<br>        Inclusion Criteria:<br><br>          -  Established diagnosis of neuroblastoma according to the international criteria (INSS)<br><br>          -  High risk (HR): stage 4 over 18 months of age and oncogen MYCN (MYCN) amplified<br>             neuroblastoma of any stage and any age until 25 years (recurrent disease (Germany and<br>             The Netherlands) after re-induction chemotherapy (+/- other modalities) or newly<br>             diagnosed disease (only The Netherlands):<br><br>          -  Complete front-line treatment including induction chemotherapy, radioisotope (mIBG)<br>             treatment, appropriate local therapy such as surgical removal and/ or local<br>             irradiation of the primary tumor and myeloablative chemotherapy with autologous stem<br>             cell reinfusion according to the actual guidelines of the GPOH/DCOG<br><br>          -  achieved response status: stable disease or better (CR, VGPR, PR, SD).<br><br>          -  Written informed consent of parents or guardian and - if appropriate - of the patient.<br><br>          -  For at least two weeks prior to start of trial medication off any standard or<br>             experimental treatment no tumour surgery no immediate requirements for palliative<br>             chemotherapy, radiotherapy or surgery<br><br>          -  The patient may have had prior central nervous system (CNS) metastases provided the<br>             following criteria are all met:<br><br>        The patient's CNS disease has been previously treated The patient's CNS disease has been<br>        clinically stable for four weeks prior to starting this study (assessed clinically and by<br>        MRI or CT) The patient is off steroids for four weeks prior to starting the study and will<br>        not require them during the course of the study A patient with seizure disorders may be<br>        enrolled if well controlled on anticonvulsants and if no seizures have occurred within a 6<br>        week period prior to starting trial treatment<br><br>          -  HIV sero-negative and neither active nor chronic-replicative hepatitis B infection<br><br>          -  Laboratory testing: The patients should have adequate functions of the cor, lung, bone<br>             marrow, liver, kidney<br><br>        Exclusion Criteria:<br>      ;<br>        Inclusion Criteria:<br><br>          -  Established diagnosis of neuroblastoma according to the international criteria (INSS)<br><br>          -  High risk (HR): stage 4 over 18 months of age and oncogen MYCN (MYCN) amplified<br>             neuroblastoma of any stage and any age until 25 years (recurrent disease (Germany and<br>             The Netherlands) after re-induction chemotherapy (+/- other modalities) or newly<br>             diagnosed disease (only The Netherlands):<br><br>          -  Complete front-line treatment including induction chemotherapy, radioisotope (mIBG)<br>             treatment, appropriate local therapy such as surgical removal and/ or local<br>             irradiation of the primary tumor and myeloablative chemotherapy with autologous stem<br>             cell reinfusion according to the actual guidelines of the GPOH/DCOG<br><br>          -  achieved response status: stable disease or better (CR, VGPR, PR, SD).<br><br>          -  Written informed consent of parents or guardian and - if appropriate - of the patient.<br><br>          -  For at least two weeks prior to start of trial medication off any standard or<br>             experimental treatment no tumour surgery no immediate requirements for palliative<br>             chemotherapy, radiotherapy or surgery<br><br>          -  The patient may have had prior central nervous system (CNS) metastases provided the<br>             following criteria are all met:<br><br>        The patient's CNS disease has been previously treated The patient's CNS disease has been<br>        clinically stable for four weeks prior to starting this study (assessed clinically and by<br>        MRI or CT) The patient is off steroids for four weeks prior to starting the study and will<br>        not require them during the course of the study A patient with seizure disorders may be<br>        enrolled if well controlled on anticonvulsants and if no seizures have occurred within a 6<br>        week period prior to starting trial treatment<br><br>          -  HIV sero-negative and neither active nor chronic-replicative hepatitis B infection<br><br>          -  Laboratory testing: The patients should have adequate functions of the cor, lung, bone<br>             marrow, liver, kidney<br><br>        Exclusion Criteria:<br>      ;<br>        Inclusion Criteria:<br><br>          -  Established diagnosis of neuroblastoma according to the international criteria (INSS)<br><br>          -  High risk (HR): stage 4 over 18 months of age and oncogen MYCN (MYCN) amplified<br>             neuroblastoma of any stage and any age until 25 years (recurrent disease (Germany and<br>             The Netherlands) after re-induction chemotherapy (+/- other modalities) or newly<br>             diagnosed disease (only The Netherlands):<br><br>          -  Complete front-line treatment including induction chemotherapy, radioisotope (mIBG)<br>             treatment, appropriate local therapy such as surgical removal and/ or local<br>             irradiation of the primary tumor and myeloablative chemotherapy with autologous stem<br>             cell reinfusion according to the actual guidelines of the GPOH/DCOG<br><br>          -  achieved response status: stable disease or better (CR, VGPR, PR, SD).<br><br>          -  Written informed consent of parents or guardian and - if appropriate - of the patient.<br><br>          -  For at least two weeks prior to start of trial medication off any standard or<br>             experimental treatment no tumour surgery no immediate requirements for palliative<br>             chemotherapy, radiotherapy or surgery<br><br>          -  The patient may have had prior central nervous system (CNS) metastases provided the<br>             following criteria are all met:<br><br>        The patient's CNS disease has been previously treated The patient's CNS disease has been<br>        clinically stable for four weeks prior to starting this study (assessed clinically and by<br>        MRI or CT) The patient is off steroids for four weeks prior to starting the study and will<br>        not require them during the course of the study A patient with seizure disorders may be<br>        enrolled if well controlled on anticonvulsants and if no seizures have occurred within a 6<br>        week period prior to starting trial treatment<br><br>          -  HIV sero-negative and neither active nor chronic-replicative hepatitis B infection<br><br>          -  Laboratory testing: The patients should have adequate functions of the cor, lung, bone<br>             marrow, liver, kidney<br><br>        Exclusion Criteria:<br>      ;<br>        Inclusion Criteria:<br><br>          -  Established diagnosis of neuroblastoma according to the international criteria (INSS)<br><br>          -  High risk (HR): stage 4 over 18 months of age and oncogen MYCN (MYCN) amplified<br>             neuroblastoma of any stage and any age until 25 years (recurrent disease (Germany and<br>             The Netherlands) after re-induction chemotherapy (+/- other modalities) or newly<br>             diagnosed disease (only The Netherlands):<br><br>          -  Complete front-line treatment including induction chemotherapy, radioisotope (mIBG)<br>             treatment, appropriate local therapy such as surgical removal and/ or local<br>             irradiation of the primary tumor and myeloablative chemotherapy with autologous stem<br>             cell reinfusion according to the actual guidelines of the GPOH/DCOG<br><br>          -  achieved response status: stable disease or better (CR, VGPR, PR, SD).<br><br>          -  Written informed consent of parents or guardian and - if appropriate - of the patient.<br><br>          -  For at least two weeks prior to start of trial medication off any standard or<br>             experimental treatment no tumour surgery no immediate requirements for palliative<br>             chemotherapy, radiotherapy or surgery<br><br>          -  The patient may have had prior central nervous system (CNS) metastases provided the<br>             following criteria are all met:<br><br>        The patient's CNS disease has been previously treated The patient's CNS disease has been<br>        clinically stable for four weeks prior to starting this study (assessed clinically and by<br>        MRI or CT) The patient is off steroids for four weeks prior to starting the study and will<br>        not require them during the course of the study A patient with seizure disorders may be<br>        enrolled if well controlled on anticonvulsants and if no seizures have occurred within a 6<br>        week period prior to starting trial treatment<br><br>          -  HIV sero-negative and neither active nor chronic-replicative hepatitis B infection<br><br>          -  Laboratory testing: The patients should have adequate functions of the cor, lung, bone<br>             marrow, liver, kidney<br><br>        Exclusion Criteria:<br>