Nab-paclitaxel Bests Docetaxel in Phase II Head-to-Head Trial

CHICAGO–A planned interimanalysis of a phase II internationalstudy of first-line nab-paclitaxel(Abraxane) vs docetaxel (Taxotere) inchemonaive patients with stage IV breastcancer shows nab-paclitaxel yielded longerprogression-free survival (PFS) at alldose levels tested. Weekly nab-paclitaxel(at 100 or 150 mg/m²) increased tumorresponse rate by more than 60% comparedwith the docetaxel regimen, withless toxicity, reported William J.Gradishar, MD (abstract 46). A total of300 patients were randomized to fourarms: Patients in arm A received nab-paclitaxelat 300 mg/m² every 3 weeks ofa 4-week cycle. Arm B received nab-paclitaxelat 100 mg/m² weekly for 3weeks. Arm C received nab-paclitaxel at150 mg/m² weekly for 3 weeks, and patientsin arm D received docetaxel at 100mg/m² every 3 weeks. In the nab-paclitaxelgroups, confirmed responserates by RECIST were 33% for nab-paclitaxelat 300 mg/m² every 3 weeks,and 58% and 62% for patients treated at the 100 mg/m² and 150 mg/m² weeklydose levels, respectively. A 36% RR wasobserved with docetaxel at 100 mg/m² every 3 weeks. Therefore, compared withthe outcome in the docetaxel group, first-linetreatment with nab-paclitaxel increasedresponse rates by 61% at the 100mg/m² weekly level (P = .004) and by72% at 150 mg/m² weekly (P = .0016).

Grade 4 neutropenia occurred in 74%of the docetaxel patients, and in 4%, 7%,and 3% of patients in the three nab-paclitaxelarms (300 mg/m² q3wk, 150mg/m² wk, 100 mg/m² wk, respectively).Febrile neutropenia occurred in 7% ofthe docetaxel patients vs 1% in each ofthe three nab-paclitaxel arms. Grade 3peripheral neuropathy was 14% withnab-paclitaxel at 300 mg/m² every 3weeks, 12% with 150 mg/m² weekly, and7% with 100 mg/m² weekly. Docetaxel at100 mg/m² every 3 weeks produced grade3 peripheral neuropathy in 5% of patients.Grade 4 peripheral neuropathy didnot occur. Final data analysis will be presentedat ASCO 2007.