In patients with metastatic breast cancer (MBC), nab-paclitaxel produced significantly higher antitumor activity compared with patients who received solvent-based paclitaxel. This phase II study examined the antitumor activity and safety of weekly and every 3 week (q3w) nab-paclitaxel compared with docetaxel as first-line treatment in patients with MBC. In this randomized, multicenter study, patients (N = 302) with previously untreated MBC received nab-paclitaxel 300 mg/m(2) q3w, 100 mg/m(2) weekly, or 150 mg/m(2) weekly or docetaxel 100 mg/m(2) q3w. nab-Paclitaxel 150 mg/m(2) weekly demonstrated significantly longer progression-free survival (PFS) than docetaxel by both independent radiologist assessment (12.9 v 7.5 months, respectively; P = .0065) and investigator assessment (14.6 v 7.8 months, respectively; P = .012). On the basis of independent radiologist review, both 150 mg/m(2) (49%) and 100 mg/m(2) (45%) weekly of nab-paclitaxel demonstrated a higher overall response rate (ORR) than docetaxel (35%), but this did not reach statistical significance. This trend was supported by statistically significant investigator ORR for both weekly nab-paclitaxel doses versus docetaxel. nab-Paclitaxel q3w versus docetaxel was not different for PFS or ORR. On the basis of both the independent radiologist and investigator review, disease control rate was significantly higher for patients receiving either dose of weekly nab-paclitaxel compared with docetaxel. Grade 3 or 4 fatigue, neutropenia, and febrile neutropenia were less frequent in all nab-paclitaxel arms. The frequency and grade of peripheral neuropathy were similar in all arms. This randomized study in first-line MBC demonstrated superior efficacy and safety of weekly nab-paclitaxel compared with docetaxel, with a statistically and clinically significant prolongation of PFS (> 5 months) in patients receiving nab-paclitaxel 150 mg/m(2) weekly compared with docetaxel 100 mg/m(2) q3w.