Successful treatment of a patient with adult T-cell leukemia by daily oral administration of low-dose etoposide. Decrease in the amount of HTLV-I proviral DNA revealed by the polymerase chain reaction method

BACKGROUND Oral administration of low-dose etoposide is known to be effective against various malignancies, including malignant lymphoma. However, the effectiveness of low-dose etoposide as a treatment for adult T-cell leukemia (ATL) has not been established. METHODS A 74-year-old woman with ATL in acute phase was treated by daily oral administration of low-dose etoposide (25 mg/m2). The authors assayed changes in the surface markers and the amount of human T-cell lymphotropic virus type I (HTLV-I) proviral DNA in peripheral blood mononuclear cells (PBMC) by using flow cytometry and the polymerase chain reaction (PCR) method, respectively. RESULTS Before treatment, generalized lymphadenopathy and hepatomegaly were observed. In laboratory examination, the leukocyte count was 13.7 x 10(3)/microliters, with 65% abnormal lymphocytes. The percentages of CD3-, CD4-, and CD25-positive cells in PBMC were 84.4%, 84.4%, and 76.5%, respectively. The serum lactic dehydrogenase (LDH) level was 1376 IU/l (normal range, less than 520 IU/l). After the initiation of treatment, lymph-adenopathy and hepatomegaly disappeared, and the serum LDH level was reduced to the normal level before the 20th day of the treatment. On the 55th day of the treatment, CD25-positive cells had virtually disappeared. In addition, the amount of the proviral DNA in PBMC was reduced to approximately one-tenth by this treatment. Subsequently, the patient was in remission for more than 16 months. No side effects were observed. CONCLUSIONS Daily oral administration of low-dose etoposide can be a safe and effective treatment for patients with ATL. The authors believe this to be the first report of a patient with ATL in whom complete remission (CR) was achieved by this treatment.