DISEASE CHARACTERISTICS:

• Clinically and radiographically (MRI) proven newly diagnosed diffuse intrinsic brainstem glioma

  • Greater than 50% intra-axial involvement of the pons, pons and medulla, pons and midbrain, or entire brainstem
  • Contiguous involvement of the thalamus or upper cervical cord allowed

PATIENT CHARACTERISTICS:

Age:

• 21 and under

Performance status:

• ECOG 0-2

Life expectancy:

• More than 2 months

Hematopoietic:

• Absolute neutrophil count at least 1,000/mm^3
• Platelet count at least 100,000/mm^3
• Hemoglobin at least 10.0 g/dL (transfusion allowed)
• No glucose 6 phosphate dehydrogenase deficiency

Hepatic:

• Bilirubin no greater than 1.5 times normal
• SGOT or SGPT less than 1.5 times normal

Renal:

• Creatinine no greater than 1.5 times normal OR
• Creatinine clearance or radioisotope glomerular filtration rate at least 70 mL/min

Other:

• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• No concurrent immunomodulating agents

Chemotherapy:

• No other concurrent chemotherapy

Endocrine therapy:

• Concurrent corticosteroid therapy allowed for increased intracranial pressure only

Radiotherapy:

• No prior cranial radiotherapy

Surgery:

• Not specified

Other:

• No prior motexafin gadolinium
• No other concurrent experimental agents