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

DISEASE CHARACTERISTICS: Histologically proven localized, regional, or metastatic adenocarcinoma of the prostate Progressive disease during prior hormonal therapy (both antiandrogen and gonadotropin-releasing hormone) and must continue hormonal therapy Measurable tumors or tumor markers Bone metastases allowed PATIENT CHARACTERISTICS: Age: 18 and over Performance status: Karnofsky 60-100% Life expectancy: At least 3 months Hematopoietic: WBC at least 3,000/mm^3 Platelet count at least 100,000/mm^3 Hepatic: No hepatic failure Bilirubin no greater than 2.5 mg/dL SGOT no greater than 2 times normal Renal: No chronic renal failure 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 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 infections or fever No other prior or concurrent second malignancy within the past 2 years PRIOR CONCURRENT THERAPY: Biologic therapy: At least 4 weeks since prior biologic therapy and recovered Chemotherapy: At least 4 weeks since prior chemotherapy and recovered Endocrine therapy: See Disease Characteristics Radiotherapy: At least 4 weeks since prior radiotherapy and recovered Surgery: Not specified Other: At least 4 weeks since prior investigational clinical trial No other concurrent treatment for metastatic prostate cancer