Multicenter phase II trial of weekly paclitaxel in women with metastatic breast cancer

We evaluated the safety and efficacy of weekly paclitaxel therapy in women with metastatic breast cancer in a phase II multicenter trial. Entry criteria were relatively liberal to reflect the heterogeneity of metastatic breast cancer in clinical practice.

Patients had histologically confirmed and measurable metastatic breast cancer. Up to two prior chemotherapy regimens for metastatic disease, including prior therapy with anthracyclines and taxanes and prior high-dose therapy, were allowed. Paclitaxel 80 mg/m(2) was administered weekly for 4 weeks per 4-week cycle.

We enrolled 212 patients; 211 were assessable for toxicity and 177 were assessable for response. Ninety percent of patients had received prior chemotherapy (adjuvant, metastatic, or both), 46% of patients had three or more involved metastatic sites, and 60% of patients had visceral-dominant disease. Responses were documented on two occasions and were independently reviewed. The overall response rate (complete plus partial response) was 21.5% (95% confidence interval, 15.4% to 27.5%), with 41.8% of patients having disease stabilization. Median time to progression was 4.7 months, and overall survival in all 212 patients enrolled was 12.8 months. Therapy was well tolerated, with a 15% incidence of grade 3/4 hematologic toxicity and a 9% incidence of grade 3 neurotoxicity; other serious toxicities were rare. The response rate and toxicity profile in the 34% of patients > or = 65 years of age were similar to that of younger patients.

Weekly paclitaxel therapy was well tolerated and demonstrated reasonable activity in this relatively heavily pretreated population with advanced disease. Further study of weekly paclitaxel in combination therapy is warranted.