Phase II Trial of Nab-Paclitaxel Compared With Docetaxel as First-Line Chemotherapy in Patients With Metastatic Breast Cancer: Final Analysis of Overall Survival

Background A randomized phase II study in first-line MBC demonstrated superior efficacy and safety of weekly nab-paclitaxel compared with docetaxel. Final survival analyses and updated safety results are reported. Patients and Methods Three hundred two patients with no previous chemotherapy for MBC were randomized to receive nab-paclitaxel 300 mg/m2 q3w, nab-paclitaxel 100 mg/m2 or 150 mg/m2 the first 3 of 4 weeks (qw 3/4), or docetaxel 100 mg/m2 q3w. The trial was powered for analyses of antitumor activity and safety. Results Treatment with nab-paclitaxel 150 mg/m2 qw 3/4 resulted in a median overall survival (OS) of 33.8 months compared with 22.2, 27.7, and 26.6 months for nab-paclitaxel 100 mg/m2 qw 3/4, nab-paclitaxel 300 mg/m2 q3w, and docetaxel, respectively (overall P = .047). Patients receiving 150 mg/m2 nab-paclitaxel had prolonged median OS compared with those in the 100 mg/m2 nab-paclitaxel arm (hazard ratio, 0.575; P = .008). A trend toward a longer OS was noted in the 150 mg/m2 nab-paclitaxel arm versus docetaxel arm (hazard ratio, 0.688). Grade 3 or 4 fatigue, neutropenia, and febrile neutropenia were less frequent in all nab-paclitaxel arms compared with docetaxel. Conclusions Consistent with previously published efficacy results, these data suggest that 150 mg/m2 qw 3/4 may represent the most clinically efficacious nab-paclitaxel dosing regimen for patients with no previous chemotherapy for MBC. A phase III trial confirming these results would be necessary and prudent before widespread adoption of the 150 mg/m2 dose in clinical practice.