Nab-paclitaxel was found to be the most active in patients with more aggressive types of breast cancer. The cumulativedata show a pathologic complete response (pCR) rate of 41 % in triple-negative breast cancer (TNBC) and 54% in HER2- positive disease. Moreover, an analysis of randomized comparisons against conventional taxane regimens showed nearly 40% higher odds of achieving pCR with nab-paclitaxel. These findings were reported at the San Antonio Breast Cancer Symposium.
"Our study demonstrates that nab-paclitaxel is an effective cytotoxic drug in neoadjuvant treatment of breast cancer, especially in patients with aggressive disease subtypes, like TNBC and HER2-positive tumors," Kunwei Shen, MD, a medical oncologist at Shanghai Ruijin Hospital in China, and colleagues concluded in a poster presentation. "Exchange of neoadjuvant nab-paclitaxel for conventional taxanes could significantly improve the probability of pathologic complete response with generally reasonable toxicities."
The search identified 21 studies and a cumulative total of 2,357 patients, including 3 randomized clinical trials. The investigators used a uniform definition of pCR (ypTO/is ypNO) to evaluate the efficacy of nab-paclitaxel.
Further analysis of the HER2-positive subgroup showed that nab-paclitaxel resulted in a higher pCR rate for patients with horrnone receptor-negative tumors compared with hormone receptor-positive tumors (61 % vs. 41 %).
The 3 randomized trials comparing nab-paclitaxel and conventional taxane formulations accounted for the vast majority of patients included in the analysis (2,053). Pooled results from the 3 trials showed that patients randomized to neoadjuvant therapy with nab-paclitaxel had a significantly higher odds ratio for pCR compared with conventional paclitaxel or docetaxel (OR I .383, 95% CI I .141-1.76, P = 0.001). Across the 3 trials, the pCR rate favored nab-paclitaxel versus the comparator by odds ratios that ranged from I .27 to I .58.