Activity Study of Bevacizumab With Temozolomide ± Irinotecan for Neuroblastoma in Children

The purpose of this study is to investigate whether Bevacizumab (an anti-VEGF monoclonal antibody) added to a backbone chemotherapy regimen (Temozolomide, Irinotecan-Temozolomide or Topotecan-Temozolomide) demonstrates activity in children with relapsed or refractory neuroblastoma. Also, to investigate whether the addition of Irinotecan or Topotecan to Temozolomide increases the activity of chemotherapy.The primary objective of the study is the best response (Complete Response or Partial Response) while trial treatment, within 18 or 24 weeks depending on the arm of the trial the participant is randomised to. Secondary endpoints are assessing the side effects, the length of time before progression (Progression Free Survival) and overall survival (OS). This trial will address two important questions: * does targeting blood vessel development using bevacizumab, (a monoclonal antibody against the Vascular Endothelial Growth Factor (VEGF)), add to the effect on a tumour when used with existing chemotherapy, compared to the effect of the existing chemotherapy alone (temozolomide)? NOTE- This question has been completed. * does the addition of a second chemotherapy drug (irinotecan or topotecan) increase the effect on a tumour compared to the effect of one alone (temozolomide) NOTE - This question has been completed. * does the addition of dinutuximab beta added to a backbone chemotherapy (temozolomide or temozolomide + topotecan) increase the effect of backbone alone. Patients aged 1-21 years of age with relapsed or refractory high-risk neuroblastoma are randomised to one of two treatment arms: temozolomide-topotecan (TTo) or dinutuximab beta-temozolomide-topotecan (dBTTo). Temozolomide (T), irinotecan-temozolomide (IT), bevacizumab-T (BT), BIT (bevacizumab-IT), bevacizumab-temozolomide-topotecan (BTTo) and dinutuximab beta-temozolomide (dBT) are now closed to recruitment.