Eflornithine (DFMO) and Etoposide for Relapsed/Refractory Neuroblastoma

Difluoromethylornithine (DFMO) will be used in an open label, multicenter, study in combination with etoposide for subjects with relapsed/refractory neuroblastoma. In this study subjects will receive six 21-day cycles of Etoposide and DFMO followed by an additional 630 days of DFMO alone. Subjects will be evaluated in 3 arms: • Arm 1: Subjects who show no active disease after receiving any additional therapy for neuroblastoma that was refractory to standard induction/consolidation therapy. Refractory: Subjects with progressive disease on upfront therapy OR did not have at least PR on induction OR required additional second line therapy to achieve remission who are now in first remission. * Arm 2: Subjects who have previously relapsed and currently show no active disease (in CR2 or greater). * Arm 3: Subjects who are relapsed or refractory with active disease.- CLOSED TO ENROLLMENT