The purpose of this study is to evaluate safety and efficacy of naxitamab, granulocyte macrophage Colony Stimulating Factor (GM CSF) and Isofosfamide/Carboplatin/Etoposide (NICE) for Patients With Relapsed /Refractory, soft tissue or anti GD2 immunotherapy refractory Neuroblastoma

The anti-GD2 monoclonal antibody Naxitamab (also known as hu3F8) in combination with macrophage colony-stimulating factor (GM-CSF) is currently under pivotal phase 3 investigation for the treatment of High-Risk Neuroblastoma Patients with Primary or Secondary Refractory Osteomedullary Disease.

A subset of patients with high-risk, resistant disease, i.e., relapsed or refractory Neuroblastoma with soft tissue involvement as measured by 123I-Meta-iodobenzylguanidine (MIBG), 18F-FDG avid or measurable computed tomography (CT)/ magnetic resonance imaging (MRI) tumors outside of the bone marrow, or disease refractory to Naxitamab in combination with GM-CSF has shown significant response rates to a chemoimmunotherapy combination of Naxitamab, GM-CSF, irinotecan and temozolomide (HITS- Hu3F8, irinotecan, temozolomide and sargramostim) (NCT03189706). Treatment is administered on an outpatient basis and toxicities include those expected from I/T (myelosuppression and diarrhea) as well as pain and hypertension expected with Naxitamab. No other greater than grade 2 related toxicities occurred in this study (n=46). Early responses, assessed after 2 cycles, were documented in 18 (39%) patients and here complete (n = 9), partial (n = 8), and mixed (n = 1) and 13 patients had stable disease. Responses were achieved in refractory (3/7;43%) and progressive disease (15/39;38%) subgroups, in patients who had previously received I/T (12/34;35%) and/or anti-GD2 MoAb (14/36;39%), and in soft tissue (6/22; 27%) MIBG-avid skeletal sites (20/36;56%) and on bone marrow histology (9/12;75%). While encouraging, new strategies are warranted to further treat resistant disease.

A high-dose combination of ifosfamide, carboplatin, and etoposide (ICE) has activity against Neuroblastoma without cross-resistance to widely used chemotherapy regimens.

Through compassionate use, 4 patients with progression of disease or refractory disease after HITS therapy, have been further treated with two cycles of a combination of naxitamab, Granulocyte-Macrophage Colony Stimulating Factor (GM-CSF) and ifosfamide/Carboplatin/Etoposide (NICE). The first patient showed a complete response.

Toxicity included G2 prolonged aplasia and G3 hypertension, both expected from the chemotherapy agents and hu3F8. One patient progressed after the 2 cycles and the other 2 showed stable disease, according to the revised (2017) International Neuroblastoma Response Criteria (INRC).

In this formal trial, the investigators will investigate whether the combination of Naxitamab and GM-CSF with ifosfamide/Carboplatin/Etoposide (ICE) has a synergistic treatment effect in relapsed or refractory disease. The safety and efficacy of NICE (Naxitamab, Ifosfamide/Carboplatin/Etoposide) in patients that have not achieved complete remission with HITS chemo-immunotherapy will be assessed.

Inclusion Criteria:

1. Diagnosis of neuroblastoma (NB) as defined per INRC as

   1. histopathology of tumor biopsy, or
   2. BM aspirate or biopsy indicative of NB by histology plus high blood or urine catecholamine metabolite levels or MYCN amplification, or
   3. Fluorodeoxyglucose (FDG), MIBG avid lesion(s)

2. High-risk NB as defined as any of the following:

   1. Stage 4 with MYCN amplification
   2. Stage 4 without MYC amplification >1.5 y of age
   3. Stage 3 with MYCN amplification

3. Relapsed/refractory Neuroblastoma with

   1. Evidence of soft tissue disease or
   2. Progessive disease/incomplete response/relapsed to previous treatment with Naxitamab plus GM-CSF

4. Prior treatment with murine and hu3F8 is allowed

5. Prior treatment with irinotecan or temozolomide or ICE is permitted

6. Evaluable (microscopic marrow metastasis, elevated tumor markers, positive MIBG or PET scans) or measurable (CT, MRI) disease documented after completion of prior systemic therapy

7. Age ≥18 months

8. Acceptable hematological status defined as:

   1. Hemoglobin ≥8 g/dL (5.0 mmol/L)
   2. White blood cell count ≥1000/μL
   3. Absolute Neutrophil Count (ANC) ≥500/μL
   4. Platelet count ≥50,000/μL

9. Acceptable liver function defined as:

   1. alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤5 times Upper Limit of Normal (ULN)
   2. Bilirubin ≤1.5 x ULN

10. Acceptable kidney function defined as:

    a. estimated Glomerular Filtration Rate (eGFR) >60 mL/min/1.73 m2 calculated by the 2009 revised Bedside Schwartz Equation

11. Written informed consent from legal guardian(s) and/or patient in accordance with local regulations. Children must provide assent as required by local regulations (≥ 12 years old).

Exclusion Criteria:

1. Existing major organ dysfunction > grade 2, with the exception of hearing loss and hematologic toxicity (defined as suppression of all subtypes of WBCs, RBCs, and platelets).
2. Active life-threatening infection.
3. Pregnant women or women who are breast-feeding.
4. Inability to comply with protocol requirements, including genetic studies.
5. History of allergy to GM-CSF ≥ G4 (Common Terminology Criteria for Adverse Events- CTCAE) or does not respond to treatment.
6. Absolute Neutrophil Count (ANC) < 500/uL .
7. Platelet count <50,000/uL.
8. Patients with relapsed/refractory Neuroblastoma with solely bone marrow/bone involvement. Only patients with B/BM compartiment disease who show progressive disease/incomplete response/relapsed to previous treatment with Naxitamab plus GM-CSF may be eligible (inclusion critèrium #3).