PRIOR CONCURRENT THERAPY: Recovered from any reversible acute toxic effects of previous therapy Biologic therapy: Not specified Chemotherapy: At least 4 weeks since chemotherapy (8 weeks since nitrosoureas or mitomycin) No prior fludarabine, pentostatin, or cladribine Endocrine therapy: Not specified Radiotherapy: No prior radiotherapy to greater than 25% of bone marrow Surgery: Not specified