Abstract P3-10-06: Real-world efficacy and safety outcomes of nab-paclitaxel (nab-P) in patients (pts) with metastatic breast cancer (MBC): Results from a US health insurance database
Authors: Patt Debra A , Liang Caihua , Li Ling , Ko Amy , Duval Fraser Cindy , Corzo Deyanira , Enger Cheryl 
Published: May 2015

Background: nab-P, an albumin-bound formulation of paclitaxel, was approved in 2005 for the treatment of breast cancer after failure of combination chemotherapy for metastatic disease or relapse within 6 mo of adjuvant chemotherapy based on clinical trials. nab-P demonstrated efficacy and safety when administered weekly in phase II trials and every 3 weeks (q3w) in an international phase III trial. Little is known about the treatment patterns and outcomes of nab-P in the real-world setting. Using health insurance claims data, this study was conducted to characterize efficacy and safety of nab-P in pts with MBC treated in US clinical practices.

Methods: This retrospective claims analysis used data in the Optum Research Database (United Health affiliate). Data were supplemented by Social Security Death Index sources. The analysis included women aged ≥ 18 y with MBC diagnosis (≥ 2 claims of BC diagnosis separated by ≥ 30 d and ≥ 2 claims of metastatic spread) prior to nab-P initiation. Pts had ≥ 6 mo of continuous enrollment in the health plan from January 2005-September 2012, complete medical coverage and pharmacy benefits, no other primary malignancy, and no prior chemotherapy. Cohorts were determined by line of therapy, nab-P regimen, and schedule. Endpoints included treatment patterns, time to next therapy or death (TNTD), overall survival (OS), and safety.

Results: Of the 664 eligible pts, most were between 40-69 y of age (88%) and had received nab-P as ≥ second-line therapy (74%), monotherapy (61%), and weekly dosing (71%). In combination, nab-P was most often given with bevacizumab (58%) or human epidermal growth factor receptor 2 (HER2)–targeted therapy (24%) vs another cytotoxic agent (19%). Median TNTD and OS were 6.1 and 17.4 mo, respectively. By line of therapy (first, second, and ≥ third), TNTD was 7.1, 6.6, and 5.3 mo, and OS was 22.7, 17.4, and 15.1 mo. The OS data are comparable with published clinical trial results (Table). In a subgroup of pts (n = 400) with aggressive disease features (≤ 50 y of age or having ≥ 3 metastases), median OS was 15.6 mo. These data are comparable with a retrospective analysis of pts with visceral dominant metastasis (VDM) or a short disease-free interval (SDFI; Table). Toxicities reported in healthcare claims were consistent with those previously published.

Conclusions: Consistent with clinical trial data, outcomes of this analysis demonstrated the efficacy and safety of nab-P across lines of therapy in a real-world population of patients with MBC.

Clinical Trial Experience in MBC for Pts Treated With nab-PTrialnab-P dose (mg/m2) and schedulenMedian OS, moCA0121 (Ph III)ITT (all lines)260 q3w22915.0≥ second line260 q3w13113.0CA0242 (Ph II, first line)300 q3w7627.7100 qw 3/47622.2150 qw 3/47433.8Median OS, moSubgroups With Aggressive Disease FeaturesnVDMnSDFICA0123 (first line)260 q3w7415.14214.6CA0243 (first line)300 q3w6127.72016.6100 qw 3/46019.62119.1150 qw 3/45932.11418.6qw 3/4, weekly for the first 3 of 4 weeks.

1 Gradishar WJ, et al. J Clin Oncol. 2005;23:7794-7803.

2 Gradishar WJ, et al. Clin Breast Cancer. 2012;12:313-321.

3 O’Shaughnessy J, et al. Breast Cancer Res Treat. 2013;138:829-837.

Citation Format: Debra A Patt, Caihua Liang, Ling Li, Amy Ko, Cindy Duval Fraser, Deyanira Corzo, Cheryl Enger. Real-world efficacy and safety outcomes of nab-paclitaxel (nab-P) in patients (pts) with metastatic breast cancer (MBC): Results from a US health insurance database [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P3-10-06.