[Prolonged remission in a patient with chronic myelocytic leukemia (CML) by methyl 6-[3-(2-chloroethyl)-3-deoxy-alpha-D-glucopyranoside (MCNU)].

A 44-year-old woman with Ph1-positive CML achieved a complete remission following small doses of MCNU. She is still in remission after more than 18 months without maintenance therapy. Chromosomal analyses revealed Ph1 chromosomes in 100% of cells before the therapy, and a mosaic of Ph1-positive cells (74%) and negative cells (26%) after the therapy. Leukocyte alkaline phosphatase scores were low before the therapy and became normal after the therapy. MCNU seems to be an effective drug for treating CML producing prolonged remission with reappearance of Ph1-negative normal clones in the present case.