Weekly ixabepilone with or without concurrent bevacizumab in the treatment of recurrent endometrial cancer.

Abstract

e15526 Background: Ixabepilone for endometrial cancer has only been evaluated in phase II studies administered at 30-40 mg/m2 q21 days (GOG 129P, GOG 86P). The objective of this study is to describe the institutional experience using a weekly dosing strategy of ixabepilone ± bevacizumab in the treatment of paclitaxel/platinum-resistant recurrent endometrial cancer. Methods: Patients who received weekly ixabepilone (16-20 mg/m2 on days 1, 8, 15 of a 28-day cycle) ± bevacizumab (10 mg/kg on days 1, 15 of a 28-day cycle) off-protocol were identified retrospectively. Results: Thirteen patients were included. Demographic/disease characteristics are provided in Table 1. Median time to first recurrence was 15.9 months (IQR: 9.5-21.66). Patients received a mean of 4.8 ± 1.9 cycles of ixabepilone; treatment is ongoing in 4 patients. A total of 46% of patients demonstrated either a partial response (PR, 8%) or disease stabilization (SD, 38%). PR/SD was associated with a mean decline in CA-125 of 56%. Approximately 50% of patients received concurrent bevacizumab. Of patients who did not receive concurrent bevacizumab, 83% experienced progression and 17% demonstrated SD. Median survival after ixabepilone initiation was 12.7 and 6.9 months in patients treated with and without concurrent bevacizumab, respectively (HR 0.42 [0.09-1.98]). Grade 1/2 hematologic (thrombocytopenia, 15.4%) and gastrointestinal toxicities (emesis/constipation, 7.7%) were observed infrequently. Median overall survival of this cohort was 2.88 years. Conclusions: Ixabepilone shows encouraging activity and promising durability in patients with heavily pre-treated paclitaxel/platinum-resistant recurrent endometrial cancer. Weekly dosing at 16-20mg/m2 on days 1, 8, and 15 ± bevacizumab is well-tolerated. Additional investigation of this regimen and long-term follow-up is warranted. [Table: see text]