PRIOR CONCURRENT THERAPY: Biologic therapy: At least 4 weeks since prior immunotherapy Chemotherapy: At least 4 weeks since prior chemotherapy (6 weeks since nitrosoureas, mitomycin, or carboplatin) Prior taxane therapy allowed No other concurrent chemotherapy Endocrine therapy: At least 1 week since prior steroid therapy No concurrent hormonal therapy Radiotherapy: At least 4 weeks since prior wide field radiotherapy (involving at least 30% of the bone marrow) No concurrent radiotherapy Surgery: Not specified Other: No other concurrent experimental anticancer medications