Cisplatin improves antitumor activity of weekly nab-paclitaxel in patients with metastatic breast cancer.

Although nanoparticle albumin-bound paclitaxel (nab-paclitaxel) is approved to be given every 3 weeks, weekly use of this drug is becoming a new standard of care in patients with metastatic breast cancer (MBC). This prospective Phase II study was conducted to improve the efficacy of weekly nab-paclitaxel with cisplatin in MBC patients. Seventy-three women with recurrent or MBC were eligible for participation. Nab-paclitaxel was administered weekly at a dose of 125 mg/m(2) on day 1, day 8, and day 15, followed by cisplatin 75 mg/m(2) on day 1, repeated every 28 days with a maximum of 6 cycles. The primary objective was investigator-assessed overall response rate (ORR). A high ORR of 67.1% was obtained, with rates of 80.6% for the first-line patients and 80% for patients not pretreated with taxanes. Among those who had objective responses, a large percentage of patients (83.7%) showed quickly remarkable tumor shrinkage during the first two cycles. The median progression-free and overall survival times were 9.8 and 26.9 months, respectively. For the patients receiving first-, second-, and third-line therapy or beyond, median progression-free survival was 11.7, 7.7, and 7.6 months, respectively (P=0.005). Molecular subtype was not significantly associated with ORR or disease progression. Grade 4 neutropenia occurred in 46 patients (63.0%), with febrile neutropenia found in 9 patients (12.3%). Grade 3 peripheral neuropathy was an accumulated dose-limiting toxicity occurring in 19 patients (26.0%). Efficacy of weekly nab-paclitaxel can be improved by adding cisplatin. The doublet is highly effective, with quick response, manageable toxicity, and possible equivalence across molecular subtypes in MBC patients.