The purpose of this study is to determine the long term safety of patients with refractory solid tumors who have experienced clinical benefit after at least 6 cycles of treatment in BMS Protocol CA124-001 or CA124-002.

Inclusion Criteria:

• Completion of at least 6 cycles of therapy on BMS clinical protocol CA124-001 or CA124-002 and who continue to derive clinical benefit and are not experiencing intolerable toxicity from the therapy
• Karnofsky score of at least 50 for subjects > 10 years of age; Lansky play scale of at least 50 for children 10 years of age and younger
• Recovery to baseline or Grade 1 from toxicities (except alopecia or asthenia) resulting from previous therapies
• Males and females, ages 1 - 21 years of age at the time of consent into CA124-001 or CA124-002

Exclusion Criteria:

• A serious uncontrolled medical disorder that in the opinion of the Investigator would impair the ability of the subject to receive protocol therapy
• Requirement to receive concurrent chemotherapy, immunotherapy, radiotherapy, or any other investigational drug while on study
• Inadequate bone marrow and renal function
• Concurrent receipt of Dilantin®(phenytoin), phenobarbital, primidone, Tegretol®(carbamazepine), Depacon®, Depakene®, Depakote®, and Deproic®(valproic acid)