Fenretinide Lym-X-Sorb + Ketoconazole + Vincristine for Recurrent or Resistant Neuroblastoma

Fenretinide has been given by mouth as a capsule to many people, including children. When Fenretinide is given in capsules, very little of the drug is absorbed through the intestines into the body. This means patients have to take many capsules of fenretinide by mouth several times a day. In this study, a new oral preparation of fenretinide (called 4-HPR/LXS oral powder) is being tested to see if more fenretinide can be absorbed into the body. 4-HPR/LXS oral powder has been tested previously in a limited number of both children and adult cancer patients. Ketoconazole, commonly used to treat fungus infections, can increase fenretinide levels in the body by interfering with the body's ability to break down fenretinide. Ketoconazole will be given at the same time as the fenretinide powder. There is preclinical data that shows that combining fenretinide and vincristine prolonged survival in animal models, therefore, it is hoped that giving the vincristine with fenretinide will work better against the neuroblastoma that either drug given alone. About 70 children with neuroblastoma have been treated with various versions of the fenretinide powder to date, including about a dozen children that also took the fenretinide powder with ketoconazole, and no toxicities have occurred that limited the dosage and no serious or unexpected side effects occurred. However, vincristine has never been given with fenretinide or fenretinide plus ketoconazole before. Vincristine has been been given before with ketoconazole to both children and adults with neuroblastomas and other cancers.