This is a study of the drug DFMO (difluoromethylornithine) for neuroblastoma that has returned or not responded to treatment. DFMO is an oral drug that inhibits a certain enzyme (protein) in blood which is associated with a bad outcome in neuroblastoma cases. Cancer cells have pathways that drive the cancer to grow and DFMO targets the specific pathway of this enzyme to turn these cells off.

You will have exams, tests, and procedures while on the study to evaluate whether you can participate in the study and how you are doing while on the study. These include physical exams, blood tests, urine tests, bone marrow aspirate and biopsies, heart tests, hearing tests, and imaging evaluations such as CT scans and MIBG or PET scans. You will receive treatment on this study for a total of about 2 years. After treatment, you will have follow-up examinations and medical tests. We would like to continue to find out about your health for about 5 years after you complete the study.