Eribulin and irinotecan for refractory or recurrent Ewing sarcoma: A retrospective study.

• DOI: 10.1200/jco.2024.42.16_suppl.e23502
• Publication Date: 2024-06-03T21:07:03Z
• Authors: Jie Xu; Lu Xie; Xin Sun; Kuisheng Liu; Xin Liang; Xiaodong Tang

e23502 Background: The effectiveness of eribulin and irinotecan in treatment of xenograft models of Ewing sarcoma is well-established but little clinical data has been reported. Encouraging results from preclinical models and a shortage of temozolomide in our hospital have prompted the administration of the eribulin as substitute for temozolomide and vincristine in combination of irinotecan at our institution from 2022 to 2023 in an off-label way. Methods: We retrospectively reviewed the medical records of patients treated for refractory or recurrent Ewing sarcoma with 1.4mg/m2 D1,8 eribulin and 20mg/m2/d D1-5,8-12 irinotecan at 21 day intervals (ERII) at Peking University People’s Hospital. Results: Finally, a total of 17 patients with median age 18.6 years were treated with a total of 77 courses of ERII between February 2022 and February 2023. The objective response rate was 35.3%, the disease control rate 58.9% and the median event-free survival (EFS) 2.07 months. 35.3% patients had 6 months EFS and overall survival was 66.9%. Grade 3 or 4 toxicities were observed in 37.6% courses and in 64.7% of the patients, with myelosuppression, especially neutropenia, being the most common and diarrhea / abdominal pain the second most common. In the dx5x2 VIT protocol the later portion was given two days after the end of early portion. However, in this substitute regimen of eribulin, the median time interval between the end of the early portion to the start of later portion was 5 days. The dose intensity of the regimen was reduced by 21% per cycle. The later portion was delayed mostly because of unrecovered myelosuppression. Conclusions: The efficacy and safety of eribulin and irinotecan as a second-line regimen was inferior to historical reports of temozolomide and irinotecan in the same institute. There was no need for further prospective trials on this combination unless mechanisms of synergy and biomarkers are identified. [Table: see text]