Phase II trial of weekly nab-paclitaxel and carboplatin treatment with or without trastuzumab as nonanthracycline neoadjuvant chemotherapy for locally advanced breast cancer

Background: Neoadjuvant chemotherapy has become standard treatment for women with locally advanced breast cancer. The aim of this study was to compare the efficacy and safety of nanoparticle albumin-bound paclitaxel (nab-paclitaxel) versus paclitaxel combined with carboplatin.

Methods: Thirty patients were treated with neoadjuvant nab-paclitaxel (125 mg/m(2), days 1, 8, and 15) and carboplatin (area under the curve =2; days 1, 8, and 15) every 21 days for four cycles. Ninety matched patients received paclitaxel (80 mg/m(2), days 1, 8, and 15) and carboplatin every 21 days for four cycles. Weekly trastuzumab is recommended for overexpression of human epidermal receptor-2. The primary endpoint was pathologic complete response (defined as ypT0/is ypN0). Matching was conducted according to six variables: body mass index, clinical tumor stage, clinical lymph node status, estrogen receptor status, HER2 status, and trastuzumab receiving rate.

Results: Ninety percent of patients in the nab-paclitaxel group and 80% of patients in the paclitaxel group experienced a clinical objective response (complete response or partial response; P=0.450). Eight patients in the nab-paclitaxel group and 23 patients in the paclitaxel group had a pathologic complete response in the breast and axillary nodes (26.7% versus 25.6%; P=0.904). Nab-paclitaxel showed a beneficial effective trend on clinical tumor stage II (36.8% versus 15.8%; P=0.051). When trastuzumab was added to nab-paclitaxel, the pathologic complete response rate was not significantly improved more than with trastuzumab and paclitaxel (43.6% versus 39.6%; P=0.769). Carboplatin plus nab-paclitaxel or paclitaxel had similarly low pathologic complete response rates (7.7% versus 10.5%) for the luminal molecular subtype. One (50%) triple-negative patient achieved a pathologic complete response. The nab-paclitaxel regimen caused more grade 4 neutropenia than the paclitaxel regimen (56.7% versus 21.1%; P<0.001).

Conclusion: Our study shows that weekly nab-paclitaxel and carboplatin with or without trastuzumab resulted in a pathologic complete response rate that was not superior to the matched cohorts. Future, larger trials are needed to validate that nab-paclitaxel is beneficial for clinical tumor stage II and the triple-negative subgroup.