Given the tolerability of high-dose DFMO demonstrated on this trial, and the robust anti-tumor activity shown for irinotecan/temozolomide combined with dinutuximab and GM-CSF for relapsed neuroblastoma patients [47], an ongoing Children’s Oncology Group Phase 2 trial randomizes patients to receive this chemoimmuntherapy with or without the addition of DFMO at 6750 mg/m2/day (NCT03794349). Here, CSF2 is linked to neoplasm.