Phase III Trial Adding Vincristine-Topotecan-Cyclophosphamide to the Initial Treatment of Patients With Nonmetastatic Ewing Sarcoma: A Children’s Oncology Group Report

Leavey PJ, Laack NN, Krailo MD, Buxton A, Randall RL, DuBois SG, Reed DR, Grier HE, Hawkins DS, Pawel B, Nadel H, Womer RB, Letson GD, Bernstein M, Brown K, Maciej A, Chuba P, Ahmed AA, Indelicato DJ, Wang D, Marina N, Gorlick R, Janeway KA, Mascarenhas L. Phase III Trial Adding Vincristine-Topotecan-Cyclophosphamide to the Initial Treatment of Patients With Nonmetastatic Ewing Sarcoma: A Children’s Oncology Group Report. J Clin Oncol. 2021 Dec 20;39(36):4029-4038. doi: 10.1200/JCO.21.00358. Epub 2021 Oct 15. PubMed PMID: 34652968; PubMed Central PMCID: PMC8677904.

The primary aim of this phase III randomized trial was to test whether the addition of vincristine, topotecan, and cyclophosphamide (VTC) to interval compressed chemotherapy improved survival outcomes for patients with previously untreated nonmetastatic Ewing sarcoma. Patients were randomly assigned to receive standard five-drug interval compressed chemotherapy (regimen A) for 17 cycles or experimental therapy with five cycles of VTC within the 17 cycles (regimen B). Patients were stratified by age at diagnosis (< 18 years and ≥18 years) and tumor site (pelvic bone, nonpelvic bone, and extraosseous). Tumor volume at diagnosis was categorized as < 200 mL or ≥ 200 mL. Local control occurred following six cycles. Histologic response was categorized as no viable or any viable tumor. Event-free survival (EFS) and overall survival (OS) were compared between randomized groups with stratified log-rank tests.