Randomized phase II study of weekly versus every-3-week ixabepilone plus bevacizumab (ixa/bev) versus paclitaxel plus bev (pac/bev) as first-line therapy for metastatic breast cancer (MBC)

1029 Background: Pac/bev is superior to pac alone as first-line therapy for MBC. Ixa/bev has greater preclinical activity than pac/bev in human tumor models. The primary objective of this trial was to evaluate objective response rates (ORR) of ixa/bev given weekly or every 3 weeks relative to pac/bev as 1st line therapy for women with advanced breast cancer. Methods: Women with measurable disease and no prior chemotherapy for advanced breast cancer (locally advanced or MBC) were randomized in a 3:3:2 ratio to Arm A (ixa 16 mg/m2 IV on days 1, 8 & 15 q28 days/ bev 10 mg/kg IV q 2 wks), Arm B (ixa 40 mg/m2 IV q3 wks / bev 15 mg/kg IV q 3 wks) or Arm C (pac 90 mg/m2 IV, schedule/bev as in Arm A). Treatment was continued until disease progression or unacceptable toxicity. Results: Key efficacy and safety results from a pre-planned analysis of all randomized subjects after at least 24 weeks of follow-up are presented. Baseline characteristics were balanced between arms except for liver metastasis. Conclusions: The combination of ixa/bev weekly or q 3 wks demonstrated encouraging clinical activity and safety comparable to 1st line pac/bev in E2100. Final PFS will be provided when data is mature. These results support ongoing clinical trials of ixa given weekly or q 3wk in 1st line MBC, and in combination with bev. [Table: see text] [Table: see text]