Albumin-bound Paclitaxel: in metastatic breast cancer

A new formulation of paclitaxel, 130-nanometre albumin-bound paclitaxel (nab-paclitaxel), solubilises hydrophobic paclitaxel and may increase paclitaxel delivery to tumour cells. Intravenous nab-paclitaxel 260 mg/m(2) had a higher maximum whole-blood concentration, shorter time to peak concentration, larger distribution volume and greater clearance than a 175 mg/m(2) dose of a conventional polyoxyethylated castor oil (Cremophor EL) solublised paclitaxel (CrEL-paclitaxel). The reconciled target-lesion response rate was significantly higher in patients receiving intravenous nab-paclitaxel 260 mg/m(2) once every 3 weeks than in those receiving CrEL-paclitaxel 175 mg/m(2) once every 3 weeks (21.5% vs 11.1%) in a randomised, nonblind, phase III trial in 454 patients with metastatic breast cancer. The objective response rate (ORR) was also significantly greater in nab-paclitaxel than in CrEL-paclitaxel recipients (33% vs 19%). In noncomparative phase II trials, ORRs of 48% and 51% were observed in patients receiving nab-paclitaxel 175 or 300 mg/m(2) once every 3 weeks. nab-Paclitaxel 260 mg/m(2) caused less grade 4 neutropenia than CrEL-paclitaxel 175 mg/m(2). The incidence of grade 3 sensory neuropathy was higher in nab-paclitaxel recipients, reflecting the higher dosage of nab-paclitaxel, and improved with treatment interruption. Despite the absence of corticosteroid and antihistamine premedication, no severe hypersensitivity reactions were reported.