A prospective evaluation of the roles of allogeneic marrow transplantation and low-dose monthly maintenance chemotherapy in the treatment of adult acute myelogenous leukemia (AML): a Southwest Oncology Group study.

Between February 1982 and December 1986, the Southwest Oncology Group conducted a prospective study in patients with newly diagnosed acute myeloid leukemia (AML) with two objectives: to evaluate the role of allogeneic marrow transplantation for patients in first remission, and to evaluate the role of low-dose monthly maintenance therapy in those patients not transplanted in first remission. Among 522 evaluable patients, 295 (57%) achieved complete remission (CR), including 70% of patients age 49 or less. Twenty-four patients (15%) age 49 or less in CR were not HLA-typed, mostly because of financial constraints. HLA-identical donors were found for 39% of patients, of whom two-thirds were transplanted in first CR. The 5-year disease-free survival among those transplanted in first CR, those with donors not transplanted in first CR, and those less than age 50 without donors was 41, 42, and 29%, respectively (P = 0.60). A total of 150 eligible patients were randomized to receive late intensification alone or late intensification plus monthly maintenance. In multivariate analyses, treatment with maintenance was associated with prolonged disease-free survival (P = 0.028), but not improved overall survival (P = 0.27). Factors associated with improved overall survival included younger age, lower white blood count (WBC) at diagnosis, having leukemia of M3 morphology, and being of white race. In this study, a diagnosis of M3 AML was particularly favorable, with disease-free and overall survivals of 75 and 56%, respectively, at 7 years.