Paclitaxel administration on days 1 and 8 every 21 days in anthracycline-pretreated metastatic breast cancer patients. A multicenter phase II trial

Paclitaxel is now included in second- and even first-line regimens in advanced breast cancer. The optimal dose and schedule of this drug, however, still remain a matter of investigation. A group of 57 consecutive patients with advanced breast cancer previously treated with anthracycline-containing regimens were submitted to treatment with single-agent paclitaxel administered at 130 mg/m2 on days 1 and 8 every 21 days. Of the 57 patients, 56 were fully evaluable, and of these 25 had an absolute anthracycline resistance, 14 a relative resistance and 17 were potentially sensitive. The median age of the patients was 57 years (range 33-71 years), their median performance status was 1 (0-3), and 27 (47%) had liver involvement, 17 (30%) lung involvement, 30 (53%) bone involvement and 15 (26%) skin/lymph node involvement. Toxicity was recorded in 295 cycles. This scheme was well tolerated, the dose-limiting toxicities being hematological and neurological. Grade 3/4 leukopenia was observed in 20% of patients at nadir, while grade 3 leukopenia was observed in 3% of patients at recycle. Only one patient experienced febrile neutropenia. Grade 2/3 neurotoxicity was observed in 26% of patients, leading to drug withdrawal in three. The treatment was given on an outpatient basis in all patients and the median relative dose intensity of 86.6 mg/m2 per week was 100% of the planned dose (range 75-100%). Three patients (5%) attained a complete clinical response and 12 (21%) a partial response for an overall response rate of 26% (95% confidence interval 18-38%), while 30 (53%) attained disease stabilization and 11 progressed (19%). Time to progression in responding patients was 10.3 months, and the median overall survival of the entire population was 15.4 months. To conclude, paclitaxel administration on days 1 and 8 every 21 days was active and manageable in advanced breast cancer patients previously treated with anthracyclines. The response obtained was durable.