Cyclophosphamide Plus Topotecan in Treating Patients With Refractory or Relapsed Acute Myelogenous Leukemia

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