PRIOR CONCURRENT THERAPY: Biologic therapy: At least 4 weeks since prior immunotherapy Chemotherapy: At least 4 weeks since prior chemotherapy (6 weeks since prior nitrosoureas, mitomycin, or carboplatin) Prior taxanes allowed No other concurrent chemotherapy Endocrine therapy: See Disease Characteristics At least 2 weeks since prior hormonal therapy No concurrent steroids No concurrent hormonal therapy (except leuprolide acetate for prostate cancer) Radiotherapy: At least 4 weeks since prior radiotherapy to 30% or more of bone marrow No concurrent radiotherapy Surgery: Not specified Other: No other concurrent investigational anticancer therapy