Randomized comparison of VAC versus VAI chemotherapy (CT) as consolidation for standard risk (SR) Ewing sarcoma tumor (ES): Results of the Euro-EWING.99-R1 trial.

9517 Background: Anthracyclines and alkylating agents are the main effective drugs known for ES. Ifosfamide and cyclophosphamide are widely used, have different toxicity profiles and unknown relative efficiency. The Euro-EWING.99-R1 trial compared, in SR localized ES, two consolidation regimens combining either ifosfamide or cyclophosphamide with vincristine and D-actinomycin (VAI vs VAC) given after an intense induction CT containing vincristine, ifosfamide, doxorubicin and etoposide (VIDE) (NCT00020566). Methods: SR tumors were localized ES with either a good histological response to VIDE chemo (<10% cells), or small tumors (< 200 ml) resected at diagnosis or receiving radiotherapy alone as local treatment. Pts entered the trial after 6 VIDE + 1 VAI courses. Allocated treatment was either 7 VAI courses with ifo = 6 g/m²/course or 7 VAC courses with cyclo = 1.5 g/m²/course. Randomization was stratified by gender, age, local treatment and data center. It was a non-inferiority trial comparing VAC to VAI wi...