Efficacy of Nab-paclitaxel in patients with poor prognostic factors or with anthracycline-resistant metastatic breast cancer (MBC)

Abstract

1082 Background: Nanoparticle albumin-bound-paclitaxel (nab-pac) demonstrated significant antitumor activity in patients with MBC compared with solvent-based paclitaxel. This retrospective analysis evaluated the antitumor activity of nab-pac in patients with MBC who were previously treated with anthracycline, had visceral (lung and/or liver) disease, or had ≥ 3 sites of metastases. Methods: Pts (N = 531) were evaluated from a phase II and a phase III study of nab-pac (Gradishar et al. J Clin Oncol. 2005;23:7794–7803). In the phase III study, pts (including first- and second-line pts) received nab-pac 260 mg/m2 q3w (A) or paclitaxel 175 mg/m2 q3w (B). In the phase II study, first-line pts received nab-pac 300 mg/m2 q3w (C), 100 mg/m2 qw (D), 150 mg/m2 qw (E); or docetaxel 100 mg/m2 q3w (F). Results: See Table. Conclusions: Nab-pac, weekly or every 3 weeks, has significant antitumor activity in patients with MBC regardless of baseline factors (eg, anthracycline use, visceral disease, or ≥ 3 sites of metastasis). Prior anthracycline Pts with visceral disease Pts with ≥3 sites of metastasis Nab-pac 77 77 62 Paclitaxel 78 81 52 Nab-pac 24 81 54 Docetaxel 24 88 59 Overall response rate (%) Overall response rate (%) Overall response rate (%) A* 34 34 26 B* 18 19 17 P-value 0.002 0.002 0.092 C 45 45 46 D 53 61 69 E 68 75 70 F 28 37 29 P-value † 0.062 0.003 0.004 Time to progression/Progression-free survival (months) Time to progression/Progression-free survival (months) Time to progression/Progression-free survival (months) A*‡ 5.3 5.0 4.5 B*‡ 3.8 3.8 3.7 P-value 0.004 0.036 0.053 C 7.9 10.9 10.2 D 7.2 7.5 7.4 E 11.4 13.1 12.9 F 5.5 7.8 7.6 P-value † 0.031 0.242 0.557 Overall survival (months) Overall survival (months) Overall survival (months) A* 14.9 13.1 14.2 B* 12.0 12.3 11.0 P-value 0.049 0.945 0.154 C,D,E,F NA NA NA Pts treated 1st- and 2nd-line; † Comparing nab-pac and docetaxel overall; ‡ TTP in the ph III trial Author Disclosure Employment or Leadership Consultant or Advisory Role Stock Ownership Honoraria Research Expert Testimony Other Remuneration Abraxis Bioscience Abraxis Abraxis