Nab-Paclitaxel Better Than Docetaxel for Metastatic Breast Cancer: Presented at SABCS
By Jill Stein
SAN ANTONIO -- December 13, 2011 -- New data show that nab-paclitaxel, at a dose of 150 mg/m2 weekly, improves overall survival (OS) more than standard docetaxel monotherapy when used as first-line therapy in women with previously untreated metastatic breast cancer.
The findings are from an open-label, multicentre, phase 2 study presented here December 9 at the 34th Annual San Antonio Breast Cancer Symposium (SABCS).
William Gradishar, MD, Northwestern University Feinberg School of Medicine, Chicago, Illinois, and colleagues presented results from 300 women with previously untreated metastatic breast cancer who were randomised to 1 of 4 treatment regimens: (1) nab-paclitaxel 300 mg/m2 every 3 weeks; (2) nab-paclitaxel 100 mg/m2 weekly for the first 3 of 4 weeks; (3) nab-paclitaxel 150 mg/m2 weekly for the first 3 of 4 weeks; or (4) docetaxel 100 mg/m2 every 3 weeks.
Nab-paclitaxel is a novel albumin bound 130-nm formulation of paclitaxel that has been shown to improve the efficacy of taxane treatment, while limiting the toxicity typically associated with solvent-based taxanes.
The study included patients aged 18 years or older with stage IV metastatic breast cancer, Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 2, and no chemotherapy within the past year. Baseline characteristics were balanced between groups.
The analysis demonstrated that the nab-paclitaxel 150-mg/m2 weekly schedule produced the longest OS. Median OS with the nab-paclitaxel 150-mg/m2 weekly schedule was 33.8 months, which translates into a survival benefit of 11.6 months over the 22.2-month median OS seen with the nab-paclitaxel 100-mg/m2 weekly dose.
The median OS was 27.7 months in patients with nab-paclitaxel 300 mg/m2 every 3 weeks and 26.6 months with docetaxel 100 mg/m2 every 3 weeks.
Progression-free survival was 10.9 months in patients on nab-paclitaxel 300 mg/m2 every 3 weeks, 7.5 months among patients receiving 100 mg/m2 weekly, 14.6 months in patients on 150 mg/m2 weekly, and 7.8 months in patients on docetaxel 100 mg/m2 every 3 weeks.
Within the 150-mg/m2 weekly treatment arm, the best response occurred at cycle 2, whereas dose reductions due to toxicities occurred at later treatment cycles.
While sensory neuropathy was more common in the 150-mg/m2 weekly nab-paclitaxel treatment arm, the time to improvement was about 20 days shorter than it was for docetaxel.
Dr. Gradishar said that the data indicate that a 150-mg/m2 dose weekly nab-paclitaxel regimen may help patients achieve a clinical response before the onset of dose-limiting adverse events.
Funding for this study was provided by Celgene Corporation.
[Presentation title: Albumin-Bound Paclitaxel (ab-pac) Versus Docetaxel for First-Line Treatment of Metastatic Breast Cancer (MBC): Overall Survival and Safety Analysis of a Randomized Phase II Trial. Abstract P5-19-03]
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