Inclusion Criteria

DISEASE CHARACTERISTICS:

- Meets 1 of the following criteria:

- Histologically confirmed solid tumor (closed to accrual as of 10/4/2007) that
relapsed after or failed to respond to front-line curative therapy and for which
no other potentially curative treatment options exist

- Curative therapy may include surgery, radiotherapy, chemotherapy, or any
combination of these modalities

- Eligible tumor types include, but are not limited to, the following:

- Rhabdomyosarcoma

- Other soft tissue sarcomas

- Ewing's sarcoma family of tumors

- Osteosarcoma

- Neuroblastoma

- Wilms' tumor

- Hepatic tumors

- Germ cell tumors

- Primary brain tumors

- Histologic confirmation may be waived for brain stem or optic
glioma

- Diagnosis of relapsed or refractory leukemia

- Patients with refractory or second or greater relapsed leukemia must have >
25% blasts in the bone marrow (M3 bone marrow) with or without active
extramedullary disease (except for leptomeningeal disease)

- Relapsed after or failed to respond to frontline curative therapy and no
other potentially curative therapy (e.g., radiotherapy, chemotherapy, or
any combination of these modalities) exists

- Patients with acute promyelocytic leukemia must be refractory to treatment with
retinoic acid and arsenic trioxide

- Patients with Philadelphia chromosome positive chronic myelogenous leukemia must
be refractory to imatinib

- No active CNS leukemia (CNS3)

PATIENT CHARACTERISTICS:

Age:

- 2 to 18 (solid tumor patients [closed to accrual as of 10/4/2007])

- 1 to 21 (leukemia patients)

Performance status:

- For patients age 11 to 21:

- Karnofsky 50-100%

- For patients age 1 to 10:

- Lansky 50-100%

Life expectancy:

- Not specified

Hematopoietic:

- Platelet count at least 100,000/mm^3 (20,000/mm^3 for leukemia patients)

- Hemoglobin ≥ 8.0 g/dL

Hepatic:

- Bilirubin less than 1.5 times upper limit of normal (ULN)

- SGOT and SGPT less than 2.5 times ULN

- No hepatic dysfunction that would preclude study

Renal:

- Creatinine normal for age OR

- Creatinine clearance at least 60 mL/min

- No renal dysfunction that would preclude study

Other:

- No known severe prior hypersensitivity reaction to agents containing Cremophor EL

- No clinically significant unrelated systemic illness (e.g., serious infections or
other organ dysfunction) that would preclude study

- No grade 2 or greater preexisting sensory neuropathy

- More than 2 month since prior and no concurrent evidence of graft vs host disease

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY:

Biologic therapy:

- Recovered from all therapy-related acute toxic effects (leukemia patients only)

- Prior epoetin alfa allowed

- At least 3 days since other prior colony-stimulating factors (e.g., filgrastim
(G-CSF), sargramostim (GM-CSF), or interleukin-11 (IL-11))

- At least 6 months since prior bone marrow transplantation

- At least 2 months since prior stem cell transplantation or rescue (leukemia patients)

- At least 7 days since prior therapy with a biological agent and hematopoietic growth
factor with the exception of erythropoietin

- More than 3 weeks since prior monoclonal antibody therapy (leukemia patients only)

- No concurrent GM-CSF or IL-11

- No concurrent immunotherapy

Chemotherapy:

- See Disease Characteristics

- Recovered from all therapy-related acute toxic effects (leukemia patients only)

- At least 4 weeks since prior chemotherapy (6 weeks for nitrosoureas)

- No other concurrent anticancer chemotherapy

Endocrine therapy:

- Concurrent corticosteroids allowed for the control of symptoms related to
tumor-associated edema in patients with brain tumors

- Patients with brain tumors must be on a stable or tapering dose of corticosteroids
for 7 days before baseline scan is performed for the purpose of assessing response to
study therapy

- Must be on a stable or tapering dose of corticosteroids for 7 days prior to study
entry (leukemia patients only)

Radiotherapy:

- See Disease Characteristics

- Recovered from all therapy-related acute toxic effects (leukemia patients only)

- At least 4 weeks since prior radiotherapy

- More than 2 weeks since prior local palliative radiotherapy (leukemia patients only)

- More than 3 months since prior total-body irradiation, craniospinal radiotherapy, or
radiotherapy to ≥50% of the pelvis (leukemia patients only)

- More than 6 weeks since prior other substantial bone marrow radiotherapy (leukemia
patients only)

- No prior extensive radiotherapy (e.g., craniospinal irradiation, total body
irradiation, or radiotherapy to more than half of the pelvis)

- No concurrent anticancer radiotherapy

Surgery:

- See Disease Characteristics

Other:

- Recovered from prior therapy

- At least 30 days since any prior investigational anticancer therapy

- At least 1 week since prior known inhibitors of CYP3A4, including any of the
following:

- Antibiotics (i.e., clarithromycin, erythromycin, or troleandomycin)

- Anti-HIV agents (i.e, delaviridine, nelfinavir, amprenavir, ritonavir, idinavir,
saquinavir, or lopinavir)

- Anti-fungals (i.e., itraconazole, ketoconazole, fluconazole [doses >
3mg/kg/day], or voriconazole)

- Anti-depressants (i.e., nefaxodone or fluovoxamine)

- Calcium channel blockers (i.e., verapamil or diltiazem)

- Anti-emetics (i.e., aprepitant [Emend®])

- Miscellaneous agents (i.e., amiodarone)

- Grapefruit juice

- No other concurrent investigational agents

- No concurrent St. John's Wort

- No concurrent known inhibitors of CYP3A4, including grapefruit juice

- Concurrent other agents inducing CYP3A4 allowed