Intensive maintenance therapy improves survival in adult acute nonlymphocytic leukemia: an eight-year follow-up

Although a large majority of adult patients with acute nonlymphocytic leukemia (ANLL) achieve complete remission with present day therapy, eventual relapse and death is the rule rather than the exception. In an effort to improve survival, an intensive maintenance therapy approach was evaluated in 86 patients with ANLL in remission (median age 47 years) entered on study from 1978 to 1982. One-third of patients in remission were randomized to chemotherapy alone, one-third to splenectomy in addition to chemotherapy, and one-third to immunotherapy in addition to chemotherapy. The chemotherapy, which was identical in the three arms of the study, consisted of cytosine arabinoside plus 6-thioguanine, each given at a dose of 100 mg/m2 every 12 hr for a variable number of days, to render the patient's marrow aplastic, and was repeated every three months for three or more years. Median remission duration for patients in all three study groups is 21 months, with 58% of patients remaining in remission at one year. Twenty-five per cent of complete remitters are in continuous complete remission five to nine years after beginning intensive maintenance therapy. The median duration of survival of remitters is 25 months. Neither splenectomy nor immunotherapy had additional impact on remission duration or survival. In comparison with the results of earlier studies at the same institution in patients with similar characteristics, using identical remission induction therapy but less intensive maintenance therapy (46 patients), there has been a significant improvement in remission duration (p less than 0.001) and a significant impact on survival (p = 0.03) attributable to the use of intensive maintenance therapy. Intensive maintenance therapy may cure some adult patients with ANLL.