Bryostatin 1 in Treating Patients With Myelodysplastic Syndrome

DISEASE CHARACTERISTICS: Histologically diagnosed refractory anemia, refractory anemia with excess blasts, refractory anemia with excess blasts in transformation, refractory anemia with ringed sideroblasts, or chronic myelomonocytic leukemia with significant cytopenias of at least 4 weeks duration No more than 1 prior treatment for disease Not eligible for allogeneic bone marrow transplantation if less than 60 years of age PATIENT CHARACTERISTICS: Age: 18 and over Performance status: Zubrod 0-2 Life expectancy: At least 12 weeks Hematopoietic: Hematocrit less than 26% (or requiring transfusion) for at least 4 weeks Absolute neutrophil count less than 1000/mm3 for at least 4 weeks Platelet count less than 50/mm3 for at least 4 weeks Hepatic: Bilirubin less than 1.5 mg/dL Transaminase less than 2.5 times upper limit of normal Renal: Creatinine less than 1.5 mg/dL Creatinine clearance of at least 60 mL/min Other: Not pregnant or lactating Fertile patients must use effective contraception while on study and for 100 days afterwards No uncontrolled or life-threatening infection PRIOR CONCURRENT THERAPY: Biologic therapy: No concurrent immunotherapy No concurrent treatment with growth factors Chemotherapy: At least 4 weeks since prior chemotherapy (8 weeks for mitomycin or nitrosourea) and recovered Endocrine therapy: No concurrent use of steroids Radiotherapy: At least 4 weeks since prior radiation therapy and recovered Surgery: Not specified