PATIENT CHARACTERISTICS: Age: 18 and over Performance status: Karnofsky 60-100% Life expectancy: Greater than 12 weeks Hematopoietic: Platelet count at least 100,000/mm3 Absolute neutrophil count at least 2,000/mm3 Hepatic: Total bilirubin no greater than upper limit of normal (ULN) AST/SGOT and/or ALT/SGPT no greater than 1.5 times ULN Alkaline phosphatase no greater than 5 times ULN Renal: Not specified Other: Not pregnant or nursing Barrier contraception required during treatment Negative for HIV 1, HIV 2, hepatitis B, and hepatitis C At least 2 years since prior malignancy, other than SCCHN No contact with former tissue or organ transplant recipients or persons with severe immunodeficiency disease within 28 days following final dose of study drug No serious concurrent medical conditions No active uncontrolled infection