Abstract
Abstract 3550
Background and Objectives Relapse after allogeneic hematopoietic stem cell transplantation (allo-HSCT) is still a major cause for the failure in treatment. It has been shown that there was a closely relationship between the level of minimal residual disease (MRD) and relapse in acute leukemia (AL) patients; However, the application of multiparameter flow cytometry (MFC) for MRD assessment in high risk patients with AL who undergoing allo-HSCT is little concerned. We retrospectively analysed the serial results of MRD of 52 high risk patients with AL to evaluates the prognostic value of MRD pre and post transplantation.
52 patients with a median age of 29 (13–55) years have been enrolled on this study in our hospital from January 2003 to September 2008.Diagnoses included AML (n=27) and ALL (n=25). The patients had been analyzed retrospectively the level of MRD pre-(day-30)and post-HSCT(day+30 and +100)using three color FCM with CD45/SSC gating and a comprehensive panel of monoclonal antibodies, at least one leukemia associated aberrant immunophenotype (LAIP) at diagnosis. According to the cutoff value 0.1%, two groups were defined based on the level of patient's MRD level< (low level group) or >= (high level group) 0.1%.
The median follow up were 23 (range 1–60) months. 1.MRD level declines significantly (P=0.03) post transplant. 2. There were significantly difference between low level and high level group at day -30 before transplant with 3 years event free survival(EFS) and relapse free survival (RFS)(77.4% and 88.4% vs. 22.3% and 25.7%, p=0.007and p=0.001 respectively). 3. Concerning about MRD at day +100 after transplant, outcome was significantly better among patients with low level MRD group versus high group including 3 years OS,EFS and RFS(84.2%, 79.5% and 89.5% versus 22.9%, 9.5% and 11.2%).4. The median time from high level MRD detected first time to clinical relapse was 2.5 (range from 1 to 33) months in relapsed patients. 5. The patients with cGVHD had better 3 years OS and EFS than that without cGVHD(86.3% vs 12.1%, p<0.001 and 65.3% vs.14.8%, p< 0.001 respectively). 6. Multivariate Cox regression analysis revealed that MRD on day +100 as well as chronic GVHD were independent parameters predictive for OS and EFS.
MRD monitoring pre- and post-transplant is an important tool to predict the outcome of transplantation for patients with high risk AL. The MRD check point at day +100 should be considered crucial for subsequent therapeutic decisions after allogeneic transplantation.
No relevant conflicts of interest to declare.
Author notes
Asterisk with author names denotes non-ASH members.
