Gemcitabine and Docetaxel in Metastatic Breast Cancer
December 02, 2004
Use of the gemcitabine (Gemzar) plus docetaxel (Taxotere) combinationin metastatic breast cancer is motivated by the different mechanismsof action of the drugs, partially nonoverlapping toxicity profiles,and good single-agent activities of both drugs in treatment-naive andanthracycline-pretreated patients. In phase II trials, combinations ofgemcitabine at 900 or 1,000 mg/m2 on days 1 and 8 and docetaxel at 75to 100 mg/m2 on either day 1 or day 8 every 3 weeks, or gemcitabine at800 mg/m2 on days 1, 8, and 15 and docetaxel at 35 mg/m2 on days 1, 8,and 15 or 100 mg/m2 on day 1 every 4 weeks, have produced responserates of 36% to 79% in patients receiving primarily second-line treatment;response rates were greater than 50% in five of six studies. Inphase II trials using every-2-week regimens of gemcitabine at 1,500 or2,000 mg/m2 on day 1 and docetaxel at 50 or 65 mg/m2 on day 1 or 55mg/m2 on day 8, response rates were 50% in pretreated patients and66% in treatment-naive patients. Neutropenia is the primary toxicity ofthe combination; in phase II studies performed with or without growthfactor support, rates of grade 3/4 neutropenia ranged from 29% to 79%and rates of febrile neutropenia ranged from 0% to 18%. An ongoingphase III trial is comparing gemcitabine at 1,000 mg/m2 on days 1 and8 plus docetaxel at 75 mg/m2 on day 1 every 21 days, vs capecitabine at1,000 mg/m2 twice daily for 14 days plus docetaxel at 75 mg/m2 on day1 every 21 days in patients with metastatic breast cancer. Results of thistrial will help to determine optimal use of taxane-based combinationsin patients with advanced disease.