Role of maintenance chemotherapy in acute promyelocytic leukemia.

The effect of maintenance chemotherapy on remission duration was analyzed in 39 of 70 patients (56%) with acute promyelocytic leukemia (APL) who achieved complete remission on induction chemotherapy. Overall, the median remission duration was 26 months, with a 3-year remission rate of 42%. The 3-year remission rate was significantly higher in patients who received 6-mercaptopurine and methotrexate (POMP) during maintenance, compared with those who did not (56% versus 30%; P less than 0.01), and in patients who received long-term maintenance therapy (P less than 0.01). A multivariate regression analysis selected maintenance therapy with POMP to be the only statistically significant factor associated with long-term remission duration. The type of maintenance chemotherapy is important in overall prognosis of patients with APL, and should be investigated further.