Longer versus Shorter Schedules of Vincristine, Irinotecan, and Temozolomide (VIT) for Relapsed or Refractory Ewing Sarcoma: A Randomized Controlled Phase 2 Trial.

Abstract

The optimal dose schedule of vincristine, irinotecan, and temozolomide (VIT) in relapsed or refractory patients with Ewing sarcoma requires clarification. Patients with relapsed or refractory Ewing sarcoma were randomly assigned (1:1) to either a shorter d × 5 schedule (irinotecan 50 mg/m2/d D1-5, vincristine 1.4 mg/m2 D1) or protracted d × 5×2 schedule (irinotecan 20 mg/m2/d D1-5,8-12, vincristine 1.4 mg/m2 D1,8) together with temozolomide (100 mg/m2/d D1-5). Patients were treated every 3 weeks for up to eight cycles until progression or unacceptable toxic effects occurred. The primary endpoint was objective response rate at 12 weeks (ORR12w). Secondary endpoints were progression-free survival (PFS), overall survival (OS), and safety. A total of 46 patients presenting with relapsed or refractory Ewing sarcoma were randomly assigned to the d × 5 (n = 24) or d × 5×2 (n = 22) schedules. Median follow-up was 10.7 months in the d × 5 group and 8.3 months in the d × 5×2 group. ORR12w was lower for d × 5 (5/24; 20.8%) patients than for d × 5×2 (12/22; 54.5%; P = 0.019), but no significant difference was found in PFS (median PFS, 2.3 months for d × 5 vs. 4.3 months for d × 5×2) or OS (median OS, 14.8 months for d × 5 and 12.8 months for d × 5×2). Patients receiving the d × 5 schedule reported more grade 3 and 4 adverse events (AE) than those receiving d × 5×2, including diarrhea/abdominal pain and vomiting/nausea. The protracted d × 5×2 VIT schedule showed superior efficacy and favorable tolerability compared with the shorter d × 5 VIT schedule in patients with relapsed or refractory Ewing sarcoma.