Hope Rugo, MD
As the search for new therapies for patients with recurrent triple-negative breast cancer (TNBC) continues, recent research demonstrates that better outcomes may be achieved through changes in existing chemotherapy protocols.
at the 2017 San Antonio Breast Cancer Symposium (SABCS), Rugo discussed the implications of these findings and the importance of individualizing doses of nab-paclitaxel.
OncLive: Can you provide an overview of the design of the study?
This is a trial that we started quite a long time ago, and it was designed to evaluate the relative efficacy of novel microtubule inhibitors given in a weekly schedule, compared with the standard of care, which was paclitaxel. At the time, bevacizumab was the standard of care as first-line therapy for metastatic HER2-negative breast cancer, based on the results of ECOG 2100. Our control arm was weekly paclitaxel at 90 mg/m2 with bevacizumab, 3 weeks on, 1 week off. If patients had responding or stable disease after 6 cycles of 4 weeks per cycle, they could stop the chemotherapy and continue on with bevacizumab alone.
We had planned to enroll 900 patients with a primary endpoint of PFS, but we had interim analyses for futility. At the first interim analysis, the ixabepilone arm was closed for futility, and at the second interim analysis, the entire study was closed because of futility.
What were the results of this study?
As one would expect, the first time we presented our data at SABCS in 2013, and when they were published in the Journal of Clinical Oncology in 2015, we showed that neither arm was superior to paclitaxel, and that the nab-paclitaxel arm, in particular, was associated with increased hematologic and nonhematologic toxicity, including both motor and sensory neuropathy. We don’t usually see much motor neuropathy. We also found that the ixabepilone arm was inferior for PFS, and that neither arm showed any difference in OS.
Was a difference seen in the subset analysis?
We also looked at the subsets based on hormone receptor [HR] status—HR-positive, HER2-negative, or TNBC. What we found was a significant test for interaction between nab-paclitaxel and paclitaxel for HR status, and no significant interaction for ixabepilone for both PFS and OS.
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