Antineoplaston Therapy in Treating Patients With Stage III or Stage IV Prostate Cancer

DISEASE CHARACTERISTICS: Histologically proven stage III or IV adenocarcinoma of the prostate not potentially curable by surgery or radiotherapy Measurable tumors or tumor markers No response to antiandrogen withdrawal PATIENT CHARACTERISTICS: Age: 18 and over Performance status: Karnofsky 60-100% Life expectancy: At least 3 months Hematopoietic: WBC at least 3000/mm^3 Platelet count at least 100,000/mm^3 Hepatic: Bilirubin no greater than 2.5 mg/dL SGOT no greater than 2 times normal No hepatic failure Renal: BUN less than 60 mg/dL Creatinine no greater than 2.5 mg/dL OR Creatinine clearance greater than 60 mL/min Blood ammonia normal No chronic renal failure Cardiovascular: No severe heart disease Pulmonary: No severe lung disease Other: Fertile patients must use effective contraception during and for 4 weeks after study participation No serious active infection or fever No other concurrent serious disease No other prior or concurrent malignancy within the past 2 years PRIOR CONCURRENT THERAPY: Biologic therapy: At least 4 weeks since prior immunotherapy and recovered Chemotherapy: At least 4 weeks since prior chemotherapy and recovered Endocrine therapy: At least 4 weeks since prior hormonal therapy and recovered Prior corticosteroids for at least 2 months allowed, but must be on stable or decreasing dose during study participation Radiotherapy: See Disease Characteristics At least 4 weeks since prior radiotherapy and recovered Surgery: See Disease Characteristics At least 4 weeks since prior surgery and recovered Other: At least 4 weeks since prior experimental clinical trial No other concurrent therapy for metastatic disease