PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: See Disease Characteristics At least 4 weeks since prior chemotherapy No other concurrent cytotoxic therapy Endocrine therapy: Not specified Radiotherapy: Recovered from prior radiotherapy At least 4 weeks since radiotherapy to at least 20% of bone marrow Surgery: Not specified Other: As least 28 days since prior investigational agent or new anticancer therapy No concurrent therapeutic heparin No other concurrent investigational therapy