Reduced intensity conditioning prior to allogeneic stem cell transplantation for patients with acute myeloblastic leukemia as a first‐line treatment

Abstract

BACKGROUND: Thirty‐three patients (median age 52; range 26–60) with acute myeloblastic leukemia (AML) were included in a pilot study of allogeneic stem cell transplantation (Allo‐SCT) following a reduced‐intensity conditioning (RIC).METHODS: Patients achieving first complete remission (CR1) were selected for their high‐risk clinical and/or leukemic features. All patients received two courses of consolidation chemotherapy including one high‐dose cytarabine course. Among them, 13 patients in addition received a high‐dose melphalan course followed by autologous SCT. Then, all patients received an RIC Allo‐SCT combining fludarabine, busulfan, and antithymocyte globulin.RESULTS: All patients engrafted had cumulative incidences of Gluksberg System Grade 2 acute and chronic graft‐versus‐host‐disease (GVHD) of 24 (9–39%) and 64 (48–80%), respectively. Three patients died from nonrelapse causes (NRD) (cumulative incidence: 9%, 95% confidence interval (CI): 0‐19) and 6 relapsed (cumulative incidence: 18%, 95% CI: 5–31). With a median follow‐up of 18 months (range 7–52) after Allo‐SCT, 26 patients are alive, of whom 24 remained in CR1 for a 2‐year overall survival and leukemia‐free survival (LFS) probabilities of 79 (range 61–90%) and 76 (range 59–87%), respectively. In a ‘landmark’ analysis starting on Day 100, the occurrence of chronic GVHD was associated with a lower relapse rate (0% vs. 44%: P = 0.007) and improved outcome (LFS; 95% vs. 53%, P = 0.007; overall survival, 95% vs. 61%, P = 0.05).CONCLUSIONS: We conclude that the sequential combination of intensive chemotherapy and allogeneic immunotherapy might offer relatively low NRD and leukemia relapse rates even in high‐risk patients. Cancer 2005. © 2005 American Cancer Society.