3-AP Followed By Fludarabine In Treating Patients With Relapsed or Refractory Acute or Chronic Leukemia or High-Risk Myelodysplastic Syndrome

DISEASE CHARACTERISTICS: Histologically confirmed diagnosis of 1 of the following: High-risk myelodysplastic syndromes (MDS), including refractory anemia with excess blasts and chronic myelomonocytic leukemia International Prognostic Scoring System (IPSS) score at least 1.5 based on the following: More than 10% marrow blasts Cytopenias in at least 2 lineages Adverse cytogenetics Acute myeloid leukemia (AML) All subtypes, including MDS/AML and treatment-related (secondary) AML Acute lymphoblastic leukemia Acute progranulocytic leukemia Ineligible for arsenic therapy Chronic myelogenous leukemia Accelerated phase or blastic crisis Chronic lymphocytic leukemia Prolymphocytic leukemia Received or ineligible for established curative regimens, including stem cell transplantation Acute and chronic leukemias must be relapsed and/or refractory with progressive disease since last therapy PATIENT CHARACTERISTICS: Age 18 and over Performance status ECOG 0-2 Life expectancy Not specified Hematopoietic No history of hemolytic anemia grade 2 or greater No known glucose-6-phosphate dehydrogenase (G6PD) deficiency G6PD screening required for high-risk groups (i.e., patients of African, Asian, or Mediterranean origin/ancestry) Hepatic SGOT and SGPT no greater than 2.5 times normal Bilirubin no greater than 2 mg/dL No chronic hepatitis Renal Creatinine normal OR Creatinine clearance at least 60 mL/min Cardiovascular No active heart disease No myocardial infarction within the past 3 months No severe coronary artery disease No arrhythmias (other than atrial flutter or fibrillation) requiring medication No uncontrolled congestive heart failure Pulmonary No dyspnea at rest or with minimal exertion No severe pulmonary disease requiring supplemental oxygen Other Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception No neuropathy grade 2 or greater No active uncontrolled infection Infections under active treatment and controlled by antibiotics are allowed No other life-threatening illness No psychiatric illness that would preclude study compliance PRIOR CONCURRENT THERAPY: Biologic therapy See Disease Characteristics At least 1 week since prior hematopoietic growth factor (e.g., epoetin alfa, filgrastim [G-CSF], sargramostim [GM-CSF], interleukin-3, and interleukin-11) No concurrent immunotherapy Chemotherapy Recovered from prior chemotherapy (no greater than grade 1 chronic toxic effects) At least 72 hours since prior hydroxyurea At least 3 weeks since prior myelosuppressive cytotoxic agents (6 weeks for mitomycin or nitrosoureas) No more than 12 prior courses of fludarabine No more than 3 prior cytotoxic chemotherapy regimens No other concurrent chemotherapy Endocrine therapy Not specified Radiotherapy At least 2 weeks since prior radiotherapy No concurrent radiotherapy Surgery Not specified Other At least 1 week since prior non-myelosuppressive treatment No more than 4 prior induction regimens No other concurrent therapy