Favorable impact of allogeneic stem cell transplantation in patients with therapy-related myelodysplasia regardless of TP53 mutational status

Outcomes with allogeneic hematopoietic stem cell transplantation in TP53-mutated myelodysplastic syndrome: A systematic review and meta-analysis

We conducted a systematic review and meta-analysis to evaluate outcomes after allogeneic hematopoietic stem cell transplantation (Allo-HSCT) in TP53-mutated myelodysplastic syndromes (MDS). A literature search was performed on PubMed, Cochrane, Embase, and Clinicaltrials.gov. After screening 626 articles, eight studies were included. Data were extracted following the PRISMA guidelines and analyzed using the meta-package by Schwarzer et al. We analyzed 540 patients. The pooled median 3 (1-5) year overall survival was 21% (95% CI 0.08-0.37, I2=91%, n=540). The pooled relapse rate was 58.9% (95% CI 0.38-0.77, I2=93%, n=487) at a median of 1.75 (1-3) years. The pooled 4-year progression- free survival was 34.8% (95% CI 0.15-0.57, I2=72%, n=105). Outcomes of Allo-HSCT for TP53-mutated MDS patients remain poor, with 21% OS at three years; however, Allo-HSCT confers a survival advantage as compared to non-transplant palliative therapies. Our findings suggest the need to explore novel therapeutic agents in prospective clinical trials.

Utility or futility? A contemporary approach to allogeneic hematopoietic cell transplantation for TP53-mutated MDS/AML

ABSTRACT

TP 53-mutated myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) are among the most lethal malignancies, characterized by dismal outcomes with currently available therapies. Allogeneic hematopoietic cell transplantation (allo-HCT) is widely thought to be the only treatment option to offer durable disease control. However, outcomes with allo-HCT in this context are quite poor, calling into question the utility of transplantation. In this review, we summarize the latest data on allo-HCT outcomes in this subgroup, evaluating the limitations of available evidence; we review the molecular heterogeneity of this disease, delineating outcomes based on distinct biological features to aid in patient selection; and we critically examine whether allo-HCT should be routinely applied in this disease on the basis of currently available data. We propose that the exceptionally poor outcomes of patients with TP53-mutated MDS/AML with biallelic loss and/or adverse-risk cytogenetics should motivate randomized-controlled trials of HCT vs non-HCT to determine whether transplantation can prolong survival and/or positively impact other clinically relevant outcomes such as patient-reported outcomes or healthcare resource utilization in this disease subset. Without dedicated prospective randomized trials, selecting who may actually derive benefit from allo-HCT for TP53-mutated MDS/AML can be described as ambiguous guesswork and must be carefully contemplated.

The clinical outcomes of haploidentical stem cell transplantation (haplo-HSCT) for patients with therapy-related myelodysplastic syndrome: comparable to de novo myelodysplastic syndrome

Therapy-related myelodysplastic syndrome (t-MDS) is defined as a complication in patients with cancer following exposure to chemotherapy and/or radiotherapy and has an inferior outcome compared with de novo myelodysplastic syndrome (de novo MDS). This study aimed to estimate and compare the clinical outcomes of haploidentical stem cell transplantation (haplo-HSCT) for t-MDS and de novo MDS. We retrospectively analyzed 96 patients with MDS who received haplo-HSCT between January 2015 and December 2021. Eleven patients with t-MDS and 85 patients with de novo MDS were matched using the case-pair method in a 1:8 ratio with the following pairing criteria: (1) sex, (2) age (± 5 years), (3) year of haplo-HSCT (± 2 years), and (4) blast cell counts (≥ 5% or not). The 3-year overall survival and disease-free survival after haplo-HSCT for t-MDS versus de novo MDS patients were 72.7% versus 75.1% (P = 0.99) and 54.5% versus 67.0% (P = 0.50), respectively. The 3-year cumulative incidence of relapse was 36.4% versus 15.5% (P = 0.08), respectively. In multivariate analysis, there was no difference in relapse between t-MDS and de novo MDS. The 3-year cumulative non-relapse mortality rates were 9.1% versus 17.6% (P = 0.45), respectively. This study confirmed the comparable clinical outcomes of haplo-HSCT on the prognosis of t-MDS and de novo MDS.

Mutation of the TP53 gene in acute lymphoblastic leukemia does not affect survival outcomes after haploidentical hematopoietic stem cell transplantation

Previous studies have demonstrated that TP53 mutation is correlated with insufficient therapy response and unfavorable prognosis in acute lymphoblastic leukemia (ALL). Few studies have investigated the impact of TP53 mutation in ALL patients after haploidentical hematopoietic stem cell transplantation (haplo-HSCT). We completed a retrospective study of 65 ALL patients with available TP53 status who underwent haplo-HSCT. They were divided into a TP53 mutation group (TP53^mut ) and a TP53 wild-type (TP53^wt ) group. TP53^mut showed comparable 2-year cumulative incidence of relapse (CIR) rates (13.1% vs 12.5%, P = .96) and 2-year leukemia-free survival (LFS) (74.2% vs 77.4%, P = .80) with TP53^wt . No significant differences in 2-year overall survival (OS) rates (82.9% vs 87.3%, P = .61) or 2-year NRM rates (12.7% vs 10.2%, P = .69) were observed in TP53^mut and TP53^wt patients. Multivariate analysis suggested that white blood cell (WBC) count at initial diagnosis (>50 × 10⁹ /L: hazard ratio [HR] = 3.860, P = .016) and age (>40 years old: HR = 4.120, P = .012) are independent risk factors for 2-year LFS. Our study showed that TP53 mutations may not be related to the unfavorable impact on survival in ALL patients after treatment with haplo-HSCT. The present results suggested that haplo-HSCT may eliminate the poor prognosis effect of TP53 mutation in ALL.

Allogeneic stem cell transplantation for patients with myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are a heterogenous group of clonal hematopoietic stem cell neoplasms primarily affecting older persons, associated with dysplastic changes of bone marrow cells, peripheral cytopenias, and various risk of leukemic transformation. Although treatment with several drugs has shown improved disease control, allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains the only curative treatment for MDS. The number of patients receiving a transplant, as well as survival, have increased past years because of the use of reduce-intensity conditioning regimens (RIC) as well as the use of haploidentical donors for transplantation. With treatment-related mortality as main limitation, pre-transplant evaluation is essential to assess risks for this older group of patients. In a recent randomized study, allo-HSCT with RIC for patients >50 years old with higher-risk MDS demonstrated superiority in survival compared with hypomethylating agents. Genetic mutations have been shown to significantly impact treatment outcomes including after transplant. Recently, a transplant-specific risk score (which includes age, donor type, performance status, cytogenetic category, recipient's cytomegalovirus status, percentage of blasts, and platelet count) has shown superiority in transplantation outcome prediction, compared with previous scoring systems. Survival remains low for most patients with TP53 mutations and novel treatment strategies are needed, such as administration of natural killer cells post-transplant, as there is no clear evidence that maintenance therapy after transplantation can improve outcomes.

Hematopoietic Cell Transplantation in the Management of Myelodysplastic Syndrome: An Evidence-Based Review from the American Society for Transplantation and Cellular Therapy Committee on Practice Guidelines

The sole curative therapy for myelodysplastic syndrome (MDS) is allogeneic hematopoietic cell transplantation (HCT). Here this therapeutic modality is reviewed and critically evaluated in the context of the evidence. Specific criteria were used for searching the published literature and for grading the quality and strength of the evidence and the strength of the recommendations. A panel of MDS experts comprising transplantation and nontransplantation physicians developed consensus treatment recommendations. This review summarizes the standard MDS indications for HCT and addresses areas of controversy. Recent prospective trials have confirmed that allogeneic HCT confers survival benefits in patients with advanced or high-risk MDS compared with nontransplantation approaches, and the use of HCT is increasing in older patients with good performance status. However, patients with high-risk cytogenetic or molecular mutations remain at high risk for relapse. It is unknown whether administration of novel therapies before or after transplantation may decrease the risk of disease relapse in selected populations. Ongoing and future studies will investigate revised approaches to disease risk stratification, patient selection, and post-transplantation approaches to optimize allogeneic HCT outcomes for patients with MDS.

Allogeneic haematopoietic stem cell transplantation with decitabine-containing preconditioning regimen in TP53-mutant myelodysplastic syndromes: A case study

Myelodysplastic syndrome (MDS) with TP53 mutations has a poor prognosis after transplantation, and novel therapeutic means are urgently needed. Decitabine (Dec) monotherapy has demonstrated improved overall response rates in MDS and acute myeloid leukaemia, although these responses were not durable. This study aimed to preliminary evaluate the efficacy of a Dec-containing allogeneic haematopoietic stem cell transplantation (allo-HSCT) preconditioning regimen in TP53-mutant MDS. Nine patients with TP53-mutant myelodysplastic syndromes received the decitabine-containing preconditioning regimen and subsequent myeloablative allo-HCT between April 2013 and September 2021 in different centres. At a median follow-up of 42 months (range, 5 to 61 months), the overall survival (OS) was 89% (8/9), progression-free survival (PFS) was 89% (8/9), and relapse incidence was 11.1%. The incidence of severe acute (grade III-IV) graft-versus-host disease (GVHD) was 22.2% (2/9) and that of chronic moderate-to-severe GVHD was 11.1% (1/9). The 1-year GVHD-free/relapse-free survival (GRFS) was 56% (5/9). In conclusion, we found real-world clinical data that supports the use of a Dec-containing preconditioning regimen before allo-HSCT for possible improved outcomes in TP53-mutant MDS patients; there is therefore an urgent call for an in-depth exploration of the involved mechanism to confirm these preliminary findings.

TP53 in Myelodysplastic Syndromes

Simple Summary

The importance of gene variants in the prognosis of myelodysplastic syndromes (MDSs) has been repeatedly reported in recent years. Especially, TP53 mutations are independently associated with a higher risk category, resistance to conventional therapies, rapid transformation to leukemia, and a poor outcome. In the review, we discuss the features of monoallelic and biallelic TP53 mutations within MDS, the carcinogenic mechanisms, and the predictive value of TP53 variants in current standard treatments including hypomethylating agents, allogeneic hematopoietic stem cell transplantation, and lenalidomide, as well as the latest progress in TP53-targeted therapy strategies in MDS.

Abstract

Myelodysplastic syndromes (MDSs) are heterogeneous for their morphology, clinical characteristics, survival of patients, and evolution to acute myeloid leukemia. Different prognostic scoring systems including the International Prognostic Scoring System (IPSS), the Revised IPSS, the WHO Typed Prognostic Scoring System, and the Lower-Risk Prognostic Scoring System have been introduced for categorizing the highly variable clinical outcomes. However, not considered by current MDS prognosis classification systems, gene variants have been identified for their contribution to the clinical heterogeneity of the disease and their impact on the prognosis. Notably, TP53 mutation is independently associated with a higher risk category, resistance to conventional therapies, rapid transformation to leukemia, and a poor outcome. Herein, we discuss the features of monoallelic and biallelic TP53 mutations within MDS, their corresponding carcinogenic mechanisms, their predictive value in current standard treatments including hypomethylating agents, allogeneic hematopoietic stem cell transplantation, and lenalidomide, together with the latest progress in TP53-targeted therapy strategies, especially MDS clinical trial data.

Biologic Assignment Trial of Reduced-Intensity Hematopoietic Cell Transplantation Based on Donor Availability in Patients 50-75 Years of Age With Advanced Myelodysplastic Syndrome

PURPOSE

Allogeneic hematopoietic cell transplantation (HCT) is the only potentially curative therapy for myelodysplastic syndromes (MDS), although it is infrequently offered to older patients. The relative benefits of HCT over non-HCT therapy in older patients with higher-risk MDS have not been defined.

METHODS

We conducted a multicenter biologic assignment trial comparing reduced-intensity HCT to hypomethylating therapy or best supportive care in subjects 50-75 years of age with intermediate-2 or high-risk de novo MDS. The primary outcome was overall survival probability at 3 years. Between January 2014 and November 2018, we enrolled 384 subjects at 34 centers. Subjects were assigned to the Donor or No-Donor arms according to the availability of a matched donor within 90 days of study registration.

RESULTS

The median follow-up time for surviving subjects was 34.2 months (range: 2.3-38 months) in the Donor arm and 26.9 months (range: 2.4-37.2 months) in the No-Donor arm. In an intention-to-treat analysis, the adjusted overall survival rate at 3 years in the Donor arm was 47.9% (95% CI, 41.3 to 54.1) compared with 26.6% (95% CI, 18.4 to 35.6) in the No-Donor arm (P = .0001) with an absolute difference of 21.3% (95% CI, 10.2 to 31.8). Leukemia-free survival at 3 years was greater in the Donor arm (35.8%; 95% CI, 29.8 to 41.8) compared with the No-Donor arm (20.6%; 95% CI, 13.3 to 29.1; P = .003). The survival benefit was seen across all subgroups examined.

CONCLUSION

We observed a significant survival advantage in older subjects with higher-risk MDS who have a matched donor identified and underwent reduced-intensity HCT, when compared with those without a donor. HCT should be included as an integral part of MDS management plans in fit older adults with higher-risk MDS.

Genetic and Genomic Landscape of Secondary and Therapy-Related Acute Myeloid Leukemia

A subset of acute myeloid leukemia (AML) arises either from an antecedent myeloid malignancy (secondary AML, sAML) or as a complication of DNA-damaging therapy for other cancers (therapy-related myeloid neoplasm, t-MN). These secondary leukemias have unique biological and clinical features that distinguish them from de novo AML. Over the last decade, molecular techniques have unraveled the complex subclonal architecture of sAML and t-MN. In this review, we compare and contrast biological and clinical features of de novo AML with sAML and t-MN. We discuss the role of genetic mutations, including those involved in RNA splicing, epigenetic modification, tumor suppression, transcription regulation, and cell signaling, in the pathogenesis of secondary leukemia. We also discuss clonal hematopoiesis in otherwise healthy individuals, as well as in the context of another malignancy, and how it challenges the conventional notion of sAML/t-MN. We conclude by summarizing the current and emerging treatment strategies, including allogenic transplant, in these complex scenarios.

TP53 in Myelodysplastic Syndromes: Recent Biological and Clinical Findings

TP53 dysregulation plays a pivotal role in the molecular pathogenesis of myelodysplastic syndromes (MDS), identifying a subgroup of patients with peculiar features. In this review we report the recent biological and clinical findings of TP53-mutated MDS, focusing on the molecular pathways activation and on its impact on the cellular physiology. In MDS, TP53 mutational status is deeply associated with del(5q) syndrome and its dysregulation impacts on cell cycle, DNA repair and apoptosis inducing chromosomal instability and the clonal evolution of disease. TP53 defects influence adversely the MDS clinical outcome and the treatment response rate, thus new therapeutic approaches are being developed for these patients. TP53 allelic state characterization and the mutational burden evaluation can therefore predict prognosis and identify the subgroup of patients eligible for targeted therapy. For these reasons, in the era of precision medicine, the MDS diagnostic workup cannot do without the complete assessment of TP53 mutational profile.

Clinical outcomes and characteristics of patients with TP53-mutated acute myeloid leukemia or myelodysplastic syndromes: a single center experience

Mutations in the tumor suppressor gene TP53 are detected in 5-10% of patients with acute myeloid leukemia (AML) and myelodysplastic syndromes. TP53 mutations have been associated with complex karyotypes, therapy-related malignancies, lower response rates to cytotoxic chemotherapy, and an overall adverse prognosis. In this single-center retrospective study, we analyzed the clinicopathologic characteristics and outcomes of 83 patients with TP53-mutated myeloid malignancies treated at Yale Cancer Center between 9/2015 and 5/2019. Complex karyotypes (n = 75; 90%) and therapy-related malignancies (n = 32; 39%) were common. Median overall survival (OS) was 7.6 months. Intensive chemotherapy did not improve OS compared to lower-intensity treatment for AML patients. Patients who underwent allogeneic hematopoietic stem cell transplant (alloHSCT) had a significantly longer median OS, despite relatively limited follow-up. In conclusion, our data confirm the limited efficacy of intensive chemotherapy approaches for TP53-mutated patients with myeloid neoplasms and suggest that a minority of patients achieve long-term survival with alloHSCT.

Cui bono? Finding the value of allogeneic stem cell transplantation for lower-risk myelodysplastic syndromes

Introduction: The myelodysplastic syndromes (MDS) vary in their risk of disease progression; progression includes increasingly severe bone marrow failure, reclassification as acute myeloid leukemia (AML), and death. Prognostic tools guide recommendations for allogeneic stem cell transplantation (alloSCT), the only curative option. AlloSCT is typically reserved for patients with higher-risk MDS as defined by existing prognostic tools, although additional clinical and biological factors in lower-risk patients may influence this dogma.Areas covered: This review discusses the current understanding of MDS risk stratification as it pertains to the use of alloSCT in subpopulations of MDS patients with a particular focus on the use of alloSCT in patients with lower-risk disease.Expert commentary: Though high-quality data are lacking, some lower-risk MDS patients may benefit from alloSCT, which offers the only prospect of cure. Understanding the etiologic role and prognostic impact of recurring genetic events may improve existing risk stratification and become integral facets of prognostic schemata. The identification of additional factors influencing the prognoses of patients currently lumped together as 'lower-risk' will likewise improve the selection of MDS patients for early intervention or aggressive therapies such as alloSCT.

MIPSS70+ v2.0 predicts long-term survival in myelofibrosis after allogeneic HCT with the Flu/Mel conditioning regimen

Although allogeneic hematopoietic cell transplantation (allo-HCT) is the only curative treatment for myelofibrosis (MF), data are limited on how molecular markers predict transplantation outcomes. We retrospectively evaluated transplantation outcomes of 110 consecutive MF patients who underwent allo-HCT with a fludarabine/melphalan (Flu/Mel) conditioning regimen at our center and assessed the impact of molecular markers on outcomes based on a 72-gene next-generation sequencing panel and Mutation-Enhanced International Prognostic Scoring System 70+ v2.0 (MIPSS70+ v2.0). With a median follow-up of 63.7 months, the 5-year overall survival (OS) rate was 65% and the nonrelapse mortality (NRM) rate was 17%. In mutational analysis, JAK2 V617F and ASXL1 mutations were the most common. By univariable analysis, higher Dynamic International Prognostic Scoring System scores, unrelated donor type, and very-high-risk cytogenetics were significantly associated with lower OS. Only CBL mutations were significantly associated with lower OS (hazard ratio [HR], 2.64; P = .032) and increased NRM (HR, 3.68; P = .004) after allo-HCT, but CALR, ASXL1, and IDH mutations did not have an impact on transplantation outcomes. Patient classification per MIPSS70 showed worse OS for high-risk (HR, 0.49; P = .039) compared with intermediate-risk patients. Classification per MIPSS70+ v2.0 demonstrated better OS when intermediate-risk patients were compared with high-risk patients (HR, 0.291) and much lower OS when very-high-risk patients were compared with high-risk patients (HR, 5.05; P ≤ .001). In summary, we present one of the largest single-center experiences of Flu/Mel-based allo-HCT, demonstrating that revised cytogenetic changes and MIPSS70+ v2.0 score predict transplantation outcomes, and thus can better inform physicians and patients in making decisions about allo-HCT.

Clinicopathological aspects of therapy-related acute myeloid leukemia and myelodysplastic syndrome

Therapy-related myeloid neoplasm (t-MN) is a rare but devastating consequence of chemotherapy and/or radiotherapy used for the treatment of solid cancers and various hematologic malignancies. Our current understanding of the etiology is that hematopoietic clones that are contemporaneous with the primary cancer and resistant to the cytotoxic exposure have the potential to undergo selective expansion and transformation to t-MN. Consequently, a large proportion of cases are associated with adverse risk factors, resulting in limited effective treatment options. Despite the emergence of some therapies with promising activity in t-MN, most effects are short-lived and allogeneic stem cell transplantation remains the only curative option for eligible patients. This review summarizes the current literature on t-AML and t-MDS, with the aim of providing practical recommendations on the clinical evaluation and management of these conditions.

An update on treatment of higher risk myelodysplastic syndromes

INTRODUCTION

Myelodysplastic syndromes (MDS) are clonal stem cell disorders mostly affecting the elderly. They are classified into lower and higher risk MDS according to prognostic scoring systems. In higher risk patients, treatments should aim to modify the disease course by avoiding progression to acute myeloid leukemia and, therefore, to improve survival. Areas covered: Stem cell transplantation remains the only curative treatment when feasible, but this concerns a small minority of patients. Treatment is principally based on hypomethylating agents (HMAs). Our understanding of MDS biology has led to the development of drugs targeting key cellular processes such as apoptosis or posttranslational protein changes, microenvironment-like immunotherapy, and gene mutations. Currently, new drugs are mainly being tested in combination with HMAs in several clinical trials. Expert commentary: Significant advances have been made in the field of MDS, especially in molecular typing, which are improving our ability to offer patients risk-adapted therapies. The current challenge in the management of higher risk MDS is to improve outcome by combining classical HMAs with novel drugs.

Bifunctional PD-1 × αCD3 × αCD33 fusion protein reverses adaptive immune escape in acute myeloid leukemia

The CD33-targeting bispecific T-cell engager (BiTE) AMG 330 proved to be highly efficient in mediating cytolysis of acute myeloid leukemia (AML) cells in vitro and in mouse models. Yet, T-cell activation is correlated with upregulation of programmed cell death-ligand 1 (PD-L1) and other inhibitory checkpoints on AML cells that confer adaptive immune resistance. PD-1 and PD-L1 blocking agents may counteract T-cell dysfunction, however, at the expense of broadly distributed immune-related adverse events (irAEs). We developed a bifunctional checkpoint inhibitory T cell-engaging (CiTE) antibody that combines T-cell redirection to CD33 on AML cells with locally restricted immune checkpoint blockade. This is accomplished by fusing the extracellular domain of PD-1 (PD-1_ex), which naturally holds a low affinity to PD-L1, to an αCD3.αCD33 BiTE-like scaffold. By a synergistic effect of checkpoint blockade and avidity-dependent binding, the PD-1_ex attachment increases T-cell activation (3.3-fold elevation of interferon-γ) and leads to efficient and highly selective cytotoxicity against CD33⁺PD-L1⁺ cell lines (50% effective concentration = 2.3-26.9 pM) as well as patient-derived AML cells (n = 8). In a murine xenograft model, the CiTE induces complete AML eradication without initial signs of irAEs as measured by body weight loss. We conclude that our molecule preferentially targets AML cells, whereas high-affinity blockers, such as clinically approved anticancer agents, also address PD-L1⁺ non-AML cells. By combining the high efficacy of T-cell engagers with immune checkpoint blockade in a single molecule, we expect to minimize irAEs associated with the systemic application of immune checkpoint inhibitors and suggest high therapeutic potential, particularly for patients with relapsed/ refractory AML.