Comparative analysis of the value of allogeneic hematopoietic stem-cell transplantation in acute myeloid leukemia with monosomal karyotype versus other cytogenetic risk categories

Acquired immune resistance is associated with interferon signature and modulation of KLF6/c-MYB transcription factors in myeloid leukemia

Resistance to immunity is associated with the selection of cancer cells with superior capacities to survive inflammatory reactions. Here, we tailored an ex vivo immune selection model for acute myeloid leukemia (AML) and isolated the residual subpopulations as "immune-experienced" AML (ieAML) cells. We confirmed that upon surviving the immune reactions, the malignant blasts frequently decelerated proliferation, displayed features of myeloid differentiation and activation, and lost immunogenicity. Transcriptomic analyses revealed a limited number of commonly altered pathways and differentially expressed genes in all ieAML cells derived from distinct parental cell lines. Molecular signatures predominantly associated with interferon and inflammatory cytokine signaling were enriched in the AML cells resisting the T-cell-mediated immune reactions. Moreover, the expression and nuclear localization of the transcription factors c-MYB and KLF6 were noted as the putative markers for immune resistance and identified in subpopulations of AML blasts in the patients' bone marrow aspirates. The immune modulatory capacities of ieAML cells lasted for a restricted period when the immune selection pressure was omitted. In conclusion, myeloid leukemia cells harbor subpopulations that can adapt to the harsh conditions established by immune reactions, and a previous "immune experience" is marked with IFN signature and may pave the way for susceptibility to immune intervention therapies.

Features of the TCR repertoire associate with patients' clinical and molecular characteristics in acute myeloid leukemia

Background

Allogeneic hematopoietic stem cell transplant remains the most effective strategy for patients with high-risk acute myeloid leukemia (AML). Leukemia-specific neoantigens presented by the major histocompatibility complexes (MHCs) are recognized by the T cell receptors (TCR) triggering the graft-versus-leukemia effect. A unique TCR signature is generated by a complex V(D)J rearrangement process to form TCR capable of binding to the peptide-MHC. The generated TCR repertoire undergoes dynamic changes with disease progression and treatment.

Method

Here we applied two different computational tools (TRUST4 and MIXCR) to extract the TCR sequences from RNA-seq data from The Cancer Genome Atlas (TCGA) and examine the association between features of the TCR repertoire in adult patients with AML and their clinical and molecular characteristics.

Results

We found that only ~30% of identified TCR CDR3s were shared by the two computational tools. Yet, patterns of TCR associations with patients' clinical and molecular characteristics based on data obtained from either tool were similar. The numbers of unique TCR clones were highly correlated with patients' white blood cell counts, bone marrow blast percentage, and peripheral blood blast percentage. Multivariable regressions of TCRA and TCRB median normalized number of unique clones with mutational status of AML patients using TRUST4 showed significant association of TCRA or TCRB with WT1 mutations, WBC count, %BM blast, and sex (adjusted in TCRB model). We observed a correlation between TCRA/B number of unique clones and the expression of T cells inhibitory signal genes (TIGIT, LAG3, CTLA-4) and foxp3, but not IL2RA, CD69 and TNFRSF9 suggestive of exhausted T cell phenotypes in AML.

Conclusion

Benchmarking of computational tools is needed to increase the accuracy of the identified clones. The utilization of RNA-seq data enables identification of highly abundant TCRs and correlating these clones with patients' clinical and molecular characteristics. This study further supports the value of high-resolution TCR-Seq analyses to characterize the TCR repertoire in patients.

What Influences the Decision to Proceed to Transplant for Patients With AML in First Remission?

Although allogeneic hematopoietic cell transplantation (allo-HCT) remains the backbone of curative treatment for the majority of fit adults diagnosed with AML, there is indeed a subset of patients for whom long-term remission may be achieved without transplantation. Remarkable changes in our knowledge of AML biology in recent years has transformed the landscape of diagnosis, management, and treatment of AML. Specifically, markedly increased understanding of molecular characteristics of AML, the expanded application of minimal/measurable residual diseases testing, and an increased armamentarium of leukemia-directed therapeutic agents have created a new paradigm for the medical care of patients with AML. An attempt is herein made to decipher the decision to proceed to transplant for patients with AML in first complete remission on the basis of the current best available evidence. The focus is on factors affecting the biology and treatment of AML itself, rather than on variables related to allo-HCT, an area characterized by significant advancements that have reduced overall therapy-related complications. This review seeks to focus on areas of particular complexity, while simultaneously providing clarity on how our current knowledge and treatment strategies may, or may not, influence the decision to pursue allo-HCT in patients with AML.

NK cell defects: implication in acute myeloid leukemia

Acute Myeloid Leukemia (AML) is a complex disease with rapid progression and poor/unsatisfactory outcomes. In the past few years, the focus has been on developing newer therapies for AML; however, relapse remains a significant problem. Natural Killer cells have strong anti-tumor potential against AML. This NK-mediated cytotoxicity is often restricted by cellular defects caused by disease-associated mechanisms, which can lead to disease progression. A stark feature of AML is the low/no expression of the cognate HLA ligands for the activating KIR receptors, due to which these tumor cells evade NK-mediated lysis. Recently, different Natural Killer cell therapies have been implicated in treating AML, such as the adoptive NK cell transfer, Chimeric antigen receptor-modified NK (CAR-NK) cell therapy, antibodies, cytokine, and drug treatment. However, the data available is scarce, and the outcomes vary between different transplant settings and different types of leukemia. Moreover, remission achieved by some of these therapies is only for a short time. In this mini-review, we will discuss the role of NK cell defects in AML progression, particularly the expression of different cell surface markers, the available NK cell therapies, and the results from various preclinical and clinical trials.

Transplantation/Zelltherapie bei Akuter Myeloischer Leukämie

To date allogeneic hematopoietic stem cell transplantation (allo-HSCT) is the most effective immunotherapeutic approach for the treatment of acute myeloid leukemia (AML). It involves the transplantation of blood stem cells from a healthy donor into a patient, with the goal of using the donor's immune system to recognize and attack cancer cells (Graft-versus-leukemia effect). Thereby, allo-HSCT is more efficient than chemotherapy alone, as it combines high dose chemotherapy +/- irradiation with immunotherapy establishing a long-term control of leukemic cells while allowing reconstitution of a healthy donor hematopoiesis and a new immune system. However, the procedure carries significant risks, including the possibility of graft-versus-host disease (GvHD), and requires careful patient selection to ensure the best possible outcome. In AML patients with high-risk, relapsed or chemo-refractory disease allo-HSCT provides the only curative option.While allo-HSCT is currently the most established form of immunotherapy in the treatment of AML, other approaches that use the immune system to fight cancer are being researched. These may include immunomodulatory drugs or cell therapies such as CAR-T cells, which stimulate the immune system to attack cancer cells. Even if this does not yet play a role in current standard therapy, as our understanding of the immune system and its role in cancer grows, it is likely that targeted immunotherapies will become increasingly important in the treatment of AML The following article gives you an overview of allo-HSCT in AML patients and the current developments.

High ME1 Expression Is a Molecular Predictor of Post-Transplant Survival of Patients with Acute Myeloid Leukemia

Several laboratory and clinical variables have been reported to be associated with the outcome of intensive chemotherapy for acute myeloid leukemia (AML), but only a few have been tested in the context of hematopoietic stem cell transplant (HSCT). This study aimed to identify genes whose expression of AML at diagnosis were associated with survival after HSCT. For this purpose, three publicly available adult AML cohorts (TCGA, BeatAML, and HOVON), whose patients were treated with intensive chemotherapy and then subjected to allogeneic or autologous HSCT, were included in this study. After whole transcriptome analysis, we identified ME1 as the only gene whose high expression was associated with shorter survival in patients subjected to HSCT. In addition, the inclusion of ME1 expression was able to improve the European LeukemiaNet risk stratification. Pathways related to lipid biosynthesis, mainly fatty acids, and cholesterol were positively correlated with ME1 expression. Furthermore, ME1 expression was associated with an M2 macrophage-enriched microenvironment, mature AML blasts hierarchy, and oxidative phosphorylation metabolism. Therefore, ME1 expression can be used as biomarker of poor response to HSCT in AML.

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?

Additional cytogenetic features determine outcome in patients allografted for TP53 mutant acute myeloid leukemia

BACKGROUND

The presence of TP53 mutations is associated with an unfavorable outcome in patients allografted for acute myeloid leukemia (AML), leading some to question the benefit of an allogeneic stem cell transplantation (allo-SCT) for this patient group, although this has not been studied in a large cohort.

METHODS

A total of 780 patients with AML in first complete remission, with either intermediate- or adverse-risk cytogenetics, whose TP53 mutation status was reported, were included in this study from the European Society for Blood and Marrow Transplantation.

RESULTS

Two-year overall survival (OS) was impaired in patients (n = 179) with evidence of a TP53 mutation at diagnosis (35.1%; 95% confidence interval [CI], 26.7-43.7) as compared to the cohort without (n = 601) (64%; 95% CI, 59.1-68.4; P = .001). In patients with mutant TP53 AML with no evidence of either chromosome 17p loss (17p-) and/or complex karyotype (CK) (n = 53, 29.6%), 2-year OS was 65.2% (95% CI, 48.4-77.6). This was not significantly different to patients without TP53 mutations. In patients with mutant TP53 AML with either 17p- and/or CK (n = 126, 70.4%), the OS was lower (24.6%; 95% CI, 16.2-34; P = .001).

CONCLUSIONS

In summary, the adverse prognostic effect of TP53 mutations in AML following an allo-SCT is not evident in patients with neither co-occurring 17p- and/or CK, and these data inform decisions regarding allo-SCT in patients with TP53 mutant AML.

Antigen-Specific TCR-T Cells for Acute Myeloid Leukemia: State of the Art and Challenges

The cytogenetic abnormalities and molecular mutations involved in acute myeloid leukemia (AML) lead to unique treatment challenges. Although adoptive T-cell therapies (ACT) such as chimeric antigen receptor (CAR) T-cell therapy have shown promising results in the treatment of leukemias, especially B-cell malignancies, the optimal target surface antigen has yet to be discovered for AML. Alternatively, T-cell receptor (TCR)-redirected T cells can target intracellular antigens presented by HLA molecules, allowing the exploration of a broader territory of new therapeutic targets. Immunotherapy using adoptive transfer of WT1 antigen-specific TCR-T cells, for example, has had positive clinical successes in patients with AML. Nevertheless, AML can escape from immune system elimination by producing immunosuppressive factors or releasing several cytokines. This review presents recent advances of antigen-specific TCR-T cells in treating AML and discusses their challenges and future directions in clinical applications.

Cord-Blood Engraftment Using an Enhanced Dual-Conditioning Regimen for Malignant Hematologic Diseases

To explore a more effective conditioning regimen for umbilical cord blood transplantation (UCBT) to treat hematologic malignancies, we conducted a cohort study of a fludarabine/busulfan/cytarabine plus cyclophosphamide 200 mg/kg regimen. Forty-two consecutive patients with leukemia, myelodysplastic syndrome, or lymphoma received the regimen. The median number of infused total nucleated cells per kilogram was 5.5 × 10⁷ (1.81–20.6), the median number of infused CD34⁺ cells per kilogram was 1.58 × 10⁵ (0.58–6.6), and the median follow-up for surviving patients was 37 months (4.0–79.5 months). The cumulative incidence of neutrophil engraftment at 31 days was 100% [95% confidence interval (CI): 0.9159–1.0], and the median time to neutrophil engraftment was 19 days. The cumulative incidence of nonrelapse mortality was 12.76% (95% CI: 0.0455–0.2356) at 180 days and 3 years. The 3-year overall survival (OS) and disease-free survival (DFS) rates were 71.6% and 59.6%, respectively. Especially in patients who received transplants in the early and intermediate stages, the 3-year OS and DFS rates were 90.3% (95% CI: 0.805–1.0) and 76.2% (95% CI: 0.608–0.956), respectively. The regimen significantly improved engraftment and survival, indicating that the high graft failure of UCBT was caused by rejection.

Clinical Characteristics and Outcome Analysis for HLA Loss Patients Following Partially Mismatched Related Donor Transplantation Using HLA Chimerism for Loss of Heterozygosity Analysis by Next-Generation Sequencing

Genomic loss of mismatched human leukocyte antigen (HLA loss) is one of the most vital immune escape mechanisms of leukemic cells after allogeneic hematopoietic stem cell transplantation (allo-HSCT). However, the methods currently used for HLA loss analysis have some shortcomings. Limited literature has been published, especially in lymphoid malignancies. This study aims to evaluate the incidences, risk factors of HLA loss, and clinical outcomes of HLA loss patients. In all, 160 patients undergoing partially mismatched related donor (MMRD) transplantation from 18 centers in China were selected for HLA loss analysis with the next-generation sequencing (NGS)-based method, which was validated by HLA-KMR. Variables of the prognostic risk factors for HLA loss or HLA loss–related relapse were identified with the logistic regression or the Fine and Gray regression model. An HLA loss detection system, HLA-CLN [HLA chimerism for loss of heterozygosity (LOH) analysis by NGS], was successfully developed. Forty (25.0%) patients with HLA loss were reported, including 27 with myeloid and 13 with lymphoid malignancies. Surprisingly, 6 of those 40 patients did not relapse. The 2-year cumulative incidences of HLA loss (22.7% vs 22.0%, P = 0.731) and HLA loss–related relapse (18.4% vs 20.0%, P = 0.616) were similar between patients with myeloid and lymphoid malignancies. The number of HLA mismatches (5/10 vs <5/10) was significantly associated with HLA loss in the whole cohort [odds ratio (OR): 3.15, P = 0.021] and patients with myeloid malignancies (OR: 3.94, P = 0.021). A higher refined-disease risk index (OR: 6.91, P = 0.033) and donor–recipient ABO incompatibility (OR: 4.58, P = 0.057) contributed to HLA loss in lymphoid malignancies. To sum up, HLA-CLN could overcome the limitations of HLA-KMR and achieve a better HLA coverage for more patients. The clinical characteristics and outcomes were similar in patients with HLA loss between myeloid and lymphoid malignancies. In addition, the results suggested that a patient with HLA loss might not always relapse.

Recent Progress in Interferon Therapy for Myeloid Malignancies

Myeloid malignancies are a heterogeneous group of clonal haematopoietic disorders, caused by abnormalities in haematopoietic stem cells (HSCs) and myeloid progenitor cells that originate in the bone marrow niche. Each of these disorders are unique and present their own challenges with regards to treatment. Acute myeloid leukaemia (AML) is considered the most aggressive myeloid malignancy, only potentially curable with intensive cytotoxic chemotherapy with or without allogeneic haematopoietic stem cell transplantation. In comparison, patients diagnosed with chronic myeloid leukaemia (CML) and treated with tyrosine kinase inhibitors (TKIs) have a high rate of long-term survival. However, drug resistance and relapse are major issues in both these diseases. A growing body of evidence suggests that Interferons (IFNs) may be a useful therapy for myeloid malignancies, particularly in circumstances where patients are resistant to existing front-line therapies and have risk of relapse following haematopoietic stem cell transplant. IFNs are a major class of cytokines which are known to play an integral role in the non-specific immune response. IFN therapy has potential as a combination therapy in AML patients to reduce the impact of minimal residual disease on relapse. Alongside this, IFNs can potentially sensitize leukaemic cells to TKIs in resistant CML patients. There is evidence also that IFNs have a therapeutic role in myeloproliferative neoplasms (MPNs) such as polycythaemia vera (PV) and primary myelofibrosis (PMF), where they can restore polyclonality in patients. Novel formulations have improved the clinical effectiveness of IFNs. Low dose pegylated IFN formulations improve pharmacokinetics and improve patient tolerance to therapies, thereby minimizing the risk of haematological toxicities. Herein, we will discuss recent developments and the current understanding of the molecular and clinical implications of Type I IFNs for the treatment of myeloid malignancies.

Pretransplant bone marrow cellularity and blood count recovery are not associated with relapse or survival risk following allogeneic stem cell transplant for AML in CR

INTRODUCTION

Allogeneic hematopoietic cell transplantation (HCT) can be curative for acute myeloid leukemia (AML). Novel therapies may render patients' bone marrow hypocellularity and lead to prolonged post-therapy pancytopenia. Patients' bone marrow cellularity (BMC) at pretransplant assessment and post-treatment pancytopenia (classification CR-incomplete [CRi]) may manifest AML persistence.

METHODOLOGY

We retrospectively examined the impact of BMC and ELN response (ELNr) on a single-center cohort of 337 patients who underwent allogeneic HCT for AML in CR1.

RESULTS

Median follow-up was 33 months. Overall survival (OS) for the whole cohort was 55.8% at 2 years, while cumulative incidence of relapse (CIR) was 20.8%, and non-relapse mortality was 27.5%. OS and CIR were not significantly different between BMC groups; and neither was ELNr. ELNr CRi was associated with BMC aplastic and hypocellular marrow states (P < 2.6e-8). Multivariate analysis confirmed neither BMC nor attainment of ELNr CR vs CRi affected OS or relapse. Significant factors for survival included age at transplant, cytogenetic risk, development of acute Gr II-IV GvHD, and moderate-severe chronic GvHD, while cytogenetic risk and chronic GvHD affected relapse.

CONCLUSION

Neither ELNr status nor pretransplant BMC influenced relapse post-HCT or OS. Hypocellularity and CRi are not negative prognostic factors for post-HCT outcomes of AML.

The evolving concept of indications for allogeneic hematopoietic cell transplantation during first complete remission of acute myeloid leukemia

The long-standing debate of whether patients with acute myeloid leukemia (AML) should proceed to allogeneic hematopoietic cell transplantation (HCT) during first complete remission (CR1) remains unsettled. Although allogeneic HCT during CR1 used to be recommended for those with intermediate or poor cytogenetics if they had a matched sibling donor, the concept of indications for allogeneic HCT during CR1 has been evolving by virtue of advances in understanding of the molecular pathogenesis of AML and innovations in transplantation practice attained over the last few decades. The incorporation of molecular profiles of leukemia has been shown to contribute to further refinements of risk classification that had previously relied mostly on cytogenetics, while the progress in transplantation procedures has made it possible to perform transplantations more safely even for patients without a matched sibling donor. These significant changes have underpinned the need to reappraise indications for allogeneic HCT during CR1 of AML. Improvements in clinical applications of genetic and measurable residual disease information as well as in transplantation technology are expected to further refine indications for allogeneic HCT during CR1, and thus promote an individualized approach for the treatment of AML.

The effect of the detection of minimal residual disease for the prognosis and the choice of post-remission therapy of intermediate-risk acute myeloid leukemia without FLT3-ITD, NPM1 and biallelic CEBPA mutations

BACKGROUND

Intermediate-risk acute myeloid leukemia (IR-AML) without FLT3-ITD, NPM1 and biallelic CEBPA mutations (here referred to as NPM1^mut-negCEBPA^dm-negFLT3-ITD^neg AML) is a clinically heterogeneous disease. The optimal post-remission therapy (PRT) is unclear for patients with NPM1^mut-negCEBPA^dm-negFLT3-ITD^neg AML who achieved first complete response (CR1). This study aims to explore clinical and molecular factors that can help determine the prognosis of those patients and their choice of PRT.

METHODS

We retrospectively analyzed 28 patients with NPM1^mut-negCEBPA^dm-negFLT3-ITD^neg AML who received induction chemotherapy and achieved CR1. For PRT, 17 patients received post-remission chemotherapy (PR-CT) and 11 patients received allogeneic hematopoietic stem cell transplantation (allo-HSCT).

RESULTS

For patients with NPM1^mut-negCEBPA^dm-negFLT3-ITD^neg AML, multivariate analysis indicated that allo-HSCT and negative minimal residual disease (MRD^neg) before PRT were favorable prognostic factors of overall survival (OS) (allo-HSCT, P = 0.002; MRD^neg, P = 0.018); whereas relapse was an adverse prognostic factor of OS (P = 0.003). Log-rank analysis showed that allo-HSCT significantly improved their OS and RFS compared with PR-CT (OS, P < 0.001; RFS, P = 001). Otherwise, allo-HSCT improved the OS and RFS of patients with NPM1^mut-negCEBPA^dm-negFLT3-ITD^neg AML, whether they obtained MRD^pos or MRD^neg before PRT (OS: MRD^neg, P = 0.036; MRD^pos, P = 0.012; RFS: MRD^neg, P = 0.047; MRD^pos, P = 0.030).

CONCLUSION

For patients with NPM1^mut-negCEBPA^dm-negFLT3-ITD^neg AML, MRD^neg before PRT and allo-HSCT were favorable prognostic factors of OS. Whether they obtain MRD^neg or not, allo-HSCT is the preferred PRT.

A personalized approach to guide allogeneic stem cell transplantation in younger adults with acute myeloid leukemia

A multistage model instructed by a large dataset (knowledge bank [KB] algorithm) has recently been developed to improve outcome predictions and tailor therapeutic decisions, including hematopoietic stem cell transplantation (HSCT) in acute myeloid leukemia (AML). We assessed the performance of the KB in guiding HSCT decisions in first complete remission (CR1) in 656 AML patients younger than 60 years from the ALFA-0702 trial (NCT00932412). KB predictions of overall survival (OS) were superior to those of European LeukemiaNet (ELN) 2017 risk stratification (C-index, 68.9 vs 63.0). Among patients reaching CR1, HSCT in CR1, as a time-dependent covariate, was detrimental in those with favorable ELN 2017 risk and those with negative NPM1 minimal residual disease (MRD; interaction tests, P = .01 and P = .02, respectively). Using KB simulations of survival at 5 years in a scenario without HSCT in CR1 (KB score), we identified, in a similar time-dependent analysis, a significant interaction between KB score and HSCT, with HSCT in CR1 being detrimental only in patients with a good prognosis based on KB simulations (KB score ≥40; interaction test, P = .01). We could finally integrate ELN 2017, NPM1 MRD, and KB scores to sort 545 CR1 patients into 278 (51.0%) HSCT candidates and 267 (49.0%) chemotherapy-only candidates. In both time-dependent and 6-month landmark analyses, HSCT significantly improved OS in HSCT candidates, whereas it significantly shortened OS in chemotherapy-only candidates. Integrating KB predictions with ELN 2017 and MRD may thus represent a promising approach to optimize HSCT timing in younger AML patients.

Glasdegib as maintenance therapy for patients with AML and MDS patients at high risk for postallogeneic stem cell transplant relapse

Posttransplantation, glasdegib maintenance therapy in patients at high risk for relapse did not meaningfully reduce relapse incidence. Use of glasdegib in the posttransplantation setting was complicated by adverse events requiring drug holds and occasional discontinuation.

Prognostic impact of the ELN2017 risk classification in patients with AML receiving allogeneic transplantation

In 2017, an updated European LeukemiaNet (ELN) risk classification was published allocating patients with acute myeloid leukemia (AML) to 3 risk groups on the basis of certain cytogenetic and molecular aberrations. To date, studies of the prognostic significance of the ELN2017 risk classification in the context of an allogeneic hematopoietic stem cell transplantation (HSCT) are lacking. We performed risk stratification according to the ELN2017 classification in 234 patients with AML who underwent allogeneic HSCT as a consolidation therapy. In our cohort, the risk of 39.7% of the patients was classified as favorable, that of 12.8% as intermediate, and that of 47.4% as adverse. In the context of allogeneic HSCT, the assignment to the 3 ELN2017 risk groups retained its prognostic significance, with patients with favorable risk having the best prognosis and those with adverse risk having the worst one. Subgroup analyses showed that patients with a monosomal karyotype or TP53 mutation had considerably increased relapse rates, even in the adverse-risk group. When we analyzed the impact of digital droplet PCR-based measurable residual disease (MRD) before allogeneic HSCT, MRD+ patients had impaired prognoses, with cumulative incidence of relapse and overall survival comparable to those of patients classified as having an ELN2017 adverse genetic risk. This study is the first to demonstrate that the ELN2017 classification distinguishes the 3 risk groups with significantly distinct prognoses, even after allogeneic HSCT, and emphasizes the dismal prognosis of patients with AML with TP53 mutations, monosomal karyotype, or MRD positivity after allogeneic HSCT.

Allogeneic Stem Cell Transplantation for Acute Myeloid Leukemia: Who, When, and How?

Although the majority of patients with acute myeloid leukemia (AML) treated with intensive chemotherapy achieve a complete remission (CR), many are destined to relapse if treated with intensive chemotherapy alone. Allogeneic stem cell transplant (allo-SCT) represents a pivotally important treatment strategy in fit adults with AML because of its augmented anti-leukemic activity consequent upon dose intensification and the genesis of a potent graft-versus-leukemia effect. Increased donor availability coupled with the advent of reduced intensity conditioning (RIC) regimens has dramatically increased transplant access and consequently allo-SCT is now a key component of the treatment algorithm in both patients with AML in first CR (CR1) and advanced disease. Although transplant related mortality has fallen steadily over recent decades there has been no real progress in reducing the risk of disease relapse which remains the major cause of transplant failure and represents a major area of unmet need. A number of therapeutic approaches with the potential to reduce disease relapse, including advances in induction chemotherapy, the development of novel conditioning regimens and the emergence of the concept of post-transplant maintenance, are currently under development. Furthermore, the use of genetics and measurable residual disease technology in disease assessment has improved the identification of patients who are likely to benefit from an allo-SCT which now represents an increasingly personalized therapy. Future progress in optimizing transplant outcome will be dependent on the successful delivery by the international transplant community of randomized prospective clinical trials which permit examination of current and future transplant therapies with the same degree of rigor as is routinely adopted for non-transplant therapies.

Optimizing Transplant Approaches and Post-Transplant Strategies for Patients With Acute Myeloid Leukemia

Acute Myeloid Leukemia (AML) is the commonest indication for allogeneic stem cell transplantation (allo-SCT) worldwide. The increasingly important role of allo-SCT in the management of AML has been underpinned by two important advances. Firstly, improvements in disease risk stratification utilizing genetic and Measurable Residual Disease (MRD) technologies permit ever more accurate identification of allo-mandatory patients who are at high risk of relapse if treated by chemotherapy alone. Secondly, increased donor availability coupled with the advent of reduced intensity conditioning (RIC) regimens has substantially expanded transplant access for patients with high risk AML In patients allografted for AML disease relapse continues to represent the commonest cause of transplant failure and the development of novel strategies with the potential to reduce disease recurrence represents a major unmet need.

Low relapse risk in poor risk AML after conditioning with 10-day decitabine, fludarabine and 2 Gray TBI prior to allogeneic hematopoietic cell transplantation

Patients with poor risk acute myeloid leukemia (AML) have a dismal outcome. We hypothesized that combining decitabine with a standard non-myeloablative (NMA) conditioning regimen prior to allogeneic hematopoietic cell transplantation (allo HCT), might decrease the relapse incidence. We conducted a multicenter prospective phase II study (NCT02252107) with 10-day decitabine (20 mg/m²/day) integrated in a standard non-myeloablative conditioning regimen (3 days fludarabine 30 mg/m² with 2 Gray total body irradiation (TBI)). Patients with AML ≥ 18 years in 1st (in)complete remission (CR/CRi) with a poor or very poor risk profile, as defined by the HOVON-132 protocol, were eligible. Results: Forty-six patients (median age 60; range 23-74) were included. Median follow up time was 44 months (range 31-65 months). The cumulative 1-year incidence of relapse and NRM were respectively 23% and 11%. Incidence of grade III-IV acute graft-vs-host-disease (GVHD) and severe chronic GVHD were 13% and 20%, respectively. One-year OS was 70%. Application of ELN 2017 risk classification to the study cohort revealed a cumulative one-year relapse rate of respectively 31% and 13% for the adverse and intermediate risk patients. To conclude, the 10-day DEC/FLU/TBI conditioning regimen prior to allo HCT in poor risk AML patients is effective and feasible.

Long-Term Outcomes After Autologous Versus Allogeneic Stem Cell Transplantation in Molecularly-Stratified Patients With Intermediate Cytogenetic Risk Acute Myeloid Leukemia: A PETHEMA Study

Acute myeloid leukemia (AML) with intermediate risk cytogenetics (IRcyto) comprises a variety of biological entities with distinct mutational landscapes that translate into differential risks of relapse and prognosis. Optimal postremission therapy choice in this heterogeneous patient population is currently unsettled. In the current study, we compared outcomes in IRcyto AML recipients of autologous (autoSCT) (n = 312) or allogeneic stem cell transplantation (alloSCT) (n = 279) in first complete remission (CR1). Molecular risk was defined based on CEBPA, NPM1, and FLT3-ITD mutational status, per European LeukemiaNet 2017 criteria. Five-year overall survival (OS) in patients with favorable molecular risk (FRmol) was 62% (95% confidence interval [CI], 50-72) after autoSCT and 66% (95% CI, 41-83) after matched sibling donor (MSD) alloSCT (P = .68). For patients of intermediate molecular risk (IRmol), MSD alloSCT was associated with lower cumulative incidence of relapse (P < .001), as well as with increased nonrelapse mortality (P = .01), as compared to autoSCT. The 5-year OS was 47% (95% CI, 34-58) after autoSCT and 70% (95% CI, 59-79) after MSD alloSCT (P = .02) in this patient subgroup. In a propensity-score matched IRmol subcohort (n = 106), MSD alloSCT was associated with superior leukemia-free survival (hazard ratio [HR] 0.33, P = .004) and increased OS in patients alive 1 year after transplantation (HR 0.20, P = .004). These results indicate that, within IRcyto AML in CR1, autoSCT may be a valid option for FRmol patients, whereas MSD alloSCT should be the preferred postremission strategy in IRmol patients.

Hematopoietic Cell Transplantation in the Treatment of Newly Diagnosed Adult Acute Myeloid Leukemia: An Evidence-Based Review from the American Society of Transplantation and Cellular Therapy

The role of hematopoietic cell transplantation (HCT) in the management of newly diagnosed adult acute myeloid leukemia (AML) is reviewed and critically evaluated in this evidence-based review. An AML expert panel, consisting of both transplant and nontransplant experts, was invited to develop clinically relevant frequently asked questions covering disease- and HCT-related topics. A systematic literature review was conducted to generate core recommendations that were graded based on the quality and strength of underlying evidence based on the standardized criteria established by the American Society of Transplantation and Cellular Therapy Steering Committee for evidence-based reviews. Allogeneic HCT offers a survival benefit in patients with intermediate- and high-risk AML and is currently a part of standard clinical care. We recommend the preferential use of myeloablative conditioning in eligible patients. A haploidentical related donor marrow graft is preferred over a cord blood unit in the absence of a fully HLA-matched donor. The evolving role of allogeneic HCT in the context of measurable residual disease monitoring and recent therapeutic advances in AML with regards to maintenance therapy after HCT are also discussed.

Pharmacologic Therapies to Prevent Relapse of Acute Myeloid Leukemia After Allogeneic Hematopoietic Stem Cell Transplantation

Relapse is the main cause of mortality in patients with acute myeloid leukemia (AML) after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Adverse cytogenetic or molecular risk factors, as well as refractory disease or persistent measurable residual disease (MRD) at the time of transplantation are associated with an increased risk of recurrence. Salvage therapy for AML relapse after allo-HSCT is often limited to chemotherapy, donor lymphocyte infusions and/or second transplants and is rarely successful. Effective post-transplant preventive intervention in high risk AML may be crucial. The most frequent and promising approach is the use of post-transplant maintenance with hypomethylating agents or with FLT3 tyrosine kinase inhibitors when the target is present. Moreover, IDH1/IDH2 inhibitors and BCL-2 inhibitors in combination with other strategies are promising approaches in the maintenance setting. Here we summarize the current knowledge about the preemptive and prophylactic use of pharmacologic agents after allo-HSCT to prevent relapse of AML.

Impact of patient: donor HLA disparity on reduced-intensity-conditioned allogeneic stem cell transplants from HLA mismatched unrelated donors for AML: from the ALWP of the EBMT

Patients with acute myeloid leukaemia (AML) who lack a matched sibling or unrelated donor commonly undergo transplantation from a donor matched at 9/10 HLA-A, -B, -C, -DRB1, -DQB1 alleles, and it is unclear if a specific locus mismatch is preferable to any other. We therefore studied 937 patients with AML in complete remission transplanted using a reduced intensity conditioning regimen from an unrelated donor mismatched at a single allele. In a multivariate analysis, patient age, adverse karyotype and patient cytomegalovirus (CMV) seropositivity were correlated with decreased leukaemia free survival (LFS) and overall survival (OS). There was no significant difference in LFS or OS between patients transplanted from donors mismatched at HLA-A, -B, -C or -DRB1 in comparison to a HLA-DQB1 mismatched transplant. In a multivariate analysis, patients transplanted with a HLA-A mismatched donor had higher rates of acute graft-versus-host disease (GVHD) and non-relapse mortality (NRM) than patients transplanted with a HLA-DQB1 mismatched donor. Patient CMV seropositivity was associated with an increase in NRM and acute GVHD and reduced LFS and OS, regardless of donor CMV status. For CMV seropositive patients lacking a fully matched donor, alternative GVHD and CMV prophylaxis strategies should be considered.

Gemtuzumab ozogamicin in acute myeloid leukemia: past, present and future

After being in the therapeutic wilderness for several decades, acute myeloid leukemia has been recently thrust into the limelight with a series of drug approvals. Technical refinements in production, genetic manipulation and chemical modification of monoclonal antibodies led to growing interest in antibodies-based treatment strategies. Much of the focus of these efforts in acute myeloid leukemia has been on CD33 as a target. On September 2, 2017, the U.S. Food and Drug Administration approved gemtuzumab ozogamicin for treatment of relapsed or refractory CD33⁺ acute myeloid leukemia. This signals a new chapter in the long and unusual story of gemtuzumab ozogamicin, which was the first antibody-drug conjugate approved for human use by the Food and Drug Administration. In this review we have analyzed the history of this drug which, among several mishaps, is experiencing a second youth and still represents a field to be further explored.

Panobinostat and decitabine prior to donor lymphocyte infusion in allogeneic stem cell transplantation

Outcome after allogeneic hematopoietic stem cell transplantation (allo-HSCT) is adversely affected by relapse to a considerable degree. To exploit the graft-versus-leukemia effect more effectively, we assessed the feasibility of early initiation of epigenetic therapy with panobinostat and decitabine after allo-HSCT and before donor lymphocyte infusion (DLI) in poor-risk patients with acute myeloid leukemia (AML) or refractory anemia with excess blasts with International Prognostic Scoring System score ≥1.5. A total of 140 poor-risk patients with AML aged 18 to 70 years were registered, and 110 proceeded to allo-HSCT. Three dose levels were evaluated for dose-limiting toxicities, including panobinostat monotherapy 20 mg at days 1, 4, 8, and 11 of a 4-week cycle (PNB mono group) and panobinostat combined with either decitabine 20 mg/m2 (PNB/DAC20 group) or decitabine 10 mg/m2 (PNB/DAC10 group) at days 1 to 3 of every 4-week cycle. After phase 1, the study continued as phase 2, focusing on completion of protocol treatment and treatment outcome. PNB mono and PNB/DAC10 were feasible, whereas PNB/DAC20 was not related to prolonged cytopenia. Sixty of 110 patients who underwent transplantation were eligible to receive their first DLI within 115 days after allo-HSCT. Grade 3 and 4 adverse events related to panobinostat and decitabine were observed in 23 (26%) of the 87 patients, and they received epigenetic therapy. Cumulative incidence of relapse was 35% (standard error [SE] 5), and overall survival and progression-free survival at 24 months were 50% (SE 5) and 49% (SE 5). Post-allo-HSCT epigenetic therapy with panobinostat alone or in combination with low-dose decitabine is feasible and is associated with a relatively low relapse rate. The trial was registered at the European Clinical Trial Registry, https://www.clinicaltrialsregister.eu, as ECT2012-003344-74.

Prognostic Impact of Cytogenetic Evolution on the Outcome of Allogeneic Stem Cell Transplantation in Patients with Acute Myeloid Leukemia in Nonremission: A Single-Institute Analysis of 212 Recipients

Recent progress in genetic analysis technology has helped researchers understand the pathogenesis of acute myeloid leukemia (AML). Considering this progress, AML karyotype is still one of the most significant prognostic factors that provides risk-adapted treatment approaches. Karyotype changes during treatment have been observed at times, but their prognostic impact is sparse, especially on allogeneic stem cell transplantation (allo-SCT). Here, we retrospectively investigated the effect of chromosomal changes between diagnosis and pretransplantation on the prognosis of allo-SCT by analyzing the outcomes of 212 consecutive patients who underwent allo-SCT for the first time at Toranomon Hospital, Tokyo, Japan, between 2008 and 2018. Cytogenetic abnormalities at diagnosis and pretransplantation were categorized based on the 2017 European Leukemia Net risk stratification. Genetic abnormalities such as FLT3-ITD and NPM1 were not considered in this study due to lack of genetic information in most patients. We defined cytogenetic evolution as chromosomal changes classified from lower category to higher category. Seventeen patients (8%) had cytogenetic evolution between diagnosis and pretransplantation, and they showed a significantly worse relapse rate than those who were categorized in the intermediate group based on the karyotype at diagnosis (3-year confidence interval [CI] of relapse, 57.4% versus 24.9%; P < .01). In multivariate analysis, cytogenetic evolution before allo-SCT had a significant impact on the CI of relapse (hazard ratio [HR], 3.89; CI, 1.75 to 8.67; P < .01), as well as the high score of the hematopoietic cell transplantation-specific comorbidity index (HR, 0.54; CI, 0.31 to 0.94; P = .03), but had no significant impact on overall survival or nonrelapse mortality. These results indicate that cytogenetic evolution has a significant impact after allo-SCT and should be considered during AML treatment.

Monosomal karyotype is associated with poor outcomes in patients with Philadelphia chromosome-negative acute lymphoblastic leukemia receiving chemotherapy but not allogeneic hematopoietic stem cell transplantation

Monosomal karyotype (MK) is associated with poor prognosis in patients with myeloid neoplasms; however, its prognostic significance in Philadelphia chromosome-negative (Ph-negative) acute lymphoblastic leukemia (ALL) remains unclear. Data of 323 patients with Ph-negative ALL treated at Peking University People's Hospital were retrospectively analyzed. MK was identified in 49 (14.8%) patients. The patients with MK had lower hemoglobin levels (P = 0.026), lower platelet count (P = 0.032), higher percentages of blasts in the peripheral blood at diagnosis (P = 0.008), and higher percentages of high-risk karyotypes (P < 0.001) compared with those without MK. The complete remission (CR) rate and the minimal residual disease negativity rate were not significantly different between patients with and without MK. In the multivariate analysis, MK was identified as an independent factor associated with higher cumulative incidence of relapse (CIR) (hazard ratio (HR), 2.07; 95% confidence interval (CI), 1.02, 4.21; P = 0.043), shorter disease-free survival (DFS) (HR, 2.80; 95% CI, 1.20, 6.54; P = 0.017) and shorter overall survival (OS) (HR, 5.75; 95% CI, 2.07, 16.03; P = 0.001) in the chemotherapy cohort; however, MK had no impact on outcomes in the allogeneic hematopoietic stem cell transplantation (allo-HSCT) cohort. Mantel-Byar analysis showed that allo-HSCT was associated with lower CIR (P < 0.001), longer DFS (P < 0.001), and longer OS (P < 0.001) in CR patients with MK. In conclusion, our study showed that MK was an independent predictor of poor outcomes in patients with Ph-negative ALL receiving chemotherapy but not allo-HSCT, and allo-HSCT could improve the outcomes of patients with MK.

PD-L1 siRNA-mediated silencing in acute myeloid leukemia enhances anti-leukemic T cell reactivity

Acute myeloid leukemia (AML) is an immune-susceptible malignancy, as demonstrated by its responsiveness to allogeneic stem cell transplantation (alloSCT). However, by employing inhibitory signaling pathways, including PD-1/PD-L1, leukemia cells suppress T cell-mediated immune attack. Notably, impressive clinical efficacy has been obtained with PD-1/PD-L1 blocking antibodies in cancer patients. Yet, these systemic treatments are often accompanied by severe toxicity, especially after alloSCT. Here, we investigated RNA interference technology as an alternative strategy to locally interfere with PD-1/PD-L1 signaling in AML. We demonstrated efficient siRNA-mediated PD-L1 silencing in HL-60 and patients' AML cells. Importantly, WT1-antigen T cell receptor⁺ PD-1⁺ 2D3 cells showed increased activation toward PD-L1 silenced WT1⁺ AML. Moreover, PD-L1 silenced AML cells significantly enhanced the activation, degranulation, and IFN-γ production of minor histocompatibility antigen-specific CD8⁺ T cells. Notably, PD-L1 silencing was equally effective as PD-1 antibody blockade. Together, our study demonstrates that PD-L1 silencing may be an effective strategy to augment AML immune-susceptibility. This provides rationale for further development of targeted approaches to locally interfere with immune escape mechanisms in AML, thereby minimizing severe toxicity. In combination with alloSCT and/or adoptive T cell transfer, this strategy could be very appealing to boost graft-versus-leukemia immunity and improve outcome in AML patients.

Which patients with acute myeloid leukemia in CR1 can be spared an allogeneic transplant?

PURPOSE OF REVIEW

Disease relapse remains the major cause of treatment failure in adults with acute myeloid leukemia (AML) in first complete remission (CR1) treated with intensive chemotherapy alone. Allogeneic stem cell transplantation (allo-SCT) reduces the risk of disease recurrence, and thus the advent of reduced intensity-conditioning regimens coupled with increased donor availability has increased the deliverability of potentially curative transplant therapy in AML. However, allo-SCT remains associated with significant additional morbidity and mortality, and it is therefore important to identify patients whose outcome if treated with chemotherapy alone is good enough to spare them the risks associated with allo-SCT.

RECENT FINDINGS

Characterization of cytogenetic and molecular abnormalities present at diagnosis coupled with dynamic assessments of measurable residual disease now permit greater accuracy in defining the relapse risk in patients treated with chemotherapy alone. At the same time, the risk of transplant-related mortality can be predicted by a number of scoring systems which assess patient comorbidity. Taken together, such assessments permit a dynamic assessment of the risks and benefits of transplantation aiding the identification of patients who are unlikely to benefit from transplantation in CR1.

SUMMARY

Increasingly accurate risk stratification in adults with AML CR1 aids the rational utilization of allo-SCT. Future research integrating the results of serial MRD analysis in molecularly defined subtypes of AML will further improve rational selection of patients for transplant.

Risk stratification using FLT3 and NPM1 in acute myeloid leukemia patients autografted in first complete remission

FLT3-ITD and NPM1 mutation refine prognostic stratification in acute myeloid leukemia (AML) with intermediate-risk cytogenetics. However, data on their role in patients undergoing autologous stem cell transplantation (Auto-SCT) as post-remission therapy (PRT) are limited. We therefore sought to retrospectively evaluate the role of FLT3-ITD and NPM1 in a cohort of AML patients (n = 405) with intermediate-risk cytogenetics, autografted in first complete remission (CR1). Patients were transplanted between 2000 and 2014 and reported to the European Society for Blood and Marrow Transplantation (EBMT) registry. Leukemia-free survival (LFS) was the primary outcome. Median follow-up was 5.5 years. FLT3-ITD^neg/NPM1^WT was the leading molecular subtype (50%), followed by FLT3-ITD^neg/NPM1^mut (30%). In the univariate analysis, molecular subtype was associated with LFS, overall survival (OS), and relapse incidence (RI) (p < 0.001); 5-year LFS: FLT3-ITD^neg/NPM1^mut 62%, FLT3-ITD^pos/NPM1^mut 38%, FLT3-ITD^neg/NPM1^WT 32%, and FLT3-ITD^pos/NPM1^WT 21%. At 5 years, OS and RI in the FLT3-ITD^neg/NPM1^mut subtype were 74% and 35%, respectively. The corresponding OS and RI in other subtypes were below 48% and over 57%. In a Cox multivariable model, molecular subtype was the strongest predictor of LFS, OS, and relapse. In conclusion, AML patients with intermediate-risk cytogenetics and FLT3-ITD^neg/NPM1^mut experience favorable outcomes when autografted in CR1, suggesting that Auto-SCT is a valid PRT option.

Monosomal karyotype affecting outcomes of allogeneic hematopoietic stem cell transplantation for acute myeloid leukemia in first complete remission

OBJECTIVES

We evaluated the prognostic impact of MK on postremission outcomes of AML patients receiving allogeneic hematopoietic stem cell transplantation (HSCT) in the first complete remission (CR1).

METHODS

We retrospectively analyzed 465 adult patients with AML who had received HSCT in the first CR between 2000 and 2016.

RESULTS

In MK + AML, the median leukocyte count was significantly lower (P < .001) and no NPM1 mutation was found (P = .042). Multivariate analysis revealed that MK was the most powerful prognostic factors for OS (hazard ratio [HR], 2.6; P = .001), EFS (HR, 3.8; P < .001), and cumulative incidence of relapse (HR, 6.1; P < .001), compared to any other poor risk factors such as complex karyotype, FLT3-ITD mutations, old age, and higher leukocyte count. The adverse prognostic impact of MK tended to be more prominent in the younger age group (<40 years) (HR, 6.3, P < .001) than in the older age group (≥40 years) (HR, 3.4, P < .001).

CONCLUSION

Novel treatment modalities for MK + AML need to be investigated to reduce the risk of relapse after HSCT.

The impact of concomitant cytogenetic abnormalities on acute myeloid leukemia with monosomy 7 or deletion 7q after HLA-matched allogeneic stem cell transplantation

Monosomy 7 or deletion 7q (-7/7q-) is the most frequent adverse cytogenetic features reported in acute myeloid leukemia (AML), and is a common indication for allogeneic stem cell transplantation (SCT). Nevertheless, -7/7q- occurs frequently with other high-risk cytogenetic abnormalities such as complex karyotype (CK), monosomal karyotype (MK), monosomy 5 or deletion 5q (-5/5q-), 17p abnormalities (abn(17p)) or inversion of chromosome 3 (inv(3)), the presence of which may influence the outcomes after SCT. A total of 1109 patients were allocated to this study. Two-year probability of leukemia-free survival (LFS) and overall survival (OS) were 30% and 36%, respectively. Two-year probability of non-relapse mortality (NRM) was 20%. We defined five different cytogenetic subgroups: the "-7/7q- ± CK group- designated group1," the "MK group-designated group 2," the "-5/5q- group- designated group 3," the "abn(17p) group- designated group 4" and the "inv(3) group- designated group 5." The 2-year probability of LFS in first remission was 48% for group 1, 36.4% for group 2, 28.4% for group 3, 19.1% for group 4 and 17.3% for group 5, respectively (P < .001). Multivariate analysis confirmed those significant differences across groups. Note, SCT in -7/7q- AML provides durable responses in one third of the patients. The presence of -7/7q- with or without CK in the absence of MK, abn(17p) or inv(3) is associated with a better survival after SCT. On the contrary, addition of MK, -5/5q-, abn(17p) or inv(3) identifies a sub-group of patients with poor prognosis even after SCT.

Allogeneic stem cell transplantation using HLA-matched donors for acute myeloid leukemia with deletion 5q or monosomy 5: a study from the Acute Leukemia Working Party of the EBMT

Deletion 5q or monosomy 5 (-5/5q-) in acute myeloid leukemia (AML) is a common high-risk feature that is referred to allogeneic stem cell transplantation. However, -5/5q- is frequently associated with other high-risk cytogenetic aberrations such as complex karyotype, monosomal karyotype, monosomy 7 (-7), or 17p abnormalities (abn (17p)), the significance of which is unknown. In order to address this question, we studied adult patients with AML harboring -5/5q- having their first allogeneic transplantation between 2000 and 2015. Five hundred and one patients with -5/5q- have been analyzed. Three hundred and thirty-eight patients (67%) were in first remission and 142 (28%) had an active disease at time of allogeneic transplantation. The 2-year probabilities of overall survival and leukemia-free survival were 27% and 20%, respectively. The 2-year probability of treatment-related mortality was 20%. We identified four different cytogenetic groups according to additional abnormalities with prognostic impact: -5/5q- without complex karyotype, monosomal karyotype or abn(17p), -5/5q- within a complex karyotype, -5/5q- within a monosomal karyotype and the combination of -5/5q- with abn(17p). In multivariate analysis, factors associated with worse overall survival and leukemia-free survival across the four groups were active disease, age, monosomal karyotype, and abn(17p). The presence of -5/5q- without monosomal karyotype or abn(17p) was associated with a significantly better survival rate while -5/5q- in conjunction with monosomal karyotype or abn(17p) translated into a worse outcome. The patients harboring the combination of -5/5q- with abn(17p) showed very limited benefit from allogeneic transplantation.

Impact of pretransplant measurable residual disease on the outcome of allogeneic hematopoietic cell transplantation in adult monosomal karyotype AML

Allogeneic hematopoietic cell transplantation (HCT) is often unsuccessful for monosomal karyotype (MK) acute myeloid leukemia (AML). To what degree failures are associated with pre-transplant measurable residual disease (MRD) – a dominant adverse risk factor – is unknown. We therefore studied 606 adults with intermediate- or adverse-risk AML in morphologic remission who underwent allogeneic HCT between 4/2006 and 1/2019. Sixty-eight (11%) patients had MK AML, the majority of whom with complex cytogenetics. Before HCT, MK AML patients more often tested MRD^pos by multiparameter flow cytometry (49% vs. 18%; P<0.001) and more likely had persistent cytogenetic abnormalities (44% vs. 13%; P<0.001) than non-MK AML patients. Three-year relapse/overall survival estimates were 46%/43% and 72%/15% for MRD^neg and MRD^pos MK AML patients, respectively, contrasted to 20%/64% and 64%/38% for MRD^neg and MRD^pos non-MK AML patients, respectively. After multivariable adjustment, MRD^pos remission status but not MK remained statistically significantly associated with shorter survival and higher relapse risk. Similar results were obtained in several patient subsets. In summary, while our study confirms higher relapse rates and shorter survival for MK-AML compared to non-MK AML patients, these outcomes are largely accounted for by the presence of other adverse prognostic factors, in particular higher likelihood of pre-HCT MRD.

The role of allogeneic stem cell transplantation in the management of acute myeloid leukaemia: a triumph of hope and experience

Acute myeloid leukaemia (AML) is the commonest indication for allogeneic stem cell transplantation (allo-SCT) worldwide. The accumulated experience of allografting in AML over the last four decades has provided critical insights into both the contribution of the conditioning regimen and the graft-versus-leukaemia effect to the curative potential of the most common form of immunotherapy utilised in standard clinical practice. Coupled with advances in donor availability and transplant technologies, this has resulted in allo-SCT becoming an important treatment modality for the majority of adults with high-risk AML. At the same time, advances in genomic classification, coupled with progress in the accurate quantification of measurable residual disease, have increased the precision with which allo-mandatory patients can be identified, whilst simultaneously permitting accurate identification of those patients who can be spared the toxicity of an allograft. Despite this progress, disease recurrence still remains a major cause of transplant failure and AML has served as a paradigm for the development of strategies to reduce the risk of relapse - notably the novel concept of post-transplant maintenance, utilising pharmacological or cellular therapies.

Risk Stratification and Prognosticators of Acute Myeloid Leukemia with Myelodysplasia-Related Changes in Patients Undergoing Allogeneic Stem Cell Transplantation: A Retrospective Study of the Adult Acute Myeloid Leukemia Working Group of the Japan Society for Hematopoietic Cell Transplantation

Although the prognosis of acute myeloid leukemia with myelodysplasia-related changes (AML-MRC) is worse than that of AML not otherwise specified (AML-NOS), transplantation outcomes and prognosticators of AML-MRC patients undergoing allogeneic stem cell transplantation (allo-SCT) remain unclear. Transplantation outcomes of AML-MRC (n = 4091) were compared with those of AML-NOS (n = 3964) in patients who underwent allo-SCT between 2003 and 2016 using a nationwide registration database. The 3-year overall survival (OS; 35.5% versus 50.6%) was lower and the relapse (42.3% versus 32.1%) and nonrelapse mortality (26.3% versus 22.0%) rates were higher in the AML-MRC group than in the AML-NOS group. Based on the hierarchical AML-MRC classification, myelodysplasia as the sole criterion was associated with better OS compared with AML-NOS, whereas monosomal or complex karyotype and -5/del(5q) were associated with poor OS. A history of myelodysplastic syndrome and -7/del(7q) did not affect OS. Accordingly, AML-MRC with complex karyotype or -5/del(5q) and that with monosomal karyotype were classified as intermediate and high risks, respectively, whereas the remaining cases were classified as low risk. The 3-year OS rates were 50.7%, 36.9%, and 13.8% in the low-, intermediate-, and high-risk groups, respectively (P < .001). Risk classification, older age, and low performance status score were significant risk factors for survival in AML-MRC, independently of the disease status. Grades I to II acute graft-versus-host disease significantly reduced the 3-year relapse (24.7% versus 31.6%), leading to better survival (hazard ratio, .64). Our prognostic risk stratification can potentially aid in elucidating the diverse transplantation outcomes in patients with AML-MRC.

Impact of induction regimen and allogeneic hematopoietic cell transplantation on outcome in younger adults with acute myeloid leukemia with a monosomal karyotype

Monosomal karyotype confers a poor prognosis in patients with acute myeloid leukemia. Here, we determined the impact of the type of remission-induction chemotherapy and the impact of having a donor in younger acute myeloid leukemia patients with a monosomal karyotype included in two phase III trials. In the first trial patients were randomized to receive either daunorubicin, mitoxantrone, or idarubicin in addition to standard-dose cytarabine and etoposide for induction chemotherapy. In the second trial patients were randomized to standard-dose cytarabine or high-dose cytarabine induction, both with daunorubicin and etoposide. In both trials, patients who achieved a complete remission with or without complete hematologic recovery underwent allogeneic hematopoietic stem cell transplantation if they had a donor; otherwise, they underwent autologous transplantation. In comparison to patients with intermediate-risk cytogenetics without a monosomal karyotype (n=1,584) and with adverse cytogenetics without a monosomal karyotype (n=218), patients with a monosomal karyotype (n=188) were more likely not to achieve a complete remission with or without count recovery [odds ratio=2.85, 95% confidence interval (95%, CI): 2.10-3.88] and had shorter overall survival [hazard ratio, (HR)=2.44, 95% CI: 2.08-2.88]. There was no impact of the type of anthracycline or of the dose of cytarabine on outcomes in patients with a monosomal karyotype. Among monosomal karyo type patients who achieved a complete remission with or without count recovery, HLA-identical related donor availability was associated with longer survival from complete remission with or without count recovery (HR=0.59, 95% CI: 0.37-0.95). ClinicalTrials.gov identifiers: AML-10: NCT00002549; AML-12: NCT00004128.

Distinct factors determine the kinetics of disease relapse in adults transplanted for acute myeloid leukaemia

BACKGROUND

Disease recurrence remains the major cause of death in adults with acute myeloid leukaemia (AML) treated using either intensive chemotherapy (IC) or allogenic stem cell transplantation (allo-SCT).

AIMS

The timely delivery of maintenance drug or cellular therapies represent emerging strategies with the potential to reduce relapse after both treatment modalities, but whilst the determinants of overall relapse risk have been extensively characterized the factors determining the timing of disease recurrence have not been characterized.

MATERIALS AND METHODS

We have therefore examined, using a series of sequential landmark analyses, relapse kinetics in a cohort of 2028 patients who received an allo-SCT for AML in CR1 and separately 570 patients treated with IC alone.

RESULTS

In the first 3 months after allo-SCT, the factors associated with an increased risk of relapse included the presence of the FLT3-ITD (P < 0.001), patient age (P = 0.012), time interval from CR1 to transplant (P < 0.001) and donor type (P = 0.03). Relapse from 3 to 6 months was associated with a higher white cell count at diagnosis (P = 0.001), adverse-risk cytogenetics (P < 0.001), presence of FLT3-ITD mutation (P < 0.001) and time interval to achieve first complete remission (P = 0.013). Later relapse was associated with adverse cytogenetics, mutated NPM1, absence of chronic graft-versus-host disease (GVHD) and the use of in vivo T-cell depletion. In patients treated with IC alone, the factors associated with relapse in the first 3 months were adverse-risk cytogenetics (P < 0.001) and FLT3-ITD status (P = 0.001). The factors predicting later relapse were the time interval from diagnosis to CR1 (P = 0.22) and time interval from CR1 to IC (P = 0.012).

DISCUSSION AND CONCLUSION

Taken together, these data provide novel insights into the biology of disease recurrence after both allo-SCT and IC and have the potential to inform the design of novel maintenance strategies in both clinical settings.

Allogeneic Hematopoietic Stem Cell Transplantation In Therapy-Related Myeloid Neoplasms (t-MN) of the Adult: Monocentric Observational Study and Review of the Literature

Background

Therapy related myeloid neoplasms (t-MN) occur due to direct mutational events of chemotherapeutic agents and radiotherapy. Disease latency, mutational events and prognosis vary with drugs categories.

Methods

We describe a cohort of 30 patients, 18 females and 12 males, with median age of 52.5 years (range, 20 to 64), submitted to allogeneic stem cell transplantation (HSCT) in our department between September 1999 and March 2017. Patients had a history of solid tumour in 14 cases, haematological disease in 15 cases and both of them in one case. After a median of 36.5 months (range, 4 to 190) from first neoplasm, patients developed t-AML in 19 cases and t-MDS in 11 cases. Molecular abnormalities were detected in 5 patients, while karyotype aberrations were found in 17 patients. Patients received conventional chemotherapy in 14 cases, azacitidine in 10 cases and both of them in one case. Five patients were submitted to HSCT without previous treatment except for supportive therapy.

Results

Seventeen patients obtained sustained CR after SCT, while 8 patients showed resistant or relapsed disease. The remaining five patients died early after SCT. At follow up time (May 2017) 13 patients were alive with a median OS of 48 months (range 3–195), while 17 patients died after a median of 4 months (range 1–27) by relapse mortality in 6 cases and non-relapse mortality in the other 11 patients.

Conclusions

Global OS was 43%. After SCT, 72.2% of patients with t-MN maintained a sustained CR.