Prognostic impact of the AML ELN2022 risk classification in patients undergoing allogeneic stem cell transplantation

A novel prognostic scoring system for AML patients undergoing allogeneic hematopoietic stem cell transplantation with real world validation

OBJECTIVES

This study aims to develop a robust predictive model for survival in AML patients undergoing allo-HSCT.

METHODS

It was performed a retrospective analysis of 336 AML patients who underwent allo-HSCT at Peking University First Hospital between September 2003 and March 2023. Univariable and multivariable Cox regression analyses were conducted to determine hazard ratios (HR) for overall survival. A predictive model was developed based on multivariable analysis results. Internal validation was carried out through bootstrap resampling, and the model's performance was assessed using the Concordance Index (C-index), Receiver Operating Characteristics (ROC) curve, calibration plots, and Decision Curve Analysis (DCA).

RESULTS

Our prognostic model, which includes age, disease stage, donor/recipient gender, mononuclear cell counts, and the Hematopoietic Cell Transplantation Comorbidity Index (HCT-CI), effectively stratified patients into low-risk and high-risk groups. The two groups showed significant differences in overall survival (P<0.0001), disease-free survival (P<0.0001), non-relapse mortality (NRM) (P<0.0001), and relapse rates (P=0.08). The model achieved a C-index of 0.71. Calibration plots and DCA confirmed strong alignment between predicted and observed outcomes. Subgroup analysis revealed that overall survival was significantly lower in the high-risk group compared to the low-risk group in both measurable residual disease (MRD) negative and MRD positive subgroups (P=0.015 for both).

CONCLUSION

The developed prognostic model, which integrates comprehensive disease and patient characteristics, enhances risk stratification for AML patients undergoing allo-HSCT. This model effectively stratifies risk in both MRD-negative and MRD-positive subgroups and may facilitate more informed MRD-based treatment decisions.

[Place of hematopoietic stem cell transplantation for very high risk acute myeloblastic leukemia and myelodysplastic syndromes (SFGM-TC)]

Allogeneic hematopoietic stem cell transplantation (alloHSCT) is a potentially curative treatment for acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS). However, these transplants are complicated by a high rate of relapse in very high cytogenetic risk or refractory diseases. The benefit of this therapeutic strategy for these serious malignant hemopathies could therefore be reassessed. As part of the 14th workshop for the harmonization of allograft practices organized by the francophone society of bone marrow transplantation and cellular therapy (SFGM-TC) (SFGM-TC) in Lille in September 2023, the role of allograft for very high risk or refractory AML and MDS was challenged after analysis of published studies.

Comparison of disease and risk classifications of AML before and after incorporation of NGS analysis of bone marrow samples

Mutation profiling by next-generation sequencing (NGS) has facilitated understanding of the molecular pathogenesis of acute myeloid leukemia (AML), and has been incorporated into the new disease classification (International Consensus Classification; ICC) and risk classification (European LeukemiaNet [ELN] 2022; ELN2022). We compared disease subtypes between the previous disease classification (4th edition of the WHO classification; WHO-4) and the ICC in 91 patients with AML diagnosed at our institution. We also compared disease risk classifications using the previous risk classification (ELN2017) and the ELN2022. Targeted sequencing of bone marrow samples was conducted at Kyoto University. We found that entities under AML with recurrent genetic abnormalities were well-established, with almost no change from the WHO-4 to the ICC. In contrast, 16.7% of cases of AML, not otherwise specified in the WHO-4 were reclassified into AML with mutated TP53, and 36.7% were reclassified into AML with myelodysplasia-related gene mutations or cytogenetic abnormalities per the ICC. Meanwhile, the ELN2017 and ELN2022 showed no difference in concordance indexes in multivariate Cox regression analysis for progression-free and overall survival. The superiority of the ELN2022 over the ELN2017 could not be confirmed in our single-center retrospective study, and further investigation including multicenter prospective studies is needed.

Dynamic Relapse Prediction by Peripheral Blood WT1mRNA after Allogeneic Hematopoietic Cell Transplantation for Myeloid Neoplasms

Although various relapse prediction models based on pretransplant information have been reported, they cannot update the predictive probability considering post-transplant patient status. Therefore, these models are not appropriate for deciding on treatment adjustment and preemptive intervention during post-transplant follow-up. A dynamic prediction model can update the predictive probability by considering the information obtained during follow-up. This study aimed to develop and assess a dynamic relapse prediction model after allogeneic hematopoietic cell transplantation (allo-HCT) for acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) using peripheral blood Wilms' tumor 1 messenger RNA (WT1mRNA). We retrospectively analyzed patients with AML or MDS who underwent allo-HCT at our institution. To develop dynamic models, we employed the landmarking supermodel approach, using age, refined disease risk index, conditioning intensity, and number of transplantations as pretransplant covariates and both pre- and post-transplant peripheral blood WT1mRNA levels as time-dependent covariates. Finally, we compared the predictive performances of the conventional and dynamic models by area under the time-dependent receiver operating characteristic curves. A total of 238 allo-HCT cases were included in this study. The dynamic model that considered all pretransplant WT1mRNA levels and their kinetics showed superior predictive performance compared to models that considered only pretransplant covariates or factored in both pretransplant covariates and post-transplant WT1mRNA levels without their kinetics; their time-dependent areas under the curve were 0.89, 0.73, and 0.87, respectively. The predictive probability of relapse increased gradually from approximately 90 days before relapse. Furthermore, we developed a web application to make our model user-friendly. This model facilitates real-time, highly accurate, and personalized relapse prediction at any time point after allo-HCT. This will aid decision-making during post-transplant follow-up by offering objective relapse forecasts for physicians.

Evaluation of European LeukemiaNet 2022 risk classification in patients undergoing allogeneic haematopoietic stem cell transplantation for acute myeloid leukaemia: Identification of a very poor prognosis genetic group

European LeukemiaNet refined their risk classification of acute myeloid leukaemia (AML) in 2022 (ELN 2022) according to the two new myeloid classifications published the same year. We have retrospectively assessed the prognostic value of the ELN 2022 in 120 AML patients undergoing allogeneic haematopoietic cell transplantation (allo-HCT), including 99 in first complete response (CR1) from 2011 to 2021 in our centre. Adverse risk patients (Adv) presented inferior outcome in terms of overall survival (OS) and leukaemia-free survival (LFS) (OS [p = 0.003], LFS [p = 0.02]), confirmed in multivariate analysis (hazard ratio [HR] for OS = 2.00, p = 0.037). These results were also seen in patients allografted in CR1. Further analysis identified a subgroup named adverse-plus (AdvP), including complex karyotype, MECOM(EVI1) rearrangements and TP53 mutations, with worse outcomes than the rest of groups of patients, including the Adv (HR for OS: 3.14, p < 0.001, HR for LFS: 3.36, p < 0.001), with higher 2-year cumulative incidence of relapse (p < 0.001). Notably, within this analysis, the outcome of Adv and intermediate patients were similar. These findings highlight the prognostic value of ELN 2022 in patients undergoing allo-HCT, which can be improved by the recognition of a poor genetic subset (AdvP) within the Adv risk group.

Stellae-123 gene expression signature improved risk stratification in taiwanese acute myeloid leukemia patients

The European Leukemia Net recommendations provide valuable guidance in treatment decisions of patients with acute myeloid leukemia (AML). However, the genetic complexity and heterogeneity of AML are not fully covered, notwithstanding that gene expression analysis is crucial in the risk stratification of AML. The Stellae-123 score, an AI-based model that captures gene expression patterns, has demonstrated robust survival predictions in AML patients across four western-population cohorts. This study aims to evaluate the applicability of Stellae-123 in a Taiwanese cohort. The Stellae-123 model was applied to 304 de novo AML patients diagnosed and treated at the National Taiwan University Hospital. We find that the pretrained (BeatAML-based) model achieved c-indexes of 0.631 and 0.632 for the prediction of overall survival (OS) and relapse-free survival (RFS), respectively. Model retraining within our cohort further improve the cross-validated c-indexes to 0.667 and 0.667 for OS and RFS prediction, respectively. Multivariable analysis identify both pretrained and retrained models as independent prognostic biomarkers. We further show that incorporating age, Stellae-123, and ELN classification remarkably improves risk stratification, revealing c-indices of 0.73 and 0.728 for OS and RFS, respectively. In summary, the Stellae-123 gene expression signature is a valuable prognostic tool for AML patients and model retraining can improve the accuracy and applicability of the model in different populations.

Validation of the 2022 European LeukemiaNet risk stratification for acute myeloid leukemia

This study aimed to validate the 2022 European LeukemiaNet (ELN) risk stratification for acute myeloid leukemia (AML). A total of 624 newly diagnosed AML patients from 1998 to 2014 were included in the analysis. Genetic profiling was conducted using targeted deep sequencing of 45 genes based on recurrent driver mutations. In total, 134 (21.5%) patients had their risk classification reassessed according to the 2022 ELN risk stratification. Among those initially classified as having a favorable risk in 2017 (n = 218), 31 and 3 patients were reclassified as having intermediate risk or adverse risk, respectively. Among the three subgroups, the 2022 ELN favorable-risk group showed significantly longer survival outcomes than the other groups. Within the 2017 ELN intermediate-risk group (n = 298), 21 and 46 patients were reclassified as having favorable risk or adverse risk, respectively, and each group showed significant stratifications in survival outcomes. Some patients initially classified as having adverse risk in 2017 were reclassified into the intermediate-risk group (33 of 108 patients), but no prognostic improvements were observed in this group. A multivariable analysis identified the 2022 ELN risk stratification, age, and receiving allogeneic hematopoietic cell transplantation as significant prognostic factors for survival. The 2022 ELN risk stratification enables more precise decisions for proceeding with allogeneic hematopoietic cell transplantation for AML patients.

Innovations in conditioning and post-transplant maintenance in AML: genomically informed revelations on the graft-versus-leukemia effect

Acute Myeloid Leukemia (AML) is the prototype of cancer genomics as it was the first published cancer genome. Large-scale next generation/massively parallel sequencing efforts have identified recurrent alterations that inform prognosis and have guided the development of targeted therapies. Despite changes in the frontline and relapsed standard of care stemming from the success of small molecules targeting FLT3, IDH1/2, and apoptotic pathways, allogeneic stem cell transplantation (alloHSCT) and the resulting graft-versus-leukemia (GVL) effect remains the only curative path for most patients. Advances in conditioning regimens, graft-vs-host disease prophylaxis, anti-infective agents, and supportive care have made this modality feasible, reducing transplant related mortality even among patients with advanced age or medical comorbidities. As such, relapse has emerged now as the most common cause of transplant failure. Relapse may occur after alloHSCT because residual disease clones persist after transplant, and develop immune escape from GVL, or such clones may proliferate rapidly early after alloHSCT, and outpace donor immune reconstitution, leading to relapse before any GVL effect could set in. To address this issue, genomically informed therapies are increasingly being incorporated into pre-transplant conditioning, or as post-transplant maintenance or pre-emptive therapy in the setting of mixed/falling donor chimerism or persistent detectable measurable residual disease (MRD). There is an urgent need to better understand how these emerging therapies modulate the two sides of the GVHD vs. GVL coin: 1) how molecularly or immunologically targeted therapies affect engraftment, GVHD potential, and function of the donor graft and 2) how these therapies affect the immunogenicity and sensitivity of leukemic clones to the GVL effect. By maximizing the synergistic action of molecularly targeted agents, immunomodulating agents, conventional chemotherapy, and the GVL effect, there is hope for improving outcomes for patients with this often-devastating disease.

The graft versus leukemia effect: donor lymphocyte infusions and cellular therapy

Allogeneic hematopoietic stem cell transplantation (HSCT) is a potentially curative therapy for many hematologic malignancies as well as non-malignant conditions. Part of the curative basis underlying HSCT for hematologic malignancies relies upon induction of the graft versus leukemia (GVL) effect in which donor immune cells recognize and eliminate residual malignant cells within the recipient, thereby maintaining remission. GVL is a clinically evident phenomenon; however, specific cell types responsible for inducing this effect and molecular mechanisms involved remain largely undefined. One of the best examples of GVL is observed after donor lymphocyte infusions (DLI), an established therapy for relapsed disease or incipient/anticipated relapse. DLI involves infusion of peripheral blood lymphocytes from the original HSCT donor into the recipient. Sustained remission can be observed in 20-80% of patients treated with DLI depending upon the underlying disease and the intrinsic burden of targeted cells. In this review, we will discuss current knowledge about mechanisms of GVL after DLI, experimental strategies for augmenting GVL by manipulation of DLI (e.g. neoantigen vaccination, specific cell type selection/depletion) and research outlook for improving DLI and cellular immunotherapies for hematologic malignancies through better molecular definition of the GVL effect.

Recent advances in allogeneic transplantation for acute myeloid leukemia

PURPOSE OF REVIEW

This review highlights recent advancements in allogeneic hematopoietic stem cell transplantation (allo-HSCT) for patients with acute myeloid leukemia (AML).

RECENT FINDINGS

Important improvements have been observed throughout the allo-HSCT procedure and patient management. Universal donor availability and reduced risk of graft-versus-host disease (GVHD) have been achieved with the introduction of posttransplant cyclophosphamide for GVHD prophylaxis. It has contributed, together with advances in conditioning regimens, GVHD treatment and supportive care, to a reduced overall toxicity of the procedure. Relapse is now the most frequent cause of transplant failure. With increased knowledge of the biological characterization of AML, better prediction of transplant risks and more profound and standardized minimal residual disease (MRD) monitoring, pharmacological, and immunological strategies to prevent relapse are been developed.

SUMMARY

Allo-HSCT remains the standard of care for high-risk AML. Increased access to transplant, reduced toxicity and relapse are improving patient outcomes. Further research is needed to optimize MRD monitoring, refine conditioning regimens, and explore new GVHD management and relapse prevention therapies.

[Prognostic factors and survival in adult acute leukemia in Burkina Faso]

Introduction

Acute leukemia is both a diagnostic and therapeutic emergency. Our study aimed to describe the prognostic factors and survival of adults with acute leukemia in Burkina Faso.

Patients and methods

Cross-sectional descriptive study with retrospective data collection covering a period of 4.5 years (2018-2022) in two university hospitals in Burkina Faso. Were included all patients over 18 years hospitalized for acute leukemia in these sites with a usable medical record.

Results

A total of 42 cases were collected, of which 45% suffered from acute lymphoblastic leukemia and 43% from acute myeloid leukemia. In 12% of cases, acute leukemia was not classified. The average age was 35 ± 15 years, with extremes of 19 and 72 years. 12% of the patients presented an age of poor prognosis. Comorbidities were present in 14% of patients. The deterioration in general condition was fairly constant with 95% of patients at WHO stages 3 and 4. All patients presented with bone marrow failure syndrome and tumor syndrome was found in 45%. Anemia and thrombocytopenia were present in almost all cases. Hyperleukocytosis at diagnosis was present in 28 patients (67%); among them 18 patients (64%) had leukocytes greater than 50 G/L. Death in hospital was found in 38% of patients and loss of sight in 31%. The median survival was 3 months. Survival was 30% at 6 months and 0% at 12 months.

Conclusion

Acute leukemias are in our practice conditions of poor prognosis with a fairly short survival.

AML classification in the year 2023: How to avoid a Babylonian confusion of languages

In parallel to the 5th edition of the World Health Organization Classification of Haematolymphoid Tumours (WHO 2022), an alternative International Consensus Classification (ICC) has been proposed. To evaluate the impact of the new classifications on AML diagnoses and ELN-based risk classification, we analyzed 717 MDS and 734 AML non-therapy-related patients diagnosed according to the revised 4th WHO edition (WHO 2017) by whole genome and transcriptome sequencing. In both new classifications, the purely morphologically defined AML entities decreased from 13% to 5%. Myelodysplasia-related (MR) AML increased from 22% to 28% (WHO 2022) and 26% (ICC). Other genetically-defined AML remained the largest group, and the abandoned AML-RUNX1 was mainly reclassified as AML-MR (WHO 2022: 77%; ICC: 96%). Different inclusion criteria of AML-CEBPA and AML-MR (i.a. exclusion of TP53 mutated cases according to ICC) were associated with differences in overall survival. In conclusion, both classifications focus on more genetics-based definitions with similar basic concepts and a large degree of agreement. The remaining non-comparability (e.g., TP53 mutated AML) needs additional studies to definitely answer open questions on disease categorization in an unbiased way.

Evolving Risk Classifications in AML in a Real-Life Scenario: After Changes upon Changes, Is It More and More Adverse?

Acute myeloid leukemia (AML) is a heterogeneous disease classified into three risk categories (favorable, intermediate and adverse) with significant differences in outcomes. Definitions of risk categories evolve overtime, incorporating advances in molecular knowledge of AML. In this study, we analyzed the impacts of evolving risk classifications in 130 consecutive AML patients in a single-center real-life experience. Complete cytogenetic and molecular data were collected using conventional qPCR and targeted Next Generation Sequencing (NGS). Five-year OS probabilities were consistent among all classification models (roughly 50-72%, 26-32% and 16-20% for favorable, intermediate and adverse risk groups, respectively). In the same way, the medians of survival months and prediction power were similar in all models. In each update, around 20% of patients were re-classified. The adverse category consistently increased over time (31% in MRC, 34% in ELN2010, 50% in ELN2017), reaching up to 56% in the recent ELN2022. Noteworthily, in multivariate models, only age and the presence of TP53 mutations remained statistically significant. With updates in risk-classification models, the percentage of patients assigned to the adverse group is increasing, and so will the indications for allogeneic stem cell transplantation.