• Age ≥ 1 and ≤ 16 years.

• Tissue diagnosis of neuroblastoma. If sufficient biopsy material is available, GD2 expression on the tumour will be confirmed. As GD2 is consistently expressed in neuroblastoma demonstration of GD2 is not mandated.

• Disease which has relapsed after or is refractory to at least one line of salvage combination chemotherapy.

• Measurable disease by cross sectional imaging or evaluable disease by uptake on 123I-MIBG scan. Patients with only bone marrow detectable disease (bone marrow aspirate or trephine) are NOT eligible for the study.

• At least 3 weeks or 5 half-lives, whichever is shorter, after treatment with agents on other early phase clinical trial.

• Performance status: Karnofsky (age ≥ 10 years) or Lansky (age \< 10) score ≥ 50%. Patients who are unable to walk because of paralysis, but who are able to sit upright unassisted in a wheelchair, will be considered ambulatory for the purpose of assessing performance score.

• Creatinine ≤1.5 ULN for age, if higher, an estimated (calculated) creatinine clearance must be ≥ 60 ml/min/1.73 m2.

• Absolute lymphocyte count ≥ 0.25 x 10\^9/L.

• For post-pubertal subjects agreement to have a pregnancy test, use adequate contraception (if applicable).

⁃ Written informed consent.