RATIONALE: Drugs used in chemotherapy use different ways to stop tumor cells from dividing so they stop growing or die. Combining more than one drug may kill more tumor cells.

PURPOSE: Phase II trial to study the effectiveness of cyclophosphamide plus topotecan in treating patients who have refractory or relapsed acute myelogenous leukemia.

OBJECTIVES: I. Evaluate the efficacy of cyclophosphamide followed by topotecan in patients with relapsed or refractory acute myelogenous leukemia. II. Confirm safety and tolerability of this combination on this schedule in these patients.

OUTLINE: Patients receive cyclophosphamide intravenously over 1 hour on day 1 followed by topotecan as a continuous 120 hour infusion starting 12 hours after completion of cyclophosphamide. Treatment may be repeated every 3-6 weeks for at least 2 courses.

PROJECTED ACCRUAL: A total of 26 patients will be accrued for this study.

DISEASE CHARACTERISTICS: Histologically proven acute myelogenous leukemia by bone marrow aspirate or biopsy Clear evidence of relapse or residual disease with greater than 5% blasts on bone marrow examination or greater than 30% peripheral blasts No active CNS leukemia Not eligible for potentially curative allogeneic or autologous bone marrow transplantation without further surgery Must have failed to achieve a complete remission with conventional chemotherapy (cytarabine based) or have relapsed within 12 months after initial remission

PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-2 Life expectancy: At least 6 weeks Hematopoietic: See Disease Characteristics Hepatic: Bilirubin less than 1.6 mg/dL (unless due to disease) Renal: Creatinine less than 1.6 mg/dL (unless due to disease) No prior hemorrhagic cystitis Other: Not pregnant Fertile patients must use effective contraception No active uncontrolled infection

PRIOR CONCURRENT THERAPY: Biologic therapy: See Disease Characteristics Chemotherapy: See Disease Characteristics Recovered from prior chemotherapy No other concurrent chemotherapy Endocrine therapy: Not specified Radiotherapy: Must have recovered from prior radiotherapy Surgery: Not specified