scholarly journals Value of Immunohistochemistry-Based Direct Visualization for Localization, Lineage Determination and Monitoring of IDH1 p.R132H Mutant Clones in AML

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 1726-1726
Author(s):  
Habibe Kurt ◽  
Carlos E. Bueso-Ramos ◽  
Joseph D Khoury ◽  
Mark Routbort ◽  
Rashmi Kanagal-Shamanna ◽  
...  

Abstract Background Isocitrate dehydrogenase 1 (IDH1) and IDH2 mutations are important prognostic biomarkers in acute myeloid leukemia (AML). Although the clinicopathologic correlates of IDH mutations have been extensively studied, the distribution of abnormal myeloid cells carrying these mutations has not been studied. Specific localization of cells carrying IDH mutations will be useful in further understanding the pathophysiology and post-treatment biology of IDH mutant cases of AML. This characterization is becoming particularly relevant for identification of minimal residual disease, especially for patients treated with novel IDHinhibitors. In this study, we characterized IDH1 p.R132H clones in bone marrow specimens involved by AML using a mutation specific antibody. Materials and Methods Bone marrow tissue sections (biopsy or clot specimens) from 32 AML cases with IDH1 p.R132H mutation were stained with IDH1 p.R132H-mutation specific antibody. These cases include 20 de novoAML and 12 cases of AML with myelodysplasia-related changes (AML-MRC). We also included 10 AML cases with wild-type IDH1 as a control. After confirmation of the positive IDH1 immunohistochemical (IHC) signal in the primary specimens, follow up bone marrow specimens (n=67) including (a) persistent disease, (b) minimal residual disease by flow cytometry, (3) complete remission by morphology and flow cytometry, but, positive for mutation by PCR, as well as (4) relapsed cases after complete remission were included in the study (in progress). We also included pre- and post-treatment (unresponsive with increasing blast counts, stable disease, persistent disease with decreasing blast counts, complete remission, and relapse) bone marrow specimens (n=72) from 16 patients treated with IDH inhibitors (in progress). Results All the IDH1 wild type AML cases were negative for IDH1 IHC stain showing 100% specificity. Positive signal was detected in all de novo AML and AML-MRC (allelic frequency ranges from 1.8% to 47% by PCR) except one AML case with 8.9% allele burden which was a limited sample; overall sensitivity was 96%. The IHC signal was detected in the cytoplasm of myelomonocytic cells, their precursors, and megakaryocytes. Erythroid precursors, lymphoid cells, endothelial cells, and osteoblasts were consistently negative. The signal intensity ranged from weak (n=10) to moderate (n=9), to strong (n=13). The positive cells predominantly showed an interstitial distribution in the bone marrow. In the de novo AML group, only the immature cells were positive in 100% of pre-treatment AML cases. However, both mature and immature cells were positive in 7/13 (54%) post-treatment AML cases (6 cases treated with hypomethylating agents). One case was transformed from MPN which also showed positivity in mature and immature cells. In two cases with complete morphologic remission and one case with minimal residual disease detected by flow cytometry, IHC signal was detected in both mature and immature cells; both patients relapsed in 8 and 11 months. In the AML-MRC group, both immature and mature cells were positive in 11/12 (92%) cases of which 2 were not previously treated indicating the possibility that IDH1 mutation is an early event. Since the remaining 9 patients were treated with hypomethylating agents, the positivity of both mature and immature cells as a result of maturation effect versus an early event cannot be assessed. Additional studies for follow-up AML cases, including cases on an IDH inhibitor clinical trial are in progress. Conclusions Our preliminary data indicate that IDH1 IHC is a highly specific and sensitive tool to detect IDH1 R132H mutated cases and can be used as a primary method to localize the population of mutation-bearing cells in the bone marrow. IHC also allows determination of whether the IDH1 mutation in the post-treatment setting is arising from immature or mature cells. IHC provides an opportunity to understand the difference between these two populations and, based on characterization of cell type and distribution, may be helpful to predict whether the risk of relapse is high. Disclosures DiNardo: Agios: Other: advisory board, Research Funding; Novartis: Other: advisory board, Research Funding; Daiichi Sankyo: Other: advisory board, Research Funding; Celgene: Research Funding; Abbvie: Research Funding.

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 1015-1015
Author(s):  
Pramod Pinnamaneni ◽  
Jeffrey L. Jorgensen ◽  
Hagop M. Kantarjian ◽  
Elias Jabbour ◽  
Sherry R. Pierce ◽  
...  

Abstract Purpose – To determine the value of Minimal Residual Disease (MRD) assessed by Multi-parameter Flow Cytometry (MFC) after achieving initial response to therapy, in predicting outcome in patients with acute myeloid leukemia (AML) Methods – We investigated the predictive value of MRD assessment by MFC in 191 patients with newly diagnosed AML treated between February 2010 and April 2014 at our institution who had available MRD assessment. MRD by MFC was assessed using an 8-color panel containing 19 distinct markers, on bone marrow specimens obtained at the time of achievement of CR and at approximately 30 days and 90 days after achieving CR. Residual leukemic blasts were identified based on phenotypic differences from normal myelomonocytic precursors. Sensitivity was estimated at 0.1% in most cases, with maximum achievable sensitivity of 0.01%, depending on the leukemic phenotype. Results – Of the 191 patients, 167 (87%) achieved complete remission (CR) or CR without platelet recovery (CRp). Their median age was 58 years (Range, 17-85). 84 (44%) were older than 60 years. Median WBC at presentation was 3.2 x 109/L(Range, 0.5-100.2 x 109/L) and median bone marrow blast percentage was 43% (Range, 11-96%). Cytogenetics was favorable risk in 4 (2%), intermediate risk in130 (68%) and adverse risk in 57 (30%). Treatment included cytarabine plus anthracycline in 170 (89%) and hypomethylating agents-based strategies in 21 (11%). 48 patients had available samples at 30 days post CR and 32 (67%) became MRD negative. Achieving MRD negative status was associated with a statistically significant improvement in CR duration (p=0.02) and overall survival (OS) (p=0.0005). 56 patients were evaluated for MRD status at 90 days and 45 (80%) were negative. Again, achieving MRD negative status was associated with a significant improvement in CR duration (p=0.002) and OS (p=0.0009). Conclusion – Achieving MRD negative status by MFC at 30 and 90 days post CR is associated with an improved outcome in patients with AML Figure 1 Figure 1. Figure 2 Figure 2. Disclosures No relevant conflicts of interest to declare.


2003 ◽  
Vol 21 (20) ◽  
pp. 3853-3858 ◽  
Author(s):  
Irene Y. Cheung ◽  
M. Serena Lo Piccolo ◽  
Brian H. Kushner ◽  
Nai-Kong V. Cheung

Purpose: A promising treatment strategy for stage 4 neuroblastoma patients is the repeated application of anti-GD2 immunotherapy after activating myeloid effectors with granulocyte-macrophage colony-stimulating factor (GM-CSF). To use early marrow response as a prognostic marker is particularly relevant for patients not likely to benefit from this therapy. Patients and Methods: Eighty-six stage 4 neuroblastoma patients older than 1 year at diagnosis were classified in four clinical groups on protocol entry: complete remission or very good partial remission (n = 33), primary refractory (n = 33), secondary refractory (n = 10), and progressive disease (n = 10). Bone marrow samples collected before and following treatment were assayed for GD2 synthase mRNA by real-time reverse transcriptase polymerase chain reaction. Response and survival analyses were performed on posttreatment samples before the third cycle at 1.8 months from protocol entry. Results: GD2 synthase mRNA was evident in pretreatment marrow samples of the four clinical groups (42%, 52%, 60%, and 80% of samples, respectively), with median transcript level of 10.0, 16.6, 26.5, and 87.2, respectively. This marker became negative following antibody plus GM-CSF in 77% of complete remission or very good partial remission, 45% of primary refractory, 25% of secondary refractory, and 0% of progressive disease group. Progression-free survival was statistically different between responder and nonresponder groups (P < .0001). Among patients with minimal residual disease, molecular responders had a significantly lower risk of disease progression at a median follow-up of 29.8 months (P = .0001). Conclusion: GD2 synthase mRNA is a sensitive response marker of neuroblastoma in the bone marrow. It is particularly useful for minimal residual disease evaluation and may potentially be useful as an early predictor of resistance to antibody plus GM-CSF immunotherapy.


Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 4626-4626
Author(s):  
Yuankai Shi ◽  
Sheng Yang ◽  
Xiaohong Han ◽  
Peng Liu ◽  
Xiaohui He ◽  
...  

Abstract Purpose: High-dose chemotherapy (HDC) supported by APBSCT has been shown to be superior to standard therapy in NHL. However, many patients relapse due to minimal residual disease (MRD) in vivo or in the graft. Rituximab has the potential to clear both blood and bone marrow of malignant CD20+ cells, prompting this multicenter trial of in vivo purging with rituximab and HDC with APBSCT in China. Methods: Cyclophosphamide 4g/m2 was used as the mobilization regimen, CY/TBI, BEAM or CBV could be used as HDC at the discretion of the institution. Four infusions of rituximab (375 mg/m2) were given: one day before mobilization, one day before harvesting, one day before transplantation and on day 8 after transplantation. BCL-2/Ig-H translocation was measured as a marker of minimal residual disease in blood or bone marrow before mobilization and during transplantation using real-time quantitative PCR. Results: Thirty-one patients from 12 centers with histologically proven CD20+ NHL (28 aggressive, 3 indolent NHL) were enrolled. Twenty-four patients were previously untreated, and 7 patients had relapsed disease. Median yields of CD34+ cells and mononuclear cells were 5.9×106/kg and 4.4×108 /kg respectively. Median time to recovery of WBC >1.5×109/L, ANC >0.5×109/L and platelets >20×109/L after APBSCT was 10 days in each case. Median time to platelet recovery >50×109/L was 13 days. Generally, this therapeutic strategy was well tolerated with few side effects attribute to rituximab. All patients achieved a complete remission after APBSCT. At a median-follow-up of 12 months, overall survival and progression-free survival (PFS) are 87% and 73% respectively for all patients. In patients with aggressive NHL, overall survival and PFS are 85% and 73% respectively and in indolent NHL are 100% and 67% respectively. PFS and overall survival were slightly higher in previously untreated compared with relapsed patients (88% vs. 83% for PFS, 73% vs. 69% for overall survival). One of five 5 patients who were initially found to be PCR-positive and achieved PCR-negative status subsequently experienced progression accompanied by a return to PCR positivity. The remaining four patients are still in complete remission and are PCR negative. Conclusion: These results suggest that the regimen of rituximab combined with HDCT and APBSCT is effective and well tolerated for the treatment of patients with NHL.


Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 2362-2362
Author(s):  
Denis Guyotat ◽  
Daniela Olaru ◽  
Pascale Flandrin ◽  
Nathalie Nadal ◽  
Lydia Campos

Abstract Flow cytometry analysis of minimal residual disease (MRD) in acute myeloid leukemia (AML) is based on the detection of aberrant phenotypes responsible for the relapse. Until now, all studies were performed by 3 or 4 color immunostaining, allowing the identification of LAIP in 80% of cases. Moreover, no data is available regarding the existence of such phenotypes in regenerating bone marrow. The new generation of cytometers allows the study of 8 parameters that permit a better distinction of malignant from normal phenotypes. In our study we analyzed 20 bone marrow samples from allogeneic donors, 20 ALL regenerating bone marrows after chemotherapy and 53 AML samples at diagnosis. Multiparameter 4 colour and 6 colour flow cytometry was used in order to define antigen combinations which are totally absent or present at very minimal levels in normal and regenerating hematopoiesis. “Blast cells” were gated according to CD45/SSC properties.For the first time we describe by 6 color flow cytometry 47 phenotypes totally absent from “blasts” gate in all normal bone marrow (ex: CD34+DR−117+33−15+, CD34+38+33−56+19−, CD14−DR+4+11B+64+). Another 41 phenotypes were identified as presents at a frequency < 0,05% of total cells (ex: CD34+DR+117−33+15+, CD14−DR+4+11B+64−, CD34+65−56+4−16−). There was no significant difference between normal and regenerating marrows. The 4 color panel of moAbs allowed us to identify only 30 phenotypes presents at a frequency < 0,05% of total cells (ex: CD34+33−13+, CD34+117+11b+, CD34+DR−13+). 53 AML at diagnosis were studied using 6 color immunophenotyping and 58 % of phenotypes described as aberrant or infrequent in normal myeloid hematopoiesis were found in at least one AML at diagnosis in more than 1% of total cells. All AML cases show at least one LAIP but frequently we observed more than one LAIP blast subpopulation in the same sample. Some examples of LAIP observed are CD34+ 38+ 33+ 56+ 19−, CD34+ 38+ 33+ 56− 19+, CD34− DR− 117+ 33+ 15−. In conclusion our results shows that (1) the ability to clearly distinguish leukemic from the healthy cells is considerably increased by 6 color approach (8 parameters analyzed) than 4 color. (2) Furthermore that these aberrant or infrequent phenotypes in normal or regenerating bone marrow samples are identified in AML cases and can be utilized in AML minimal residual disease study. (3) Knowledge of the expression of different markers in normal hematopoietic development provides a frame of reference for identification of abnormal differentiation patterns.


Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 1717-1717
Author(s):  
Maya Danielle Hughes ◽  
Rong Zeng ◽  
Kristen L. Miller ◽  
Soheil Meshinchi

Abstract Abstract 1717 FLT3 internal tandem duplication (FLT3/ITD) is a somatic mutation that is associated with therapy resistance in acute myeloid leukemia (AML). Early data demonstrated low sensitivity for this assay, thus limiting its utility to the evaluation of diagnostic specimens, and precluding its utility in remission samples. We inquired whether the standard FLT3/ITD assay can be modified to enable its utility to detect presence of residual disease in remission specimens. Enhanced FLT3/ITD assay sensitivity was accomplished by altering annealing temperature, increasing the number of cycles as well as amount and concentration of the product that was subjected to capillary electropheresis. To assess the sensitivity of the enhanced assay, FLT3/ITD positive cells M4V11 were serially diluted in a population of ITD negative cells (HL60). The concentration of M4V11 cells in each sample ranged from 10% to 0.0001%. PCR product was subjected to capillary electropheresis and the appropriate region of the electropherogram was examined for the presence of the appropriate mutant product length. Appropriate FLT3/ITD signal was detected in dilutions down to 0.01%, validating our ability to detect extremely low levels of FLT3/ITD. We subsequently examined the remission marrows from patients with a history of FLT3/ITD who had undergone stem cell transplantation. Available bone marrow specimens (N = 51) from patients who underwent stem cell transplantation for FLT3/ITD-positive AML were analyzed and the result was correlated with the available standard PCR as well as the available MRD assessment by muti-dimensional flow cytometry; samples negative for FLT3/ITD by standard assay (N=11) were then subjected to the enhanced PCR methodology. Available ITD length for each patient was used for examination of the appropriate region of the electropherogram in each case. Of the available 51 bone marrow specimens analyzed, 23 specimens had FLT3/ITD detectable by standard PCR protocol. Using our modified PCR method and capillary electrophoresis, an additional 13 specimens had identifiable FLT3/ITD. In 6/11 patients, where initial FLT3/ITD was negative by standard methodology, enhanced assay identified FLT3/ITD signal. In each case, detection of FLT3/ITD by the enhanced assay was followed by morphologic or immunophenotypic emergence of disease, prompting therapeutic intervention. We further evaluated the ability to detect FLT3/ITD in patients with minimal residual disease by flow cytometry. 33 of the bone marrow specimens analyzed had a less than 5% abnormal blast population as detectable via flow cytometry. Among these samples, 7 had FLT3/ITD detectable using standard detection techniques. An additional 11 samples had detectable FLT3/ITD when our modified protocol was employed. Of the specimens that had less than 1% abnormal blast population as detectable via flow cytometry (N = 27), 4 had FLT3/ITD detectable using the standard detection assay; when our modified protocol was employed, an additional 6 samples had detectable FLT3/ITD. 17 bone marrow specimens had no abnormal blast cells detectable via flow cytometry; of these samples 1 had detectable FLT3/ITD using the standard detection assay, while an additional 3 had detectable FLT3/ITD using our modified assay. In four patients, FLT3/ITD was detected in bone marrow specimens found to have flow cytometric MRD of 0% (N=2), 0.1% (N=1) and 0.4% (N=1). In two patients with no detectable disease by MDF, both had emergence of morphologic (60% blast) or immunophenotypic disease by MDF (1.1%) within 4–6 weeks of detection of FLT3/ITD by enhanced assay. In this study, we demonstrate that simple modifications to the FLT3/ITD genotyping assay significantly increases its sensitivity and provides a highly sensitive and very specific assay for identifying this disease associated mutation in remission specimens. The enhanced assay can be incorporated into the standard evaluation of remission status for patients with FLT3/ITD. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 3416-3416 ◽  
Author(s):  
Andy C Rawstron ◽  
Walter Gregory ◽  
Ruth M de Tute ◽  
Faith E Davies ◽  
Susan E Bell ◽  
...  

Abstract Minimal residual disease (MRD), as assessed by flow cytometry is a powerful predictor of outcome in multiple myeloma (MM). We and others have previously demonstrated that such analyses are informative in patients treated with autologous stem cell transplant (ASCT) and non-transplant regimens. It predicts outcome in patients in conventional CR and is applicable to patients with standard and adverse risk cytogenetics. As a consequence MRD assessment is under consideration as a surrogate endpoint for clinical trials. This is urgently needed in MM as >5yrs follow-up is typically required to demonstrate survival differences in trials of upfront therapy. If surrogate end points are to be used in clinical trials it is essential that a reproducible effect is demonstrable using multivariate models. Previous studies have confirmed the effect of MRD on PFS but a consistent effect on OS has been not been definitively shown. This may in part be due to the availability of effective salvage therapy but it is also possible that the traditional threshold of 10-4 for analysis and the categorization of patients as MRD-postive or negative is suboptimal. Flow cytometry does provide a quantitative assessment of residual tumour over a large range and the degree of tumour depletion may be more informative than a positive-negative analysis. 397 patients from the MRC Myeloma IX trial were included in this analysis. Patients were randomly assigned to CTD (cyclophosphamide, thalidomide, and dexamethasone) or CVAD (cyclophosphamide, vincristine, doxorubicin, and dexamethasone) induction for 4-6 cycles followed by standard high-dose melphalan (HDM) ASCT. BM aspirates were obtained at day 100 for MRD analysis. 500,000 cells were evaluated with six-colour antibody combinations including CD138/CD38/CD45/CD19 with CD56/CD27 in all cases and CD81/CD117 in additional cases as required. PFS and OS data analysis was landmarked from the date of the MRD assesment. Of the 397 patients with MRD data available at day 100 after ASCT, 247/397 (62.2%) achieved <0.01% MRD. The level of residual disease varied across four logs in MRD-positive patients (0.01-<0.1% in 49/397, 0.1-<1% in 72/397, 1-<10% in 26/397 and ≥10% in 3/397). The PFS and OS for individuals with ≥1% residual disease was comparable to individuals with a PR/MR/SD confirming that MRD assessment is most relevant in CR. The level of MRD correlated with outcome. The median PFS for patients with ≥10% MRD at day 100 after ASCT was 0.8 years, with 1-<10% MRD was 1.7 years, with 0.1-<1% MRD was 1.9 years, with 0.01-<0.1% MRD was 2.7 years and for patients with <0.01% MRD was 3.1 years (P<0.001). The median OS for these groups was 1 yr, 4 yrs, 5.9 yrs, 6.8 yrs and for patients with <0.01% MRD not reached with >7.5 yrs median follow-up (P<0.001, see figure). A Cox proportional hazards model was used to further evaluate factors influencing outcome. B2M and MRD were log-transformed and along with age were considered as continuous variables. ISS, haemoglobin (<115g/l), platelets (<150x10^9/l) and cytogenetics were used as stratification factors. Cytogenetic groups were classified as unfavourable for patients with gain(1q), del(1p32), t(4;14), t(14;20), t(14;16), and del(17p), or favourable for hyperdiploidy, t(11;14) and t(6;14), or unknown/inevaluable. MRD assessment (χ2 11.8, P=0.0006) and cytogenetics (χ2 35.5, P=<0.0001) were the only factors that retained significance in this multivariate model. Conventional categorical response, ISS and B2M were not predictive of OS (p=0.99, 0.16 and 0.56 respectively). We would conclude that MRD quantitation is more informative than a positive or negative categorization with a 10-4 threshold and independently predicts outcome. In this analysis we were able to demonstrate an approximate 1 year survival benefit per log tumour depletion. A lower cutpoint for predicting improved outcome was not reached and more sensitive assays will likely improve outcome prediction further. This data strongly supports the role of MRD assessment as a surrogate endpoint in clinical trials. Figure 1 Figure 1. Disclosures Rawstron: Celgene: Consultancy; BD Biosciences: Consultancy, Intrasure Patents & Royalties. Gregory:Celgene: Consultancy. Davies:Celgene: Consultancy, Honoraria; Janssen-Cilag: Consultancy, Honoraria; Novartis: Consultancy. Cook:Celgene: Consultancy, Honoraria, Research Funding; Janssen-Cilag: Consultancy, Honoraria. Jackson:Celgene: Honoraria; Janssen-Cilag: Honoraria. Morgan:Celgene: Consultancy, Honoraria, Research Funding; Janssen-Cilag: Consultancy, Honoraria; Merck: Consultancy, Honoraria; Novartis: Consultancy, Honoraria. Owen:Celgene: Consultancy, Honoraria, Research Funding.


Hematology ◽  
2021 ◽  
Vol 2021 (1) ◽  
pp. 37-45
Author(s):  
Andrew J. Yee ◽  
Noopur Raje

Abstract Improvements in multiple myeloma therapy have led to deeper responses that are beyond the limit of detection by historical immunohistochemistry and conventional flow cytometry in bone marrow samples. In parallel, more sensitive techniques for assessing minimal residual disease (MRD) through next-generation flow cytometry and sequencing have been developed and are now routinely available. Deep responses when measured by these assays correspond with improved outcomes and survival. We review the data supporting MRD testing as well as its limitations and how it may fit in with current and future clinical practice.


Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 22-23
Author(s):  
Hiroyuki Takamatsu ◽  
Naoki Takezako ◽  
Takeshi Yoroidaka ◽  
Takeshi Yamashita ◽  
Ryoichi Murata ◽  
...  

Background: Autologous stem cell transplantation (ASCT) in conjunction with novel therapeutic drugs can dramatically improve response rates and the prognoses of patients with multiple myeloma (MM). However, most patients with MM ultimately relapse due to minimal residual disease (MRD). Next-generation multiparameter flow cytometry (MFC) (EuroFlow-NGF) and next-generation sequencing (NGS) are currently the standard methods to assess MRD. Aims: To compare the prognostic value of MRD detection in autografts and bone marrow (BM) cells using 8-color MFC (EuroFlow-NGF) and NGS (Adaptive Biotechnologies), and also MRD levels between fresh and cryopreserved autografts using NGF. Methods: The study enrolled 52 newly-diagnosed MM patients who underwent ASCT. The median age ASCT was 61 (range 41-69) years and included 29 males and 23 females at ISS I (n = 17), II (n = 23), and III (n = 12). Of these, 18 patients harbored high-risk chromosomal abnormalities including t(4;14) (n = 15), del17p and t(4;14) (n = 2), and complex (n = 1). Bortezomib-based chemotherapy was used for induction together with melphalan at 140 mg/m2 (n = 1) and 200 mg/m2 (n = 51) for conditioning before ASCT. 39 of 52 (75%) patients received maintenance therapy until progressive disease. The best responses achieved post-ASCT included 30 sCR, 4 CR, 15 VGPR, and 3 PR. Forty autografts, one from each MM patient, were analyzed using NGF and NGS protocols, and BM cells at pre/post-ASCT and autografts derived from 16 patients were analyzed using NGS. The EuroFlow-NGF method uses standard sample preparation; large numbers of cells are evaluated using an optimized 8-color antibody panel that facilitates accurate identification of discrimination between phenotypically aberrant plasma cells (aPCs) and their normal counterparts (Flores-Montero et al., Leukemia 2017). NGS-based MRD assessment was performed using Adaptive's standardized NGS-MRD Assay (Seattle, WA) (Martinez-Lopez et al., Blood 2014). Eight additional autografts were used to assess MRD in both fresh and cryopreserved samples by NGF. Results: MRD was evaluated in 48 of 52 autografts (92%) using NGF and in 44 of 52 autografts (85%) using NGS. We identified aPCs in autografts based on multivariate analysis of individual cell populations (e.g., CD56+, CD19−, CyIgκ+, and CD117+). As the results of NGF revealed a strong correlation with respect to MRD in fresh vs. thawed autografts (r = 0.999, P &lt; 0.0001), MRD was subsequently evaluated in thawed autografts. The sensitivity of NGF was 1 × 10−5-2 × 10−6; the sensitivity of NGS was 1 × 10−6. 28 of 48 (58%) of the autografts were MRD-positive by NGF; 30 of 44 (68%) of the autografts were MRD-positive by NGS. MRD levels in autografts using NGF and NGS correlated with one another (r = 0.69, P &lt; 0.0001; Fig. 1A). MRD negative in autografts by NGF cases (MRDNGF (-)) and MRDNGS (-) tended to show better progression-free survival (PFS) than MRDNGF (+) (P = 0.195) and MRDNGS (+) (P = 0.156), respectively. Furthermore, MRDNGS (-) showed significantly better overall survival (OS) than MRDNGS (+) (P = 0.03) (Fig. 1C) while MRDNGF (-) showed better OS than MRDNGF (+) (P = 0.09) (Fig. 1B). Our data revealed only a minimal correlation between MRD in the autografts (median 1.1 × 10−5,range 0-7.29 × 10−4) and in the BM cells at pre-ASCT (median 5.05 × 10−3,range 6 × 10−6-2.64 × 10−1; r = 0.09, P = 0.7) or at post-ASCT (median 2.11 × 10−4,range 0-9.09 × 10−3; r = 0.14, P = 0.6); MRD detected in the autografts was &gt; 27 times lower than that detected in pre-ASCT BM cells, and MRD detected in the post-ASCT BM cells was &gt; 3 times lower than that detected in pre-ASCT BM cells except for one case in which the ratio was increased by two times. Interestingly, while MRD was detected in all BM cells at pre-ASCT (n = 16), 4 of 16 (25%) of these autografts were MRDNGS-negative. The median of MRD levels of the 4 cases in pre-ASCT and post-ASCT BM cells were 4.14 × 10−4 (range 6-583 × 10−6)and 1.8 × 10−5 (range 0-27 × 10−6), respectively. Conclusion: Although EuroFlow-NGF is a rapid and accurate method for detecting MRD, NGS was more sensitive and provided greater prognostic value than EuroFlow-NGF. Disclosures Takamatsu: Adaptive Biotechnologies: Honoraria; Bristol-Myers Squibb: Honoraria, Research Funding; Janssen Pharmaceutical: Consultancy, Honoraria, Research Funding; Ono pharmaceutical: Honoraria, Research Funding; SRL: Consultancy, Research Funding. Takezako:Bristol-Myers Squibb: Honoraria, Research Funding; Takeda: Honoraria, Research Funding; Janssen: Research Funding; Abbvie: Research Funding. Nakao:Symbio: Consultancy; Kyowa Kirin: Honoraria; Alexion: Research Funding; Novartis: Honoraria.


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