Purpose: To determine the response rate (RR), progression-free survival (PFS), and toxicity in patients with HER-2/neu-negative metastatic breast cancer treated with first-line paclitaxel in a de-escalating dosing schedule.
Patients and methods: Between August 1999 and December 2000, 73 patients were enrolled. Paclitaxel was administered on day 1 (175 mg/m(2)) and on days 8 and 15 (80 mg/m(2) each) in each 4-week cycle (1 week of rest). Doses were de-escalated with the aim of reducing toxicity. An Eastern Cooperative Oncology Group performance status of 0, 1, or 2 was found in 55%, 41%, and 4% of patients, respectively. Median age was 59 years (range, 38 to 84 years), and 86% of patients had received prior surgery; 60%, adjuvant chemotherapy; and 59%, radiation therapy.
Results: Based on an intention-to-treat analysis (N = 73), there were five patients with a complete response (6.8%), 16 with a partial response (21.9%), 17 with stable disease (23.3%), and 23 with progressive disease (31.5%) for an RR of 28.7%. Twelve patients (16.4%) were not assessable for response due to toxicity (seven patients, mainly neuropathy), withdrawal of consent (two patients), early death (two patients), or noncompliance (one patient). Median PFS was 6.5 months (range, < 1 to 36.1 months), median survival was 22.8 months (range, < 1 to 36.1 months), and median duration of response was 8.8 months (range, 3.0 to 31.8 months). Patients (n = 72) were evaluated for toxicity. Grade 3 to 4 treatment-related toxicities occurring in more than 5% of patients included neutropenia (22.2%), neuropathy (18.1%), fatigue (6.9%), and leukopenia (5.6%).
Conclusion: In a unique de-escalating schedule, this study of single-agent paclitaxel produced a response rate similar to other single-agent paclitaxel schedules, in first-line therapy for metastatic breast cancer, published in the literature. However, this schedule is not recommended for the therapy of metastatic breast cancer because of the higher rate of toxicity.