DISEASE CHARACTERISTICS:

• Histologically confirmed glioblastoma multiforme in first relapse

PATIENT CHARACTERISTICS:

Age:

• 18 and over

Performance status:

• Karnofsky 60-100%

Life expectancy:

• More than 12 weeks

Hematopoietic:

• WBC at least 3,000/mm^3
• Absolute neutrophil count at least 1,500/mm^3
• Platelet count at least 100,000/mm^3

Hepatic:

• Bilirubin less than 1.5 times upper limit of normal (ULN)
• AST/ALT no greater than 2.5 times ULN

Renal:

• Creatinine less than 1.5 times ULN

Cardiovascular:

• No symptomatic congestive heart failure
• No unstable angina pectoris
• No cardiac arrhythmia

Other:

• No other uncontrolled concurrent illness
• No ongoing or active infection
• No psychiatric illness or social situation that would preclude study compliance
• No prior allergic reactions to compounds of similar chemical or biologic composition to ZD 1839
• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception
• Ocular inflammation must be fully treated before study entry

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• Not specified

Chemotherapy:

• At least 4 weeks since prior chemotherapy (6 weeks for nitrosoureas or mitomycin) and recovered

Endocrine therapy:

• Must be on stable dose of steroids for at least 1 week

Radiotherapy:

• At least 4 weeks since prior radiotherapy and recovered

Surgery:

• At least 1 week since prior surgery

Other:

• No other concurrent investigational agents
• No other concurrent anticancer therapy
• No concurrent combination antiretroviral therapy for HIV
• No concurrent enzyme-inducing anticonvulsant drugs