Summary

Difluoromethylornithine (DFMO) will be used in an open label, multicenter, study in
combination with etoposide for subjects with relapsed/refractory neuroblastoma.

Objectives

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.

Eligibility

1. All patients must have a pathologically confirmed diagnosis of neuroblastoma, = 30.99 years of age with history of relapsed/refractory neuroblastoma.
2. All patients must have completed upfront therapy with at least 4 cycles of aggressive multi-drug chemotherapy.
3. Specific Criteria by Arm: Arms 1 and 2: Subjects with no active disease: i. No evidence of residual disease by CT/MRI and MIBG scan (or PET for patients who have a history of MIBG non-avid disease). o Note: Patients with residual masses detected by CT/MRI may be considered in CR if their MIBG is negative or if MIBG positive and evaluated by PET and found to have negative PET scans; biopsy confirmation may be considered if there is still reasonable concern for persistent disease but is not required. ii. No evidence of disease metastatic to bone marrow. Arm 3: Measurable or evaluable disease, including at least one of the following: Measurable tumor by CT or MRI; or a positive MIBG and PET; or positive bone marrow biopsy/aspirate in at least one site.
4. Timing from prior therapy: Enrollment (first dose of DFMO) no later than 60 days from last dose of the most recent therapy.
5. Subjects must have fully recovered from the acute toxic effects of all prior anti- cancer chemotherapy and be within the following timelines:
6. Myelosuppressive chemotherapy: Must not have received within 2 weeks of enrollment onto this study (6 weeks if prior nitrosourea).
7. Hematopoietic growth factors: At least 5 days since the completion of therapy with a growth factor.
8. Biologic (anti-neoplastic agent): At least 7 days since the completion of therapy with a biologic agent. For agents that have known adverse events occurring beyond 7 days after administration, this period must be extended beyond the time during which adverse events are known to occur. The duration of this interval must be discussed with the Study Chair.
9. Immunotherapy: At least 6 weeks since the completion of any type of immunotherapy, e.g. tumor vaccines, CAR-T cells.
10. Anti-GD2 Monoclonal antibodies: At least 2 weeks must have elapsed since prior treatment with a monoclonal antibody.
11. XRT: At least 14 days since the last treatment except for radiation delivered with palliative intent to a non-target site.
12. Stem Cell Transplant:
13. Allogeneic: No evidence of active graft vs. host disease
14. Allo/Auto: = 2 months must have elapsed since transplant.
15. MIBG Therapy: At least 8 weeks since treatment with MIBG therapy
16. Subjects must have a Lansky or Karnofsky Performance Scale score of 60% or higher.
17. Life expectancy > 2 months
18. All clinical and laboratory studies for organ functions to determine eligibility must be performed within 7 days prior to first dose of study drug unless otherwise indicated below.
19. Subjects must have adequate organ functions at the time of registration:
20. Hematological: Total absolute neutrophil count ANC =750/µL
21. Liver: Subjects must have adequate liver function as defined by AST and ALT <5x upper limit of normal (Normal=45), Bilirubin <1.5x upper limit normal (Normal=1.0). Normal PT, PTT, fibrinogen.
22. Renal: Adequate renal function defined as (perform one of the following): Creatinine clearance or radioisotope GFR 70 mL/min/1.73 m2 or greater or a serum creatinine based on age/gender
23. Females of childbearing potential must have a negative pregnancy test. Patients of childbearing potential must agree to use an effective birth control method. Female patients who are lactating must agree to stop breast-feeding.
24. Written informed consent in accordance with institutional and FDA guidelines must be obtained from all subjects (or patients' legal representative).

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