients who received docetaxel therapy alone experienced a higher incidence of neutropenic fever, myalgia, and arthralgia.