Naxitamab for High-Risk Neuroblastoma Patients With Primary Refractory Disease or Incomplete Response to Salvage Treatment in Bone and/or Bone Marrow

Each patient will receive treatment for up to 93 weeks following the first Naxitamab
administration and remain in the trial for 101 weeks. After the end of trial visit, each
patient will enter a long-term follow-up where they will be monitored for up to 5 years after
first treatment cycle.

Each investigational cycle is started with 5 days, days -4 to 0, of Granulocyte-Macrophage
Colony Stimulating Factor (GM-CSF) administered at 250 µg/m2/day in advance of the start of
Naxitamab administration. GM-CSF is thereafter administered at 500 µg/m2/day on days 1 to 5.
As standard treatment, Naxitamab is administered at 3 mg/kg/day on days 1, 3, and 5,
totalling 9 mg/kg per cycle.

Treatment cycles are repeated every 4 weeks (±1 week) until complete response or partial
response followed by 5 additional cycles every 4 weeks (±1 week). Subsequent cycles are
repeated every 8 weeks (±2 weeks) through 101 weeks from first infusion at the discretion of
the investigator. End of treatment will take place around 8 weeks after the last cycle and
thereafter long-term follow-up will continue.

Inclusion Criteria:

- Diagnosis of neuroblastoma as defined per International Neuroblastoma Response
Criteria

- High-risk neuroblastoma patients with either primary refractory disease or incomplete
response to salvage treatment (in both cases including stable disease, minor response
and partial response) evaluable in bone and/or bone marrow.

- Life expectancy ≥ 6 months

Exclusion Criteria:

- Any systemic anti-cancer therapy, including chemotherapy or immunotherapy, within 3
weeks before 1st dose of GM-CSF

- Evaluable neuroblastoma outside bone and bone marrow

- Existing major organ dysfunction > Grade 2, with the exception of hearing loss,
hematological status, kidney and liver function

- Active life-threatening infection