Nab-Paclitaxel vs Paclitaxel in Neoadjuvant Treatment of HER2-Negative Breast Cancer
In a European phase III trial (ETNA) reported in JAMA Oncology, Gianni et al found no significant difference in pathologic complete response rate with nab-paclitaxel (Abraxane) vs paclitaxel followed by an anthracycline regimen in neoadjuvant treatment for HER2-negative breast cancer.
Study Details
In the open-label trial, 695 patients with newly diagnosed disease from 62 sites in Europe were randomized between May 2013 and March 2015 to receive neoadjuvant nab-paclitaxel 125 mg/m2 (n = 346) or paclitaxel 90 mg/m2 (n =349) at weeks 1, 2, and 3 followed by 1 week of rest for 4 cycles before 4 cycles of investigator’s choice of an anthracycline regimen. The primary endpoint was the rate of pathologic complete response—defined as absence of invasive cells in the breast and axillary nodes (ie, ypT0/is ypN0) at surgery—in the intent-to-treat population.
Pathologic Complete Response Rates
Rates of pathologic complete response were 22.5% in the nab-paclitaxel group vs 18.6% in the paclitaxel group (odds ratio [OR] = 0.77, P = .19). Nonsignificant improvements in the nab-paclitaxel group were also observed among subgroups including luminal B-like (13.9% vs 10.0%) and triple-negative disease (41.3% vs 37.7%); early (23.1% vs 20.7%) and locally advanced disease (20.7% vs 12.5%); and age ≤ 50 (22.0% vs 20.7%) and > 50 years (23.1% vs 16.1%). On multivariate analysis, tumor subtype (triple-negative vs luminal B-like OR = 4.85, 95% confidence interval = 3.2–7.18) was the most significant factor in treatment outcome.
Adverse Events
Serious adverse events occurred in 16.0% of the nab-paclitaxel group vs 11.3% of the paclitaxel group. Grade ≥ 3 peripheral neuropathy occurred in 4.5% vs 1.8%. Grade ≥ 3 neutropenia occurred in 30.6% vs 19.7%. Grade ≥ 3 adverse events considered drug-related occurred in 22.3% vs 17.3%.
The investigators concluded, “The improved rate of [pathologic complete response] after nab-paclitaxel was not statistically significant…[T]umor subtype…was the most significant factor influencing treatment outcome.”
The study was supported by Celgene.
Luca Gianni, MD, of San Raffaele Scientific Institute, Milan, is the corresponding author for the JAMA Oncology article.
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