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)