Single-agent therapy with oral mercaptopurine for nonlymphoid blast crisis of chronic myeloid leukemia

Currently, no effective treatment is available for the nonlymphoid blast crisis (BC) of chronic myeloid leukemia (CML) and because of this the prognosis for such patients remains invariably poor. In an attempt to determine the results provided by palliative treatment with oral 6-mercaptopurine (6-MP) in the above hematological condition, 30 such patients were analyzed for hospital stay, days of intravenous (i.v.) antibiotics, transfusion requirements, response rate, and survival. Thirty patients with nonlymphoid BC matched for their initial characteristics and treated with different i.v. regimens were used for comparison purposes. Patients managed with 6-MP spent less days in hospital (median: 9, range: 0-46 vs median: 42, range: 5-140; P<0.0001), needed antibiotics for less days (median: 0. range: 0-46 vs median: 20, range: 0-57; P<0.0001), and received less platelet transfusions (median: 0, range: 0-20 vs median: 6, range: 0-63; P=0.004) than those treated with i.v. chemotherapy. Although no complete or partial remission was achieved by patients receiving 6-MP vs six in the i.v. chemotherapy group, no significant difference was observed when the survival of both groups was compared (median: 4.7 months, range: 0.1-22.7 vs median: 3.8 months, range: 0.2-12, respectively). These results indicate that 6-MP therapy constitutes a good palliative treatment for patients with nonlymphoid BC of CML. However, new treatment strategies for this hematological condition are required.