Inclusion Criteria:

• Patients must have histologically proven neuroblastoma and confirmation of refractory or recurrent disease or medulloblastoma with histologic confirmation at diagnosis or at the time of recurrence/progression
• Patients must be age >12 months and diagnosed before the age of 21;
• Life expectancy must be more than 3 months
• If measurable disease, this must be demonstrated by residual abnormal tissue at a primary or metastatic site measuring more than 1 cm in any dimension by standardized imaging (CT or MRI). For patients with neuroblastoma, there must be at least two persisting skeletal foci on meta-iodobenzylguanidine (MIBG) follow-up scans
• Current disease state must be one for which there is currently no known curative therapy
• Lansky Play Score must be more than 30 and/or ECOG performance status must be 0 to 2
• For patients with medulloblastoma receiving steroids, the dose must be stable (i.e. not increasing) for at least one week before starting study
• Patients without bone marrow metastases must have an ANC > 750/μl and platelet count >50,000/μl

• Adequate liver function must be demonstrated, defined as:

  • Total bilirubin ≤ 1.5 x upper limit of normal (ULN) for age AND
  • SGPT (ALT) < 10 x upper limit of normal (ULN) for age
• No other significant organ toxicity defined as >Grade 2 by National Cancer Institute Common Toxicity Criteria for Adverse Events version 3 (NCI-CTCAE V3.0 (http://ctep.cancer.gov/forms/CTCAEv3.pdf))
• A negative urine pregnancy test is required for female participants of child bearing potential (≥13 years of age or after the onset of menses)
• Both male and female post-pubertal study subjects need to agree to use one of the more effective birth control methods during treatment and for six months after treatment is stopped. These methods include total abstinence (no sex), oral contraceptives ("the pill"), an intrauterine device (IUD), levonorgestrol implants (Norplant), or medroxyprogesterone acetate injections (Depo-provera shots). If one of these can not be used, contraceptive foam with a condom is recommended.
• Informed Consent: All patients and/or legal guardians must sign informed written consent. Assent, when appropriate, will be obtained according to institutional guidelines
• Patients may have received microtubulin inhibitors and/or temozolomide during previous therapies.

Exclusion Criteria:

• Patients who have received any chemotherapy administered within the last 21 days
• Patients who have received radiotherapy within the last 30 days.
• Patients who have received myeloablative therapy within the previous 3 months
• Patients receiving anti-tumor therapy for their disease or any investigational drug concurrently
• Patients with serious infection or a life-threatening illness (unrelated to tumor) that is > Grade 2 (NCI CTCAE V3.0), or active, serious infections requiring parenteral antibiotic therapy within 4 weeks prior to screening
• Any other medical condition, including malabsorption syndromes, mental illness or substance abuse, deemed by the Investigator to be likely to interfere with the interpretation of the results or which would interfere with a patient's ability to sign or the legal guardian's ability to sign the informed consent, and patient's ability to cooperate and participate in the study
• Patients with known hypersensitivity to any of the components of the drugs to be administered on study
• Patients who in the opinion of the investigator may not be able to comply with the safety monitoring requirements of the study.