VERITAS

The main objective is to evaluate the efficacy of two intensified consolidation strategies in very-high risk neuroblastoma (VHR-NBL) patients in terms of event-free survival from randomisation date. This evaluation will follow a hierarchical testing procedure: each experimental treatment will be first evaluated as a single-arm phase 2 study, and in case of positive conclusion, the relative efficacy of both arms will then be evaluated comparatively.

Following randomisation, all patients will continue with standard dose chemotherapy with irinotecan and temozolomide for three courses to allow for PBSC harvest (it is not mandatory to have clear bone marrows before attempting a harvest) and to facilitate scheduling of the randomised element of the study which may necessitate referral to another centre.

The patients will then receive one of two investigational intensification therapies according to random allocation:

• high administered activity 131I-mIBG and topotecan and ASCR.
• high-dose thiotepa and ASCR Then all patients will proceed to second high-dose chemotherapy: BuMel and ASCR.

The intensified consolidation chemotherapy will be followed by external radiotherapy as appropriate, by local surgery of the tumour residues as appropriate.