[Continuation of complete remission by oral administration of cytarabine ocfosfate in a patient with M0, who achieved remission by small doses of cytosine arabinoside with G-CSF].

A 70-year-old male was admitted to our hospital because of leukocytosis. The laboratory examination revealed leukocytosis (44,500/microliters) with blasts (99%) in the peripheral blood. Myeloperoxidase staining of the leukemia cells was negative, but the surface phenotype was CD13- and CD33-positive, and negative for all lymphoid antigens. Peroxidase staining using the electron microscope was positive. Thus, the patient was diagnosed as acute myeloblastic leukemia (M0), according to the FAB classification. Although the therapy regimens commonly used for ANLL were effective for some cases with M0, the regimens mainly for ALL were more effective for the others. Thus we cannot determine what is the most effective regimen for M0. Since the patient had many complications, he was treated with low-dose AraC instead of combination chemotherapy. After the beginning of treatment, he became febrile and we added G-CSF to Ara-C. One month later, the patient achieved complete remission without severe infection. After four courses of consolidation therapy, the patient was discharged. He has been maintained in remission for more than 3 years and 8 months with only 5-day oral administration of cytarabine ocfosfate every four weeks.