PRIOR CONCURRENT THERAPY: Biologic therapy: At least 2 weeks since prior hematopoietic growth factor or cytokine therapy and recovered No concurrent immunotherapy Chemotherapy: At least 4 weeks since prior chemotherapy (at least 6 weeks since prior nitrosoureas or mitomycin) and recovered No concurrent chemotherapy Endocrine therapy: No concurrent corticosteroids except for steroid replacement therapy or chronic low dose (no greater than 10 mg/day oral prednisone) therapy for nonmalignant conditions No concurrent hormonal therapy except oral contraceptives or hormonal replacement therapy Radiotherapy: At least 2 weeks since prior radiotherapy and recovered No concurrent radiotherapy Surgery: At least 2 weeks since prior surgery and recovered Other: At least 4 weeks since other prior investigational drugs No concurrent oral or parenteral anticoagulants except anticoagulants for central venous catheters including low dose warfarin (1-2 mg/day) and/or heparin No concurrent oral COX-2 specific inhibitors (e.g., celecoxib or rofecoxib)