Outcome of patients with relapsed or progressive Ewing sarcoma enrolled on cooperative group phase 2 clinical trials: A report from the Children’s Oncology Group

Collier AB 3rd, Krailo MD, Dang HM, DuBois SG, Hawkins DS, Bernstein ML, Bomgaars LR, Reed DR, Gorlick RG, Janeway KA. Outcome of patients with relapsed or progressive Ewing sarcoma enrolled on cooperative group phase 2 clinical trials: A report from the Children’s Oncology Group. Pediatr Blood Cancer. 2021 Dec;68(12):e29333. doi: 10.1002/pbc.29333. Epub 2021 Sep 8. PubMed PMID: 34496122; PubMed Central PMCID: PMC8541905.

Seven Children’s Oncology Group phase 2 trials for patients with relapsed/progressive solid tumors were analyzed to estimate the event-free survival (EFS) for relapsed/progressive Ewing sarcoma. One hundred twenty-eight Ewing sarcoma patients were enrolled and 124 events occurred. The 6-month EFS was 12.7%, demonstrating the poor outcome of these patients. Only docetaxel achieved its protocol-specified radiographic response rate for activity; however, the EFS for docetaxel was similar to other agents, indicating that a higher radiographic response rate may not translate into superior disease control. This EFS benchmark could be utilized as an additional endpoint in trials for recurrent Ewing sarcoma.