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/m(2) q3w, nab-paclitaxel 100 mg/m(2) or 150 mg/m(2) the first 3 of 4 weeks (qw 3/4), or docetaxel 100 mg/m(2) q3w. The trial was powered for analyses of antitumor activity and safety.

Results: Treatment with nab-paclitaxel 150 mg/m(2) 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/m(2) qw 3/4, nab-paclitaxel 300 mg/m(2) q3w, and docetaxel, respectively (overall P = .047). Patients receiving 150 mg/m(2)nab-paclitaxel had prolonged median OS compared with those in the 100 mg/m(2)nab-paclitaxel arm (hazard ratio, 0.575; P = .008). A trend toward a longer OS was noted in the 150 mg/m(2)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/m(2) 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/m(2) dose in clinical practice.