Mistletoe Lectin in Treating Patients With Advanced Solid Tumors That Have Not Responded to Previous Therapy

DISEASE CHARACTERISTICS: * Histologically or cytologically proven progressive advanced solid tumor that is not amenable to standard therapy (i.e., resistant to standard therapy or for which no standard therapy exists) * No clinically symptomatic CNS involvement PATIENT CHARACTERISTICS: Age: * 18 and over Performance status: * ECOG 0-2 Life expectancy: * At least 3 months Hematopoietic: * WBC at least 3,000/mm\^3 * Neutrophil count at least 1,500/mm\^3 * Platelet count at least 100,000/mm\^3 Hepatic: * Bilirubin no greater than 1.5 times upper limit of normal (ULN) * AST and ALT less than 2.5 times ULN (5 times ULN if liver metastases present) * Alkaline phosphatase less than 2.5 times ULN (5 times ULN if liver metastases present) Renal: * Creatinine less than 1.4 mg/dL Cardiovascular: * No ECG abnormalities of clinical relevance Other: * No severe or unstable systemic disease or infection * No circumstances (e.g., alcoholism or substance abuse) that would preclude study participation * HIV negative * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception PRIOR CONCURRENT THERAPY: Biologic therapy: * At least 4 weeks since prior immunostimulating substances, biologic response modifiers, or colony-stimulating factors * No concurrent immunostimulating substances, colony-stimulating factors (except in life-threatening situations), biologic response modifiers, or monoclonal antibodies Chemotherapy: * At least 4 weeks since prior chemotherapy Endocrine therapy: * At least 4 weeks since prior hormonal therapy * At least 4 weeks since prior systemic steroids * No concurrent systemic steroids Radiotherapy: * At least 4 weeks since prior radiotherapy * No concurrent radiotherapy Surgery: * Not specified Other: * No prior mistletoe preparations * At least 4 weeks since prior investigational treatment * No other concurrent anticancer agents