DISEASE CHARACTERISTICS:

• Histologically or cytologically confirmed renal cell carcinoma or malignant melanoma
• Strong clinical evidence or biopsy proof of metastases to a site or sites distant from the primary tumor
• Bidimensionally measurable of evaluable disease
• No significant effusions and/or ascites
• No more than 3 prior regimens for metastatic disease
• No known CNS metastases

PATIENT CHARACTERISTICS:

Age:

• 18 and over

Performance status:

• ECOG 0-1

Life expectancy:

• At least 3 months

Hematopoietic:

• WBC at least 3,000/mm^3
• Platelet count at least 100,000/mm^3
• Hemoglobin at least 9.5 g/dL

Hepatic:

• Bilirubin no greater than 1.5 mg/dL
• ALT/AST no greater than 3 times upper limit of normal

Renal:

• Creatinine no greater than 1.8 mg/dL
• Calcium no greater than 11.5 mg/dL

Cardiovascular:

• No history of serious cardiac arrhythmia or cardiac arrhythmia requiring treatment
• No congestive heart failure
• No angina pectoris
• No New York Heart Association class III or IV heart disease

Other:

• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception
• No active peptic ulcer
• No autoimmune disease
• No inflammatory bowel disease
• No local or systemic infections requiring IV antibiotics within the past 28 days
• No known seizure disorder
• No other prior malignancy except basal cell or squamous cell skin cancer, carcinoma in situ of the cervix, or any curatively treated malignancy in complete remission for at least 3 years
• HIV, hepatitis B surface antigen, and hepatitis C negative

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• See Disease Characteristics
• Recovered from prior biologic therapy

Chemotherapy:

• See Disease Characteristics
• Recovered from prior chemotherapy

Endocrine therapy:

• See Disease Characteristics
• At least 28 days since prior hormonal therapy and recovered
• No concurrent corticosteroids except for replacement steroids

Radiotherapy:

• See Disease Characteristics
• Recovered from prior radiotherapy
• At least 28 days since prior radiotherapy for control of pain from skeletal lesions

Surgery:

• See Disease Characteristics
• At least 28 days since prior major surgery requiring general anesthesia
• No organ allografts

Other:

• No concurrent aspirin
• No concurrent barbiturates
• No other concurrent investigational agents