Bryostatin 1 Plus Cladribine in Treating Patients With Relapsed Chronic Lymphocytic Leukemia

DISEASE CHARACTERISTICS: Diagnosis of relapsed chronic lymphocytic leukemia Intermediate- or high-risk (stage I-IV) disease Intermediate-risk patients must have active disease, defined by at least 1 of the following criteria: Presence of any 1 of the following disease-related B symptoms: 10% or more loss of body weight within the past 6 months Extreme fatigue Fever greater than 100 degrees Fahrenheit without evidence of infection Night sweats Massive (greater than 6 cm below left costal margin) or progressive splenomegaly Massive (greater than 10 cm in longest diameter) or progressive lymphadenopathy Progressive lymphocytosis with an increase of more than 50% over a 2-month period or anticipated doubling time of less than 12 months Progressive bone marrow failure as manifested by the development or worsening of anemia and/or thrombocytopenia Autoimmune anemia and/or thrombocytopenia poorly responsive to corticosteroids Failed 1-2 prior front-line regimens Failed prior fludarabine Ineligible for any known treatment of higher potential efficacy PATIENT CHARACTERISTICS: Age: 18 and over Performance status: Zubrod 0-2 Life expectancy: At least 12 weeks Hematopoietic: See Disease Characteristics Absolute neutrophil count at least 1,000/mm^3 Platelet count at least 50,000/mm^3 Hepatic: Bilirubin less than 1.5 mg/dL Transaminases less than 2.5 times normal Renal: Creatinine less than 1.5 mg/dL OR Creatinine clearance at least 60 mL/min Cardiovascular: No history of severe coronary artery disease, cardiomyopathy, uncontrolled congestive heart failure, or arrhythmias Neurologic: No prior drug-related neurotoxicity No other neurologic disorder Other: Not pregnant or nursing Fertile patients must use effective barrier or non-hormonal contraception during and for 2 months after study participation No HIV infection No AIDS PRIOR CONCURRENT THERAPY: Biologic therapy: No prior bone marrow transplantation Chemotherapy: See Disease Characteristics At least 4 weeks since prior chemotherapy (8 weeks for mitomycin or nitrosoureas) and recovered Endocrine therapy: See Disease Characteristics No concurrent steroids No concurrent hormonal contraceptives Radiotherapy: At least 4 weeks since prior radiotherapy and recovered Surgery: Not specified Other: No other concurrent therapy