Single-agent chemotherapy (CT) is widely used in the management of HER2-negative breast cancer patients (pts). As both Paclitaxel (P) and Vinorelbine (V) have demonstrated efficacy in the treatment of Metastatic Breast Cancer (MBC), they are recommended among the standard available CT agents for MBC patients. This study compares the efficacy and safety profile of most frequently used three treatment regimens: Paclitaxel every-3-weeks (3-w-P) versus weekly Paclitaxel(w-P) and versus weekly Vinorelbine (w-V) in MBC. Primary objective: Time to progression (TTP). Secondary objectives: evaluation of safety profiles, clinical benefit and response rate (RR) of all arms.
In this open-label randomized prospective study, pts were randomized (2:2:1) to receive either: intravenously 3-w-P every 21 days, w-P 80 mg/m2/week (day 1, 8, 15) every 28 days or w-V 25 mg/m2/week (day 1, 8, 15) every 28 days. Main eligibility criteria: age ≥18 years, documented metastatic disease previously untreated by CT for metastatic setting, ER/PR positive and HER2-negative disease, or triple negative disease. ECOG≤2.
From April 2014 to April 2015, 95 pts were included. 39 received 3-w-P; 38 received w-P and 18 received w-V per protocol. Median age was 58 years (range 38-79), median duration of treatment 11.5 weeks (range 9-24). Efficacy: with a median follow up of 24 months (m), median time to progression (primary endpoint) was 10.3m, 9.8m and 9.6m in 3-w-P arm, w-P and in w-V arm respectively (p = 0.006). Safety: w-V was much better tolerated with fewer G 3/4 toxicity events (n = 2) than w-P and 3-w-P (n = 23 and 16). Neuropathy G3/4 was mostly reported in 3-w-P and w-P arm than in V arm (75% vs. 69% vs. 17%). G3/4 alopecia was reported in both P arms (94%) when in V arm G3 alopecia was only in 6% of pts.
Weekly Paclitaxel appeared as effective as every-3-weekly regimen and weekly Vinorelbine, however neurotoxicity is a treatment-limiting toxicity for both Paclitaxel regimen. Vinorelbine had fewer significant grade 3-4 toxicities than both Paclitaxel arms and had better RR. Larger randomised studies are needed to determine the efficacy and overall survival of Paclitaxel versus Vinorelbine.
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All authors have declared no conflicts of interest.