Evaluation of the clinical benefits of nanoparticle albumin-bound paclitaxel in women with metastatic breast cancer in British Columbia.

BACKGROUND

Altered formulations of taxanes may lack cross-resistance with standardly used solvent-based taxanes. The primary objective of the present study was to assess the clinical benefit of nanoparticle albumin-bound (nab)-paclitaxel in women with metastatic breast cancer previously treated with and without adjuvant taxane in British Columbia.

METHODS

The BC Cancer Agency Pharmacy data repository and Breast Cancer Outcomes Unit database were linked to identify all patients who received nab-paclitaxel in British Columbia since its introduction in 2007. Hormone receptor status, demographic characteristics, number of cycles prescribed, and time to treatment failure were extracted and analyzed.

RESULTS

From 2007 to 2011, 138 patients in British Columbia received nab-paclitaxel, with 122 patients available for analysis. Most (70.5%) received adjuvant chemotherapy; about a quarter (24.6%) received an adjuvant taxane. Patients who received adjuvant taxane were more likely to have node-positive (86.7% vs. 48.9%, p = 0.007), estrogen receptor-negative (46.7% vs. 13.0% p < 0.001) disease and to receive initial adjuvant radiotherapy (76.7% vs. 51.1%, p < 0.001). For the entire cohort, the median number of nab-paclitaxel cycles prescribed was 4.4 (range: 0.3-13). The median number of nab-paclitaxel cycles was greater when that agent was given as first- or second-line therapy than as third-line or greater therapy (5.0 cycles vs. 3.7 cycles respectively). The median time to treatment failure was 96 days in the prior adjuvant taxane group (range: 0-361) and 73.5 days in the no prior adjuvant taxane group (range: 0-1176).

CONCLUSIONS

This retrospective study demonstrates potential clinical activity of nab-paclitaxel in metastatic breast cancer regardless of whether patients had prior exposure to adjuvant taxanes.