Primary analysis of a randomized phase II, multicenter trial: Neoadjuvant weekly nab-paclitaxel 100mg/m2 followed by FE100C compared with docetaxel 75mg/m2 followed by FE100C for early breast cancer in Japan.

Abstract

136 Background: Nanoparticle Albumin-Bound Paclitaxel (nab-PTX) is a new solvent free taxane-based anticancer drug. According to CA024 trial, nab-PTX 100mg/m2 demonstrated superior response to docetaxel (DTX) in patients with metastatic breast cancer. Besides, nab-PTX 100mg/m2 was less toxicity. In operable breast cancer, GeparSepto study was reported that the pCR rate were significantly higher with nab-PTX 125/150 mg/m2 compared to paclitaxel. We planned the randomized parallel design phase II trial to evaluate nab-PTX 100mg/m2in early breast cancer. Methods: Stage II-III HER2-negative breast cancer patients were included in this trial and received either 4 cycles of DTX (75 mg/m2 day1) q 3 w or 4 cycles of nab-PTX (100 mg/m2 day1/8/15) q4w followed by 4 cycles of FE100C. The primary end point is pCR (ypT0/is ypN0) rate, and the secondary end points are response rate, histological effect of treatment, breast conservation rate, and toxicity. Results: Between March 2011 to March 2014, 152 eligible patients were enrolled at 6 centers (75 pts were allocated for nab-PTX). Baseline characteristics were well balanced; median age was 51/49 years (DTX/nab-PTX), 61/61% of the patients with ER positive, 38/36% triple negative breast cancer, 57/65% Ki67 > 20%. Clinically response rate was similar to each drug. (53/57%) The pCR rate was 12/17% (p = 0.323). In TNBC group, the pCR rate was 28/30% (p = 0.866). In Ki67 > 20% group, the pCR rate was significantly higher, 16/48% (p = 0.021) with nab-PTX arm. The most common grade3-4 adverse event was neutropenia, which was observed in 40/36% of cases. Non-hematological adverse events of any grade were; 34/32% myalgia (DTX/nab-PTX), 42/35% arthralgia, 55/65% peripheral sensory neuropathy. No Grade3-4 peripheral sensory neuropathy was observed in nab-PTX arm. Infusion reaction of DTX occurred in 1 patient. Conclusions: In this initial effectively analysis, neoadjuvant weekly nab-paclitaxel 100mg/m2 were promising drug in HER2-negative operable breast cancer patients. Larger studies will be needed to evaluate neoadjuvant weekly nab-paclitaxel compared with DTX. Clinical trial information: 000005388.