Randomized phase II study to determine the optimal dose of 3-week cycle nab-paclitaxel in patients with metastatic breast cancer

Background: Chemotherapy-induced peripheral neuropathy is commonly observed in patients treated with nanoparticle albuminebound paclitaxel (nab-PTX). We conducted a multicenter randomized controlled study to evaluate the optimal dose of nab-PTX. Methods: We compared three different doses of q3w nab-PTX (Standard: 260 mg/m(2) [SD260] vs Medium: 220 mg/m(2) [MD220] vs Low: 180 mg/m(2) [LD180]) in patients with HER2-negative metastatic breast cancer (MBC). Primary endpoint was progression-free survival (PFS). Grade 3/4 neuropathy rates in the three doses were estimated using the logistic regression model. The optimal dose was selected in two steps. Initially, if the hazard ratio (HR) for PFS was <0.75 or >1.33, the inferior dose was excluded, and we proceeded with the non-inferior dose. Then, if the estimated incidence rate of grade 3/4 neurotoxicity exceeded 10%, that dose was also excluded. Results: One hundred forty-one patients were randomly assigned to SD260 (n = 47), MD220 (n = 46), and LD180 (n = 48) groups, and their median PFS was 6.66, 7.34, and 6.82 months, respectively. The HRs were 0.73 (95% confidence interval [CI]: 0.42-1.28) in MD220 vs SD260, 0.77 (95% CI 0.47-1.28) in LD180 vs SD260, and 0.96 (95% CI 0.56-1.66) in LD180 vs MD220. SD260 was inferior to MD220 and was excluded. The estimated incidence rate of grade 3/4 neurotoxicity was 29.5% in SD260, 14.0% in MD220, and 5.9% in LD180. The final selected dose was LD180. Conclusions: Intravenous administration of low-dose nab-PTX at 180 mg/m(2) q3w may be the optimal therapy with meaningful efficacy and favorable toxicity in patients with MBC. (C) 2020 The Authors. Published by Elsevier Ltd.

Automated summary

The study compared different doses of nab-PTX in patients with HER2-negative metastatic breast cancer and ultimately selected the low dose of 180 mg/m(2) as the optimal treatment option.