Role of pre-transplant MRD level detected by flow cytometry in recipients of allogeneic stem cell transplantation with AML

OBJECTIVES AND METHODS: We analyzed the impact of pre-transplant MRD level in bone marrow measured by flow cytometry using "different from normal" method on outcomes for 189 AML patients (108 males; median age, 58 (21-80) years). All patients were subdivided into negative (n=96), "low" (0.1-0.5%, n=32) and "high" MRD (>0.5%, n=61) groups.

RESULTS: In multivariate analysis, the hazard ratios for "high" and "low" MRD levels related to MRD negativity were 7.9 (95% CI 3.5-18.1, p<0.001) and 5.4 (95% CI 2.1-14, p=0.0058) for relapse; 2.3 (95% CI 1.3-4.1, p=0.006) and 1.6 (95% CI 0.82-3.3, p=0.16) for OS; 2.8 (95% CI 1.7-4.7, p<0.001) and 2.2 (95% CI 1.1-4.2, p=0.02) for LFS, respectively. We found no significant impact of "low" MRD level on relapses (0.68, 95% CI 0.33-1.4, p=0.30), OS (0.72, 95% CI: 0.36-1.5, p=0.36) and LFS (0.79, 95% CI: 0.42-1.5, p=0.46) related to "high" MRD group.

CONCLUSIONS: Presence of detectable MRD was indicative for a high relapse risk, low LFS and OS. "Low" MRD level showed no significant impact on relapse, LFS and OS related to "high" MRD group.