Temozolomide and O6-benzylguanine in Treating Children With Solid Tumors

DISEASE CHARACTERISTICS:

Histologically confirmed solid tumor refractory to standard therapy and for which no potentially curative therapy exists, including, but not limited to:

Rhabdomyosarcoma and other soft tissue sarcomas
Ewing's family of tumors
Osteosarcoma
Neuroblastoma
Wilms' tumor
Hepatic tumors
Germ cell tumors
Primary brain tumor
Histological confirmation may be waived for brainstem or optic gliomas
Measurable or evaluable disease
Evidence of progressive disease on prior chemotherapy or radiotherapy or persistent disease after prior surgery

PATIENT CHARACTERISTICS:

Age:

21 and under

Performance status:

ECOG 0-2

Life expectancy:

At least 8 weeks

Hematopoietic:

Absolute granulocyte count greater than 1,500/mm^3
Hemoglobin greater than 8 g/dL
Platelet count greater than 100,000/mm^3

Hepatic:

Bilirubin normal
SGPT less than 2 times upper limit of normal
No significant hepatic dysfunction

Renal:

Creatinine normal OR
Creatinine clearance at least 60 mL/min

Cardiovascular:

No significant cardiac dysfunction

Pulmonary:

No significant pulmonary dysfunction

Other:

Not pregnant or nursing
Negative pregnancy test
Fertile patients must use effective contraception
Able to swallow capsules
No significant unrelated systemic illness that would preclude study (e.g., serious infections or organ dysfunction)
No prior hypersensitivity to dacarbazine, temozolomide, or polyethylene glycol

PRIOR CONCURRENT THERAPY:

Biologic therapy:

At least 1 week since prior colony-stimulating factors (e.g., filgrastim [G- CSF], sargramostim [GM-CSF], or epoetin alfa)
At least 4 months since prior myeloablative therapy requiring bone marrow or stem cell transplantation
No concurrent anticancer immunotherapy

Chemotherapy:

See Disease Characteristics
At least 3 weeks since prior chemotherapy (4 weeks for nitrosoureas) and recovered
Prior temozolomide allowed provided not administered within past 3 months, no severe toxicities experienced during prior course, and not given in combination with other agents designed to inactivate alanine-glyoxylate aminotransferase
No other concurrent investigational or standard anticancer chemotherapy

Endocrine therapy:

Concurrent corticosteroids for control of brain tumor-associated edema allowed provided on stable or decreasing dose for at least 1 week prior to study

Radiotherapy:

See Disease Characteristics
At least 4 weeks since prior limited-field radiotherapy
At least 4 months since prior craniospinal irradiation, total body irradiation, or radiotherapy to more than half of the pelvis
Recovered from prior radiotherapy
No concurrent anticancer radiotherapy

Surgery:

See Disease Characteristics

Other:

At least 4 weeks since other prior investigational therapy and recovered
No other concurrent anticancer investigational agents