Acute Myeloid Leukemia In CR1 Research Articles

Impact of measurable residual disease in combination with CD19 on postremission therapy choices for adult t(8;21) acute myeloid leukemia in first complete remission.

The post-remission therapy (PRT) choices for adult t(8;21) acute myeloid leukemia (AML) in first complete remission (CR1) need to be further explored. We aimed to investigate the impact of measurable residual disease (MRD) combined with CD19 on PRT choices for adult t(8;21) AML in CR1. A total of 150 t(8;21) AML patients were enrolled, including 67 underwent chemotherapy (CMT) and 83 allogeneic hematopoietic stem cell transplantation (allo-SCT) as PRT in CR1. Subgroup analyses were performed according to MRD level after three cycles of chemotherapy combined with CD19 expression. Multivariate analysis indicated MRDhigh after three courses of treatment (HR, 0.14 [95% CI, 0.03-0.66]; p = 0.013) and CD19 negativity (HR, 0.14 [95% CI, 0.02-0.96]; p = 0.045) were risk factors for relapse, while allo-SCT was protective factor for relapse (HR, 0.34 [95% CI, 0.15-0.75]; p = 0.008). Grouped by MRD after three courses of chemotherapy, allo-SCT had lower CIR (p < 0.001) and better OS (p = 0.003) than CMT for MRDhigh patients, CMT showed a higher CIR (35.99% vs. 15.34%, p = 0.100) but comparable OS (p = 0.588) than allo-SCT for MRDlow patients. Grouped by CD19 expression, allo-SCT demonstrated lower CIR (p < 0.001) and better OS (p = 0.002) than CMT for CD19- patients. CMT had a higher CIR (41.37% vs. 10.48%, p = 0.007) but comparable OS (p = 0.147) than allo-SCT for CD19+ patients. Grouped by MRD combined with CD19, MRDhigh /CD19+ subsets were identified out of CD19+ patients benefiting from allo-SCT with lower CIR (p = 0.002) and superior OS (p = 0.020) than CMT. CMT preserved comparable CIR (p = 0.939) and OS (p = 0.658) with allo-SCT for MRDlow /CD19+ patients. MRDlow /CD19- subsets were also identified from MRDlow patients requiring allo-SCT with lower CIR (p < 0.001) and superior OS (p = 0.008) than CMT. Allo-SCT maintained lower CIR (p < 0.001) and superior OS (p = 0.008) than CMT for MRDhigh /CD19- patients. MRD combined with CD19 might optimize PRT choices for adult t(8;21) AML patients in CR1.

Auto-hematopoietic stem cell transplantation or chemotherapy? Meta-analysis of clinical choice for AML.

For patients with acute myeloid leukemia (AML) who are not candidates for allogeneic stem cell transplantation (SCT) or do not have a human leukocyte antigen (HLA)-matched donor, it is unclear whether autologous SCT (ASCT) has a better prognosis after the first complete response (CR1) compared to further chemotherapy treatment. A meta-analysis evaluating ASCT compared to further chemotherapy for AML patients in CR1 was performed. The Medline, Embase, Cochrane Controlled Trials Registry, Cochrane Library, Web of Science, and National Knowledge Infrastructure of China databases were searched for relevant literature as of May 26, 2023. Eligible studies included prospectively enrolled adults with AML and randomized first-time respondent patients who did not have a matched sibling donor. Fourteen randomized controlled trials were identified and included 4281 participants, of which 1499 patients received ASCT and 2782 underwent chemotherapy and continued follow-up. In patients with AML in CR1, a lower relapse rate was associated with ASCT compared to chemotherapy [odds ratio (OR) = 0.49, 95% confidence interval (CI) = 0.41-0.57]. Significant disease-free survival (DFS; OR = 1.37, 95% CI = 1.02-1.84) and relapse-free survival (RFS; OR = 2.78, 95% CI = 1.28-6.02) ASCT benefits were documented, and there was no difference in the overall survival (OS) when the studies were pooled (OR = 1.12, 95% CI = 0.85-1.48). The study results indicated that after the first remission, AML patients receiving autologous stem cell transplantation had higher DFS and RFS, similar OS, and lower relapse compared to patients undergoing chemotherapy treatment. This indicated that autologous stem cell transplantation may have a better prognosis.

Cytogenetic abnormalities predict survival after allogeneic hematopoietic stem cell transplantation for pediatric acute myeloid leukemia: a PDWP/EBMT study.

Poor-risk (PR) cytogenetic/molecular abnormalities generally direct pediatric patients with acute myeloid leukemia (AML) to allogeneic hematopoietic stem cell transplant (HSCT). We assessed the predictive value of cytogenetic risk classification at diagnosis with respect to post-HSCT outcomes in pediatric patients. Patients younger than 18 years at the time of their first allogeneic HSCT for AML in CR1 between 2005 and 2022 who were reported to the European Society for Blood and Marrow Transplantation registry were subgrouped into four categories. Of the 845 pediatric patients included in this study, 36% had an 11q23 abnormality, 24% had monosomy 7/del7q or monosomy 5/del5q, 24% had a complex or monosomal karyotype, and 16% had other PR cytogenetic abnormalities. In a multivariable model, 11q23 (hazard ratio [HR] = 0.66, P = 0.03) and other PR cytogenetic abnormalities (HR = 0.55, P = 0.02) were associated with significantly better overall survival when compared with monosomy 7/del7q or monosomy 5/del5q. Patients with other PR cytogenetic abnormalities had a lower risk of disease relapse after HSCT (HR = 0.49, P = 0.01) and, hence, better leukemia-free survival (HR = 0.55, P = 0.01). Therefore, we conclude that PR cytogenetic abnormalities at diagnosis predict overall survival after HSCT for AML in pediatric patients.

Measurable Residual IDH1 before Allogeneic Transplant for Acute Myeloid Leukemia

Introduction: Detection of measurable residual disease (MRD) prior to allogeneic hematopoietic cell transplant (alloHCT) in patients with acute myeloid leukemia (AML) in remission is associated with increased relapse and inferior survival after transplant. We recently reported that next-generation sequencing (NGS) detection of mutated NPM1 or FLT3-ITD in first complete remission (CR1) blood prior to alloHCT is strongly associated with increased relapse and death (PMID: 36881031). However, the prognostic implications of detecting persistence of other common AML-associated mutations at this treatment landmark remain incompletely defined. Around 20% of patients diagnosed with AML have variants in isocitrate dehydrogenase ( IDH) genes (~7% for IDH1) and clinical outcomes are known to differ due to co-occurrence of other mutations, IDH subtypes, treatment strategies, and patient factors. Studies have examined the relationship between residual IDH1 variants ( IDH1m) in CR and subsequent clinical outcomes, but definitive standardized evidence to inform decision-making for the clinical utility of IDH1m as a target for AML MRD testing was not previously available. Methods: Adult patients undergoing alloHCT for IDH1 mutated AML in CR1 at CIBMTR sites in the USA between 2013-2019 were eligible for the study if remission blood sample collected within 100 days before alloHCT and outcome data were available. Ultrasensitive error-corrected NGS (NGS-MRD) targeting IDH1, NPM1, and FLT3 genes was performed on DNA from pre-conditioning blood to identify residual variants. Detected IDH1m were validated by digital droplet PCR (ddPCR). The day of transplant was considered as day 0. Median follow-up time was calculated for censored patients. Overall survival (OS) was estimated using Kaplan-Meier (log-rank tests) and Cox proportional hazards models (forward selection); cumulative incidence of relapse was examined using Fine-Gray regression models with non-relapse mortality as a competing risk. Results: A total of 148 patients were included in the study, with a median follow-up time of 24 months. Relapse was observed in 37 (25%) patients, with the majority occurring within 1 year after alloHCT (n = 28, 76%). Pre-transplant flow cytometry results were reported by the transplant centers for 97% of patients (n = 144), but no statistically significant differences in clinical outcomes were observed between the positive and negative groups (OS: p = 0.3; relapse: p = 0.07). 53 patients (36%) tested positive for IDH1m persistence in CR1, with a 100% validation rate by ddPCR for variants with an orthogonal assay available. Logistic regression indicated that IDH1m persistence in remission was more likely to occur in patients older than 40 years (OR: 1.02 with every 1-year increase after 40, p = 0.04). Clinical outcomes showed no statistically significant difference between the pre-alloHCT IDH1m positive and negative groups (Figure 1A), and this remained true after further subgroup analysis by age. The variant allele fraction (VAF) of the residual IDH1m ranged from 0.09% to 48.5% (median: 1.5%), and no differences in clinical outcomes were observed when stratifying by high (≥2.5%) or low VAF (&amp;lt;2.5%). Among patients with co-mutated NPM1 and/or FLT3-ITD at baseline (n=69), those with residual mutated NPM1 and/or FLT3-ITD in pre-transplant remission had significantly higher rates of relapse compared to those with residual IDH1m only or NGS-negative groups (p = 0.01, Figure 1B). The cohort excluding patients with co-mutated NPM1 and/or FLT3-ITD did not show any significant clinical outcome differences based on IDH1m persistence. Conditioning intensity did not show an association with clinical outcomes, and multivariable analysis for overall survival and relapse did not identify residual IDH1m as an important marker. Conclusion: Detection of persistent IDH1 variants in the blood of adult patients with AML in CR1 prior to first alloHCT is common, but not associated with increased relapse or death after transplant compared with those testing negative. For those patients with IDH1 mutated AML co-mutated with either NPM1 and/or FLT3-ITD, detection of persistent NPM1 and/or FLT3-ITD was associated with higher rates of relapse. These findings, from the largest study to date, do not support the detection of isolated IDH1 variants in CR1 blood prior to alloHCT as evidence of AML MRD or increased post-transplant relapse risk.

Comparing Older Matched Related to Younger Matched Unrelated Donors in Acute Myeloid Leukemia in Remission Using Post-Transplant Cyclophosphamide

Backgroud. Over the past 25 years, the landscape of allogeneic stem cell transplantation (allo-SCT) changed from being rarely performed in patients 50 years or older to accounting for a little less than half of the transplantations reported in USA and Europe. Older patients will on average have older matched related siblings (MRD) being considered as donors with issues such as comorbidities, risk of clonal haematopoiesis of indeterminate potential, and impaired immune and regenerative potential of stem cells. Although younger HLA-matched unrelated donors (MUD) are an important alternative in this context, it remains unclear whether the use of MUD is associated with better outcomes. This is especially true in the context of post-transplant cyclophosphamide (PTCy) as graft-versus-host disease (GvHD) prophylaxis. Methods. The aim of this study was to compare the graft-relapse-free survival (GRFS) for patients diagnosed with acute myeloid leukemia (AML) in first complete remission (CR1), aged 50y or more, and having received a first allo-SCT from a 10/10 MUD younger than 40y or a MRD older than 50y using PTCy for in-vivo T-cell depletion. All transplants were performed between 2015-2021 at the EBMT centres. Results. A total of 410 consecutive patients were included, 172pts receiving a MRD, 238pts transplanted from a MUD. All patients with detailed conditioning regimen dosages were classified according to the transplant conditioning intensity (TCI) score in low (1-2), intermediate (2.5-3.5), high (4-6). TCI-score was available for 345 patients and was as follows: low in 53pts (36.8%), intermediate in 79pts (54.9%) and high in 12pts (8.3%) for MRD, low in 91pts (45.3%), intermediate in 93pts (46.3%) and high in 17pts (8.5%) for MUD (p=0.26). Only patients with available TCI-score were analysed. In univariate analysis the 2-year GRFS was 58% (49.8-65.3%) for TCI intermediate-high and 43.1% [34.3-51.5] for TCI low (p=0.005). In TCI-score intermediate-high non-relapse mortality (NRM) wasn't higher compared to TCI-score low (12.7% [12.2-24] vs 13.7% [8.4-20.3], p=0.53) but relapse incidence (RI) was lower (17.7% [12.2-24] vs 33.2% [25.1-41.5], p=0.003). As a strong interaction between TCI-score and type of donor was found, we compared transplant outcomes between MRD and MUD separately for TCI-score low and TCI-score intermediate-high. In TCI-score low, 2-year GRFS was 44.4% [33.5-54.8] for MUD and 40.9% [26.4-54.9] for MRD (p=0.83) (Figure 1A). In multivariable analysis (MVA) type of donor was not a risk factors for neither GRFS (HR 0.98, CI: 0.57-1.69; p=0.95) nor for any other transplant outcome. In TCI-score intermediate-high, 2-year GRFS was 67.2% [55.8-76.2] for MUD and 46.1% [34.4-57.1] for MRD (p=0.001) (Figure 1B). In MVA MUD were associated to better GRFS (HR 0.41, CI: 0.24-0.7; p=0.001), lower NRM (HR 0.19, CI: 0.07-0.55; p=0.002) and lower RI (HR 0.32, CI: 0.14-0.73; p=0.007) without advantages in terms of neither aGvHD nor cGvHD. Conclusions. In patients with AML in CR1, aged 50y or more and receiving a conditioning regimen with TCI-score ≥ 2.5 in the PTCy setting, a MUD younger than 40y is associated to longer GRFS, lower NRM and lower RI compared to a MRD older than 50y. For patients receiving regimens with TCI-score low transplant outcomes are independent on the type of HLA-matched donor.

Mismatched Unrelated Donor Transplantation with Ptcy-Based Gvhd Prophylaxis Is Associated with Better Survival Than Double Unit Umbilical Cord Blood Transplantation in Patients with AML in First CR: A Study from the ALWP of the EBMT

Background: The best donor option for acute myeloid leukemia (AML) patients lacking an HLA-matched donor has remained unknown. The recently reported BNT CTN 1101 trial observed higher non-relapse mortality (NRM) and lower overall survival (OS) in patients randomized to double-unit unrelated umbilical cord blood transplantation (dCBT) in comparison to those randomized to HLA-haploidentical bone marrow transplantation with post-transplant cyclophosphamide (PTCy)-based graft-versus-host disease (GVHD) prophylaxis 1. In addition, recent registry studies observed at least as good transplantation outcomes in AML patients given grafts from 9/10 HLA-matched unrelated donor (UD 9/10) with PTCy-based GVHD prophylaxis as those given grafts from HLA-haploidentical donors 2,3. These observations prompted us to perform a retrospective registry study comparing hematopoietic cell transplantation (HCT) outcomes between UD 9/10 and dCBT. Methods: Inclusion criteria consisted of adult patient, AML in CR1 at transplantation, either peripheral blood stem cells (PBSC) from UD 9/10 with PTCy as GVHD prophylaxis or dCBT, transplantation between 2013 and 2021, and no in vivo T-cell depletion. Results: A total of 208 dCBT patients and 270 UD 9/10 allo-HCT were included. The 180-day cumulative incidence of grade II-IV acute GVHD was 29% in UD 9/10 versus 44% in dCBT recipients (P=0.001). The 2-year cumulative incidences of relapse and of NRM were 23.5% and 12.5%, respectively, in UD 9/10 recipients versus 27% (P=0.39) and 18% (P=0.07), respectively in dCBT recipients. Two-year OS and LFS were 70% and 64%, respectively, in UD 9/10 recipients versus 60% (P=0.016) and 55% (P=0.028), respectively in dCBT recipients. In multivariate analyses, in comparison with UD 9/10 recipients, dCBT patients had a higher non-relapse mortality (HR=2.35, 95% CI: 1.23-4.48; P=0.01), comparable relapse incidence (HR=1.12, 95% CI: 0.67-1.86; P=0.66), lower leukemia-free survival (HR=1.5, 95% CI: 1.01-2.23; P=0.047), and lower overall survival (HR=1.66, 95% CI: 1.08-2.55; P=0.02). Conclusions: In summary, our results suggest that transplantation outcomes are better with UD 9/10 with PTCy-based GVHD prophylaxis than with dCBT for AML patients in CR1. These data might support the use of UD 9/10 with PTCy-based GVHD prophylaxis in AML patients lacking an HLA-matched donor. References Fuchs, E. J. et al. Double unrelated umbilical cord blood vs HLA-haploidentical bone marrow transplantation: the BMT CTN 1101 trial. Blood 137, 420-428 (2021).Baron, F. et al. Comparison of HLA-mismatched unrelated donor transplantation with post-transplant cyclophosphamide versus HLA-haploidentical transplantation in patients with active acute myeloid leukemia. Bone Marrow Transplant. 57, 1657-1663 (2022).Battipaglia, G. et al. Post-transplant cyclophosphamide in one-antigen mismatched unrelated donor transplantation versus haploidentical transplantation in acute myeloid leukemia: a study from the Acute Leukemia Working Party of the EBMT. Bone Marrow Transplant. 57, 562-571 (2022).

Comparison of Autologous, Matched Sibling, and Alternative Donor Stem Cell Transplant Outcomes for Acute Myeloid Leukemia Patients in First Remission: A Propensity Score Matching Study

Introduction Autologous hematopoietic stem cell transplantation (auto-HSCT), matched sibling donor HSCT (MSD-HSCT), and alternative donor HSCT (AD-HSCT) are viable post-remission treatment options for acute myeloid leukemia (AML). Auto-HSCT is more commonly administered in favorable- and intermediate-risk AML with good remission, while MSD-HSCT and AD-HSCT are suggested for patients with high-risk factors. In the present study, we aim to retrospectively compared auto-HSCT with MSD-HSCT and AD-HSCT in de novo AML patients who are in first complete remission (CR1) with favorable or intermediate risk, according to 2022 ELN criteria. Methods We conducted a single-center retrospective comparative analysis, comparing auto-HSCT and allo-HSCT for favorable and intermediate-risk de novo AML in CR1. Patients with secondary AML, acute promyelocytic leukemia, poor-risk AML, those receiving syngeneic HSCT, those not in CR1 before HSCT, or those who achieved CR1 with ≥ 3 cycles of induction chemotherapy were excluded from the study. A total of 283 de novo favorable- and intermediate-risk AML patients, based on the ELN 2022 criteria, in first complete remission were initially included for propensity score matching. Persistent undetectable MRD (uMRD) was defined as uMRD after one course of chemotherapy without recurrent positive MRD before HSCT, while non-persistent uMRD was characterized by the presence of detectable MRD at least once before HSCT. The variables used for propensity score matching included induction chemotherapy cycles, consolidation chemotherapy cycles, and measurable residual disease (MRD) measurement by flow cytometer before HSCT. A caliper width of 0.2 was used. Following the matching process, 126 patients were selected for further analysis, with 42 patients in each of the auto-HSCT, MSD-HSCT, and AD-HSCT groups. Results After applying propensity score matching, a final cohort of 126 patients was available for analysis. This cohort consisted of 42 patients in each group: auto-HSCT, MSD-HSCT, and AD-HSCT. Among the AD-HSCT group, 38 of 42 (90.5%) patients received haploidentical HSCT (haplo-HSCT). All patients received myeloablative conditioning regimen. There were no significant differences observed in the 3-year overall survival (OS) and disease-free survival (DFS) among the auto-HSCT, MSD-HSCT, and AD-HSCT groups [3-year OS: 79.5% (95% CI, 67.8-93.3%), 83.0% (95% CI, 72.2-95.3%), and 65.7% (95% CI, 50.5-85.5%), respectively; P=0.21. 3-year DFS: 72.6% (95% CI, 59.9-87.9%), 83.0% (95% CI, 72.2-95.3%), and 67.5% (95% CI, 54.2-84.1%), respectively; P=0.32]. The cumulative incidence of 3-year NRM was 2.7% (95% CI, 2.0-12.5%), 7.3% (95% CI, 1.8-17.9%), and 21.9% (95% CI, 10.7-35.6%), respectively (P=0.008). The 1-year probability of OS after relapse was higher in the auto-HSCT group (44.4%; 95% CI, 21.4-92.3%) compared with MSD-HSCT (0.0%) and AD-HSCT (37.5%; 95% CI, 8.4-99.9%) (P=0.0017). The MRD status before HSCT had an impact on DFS (persistent uMRD versus non-persistent uMRD: HR=0.29; 95% CI 0.09-0.94, P=0.04) and relapse (persistent uMRD versus non-persistent uMRD: HR=0.17; 95% CI 0.05-0.66, P=0.01) following auto-HSCT. The subgroup analysis was then performed based on MRD status before HSCT. In patients with uMRD before transplant (n=83), OS was similar across the groups. However, auto-HSCT showed a trend of increased DFS compared to AD-HSCT (HR 2.85, P=0.09), resulting in a 3-year DFS and OS of 79.1% and 82.8%, respectively. In the non-persistent uMRD group (n=38), auto-HSCT exhibited a tendency to increase the risk of relapse, particularly when compared to AD-HSCT (HR 0.24, P=0.07), but this did not result in inferior OS. The monthly direct medical cost per patient within the first two years after HSCT was significantly lower in auto-HSCT compared to MSD-HSCT (P=0.015) and AD-HSCT (P&amp;lt;0.001). Conclusions Our results provide evidence for the use of auto-HSCT as a viable therapeutic option for favorable- and intermediate-risk de novo AML patients in first complete remission with persistent uMRD. Additionally, our findings demonstrated a notable cost advantage associated with auto-HSCT compared to MSD-HSCT and AD-HSCT.

Persistence of FLT3-TKD in Blood Prior to Allogeneic Transplant Is Associated with Increased Relapse and Death in Adults with AML in First Remission

Introduction: Next-generation sequencing (NGS) represents a promising modality for measurable residual disease (MRD) testing in patients with acute myeloid leukemia (AML), but systematic efforts are required to define the appropriate targets, test characteristics, and clinical implications. We recently reported that detection of persistent NPM1 or FLT3 internal tandem duplication (ITD) mutations in adults with AML in first complete remission (CR1) prior to allogeneic hematopoietic cell transplantation (alloHCT) is associated with increased relapse and death compared with those testing negative (JAMA 2023, PMID: 36881031). FLT3 tyrosine kinase domain (TKD) variants are present in 7-10% of adult patients with AML but the utility of this target for AML MRD testing in CR1 prior to alloHCT was previously unknown. Methods: Patients aged 18 or older who underwent alloHCT for AML in CR1 between 2013 and 2019 reported to have a FLT3-TKD variant at diagnosis and a pre-conditioning remission blood sample available in the CIBMTR biorepository were eligible for this study. Single-amplicon NGS (SA-NGS) library generation utilizing UMI-tagged primers targeting the D835 and I836 codons of FLT3 was performed on 400ng genomic DNA sequenced with unique dual indices, with error-corrected variant calling. Primary outcomes were overall survival (OS) and cumulative incidence of relapse (CIR). Secondary outcomes were relapse-free survival (RFS) and non-relapse mortality (NRM), with NRM being considered as a competing risk. Results: A total of351 patients met inclusion criteria for this study, and 342 (97.4%) had sufficient DNA for SA-NGS and were analyzed for clinical outcomes. Of these patients, 81 (23.7%) experienced relapse at a median of 5 months post-alloHCT. Using the current ELN-recommended variant allele fraction (VAF) threshold of 0.1% for NGS-based AML MRD, 14 patients (4.1%) tested positive. Patients with FLT3-TKD MRD VAF≥0.1% experienced higher rates of relapse (73.8% vs. 20.5%, p &amp;lt; 0.0001) and decreased OS (11.4% vs. 66.8%, p &amp;lt; 0.001) compared to VAF&amp;lt;0.1%. The highly sensitive SA-NGS method allowed for exploration to determine if a deeper VAF threshold of 0.01% (previously validated for NPM1 and FLT3-ITD in the Pre-MEASURE study) was prognostic for FLT3-TKD as an MRD target. This led to an additional 20 patients being reclassified as positive (n = 34 with VAF above 0.01%, =9.9%). However, there was no significant difference in CIR (33.6% vs. 19.7%, p = 0.089) or OS (65.2% vs. 66.9%, p = 0.267) between patients with 0.01%≤VAF&amp;lt;0.1% and VAF&amp;lt;0.01% ( Figure). Out of 28 SA-NGS positive calls, 6 could not be validated by orthogonal digital droplet PCR testing, and interestingly, none of those 6 patients experienced relapse. Site-reported pre-transplant remission multiparametric flow cytometry (MFC) was available for 335 patients (98%). Results of MFC were not associated with differences in CIR (HR 1.2, 95% CI 0.52 - 2.76, p = 0.67) or OS (HR 0.78, 95% CI 0.34 - 1.77, p = 0.551).In multivariable analysis, FLT3-TKD NGS-MRD VAF≥0.1% remained prognostic for CIR (HR 6.1, 95% CI 3.1 - 12.0, p &amp;lt; 0.001) and OS (HR 3.2, 95% CI 1.7 - 5.9, p &amp;lt; 0.001). Conclusions: Detectable persistence of FLT3-TKD variants in blood from AML patients in first remission prior to first alloHCT is rare, but at a VAF level of 0.1% was strongly associated with increased relapse and death after transplant compared to those testing negative. In contrast to FLT3-ITD NGS-MRD, no evidence was found to support lowering the NGS-MRD VAF threshold from 0.1% to 0.01% for FLT3-TKD. Alternative methodology may further improve NGS-MRD test performance. Site-reported MFC prior to alloHCT did not stratify for post-transplant relapse or survival. Optimal NGS-MRD testing for patients with AML will likely require a multi-target approach and testing for persistence of FLT3-TKD MRD is shown here to represent an important component of this strategy.

Low-Dose Decitabine Plus Venetoclax As Post-Transplant Maintenance for High-Risk Myeloid Malignancies

Background: Allogeneic stem cell transplantation (allo-SCT) is potentially curative for patients with acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). However, post-SCT relapse remains a major cause of treatment failure for these patients and strategies to prevent post-transplant relapse are urgently needed. The combination of venetoclax (VEN) with either azacitidine (AZA) or decitabine (DEC) has shown promising results in older or unfit patients with AML and is now being investigated in younger patients as well. Herein, we report our experience of administering low-dose DEC and VEN as post-transplant maintenance in patients with high-risk myeloid malignancies. Methods: A retrospective chart review was performed to evaluate outcomes of patients with AML and MDS that received post-SCT maintenance with DEC and VEN at the University of Alabama at Birmingham. DEC was administered at 10mg/m 2 on days 1-3 per cycle and VEN was given at a target dose of 200mg on days 1-28 for AML and days 1-14 for MDS. The dose of VEN was reduced to 20mg when administered with voriconazole or posaconazole or 100mg when administered with fluconazole or isavuconazium. The cycle length was 4 weeks. Results: We identified 19 patients between March 2021 and May 2023 that received post-SCT DEC/VEN for AML and MDS (Table 1). The median follow-up was 10m (range 3-26m). The median age was 60y (range 34-69y). There were 10 (53%) females and 13 (68%) non-Hispanic whites (NHWs). Fourteen patients had AML and 5 had MDS. For patients with AML, 10 had poor-risk and 4 had intermediate-risk disease per ELN 2017. At the time of transplant, 11 patients with AML were in CR1 (CR1=6, CRi1=5), 2 were in CR2 (CR2=1, CRi2=1) and 1 was in CR3. Three patients with AML had MRD+ at the time of transplant (CRi1=2, CR3=1). For patients with MDS, 2 had very-high and 2 had high-risk disease per R-IPSS. One patient had therapy-related MDS. Two patients with MDS had CR, 2 had stable disease and 1 had hematological-improvement at the time of transplant. Overall, 6 patients (32%) had a TP53 mutation. Donor type was matched-related in 5 patients, matched-unrelated in 12 patients and haploidentical in 2 patients. Seventeen patients received reduced-intensity conditioning (RIC). GVHD prevention consisted of tacrolimus and methotrexate in 14 patients and post-transplant cyclophosphamide-based in 5 patients. The median time to initiating maintenance therapy was 69d (range 54-200d) post-SCT. The median number of cycles administered was 6 (range 2-24). Grade III-IV neutropenia, anemia and thrombocytopenia occurred in 5, 1 and 2 patients, respectively. Two patients had febrile neutropenia and one patient had candida esophagitis. Five patients required a reduction or interruption in the dose due to adverse events. In all cases, the VEN duration was shortened by 1 week. The cumulative incidence (CI) of day 100 grade II-IV and III-IV aGVHD was 13% and 5%, respectively. There were no grade IV cases. The 1y CI of moderate-severe cGVHD was 26%. To date, one patient who received a RIC haplo-SCT for poor-risk AML in CR2 relapsed 14m after SCT. The 1y non-relapse mortality was 11%. The 1y OS for the entire cohort was 84% (Figure 1). Conclusion: Our preliminary data suggests that the combination of low-dose DEC plus VEN is a safe and potentially effective strategy to reduce the risk of post-SCT relapse. Adverse effects mainly included manageable cytopenias with no increase in risk of GVHD. The efficacy of the combination appears to be promising but needs longer follow-up as well as confirmation in large, randomized studies.

Etoposide plus cytarabine versus cyclophosphamide or melphalan in busulfan-based preparative regimens for autologous stem cell transplantation in adults with acute myeloid leukemia in first complete remission: a study from the Acute Leukemia Working Party of the EBMT.

We retrospectively compared the impact of the conditioning regimen in adult patients with acute myeloid leukemia (AML) in first complete remission (CR1) that received high-dose myeloablative chemotherapy followed by autologous stem cell transplantation (ASCT) from 2010 to 2021 with either high-dose cytarabine, etoposide and busulfan (BEA), busulfan with cyclophosphamide (BUCY) or busulfan and high-dose melphalan (BUMEL) registered in the EBMT database. Overall 1560 patients underwent ASCT, of which 156, 1143 and 261 received BEA, BUCY and BUMEL, respectively. Compared to BUCY and BUMEL, BEA patients were younger (p < 0.001) and less frequently had NPM1 mutations (p = 0.03). Transplant outcomes at 5 years with BEA, BUCY and BUMEL were: cumulative incidence of relapse 41.8%, 46.6% and 51.6%; non-relapse mortality (NRM) 1.5%, 5.2% and 7.3%; probability of leukemia-free survival (LFS) 56.7%, 48.2% and 41.1%; and overall survival (OS) 71.3%, 62.3% and 56%, respectively. In multivariable analysis the BEA regimen showed significant improvement in OS compared to BUCY (hazard ratio [HR] 0.65; 95% CI, 0.42-0.83; p = 0.048) and BUMEL (HR 0.59; 95% CI, 0.37-0.94; p = 0.029). In conclusion, high-dose myeloablative combination chemotherapy with BEA offered improved outcomes compared to classical BUCY or BUMEL in patients with AML in CR1 undergoing ASCT.

More than two courses of pre-transplant consolidation therapy benefits patients with acute myeloid leukemia in the first complete remission who underwent human leukocyte antigen-matched sibling allografts: a multicenter study.

Although the need for consolidation chemotherapy after successful induction therapy is well established in patients with acute myeloid leukemia (AML) in first complete remission (CR1), the value of consolidation chemotherapy before allogeneic hematopoietic stem cell transplantation remains controversial. We retrospectively compared the effect of the number of pre-transplant consolidation chemotherapies on outcomes of human leukocyte antigen-matched sibling stem cell transplantation (MSDT) for patients with AML in CR1 in multicenters across China. In our study, we analyzed data of 373 AML patients in CR1 from three centers across China. With a median follow-up of 969 days, patients with ≥ 3 courses of consolidation chemotherapy had higher probabilities of leukemia-free survival (LFS) (85.6% vs . 67.0%, P < 0.001) and overall survival (89.2% vs . 78.5%, P = 0.007), and better cumulative incidences of relapse (10.5% vs . 19.6%, P = 0.020) and non-relapse mortality (4.2% vs . 14.9%, P = 0.001) than those with ≤ 2 courses of consolidation chemotherapy. Pre-transplantation minimal residual disease-negative patients with AML in CR1 who received MSDT with ≥ 3 courses of consolidation chemotherapy had a higher probability of LFS (85.9% vs . 67.7%, P = 0.003) and a lower cumulative incidence of relapse (9.6% vs . 23.3%, P = 0.013) than those with ≤ 2 courses. Our results indicate that patients with AML in CR1 who received MSDT might benefit from pre-transplant consolidation chemotherapy.

Allogeneic hematopoietic cell transplantation for patients with AML aged 70 years or older in first remission. A study from the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation (EBMT).

Accessibility to allogeneic hematopoietic cell transplantation (HCT) programs for older patients is growing constantly. We report on the clinical outcomes of a group of 701 adults aged ≥70 years, with acute myeloid leukemia (AML) in first complete remission (CR1), who received a first HCT, from HLA-matched sibling donors (MSD), 10/10 HLA-matched unrelated donors (UD), 9/10 HLA-mismatched unrelated donors (mUD) or haploidentical (Haplo) donors. The 2-year overall survival (OS) was 48.1%, leukemia-free survival (LFS) 45.3%, relapse incidence (RI) 25.2%, non-relapse mortality (NRM) 29.5% and GVHD-free, relapse-free survival (GRFS), 33.4%. Compared to MSD, patients transplanted from Haplo and UD presented lower RI (HR 0.46, 95% CI 0.25-0.8, p = 0.02 and HR 0.44, 95% CI: 0.28-0.69, p = 0.001, respectively); this translated into prolonged LFS for Haplo (HR 0.62, 95% CI: 0.39-0.99, p = 0.04). Patients transplanted from mUD exhibited the highest NRM incidence (HR 2.33, 95% CI: 1.26-4.31, p = 0.007). HCT in selected adult CR1 AML patients >70 years is feasible and could be associated with good clinical outcomes. Prospective clinical trials are warranted.

Transplant in AML with measurable residual disease: proceed or defer?

Allogeneic stem cell transplantation plays a central role in the management of fit adults with high-risk acute myeloid leukemia (AML) in first complete morphologic remission (CR1). Advances in both donor selection and transplant technology have both dramatically increased accessibility of transplant and led to significant reductions in transplant-related mortality over the past 2 decades. There has, however, been no concomitant reduction in the risk of disease relapse, which remains the major cause of transplant failure. Pivotal to the design of innovative strategies with the potential to reduce relapse risk is accurate identification of patients at the highest risk of disease recurrence. Multiple retrospective studies have identified an increased risk of disease relapse in patients allografted for AML in CR1 with evidence of pretransplant measurable residual disease (MRD). The prognostic significance of pretransplant MRD has been confirmed recently in prospective analyses. The optimal management of patients with evidence of pretransplant MRD remains a matter of conjecture with regard to 2 key issues. First, should the presence of pretransplant MRD delay a decision to proceed to transplant, allowing time for delivery of additional MRD-directed therapy prior to transplant? Second, to what extent can the intensity of the conditioning regimen or the magnitude of the graft-vs-leukemia effect be manipulated to improve the outcome of such patients?

Specific Cytogenetic Abnormalities at Diagnosis Predict Survival after Hematopoietic Cell Transplant in Poor-Risk Pediatric Acute Myeloid Leukemia: A PDWP/EBMT Study

Introduction: Cytogenetic abnormalities are an important prognostic factor for predicting overall survival (OS) and relapse incidence (RI) in children with acute myeloid leukemia (AML). Although allogeneic hematopoietic cell transplant (HCT) is generally recommended for patients with AML in first complete remission (CR1) and poor-risk (PR) cytogenetics, whether these cytogenetic and molecular features retain their prognostic value after HCT is unknown. Additionally, PR AML is a heterogeneous category that includes several distinct cytogenetic abnormalities, some of which might have a worse prognosis than others. In this study, we evaluated whether the cytogenetic risk classification at diagnosis of AML was predictive of post-HCT outcomes in pediatric patients. Methods: All patients <18 years of age at the time of HCT reported to the European Society for Blood and Marrow Transplantation (EBMT) registry, who had received their first allogeneic HCT for AML in CR1 between 2005 and 2020, and who had their karyotype evaluation at diagnosis available were included in this analysis. Patients were subgrouped as (a) monosomy 7/del7q or monosomy 5/del5q, (b) 11q23 abnormality excluding t(9;11), (c) complex or monosomal karyotype, or (d) other. A complex karyotype was defined as one with three or more structural abnormalities, and a monosomal karyotype was defined as a monosomy with one or more structural abnormalities, excluding WHO-designated recurring translocations or inversions based on 2017 ELN recommendations. Other cytogenetic abnormality subgroup included t(6;9), t(3;5), t(9;22), t(8;16), inv(3) or t(3;3), t(16;21), abn(11p15), and del(12p) or abn(12p13). Cytogenetic subgroup, age at HCT, whether HCT was from a female donor to a male recipient, patient/donor CMV status, time from AML diagnosis to HCT, and year of HCT were included as predictors for OS, RI and non-relapse mortality (NRM) in the multivariate analysis. Results: We included 744 pediatric patients (42.2% female; median age at HCT: 8.6 years [range: 0.3-18 years]) from 139 participating centers in the study. Median follow-up after HCT was 4.4 years. Thirty-seven percent had an 11q23 abnormality, 24% had monosomy 7/del7q or monosomy 5/del5q, 24% had a complex or monosomal karyotype, and 15% met the criteria for other PR cytogenetic abnormalities. Only 7% had secondary AML. Pre-HCT minimal residual disease (MRD) data were available for 346 patients, 86% of whom were MRD negative at the time of HCT. Patients received grafts from a matched related donor (27%), a mismatched related donor (11%), an unrelated donor (46%), or a cord blood donor (16%). Of the total patients, 55% received bone marrow, 29% received peripheral blood-derived stem cells and the rest (16%) received cord blood as the stem cell source. Myeloablative conditioning was used in 97% of the patients. The OS and leukemia free survival for the entire cohort was 76% and 70% respectively at 2 years. In a multivariate model, 11q23 (hazard ratio [HR] = 0.59, P = 0.01) and other poor-risk cytogenetic abnormalities (HR = 0.49, P < 0.01) were associated with significantly better OS when compared with monosomy 7/del7q or monosomy 5/del5q. The "other PR cytogenetic abnormalities" category was also associated with a lower risk of disease relapse after HCT (HR = 0.4, P = 0.01). Receiving an HCT from an unrelated donor, as compared with a matched related donor, was associated with lower RI (HR = 0.58, P = 0.03). Additionally, older age at HCT (12-18 years) was associated with the highest risk of NRM (HR = 1.95, P = 0.02) and with worse OS (HR = 1.71, P < 0.01) than seen in younger patients (aged 4-12 years). Conclusion: PR cytogenetic abnormalities at diagnosis remain predictive of OS after HCT for AML in pediatric patients. Monosomy 7/del7q or monosomy 5/del5q confer a poor prognosis even after HCT, whereas 11q23 abnormality and other PR cytogenetic abnormalities predict a favorable outcome after HCT. Our data also suggest that an HCT from an unrelated donor may offer greater protection against relapse than an HCT from a matched related donor, but this requires further validation. Efforts for improving conditioning regimens and transplant techniques should focus on reducing NRM and reducing RI in this population. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Autologous Versus Haploidentical Stem Cell Transplantation in Adult Patients with Intermediate Risk Actue Myelogenous Leukemia in First Complete Remission and Undetectable Minimal Residual Disease: A Global Preliminary Analysis of Chinese Data

Background: Stem cell transplantation (SCT) is a potentially curative post-remission therapy for intermediate-risk acute myeloid leukemia (AML) patients. For patients in first remission (CR1) with negative measurable residual disease (MRD) and without a HLA-matched donor, both autologous SCT (ASCT) and haploidentical donor SCT (haplo-SCT) were acceptable options, but it is controversial that which one is preferred. Methods: A retrospective study was conducted in 8 Chinese centers. The inclusion criteria were: 1) adult patients >18 years old; 2) diagnosis as AML with intermediate-risk according to ELN 2017; 3) ASCT or haplo-SCT underwent between 2010-2019; 4) in CR1 and MRD negative before transplant. The Primary endpoint was overall survival (OS). Secondary endpoints were progression-free survival (PFS), cumulative incidence of relapse (CIR), treatment-related mortality (TRM), and graft-versus-host disease-free and relapse-free survival (GRFS). Results: Totally 299 patients were enrolled in this study, including 97 recepients after ASCT and 202 recipients after haplo-SCT (Table 1). The median follow-up was 28 months in ASCT group versus 35 months in haplo-SCT group. Compared to haplo-SCT, patients after ASCT had increased 3-year CIR (27.0% ± 0.2% versus 13.5% ± 0.1%, p = 0.004) but reduced 3-year TRM (3.5% ± 0.0% versus 12.0% ± 0.0%, p = 0.013), which led to similar 3-year OS (80.8% ± 4.3% versus 79.2% ± 3.1%, p = 0.796) and PFS (69.5% ± 5.0% versus 73.7% ± 3.3%, p = 0.504). Moreover, the 3-year GRFS was remarkable better in ASCT group (69.5% ± 5.0% versus 55.9% ± 3.6%, p = 0.009) (Figure 1), which implied a survival with superior quality of life (QoL). In multivariate analysis, haplo-SCT independently related to an improved CIR, while increased TRM and reduced GRFS. Additionally, age more than 50 was associated with the worse OS, CIR and GRFS. Conclusions: We concluded that both ASCT and haplo-SCT were applicable for patients with intermediate-risk AML in MRD-negative CR1, but the absence of GVHD might potentially favor the QoL for patients receiving ASCT. Randomized trials are needed to confirm our conclusion. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Post-remission measurable residual disease directs treatment choice and improves outcomes for patients with intermediate-risk acute myeloid leukemia in CR1

ObjectivesThis study retrospectively investigated in which cycle measurable residual disease (MRD) is associated with prognosis in patients in first complete remission (CR1) of intermediate-risk acute myeloid leukemia (AML).MethodsThe study enrolled 235 younger patients with intermediate-risk AML. MRD was evaluated by multiparameter flow cytometry after the 1st, 2nd, and 3rd chemotherapy cycles (MRD1–3, respectively).ResultsNo significant association was detected after the 1st and 2nd cycles. However, the 5-year incidence of relapse was higher in the MRD3-positive group (n = 99) than in the negative group (n = 136) (48.7% vs. 13.7%, P = 0.005), while 5-year disease-free survival (DFS) and overall survival (OS) were lower in the MRD3-positive group than in the negative group (43.2% vs. 81.0% and 45.4% vs. 84.1%; P = 0.003 and 0.005, respectively). Allogeneic hematopoietic stem cell transplantation led to a lower 5-year relapse, and higher DFS and OS rates than chemotherapy in the MRD3-positive group (22.3% vs. 71.5%, 65.9% vs. 23.0%, and 67.1% vs. 23.9%; P < 0.001, 0.002, and 0.022, respectively), but did not affect the MRD-negative group.ConclusionsMRD3 could serve as an indicator for post-remission treatment choice and help improve outcomes for intermediate-risk AML in CR1.

Favorable Outcome with Conditioning Regimen of Flu/Bu4/Mel in Acute Myeloid Leukemia Patients in Remission Undergoing Cord Blood Transplantation

Cord blood transplantation (CBT) is a curative therapeutic option for patients with acute myeloid leukemia (AML) who do not have an HLA-matched donor. The decline in early nonrelapse mortality (NRM) after CBT has significantly improved overall survival (OS) during the past 20 years because of advances in CBT practices, including more careful patient selection, use of safer conditioning regimens, better cord blood unit selection, and improved supportive care. A previous study reported a conditioning regimen comprising fludarabine, busulfan, and melphalan (Flu/Bu4/Mel) developed for patients undergoing CBT in non-complete remission (CR) myeloid malignancies that showed durable engraftment and remission with acceptable nonrelapse mortality (NRM), leading to excellent survival outcomes. However, no prior study has focused on the role of Flu/Bu4/Mel in CBT conditioning and compared it with conventional myeloablative conditioning (MAC) for AML patients in CR. We aimed to investigate the efficacy and safety of Flu/Bu4/Mel compared with cyclophosphamide and total body irradiation (CY/TBI)-based MAC for AML patients in CR who underwent CBT. Patients were selected from the Japanese nationwide transplantation registry according to the following inclusion criteria: (1) patients with AML aged ≥16 years, (2) first single-unit CBT, and (3) CR at the time of transplantation. Of 477 eligible patients, 148 (31.0%) received CY/TBI, 223 (46.8%) received high-dose cytarabine (HDCA)/CY/TBI, and 106 (22.2%) received Flu/Bu4/Mel. The probability of OS at 3 years was 64.8% (95% confidence interval [CI], 56.0% to 72.3%) in the CY/TBI group, 65.1% (95% CI, 57.8% to 71.4%) in the HDCA/CY/TBI group, and 65.5% (95% CI, 53.7% to 74.9%) in the Flu/Bu4/Mel group (P=.71); the cumulative incidence of relapse at 3 years was 22.0% (95% CI, 15.2% to 29.5%), 17.2% (95% CI, 12.2% to 22.9%), and 18.0% (95% CI, 11.2% to 26.2%), respectively (P=.40); and the cumulative incidence of NRM at 3 years was 17.2% (95% CI, 11.5% to 24.0%), 20.7% (95% CI, 15.4% to 26.7%), and 18.6% (95% CI, 11.4% to 27.2%), respectively (P=.95). Multivariate analysis identified Flu/Bu4/Mel as a favorable factor for OS; however, it was not significantly favorable for relapse and NRM in the CY/TBI, HDCA/CY/TBI, and Flu/Bu4/Mel groups (hazard ratio [HR], .50 [95% CI, .29-.88], P=.015; .67 [95% CI, .31-1.46], P=.31; and .55 [95% CI, .26-1.18], respectively; P=.12). Flu/Bu4/Mel was a favorable factor for neutrophil engraftment (HR, 1.51; 95% CI, 1.08 to 2.12; P=.016). Multivariate analysis showed that Flu/Bu4/Mel had a favorable prognostic impact on OS and neutrophil engraftment despite the non-TBI regimen. Our findings suggest that Flu/Bu4/Mel may sustain the antileukemia effect with decreasing NRM and could be a favorable CBT conditioning regimen for patients with AML in CR.

P499: THE PHASE 1B OMNIVERSE TRIAL OF ORAL AZACITIDINE IN COMBINATION WITH VENETOCLAX FOR TREATMENT OF RELAPSED/REFRACTORY OR NEWLY DIAGNOSED ACUTE MYELOID LEUKEMIA (TRIAL IN PROGRESS)

Background: For older patients (pts) with acute myeloid leukemia (AML) who are ineligible for standard intensive chemotherapy (IC) regimens, traditional lower-intensity AML treatment (Tx) options include low-dose cytarabine (LDAC) or hypomethylating agents (HMAs; azacitidine [AZA] and decitabine), which are generally well tolerated but associated with suboptimal outcomes vs IC [Vey 2020]. Therefore, there remains a need for less toxic and more efficacious lower-intensity AML Tx regimens, especially agents that can be administered in the outpatient setting, which may increase convenience and reduce resource utilization. Venetoclax (VEN) is an oral, selective, small-molecule BCL2 inhibitor that has demonstrated considerable activity when combined with LDAC or HMAs in older pts with AML. In a recent phase 3 trial, VEN + injectable AZA significantly improved response and survival vs AZA alone in IC-ineligible pts with newly diagnosed (ND) AML [DiNardo 2020]. In the USA, VEN is approved in combination with an HMA or LDAC for Tx of pts with ND AML ≥ 75 years (y) of age or who cannot use IC due to comorbidities. Oral-AZA (CC-486) is approved for pts with AML in first remission (CR1) after IC who are ineligible for transplant or other curative therapies. In the randomized, phase 3 QUAZAR AML-001 trial of Oral-AZA in pts with AML in CR1 after IC, Oral-AZA 300 mg QD for 14 days (d)/28d Tx cycle was generally well tolerated and associated with significantly improved overall survival vs placebo. Gastrointestinal symptoms were the most common adverse events reported with Oral-AZA [Wei 2020]. Oral-AZA has also shown clinical activity in pts with active AML [Savona 2015]. As incorporation of AZA into DNA is S-phase-restricted, extended Oral-AZA dosing regimens (> 7d/28d Tx cycle) increase drug incorporation into cycling tumor cells to prolong epigenetic activity throughout the Tx cycle [Laille 2015]. An all-oral VEN + Oral-AZA combination regimen allows for outpatient administration and thus improves pt adherence [Eek 2016]. Aims: Describe the study design and objectives of the OMNIVERSE trial of Oral-AZA + VEN in older pts with ND AML or pts with AML relapsed/refractory (R/R) to prior Tx. Methods: OMNIVERSE (NCT04887857) is a multicenter, open-label, 2-part phase 1b trial (Figure). The key objectives of the trial are to assess safety and determine the maximum tolerated dose of Oral-AZA + VEN in pts with R/R AML (WHO 2016 criteria) ineligible to receive further IC (part I), and then in pts with ND AML ≥ 75 y of age, or those ≥ 18–74 y of age ineligible for IC or HSCT due to comorbidities (part 2). Main eligibility criteria include an ECOG performance status of 0–2 (ECOG 3 is allowed for pts ≥ 18–74 y of age with comorbidities) and an unfavorable cytogenetic risk profile for pts with ND AML. The initial dose of Oral-AZA is 300 mg QD × 14d/28d cycle, with de-escalation to 200 mg × 14d/28d cycle allowed for dose-limiting toxicities. VEN 400 mg is taken orally QD in continuous 28d cycles (or for 21d/cycle for dose level –2). A modified toxicity probability interval-2 design is used to evaluate the planned dose levels. The sample size is dependent on the dose levels included in the study (≤ 18 pts/part). Results: N/A Image:Summary/Conclusion: Study enrollment began in 2021. The trial is ongoing at clinical sites in the United States and Australia.

Age is no barrier for adults undergoing HCT for AML in CR1: contemporary CIBMTR analysis

Acute Myeloid Leukemia (AML) has a median age at diagnosis of 67 years. The most common curative therapy remains an allogeneic hematopoietic stem cell transplantation (HCT), yet it is complicated by treatment-related mortality (TRM) and ongoing morbidity including graft versus host disease (GVHD) that may impact survival, particularly in older patients. We examined the outcomes and predictors of success in 1,321 patients aged 60 years and older receiving a HCT for AML in first complete remission (CR1) from 2007–2017 and reported to the CIBMTR. Outcomes were compared in three age cohorts (60–64; 65–69; 70+). With median follow-up of nearly 3 years, patients aged 60–64 had modestly, though significantly better OS, DFS and lower TRM than those either 65–69 or 70+; cohorts with similar outcomes. Three-year OS for the 3 cohorts was 49.4%, 42.3%, and 44.7% respectively (p=0.026). TRM was higher with increasing age, cord blood as graft source and HCT-CI score of ≥ 3. Conditioning intensity was not a significant predictor of OS in the 60–69 cohort with 3-year OS of 46% for RIC and 49% for MAC (p=0.38); MAC was rarely used over age 70. There was no difference in the relapse rate, incidence of Grade III/IV acute GVHD, or moderate-severe chronic GVHD across the age cohorts. After adjusting for other predictors, age had a small effect on OS and TRM. High-risk features including poor cytogenetics and measurable residual disease (MRD) prior to HCT were each significantly associated with relapse and accounted for most of the adverse impact on OS and DFS. Age did not influence the incidence of either acute or chronic GVHD; while graft type and associated GVHD prophylaxis were most important. These data suggest that age alone is not a barrier to successful HCT for AML in CR1 and should not exclude patients from HCT. Efforts should focus on minimizing residual disease and better donor selection.

The Impact of CD19 Expression Combined with Measurable Residual Disease on Post-Remission Treatment and Outcome in Adult t(8;21) Acute Myeloid Leukemia

Background: Acute myeloid leukemia (AML) with t(8;21) has considerable clinical heterogeneity. Only 50% of these patients receiving multiple cycles of high-dose cytarabine as post-remission treatments could achieve long term survival, and relapse occures in up to 40% of them. Therefore, further risk stratification is needed to guide appropriate post-remission treatment for t(8;21) AML patitents in first complete remission(CR1). Measurable residual disease (MRD) monitored by RUNX1-RUNX1T1 transcript levels after treatment is established as a powerful marker to predict relapse and guide treatment. Recent studies revealed cell-surface antigen CD19 negativity (CD19-) was a risk factor for relapse in t(8;21) AML. However, reports about the impact of CD19 expression combined with RUNX1-RUNX1T1 MRD on post-remission treatment remains absent to date.Methods: A total of 155 consecutive patients diagnosed with t(8;21) AML were enrolled in this study, including 69 patients who received chemotherapy (CMT) and 86 who received allogeneic stem cell transplantation (allo-SCT) as post remission treatment in CR1. MRD+ was defined as a < 3 log reduction of RUNX1/RUNX1T1 level after the second consolidation therapy.Results:With a median follow-up of 40 months (range, 4-133 months), the 3-year OS, LFS and CIR rates were 75.57% ,70.46% and 27.50% for the entire population, respectively. The 3-year CIR was dramatically decreased in allo-SCT than in CMT group (13.47% vs 49.19%, p<0.001). Allo-SCT demonstrated a significantly superior 3-year OS (85.78% vs 58.89%, p< 0.001) and LFS (85.64% vs 45.84%, p< 0.001) over CMT, respectively. The 3-year cumulative incidence of TRM was 9.27% and 7.04% in the CMT and allo-HSCT groups, respectively (p=0.890). KIT exon 17 mutation was a risk factor for OS in multivariate analysis, CD19 negativity was a risk factor for RFS in univariate analysis. Allo-SCT was a beneficial factor for LFS and OS in multivariate analysis when taking CMT as a reference. For CD19- patients (n=59), allo-HSCT demonstrated significantly lower CIR (17.20% vs 51.03%, p=0.006) , better OS (95.24% vs 51.55%, p < 0.001) and LFS (82.8% vs 39.71%, p = 0.001) than CMT. On the other hand, CMT had a comparable CIR (26.70% vs 11.40, p=0.064 ), OS (73.19% vs 86.01%, p=0.153) and LFS (71.58% vs 87.76%, p=0.067) with allo-SCT for CD19+ patients (n=80). Notably, when combined with RUNX1-RUNX1T1 transcripts after the second consolidation, allo-SCT preserved a significantly lower CIR (6.67% vs 66.67%, p=0.002), improved OS (100% vs 33.33%, p< 0.001) and LFS (93.33% vs 33.33%, p=0.001) than CMT in CD19-MRD+ group (n=22), respectively. In contranst, CMT revealed similar OS (80.0% vs 87.5%, p=0.677 ), LFS (60% vs 62.5%, p=0.663) and CIR (40.00% vs 37.50%, p=0.795 ) with allo-SCT in CD19-MRD- patients (n=13), respectively. For CD19+ patients, addition of MRD status had no impact on the outcome of allo-SCT and CMT. CMT preserved comparable OS (75% vs 84.66%, p =0.516), LFS (85.71% vs 96.30%, p =0.357 ) and CIR (12.50% vs 3.70%, p =0.367) with allo-SCT for CD19+MRD+ patients (n=36), and comparable OS (100% vs 92.31%, p =0.459), LFS (83.33% vs 85.29%, p =0.940 ) and CIR (16.67% vs 13.54%, p =0.998) with allo-SCT in CD19+MRD- patients (n=33).Conclusion: Combination of CD19 expression and RUNX1-RUNX1T1 MRD improved risk stratification and treatment guidance for t(8;21) AML in CR1. Allo-SCT might be recommended for the CD19-MRD+ patients, while CMT might be a reasnonable choice for CD19-MRD+ and CD19+ patients. Multicenter prospective studies are warranted to confirm the current results.Key words: t(8;21) AML, CD19, measurable residual disease, post-remission treatment, allo-SCT, chematherapy DisclosuresNo relevant conflicts of interest to declare.