[46] A randomized phase 2 trial of qw or q3w ABI-007 (ABX) vs. q3W solvent-based docetaxel (TXT) as first-line therapy in metastatic breast cancer (MBC).

Gradishar W, Krasnojon D, Cheporov S, Makhson A, Manikhas G, Hawkins MJ.. Northwestern University, Chicago, IL; Leningrad Regional, St Petersburg, Russian Federation; Yaroslavl Regional, Yaroslavl, Russian Federation; City Oncology Hospital, Moscow, Russian Federation; St Petersburg Oncology Center, St Petersburg, Russian Federation; Abraxis BioScience, Los Angeles, CA

Background: Compared with solvent-based paclitaxel in phase 3 studies in pts with MBC, TXT improved survival and time to progression but had greater toxicity (1) while ABX had significantly greater overall response rate (p=0.001) and time to progression (p=0.006), with less toxicity (2). In these studies gr 3-4 neutropenia and febrile neutropenia (FN) were 93% and 15% respectively for TXT (1) and 30% and <2% for ABX (2). The objective of our study was to obtain comparative toxicity and preliminary antitumor response data for qw and q3w ABX and q3w TXT. Methods: 300 pts with MBC were randomly assigned to ABX 300 mg/m² q3w (A); ABX 100 mg/m² (B) or 150 mg/m² (C) days 1, 8, and 15, q28 days; or TXT 100 mg/m² q3w (D). All pts were assessed for antitumor response q8w. Results: Pts were enrolled from 11/05 to 6/06 (mean age = 53.6 yrs, 73% postmenopausal). At a planned interim analysis in 7/06, 210 pts (70%) had at least 1 antitumor response assessment with 59 confirmed responses (20%, 29%, 44%, 20%, respectively; A vs. C, p=0.042; B vs. C, p=0.004; C vs. D, p=0.014) and an additional 29 as of yet unconfirmed responses (total response: 33%, 42%, 62%, 31%). To date, only 38 pts (18%) have had tumor progression and/or died (A, 11%; B, 12%; C, 9%; D, 25%). Grade 4 neutropenia was: A, 5%; B, 3%; C, 8%; D, 67%; (A, B or C vs. D, p<0.001). In the 3 ABX groups 1 pt (on B) had FN compared to 4 pts (1 fatal) in the TXT group. Data on PN are preliminary; 8 pts are reported to have grade 3 PN (A, 2 pts; C, 4 pts; D, 2 pts). Discussion: These preliminary results suggest that: (1) ABX and high dose TXT given q3w have comparable response rates; (2) ABX qw may be more active than TXT or ABX q3w; (3) a dose-response for ABX given qw may exist; and (4) ABX results in less neutropenia and FN than TXT. To date, twice as many patients on TXT have progressed and/or died compared to each ABX arm. Updated data, including more mature progression data, from a planned analysis in 11/06 will be presented. 1. Jones et al, JCO, 2005; 2. Gradishar et al, JCO, 2005.

Sunday, December 17, 2006 10:45 AM

General Session 7 (9:00 AM-11:30 AM)