AL-06. Impact of pre allo-HSCT MRD status on relapse prophylaxis in high-risk acute myeloid leukemia in children
Zhemal Z. Rakhmanova, Svetlana V. Razumova, Olesya V. Paina, Polina V. Kozhokar, Anastasia S. Frolova, Liubov A. Tsvetkova, Elena V. Babenko, Tatyana L. Gindina, Alexandr L. Alyanskiy, Ildar M. Barkhatov, Elena V. Semenova, Ludmila S. Zubarovskaya
RM Gorbacheva Research Institute, Pavlov University, St. Petersburg, Russia
Dr. Zhemal Z. Rakhmanova, phone +7 (999) 206-12-76, e-mail: firstname.lastname@example.org
Relapse of acute myeloid leukemia (AML) remains one of the main causes of mortality and, therefore, lower long-term survival in children after allogeneic hematopoietic stem cell transplantation (allo-HSCT). The relapse incidence reaches 40% depending on cytogenetic and molecular biological risk factors, the remission status at the time of allo-HSCT. The role of the level of minimal residual disease (MRD) is being studied. It is known that MRD(+) status after allo-HSCT requires preventive therapy. The predictive value of MRD (±) before allo-HSCT in children with AML in the need for prophylactic therapy after allo-HSCT has not been determined.
To study the effect of prophylactic therapy after allo-HSCT on the overall and relapse free survival of children with high risk AML, depending on the MRD (±) status before allo-HSCT. Patients and methods. Data of 57 children with high risk AML who underwent allo-HSCT at R. M. Gorbacheva Research Institute between 2003 and 2020, age – from 0.5 to 18 years (the median age – 9 years) were analyzed. The retrospective analysis included patients (pts) who were in MRD(+) or MRD(-) in AML remission at the time of allo-HSCT, and during the entire follow-up period after transplantation they had MRD-negative status and complete donor chimerism. Patients with primary graft failure, relapse within 2 months after allo-HSCT, graft-versus-host disease (GVHD) 2-4 grade who didn’t allow performing prophylaxis of disease recurrence were excluded from analysis. Depending on the post-transplant prophylaxis, the pts were divided into 2 groups (Table 1).
Median follow-up of pts after allo-HSCT is 68 months. Overall survival (OS) in the group of children with AML who received post-transplant disease prophylaxis after allo-HSCT is 87.5%, in pts without prophylactic therapy – 90% (p=0.727). Relapse free survival (RFS) – 93.8% and 75.6%, respectively (p=0.130). Graft-versus-host/relapse-free-survival (GRFS) is 62% vs 56.1%, respectively (p=0.655). Post-transplant disease prophylaxis in MRD (+) pts prior to allo-HSCT increased RFS compared to MRD (+) pts before allo-HSCT who did not receive therapy – 100% vs 36.4%, respectively (p=0.008), which did not affect on OS – 87.5% vs 92%, respectively (p=0.268). In high risk AML pts with MRD(-) status before transplantation, post-transplant prophylaxis of relapse had no effect on OS – 88.7% vs 100% (p=0.083) and RFS – 87.5% vs 92 % (p=0.671), respectively.
Post-transplant prophylaxis of relapse is advisable in a cohort of children with high risk AML with MRD(+) status before allo-HSCT. An increase in OS in this group should be considered in the structure of other complications (GVHD, infections).
Allogeneic hematopoietic stem cell transplantation, acute myeloid leukemia, post-transplant prophylaxis of acute myeloid leukemia relapse, minimal residual disease.
Table 1. Characteristics of patients
* ptCy – post-transplant cyclophosphamide