
 
        
         
		DETECTABLE MINIMAL MEASURABLE DISEASE BY FLOW CYTOMETRY BEFORE ALLOGENEIC  
 TRANSPLANTATION IS A FACTOR OF POOR OUTCOMES IN ACUTE MYELOID LEUKEMIA  
    
 Claudia Núnez-Torrón Stock, Valentin García Gutiérrez, Adolfo Sáez Marín, Alejandro Luna de Abia,  
 Anabelle  Chinea,  Juan Marquet Palomares,  Miguel Piris  Villaespesa, Jesus Villarrubia,  Gemma  
 Moreno Munoz, Francisco Javier López Jiménez and Pilar Herrera Puente   
   
 Hospital Ramón y Cajal, Madrid, Spain  
    
 Introduction: in acute myeloid leukemia (AML) positive measurable residual disease (MRD) by flow  
 cytometry prior  to hematopoietic  stem cell  transplantation (HSCT) predicts poor  outcomes  and is  
 uncertain if  reduced intensive  conditioning (RIC)  regimens  could reverse  bad prognosis  in this  
 subgroup.  
 Methods: We performed a single-center retrospective analysis of 63 patients with AML transplanted  
 in  our  center  between  2013-2019. All patients  reached complete  remission  with  or  without  
 hematologic recovery before  HSCT and we  divide  our  cohort  in two groups according to MRD  
 measured  by  flow  cytometry:  1)  MRD  ≤0,1%  (MRD-) 2) MRD  >  0,1%  (MRD+).We calculate overall  
 survival (OS) and relapse-free  survival (RFS) after HSCT  with  Kaplan-Meier  method and  Cox  
 regression method to assess risk.  
 Results: baseline characteristics of the sample are represented in Table 1. The median follow-up was  
 16 months  (mo)  (0-67). In our  cohort the median RFS was  not reached  (NR)  and OS  was  47mo.  
 According to MRD the median RFS was NR in group 1 and 9mo in group 2 with a hazard ratio (HR) of  
 2.4  (CI  95%  0.95-4.4)  and the  OS  was  NR  vs  20mo with a  HR  of 1.6 (CI  95%  0.7-3.9) (Figure  1).  
 Comparing myeloablative conditioning (MA) with RIC, in group 1 we found a median RFS NR with MA  
 vs 11mo with RIC (HR 2.2 (CI 95% 0.8-5.7) and a median OS NR vs 47mo (HR 1.7 (CI 0.6-4.7). In group  
 2 the median RFS was 16mo vs 6mo (HR 2.5 (CI 95% 0.6-9.6) and median OS was NR vs 9mo (HR 5.6  
 (CI 95% 1.2-26) respectively.  
 According to European LeukemiaNet (ELN) risk classification the median OS in group 1 was NR vs NR  
 vs 47mo for favorable, intermediate and adverse risk subgroups and in group 2 was NR vs 17mo vs  
 11mo (HR 1.5 (CI 95% 0.8-2.5). The median RFS in group 1 was NR for all risk groups and in group 2  
 was NR vs 11mo vs 7mo for favorable, intermediate and adverse risk (HR 1.7 (CI 95% 1.02-3.9).In the  
 multivariate analysis  including baseline  characteristics  and MRD status there  was  no independent  
 risk factor for OS and MRD+ prior to HSCT was the only significant factor for RFS (HR 5.1 CI 95% 1.2- 
 23.6).  
 Conclusions: in our cohort MRD+ prior to HSCT predicts higher risk of relapse and death, especially in  
 intermediate and adverse risk of ELN and RIC regimens are insufficient to reverse bad prognosis in  
 this subgroup.  
 SCIENTIFIC  
 PROGRAMME 
 RARE SUBSETS OF  
 ACUTE LEUKAEMIA 
 TRACKING LEUKAEMIC  
 STEM CELLS (LSCs) 
 ROUTINE DIAGNOSIS  
 GENE EXPRESSION  
 AND MUTATIONAL  
 PROFILING 
 DEBATE 1 – ALL  
 PATIENTS WITH  
 INTERMEDIATE-RISK  
 AML MUST BE  
 TRANSPLANTED 
 INTERACTIVE   
 CASES 1 – MUTATION-BASED  
 THERAPY   
 OFF-LABEL 
 ROUNDTABLE –  
 SHOULD WE REALLY  
 USE NEW TARGETED  
 INHIBITORS AS SINGLE  
 AGENTS ? 
 ADDITION OF A 3RD  
 AGENT TO FRONTLINE  
 7+3 
 ROUNDTABLE –  
 CURATIVE OPTIONS  
 FOR OLDER AML 
 INTERACTIVE CASES 2 
 DEBATE 2 - BEST  
 TREATMENT FOR  
 NPM1-MUTATED AML IN  
 THE NEXT FUTURE ? 
 ALLOGENEIC  
 HAEMATOPOIETIC  
 STEM CELL  
 TRANSPLANTATION  
 (HSCT) 
 IMMUNOTHERAPY FOR  
 ACUTE LEUKAEMIA 
 DEBATE 3 - T-ALL:  
 WHERE ARE WE GOING  
 NOW? 
 SELECTED ABSTRACTS  
 AND CLINICAL  
 CASES FOR AN ORAL  
 PRESENTATION 
 SELECTED ABSTRACTS  
 FOR A POSTER  
 PRESENTATION 
 DISCLOSURES