Management of lower-risk myelodysplastic syndromes without del5q: current approach and future trends

A new therapeutic perspective: Erastin inhibits tumor progression by driving ferroptosis in myelodysplastic syndromes

Ferroptosis is a recently identified and evolutionarily conserved form of programmed cell death. This process is initiated by an imbalance in iron metabolism, leading to an overload of ferrous ions. These ions promote lipid peroxidation in the cell membrane through the Fenton reaction. As the cell's antioxidant defenses become overwhelmed, a fatal buildup of reactive oxygen species (ROS) occurs, resulting in the rupture of the plasma membrane. Ferroptosis is implicated in conditions such as ischemia-reperfusion injuries and a range of cancers. In our research, we explored ferroptosis in myelodysplastic syndromes (MDS) by measuring iron levels, transferrin receptor expression, and glutathione peroxidase 4 (GPX4) mRNA. Our findings revealed that MDS patients had significantly higher Fe2+ levels in CD33+ cells and increased transferrin receptor mRNA compared to healthy individuals. GPX4 expression was also higher in MDS but not statistically significant. To investigate potential treatments for myeloid hematological diseases through ferroptosis induction, we treated the myelodysplastic syndrome cell line (SKM-1) and two myeloid leukemia cell lines (KG-1 and K562) with erastin, an iron transfer inducer. We observed that erastin treatment led to glutathione depletion, reduced GPX4 activity, and increased ROS, culminating in cell death by ferroptosis. Furthermore, combining erastin with azacitidine demonstrated a synergistic effect on MDS and leukemia cell lines, suggesting a promising approach for treating these hematological conditions with this drug combination. Our experiments confirm erastin's ability to induce ferroptosis in MDS and highlight its potential synergistic use with azacitidine for treatment.

Clinical Management of Anemia in Patients with Myelodysplastic Syndromes: An Update on Emerging Therapeutic Options

For the majority of patients with lower-risk myelodysplastic syndrome (LR-MDS), one of the primary clinical goals is to alleviate the symptoms associated with the resultant cytopenias and to minimize the transfusion burden. While supportive red blood cell (RBC) transfusions and erythropoiesis-stimulating agents (ESAs) may lead to clinical improvement, frequent transfusions are often complicated by iron overload and decreased quality of life; furthermore, most patients either do not respond to ESAs or will eventually develop resistance. As such, there is a great need for further therapeutic options in the management of anemia related to MDS. Several additional therapeutics are now available in select patients with LR-MDS and symptomatic anemia including luspatercept, lenalidomide, and immunosuppressive therapy. Furthermore, several novel agents are currently in development to address this area of clinical need such as imetelstat and roxadustat. In this article, we review the currently available therapeutic options for symptomatic anemia in LR-MDS as well as review the therapeutic agents in development.

Emerging treatment options for patients with high-risk myelodysplastic syndrome

Myelodysplastic syndromes (MDS) are clonal hematopoietic stem cell disorders characterized by ineffective hematopoiesis with peripheral blood cytopenias, dysplastic cell morphology, and a variable risk of progression to acute myeloid leukemia (AML). The hypomethylating agents (HMA) azacitidine and decitabine have been used for over a decade in MDS treatment and lead to a modest survival benefit. However, response rates are only around 40% and responses are mostly transient. For HMA-refractory patients the prognosis is poor and there are no therapies approved by the United States Food and Drug Administration.

Combinations of HMAs, especially along with immune checkpoint inhibitors, have shown promising signals in both the frontline and HMA-refractory setting. Several other novel agents including orally available and longer acting HMAs, the BCL-2 inhibitor venetoclax, oral agents targeting driver mutations (IDH1/2, FLT3), immunotherapies, and new options for intensive chemotherapy have been studied with variable success and will be reviewed herein. Except for the minority of patients with targetable driver mutations, HMAs – likely as part of combination therapies – will remain the backbone of frontline MDS treatment. However, the wider use of genetic testing may enable a more targeted and individualized therapy of MDS patients.

Therapeutic strategies in low and high-risk MDS: What does the future have to offer?

Myelodysplastic syndromes (MDS) are a heterogeneous group of myeloid disorders characterized by cytopenias and increased risk of acute leukemia transformation. Prognosis of MDS patients can be assessed by various scoring systems, the most common being the International Prognostic Scoring System (IPSS) now refined by the revised version (IPSS-R). Genomic information at baseline, that is currently not included in clinical prognostic scores, will, in the future, help us to stratify patients with various prognoses. Therapy of MDS is based on risk stratification. The aim of therapy in low-risk MDS is to improve anemia or thrombocytopenia, decrease transfusion needs, improve quality of life, attempt to prolong overall survival, and reduce the risk of progression. In higher-risk MDS, the goal of therapy is to prolong survival and reduce the risk of transformation into acute leukemia. Only a few drugs are currently available for treatment, but more drugs are now under clinical investigation, in line with new, recently discovered molecular and immunological pathways. This review describes potential new drugs for low and high-risk MDS. The increasing knowledge of immunological and signalling pathways in MDS will assist us in identifying targeted patient-oriented treatments. In the near future, initial molecular stratification will lead the way to a personalized approach and targeted therapy.

RBC transfusion independence among lower risk MDS patients receiving hypomethylating agents: a population-level analysis

Most patients with lower risk myelodysplastic syndromes (LR-MDS) become red blood cell (RBC) transfusion dependent at some time during their disease course. Hypomethylating agents (HMAs) are frequently used in this setting; however, reported rates of in RBC transfusion independence (TI) achieved with HMA therapy vary significantly between studies. Here we study the real-life clinical effectiveness of HMA in inducing RBC TI in anemic LR-MDS patients using the Surveillance, Epidemiology and End Results (SEER)-Medicare database. We find that approximately 40% of LR-MDS patients who were receiving RBC transfusions and 33% who were dependent on RBC transfusions at HMA initiation ultimately achieved TI. The receipt of ≥3 transfusions in the 8-week period before HMA initiation was significantly associated with lower odds of achieving TI. Our study provides important population level estimates of clinical effectiveness of HMAs in LR-MDS.

Transforming growth factor (TGF)-β pathway as a therapeutic target in lower risk myelodysplastic syndromes

The transforming growth factor (TGF)-β superfamily comprises more than 30 soluble growth factors that play a central role in erythropoiesis and are part of a tightly regulated myelosuppressive negative feedback loop under physiologic conditions. TGF-β receptor activation and phosphorylation trigger a regulatory circuit of activating and inhibitory SMAD proteins and increased activation of the TGF-β signaling pathway either by a loss of negative feedback or constitutive activation has been associated with the myelosuppression and ineffective erythropoiesis in myelodysplastic syndromes (MDS). Anemia is the predominant cause of morbidity and quality of life impairment in patients with lower-risk (LR)-MDS, and there are very limited therapy options for these patients after failure of erythropoiesis stimulating agents (ESAs). Targeting the aberrant TGF-ß signaling pathway has therefore been investigated as a promising therapeutic approach to resolve the ineffective erythropoiesis in LR-MDS. In this article, we provide a brief overview of the TGF-β signaling cascade in hematopoiesis under physiologic conditions and its role in MDS pathogenesis. We also review preclinical and clinical data for the activin receptor type IIA ligand traps sotatercept and luspatercept that have recently shown promising results in overcoming the myelosuppressive effects of TGF-β signaling alterations to improve hematopoiesis in transfusion-dependent, non-del(5q) LR-MDS patients. Additional potential targets within the TGF-β pathway have also been identified in preclinical experiments and may provide further therapeutic options. Finally, combining different TGF-β pathway inhibitors or using them in combination with ESAs or the immunomodulator lenalidomide might have synergistic effects as well.

Systematic review and meta-analysis of the effect of iron chelation therapy on overall survival and disease progression in patients with lower-risk myelodysplastic syndromes

The impact of iron chelation therapy (ICT) on overall survival (OS) and progression to acute myeloid leukemia (AML) in patients with iron overload and International Prognostic Scoring System low- or intermediate-risk myelodysplastic syndromes (MDS) is not well understood. We conducted a systematic review and meta-analysis of published studies of ICT in patients with MDS to better elucidate these relationships. We searched PubMed, EMBASE, Cochrane databases, and the World Health Organization Clinical Trial Registry for studies reporting the impact of ICT on OS in patients with low- or intermediate-risk MDS. Studies were examined for demographics, effect measures, and potential bias risk. Fixed and random-effects models were used to calculate adjusted OS and adjusted hazards ratio (aHR) estimates, respectively, among the different studies. Nine observational studies (four prospective and five retrospective) were identified. For patients with MDS, ICT was associated with an overall lower risk of mortality compared with no ICT (aHR 0.42; 95% confidence interval (CI) 0.28-0.62; P < 0.01); however, there was significant heterogeneity across the studies. In studies reporting progression to AML, ICT was not associated with decreased risk of progression (odds ratio 0.68; 95% CI 0.31-1.43; P < 0.030). This systematic review and meta-analysis of nine nonrandomized trials demonstrated significant reduction in risk of mortality in patients with iron overload and low- or intermediate-risk MDS treated with ICT; however, a causal relationship cannot be established. Randomized, controlled trials are needed to more definitively evaluate the relationship between ICT and survival in patients with iron overload and low- or intermediate-risk MDS.

Immunosuppressive therapy in myelodysplastic syndromes: a borrowed therapy in search of the right place

INTRODUCTION

Myelodysplastic syndromes (MDS) encompass a heterogenous collection of clonal hematopoietic stem cell disorders defined by dysregulated hematopoiesis, peripheral cytopenias, and a risk of leukemic progression. Increasing data support the role of innate and adaptive immune pathways in the pathogenesis and disease course of MDS. The role of immunosuppressive therapy has an established role in the treatment of other hematologic diseases, such as aplastic anemia whose pathogenesis is postulated to reflect that of MDS with regards to many aspects of immune activation. Areas covered: This paper discusses the current understanding of immune dysregulation as it pertains to MDS, the clinical experience with immunosuppressive therapy in the management of MDS, as well as future prospects which will likely improve therapeutic options and outcomes for patients with MDS. Expert commentary: Though limited by paucity of high quality data, immunomodulatory and immunosuppressive therapies for the treatment of MDS have shown meaningful clinical activity in selected patients. Continued clarification of the immune pathways that are dysregulated in MDS and establishing predictors for clinical benefit of immunosuppressive therapy are vital to improve the use and outcomes with these therapies.

The use of immunosuppressive therapy in MDS: clinical outcomes and their predictors in a large international patient cohort

Most studies of immunosuppressive therapy (IST) in myelodysplastic syndromes (MDS) are limited by small numbers and their single-center nature, and report conflicting data regarding predictors for response to IST. We examined outcomes associated with IST and predictors of benefit in a large international cohort of patients with MDS. Data were collected from 15 centers in the United States and Europe. Responses, including red blood cell (RBC) transfusion independence (TI), were assessed based on the 2006 MDS International Working Group criteria, and overall survival (OS) was estimated by Kaplan-Meier methods. Logistic regression models estimated odds for response and TI, and Cox Proportional Hazard models estimated hazards ratios for OS. We identified 207 patients with MDS receiving IST, excluding steroid monotherapy. The most common IST regimen was anti-thymocyte globulin (ATG) plus prednisone (43%). Overall response rate (ORR) was 48.8%, including 11.2% (95% confidence interval [CI], 6.5%-18.4%) who achieved a complete remission and 30% (95% CI, 22.3%-39.5%) who achieved RBC TI. Median OS was 47.4 months (95% CI, 37-72.3 months) and was longer for patients who achieved a response or TI. Achievement of RBC TI was associated with a hypocellular bone marrow (cellularity < 20%); horse ATG plus cyclosporine was more effective than rabbit ATG or ATG without cyclosporine. Age, transfusion dependence, presence of paroxysmal nocturnal hemoglobinuria or large granular lymphocyte clones, and HLA DR15 positivity did not predict response to IST. IST leads to objective responses in nearly half the selected patients with the highest rate of RBC TI achieved in patients with hypocellular bone marrows.

To chelate or not to chelate in MDS: That is the question!

Myelodysplastic syndromes (MDS) are a heterogeneous group of hemopathies that exhibit physical manifestations with clinical consequences of bone marrow failure and inherent risk of progression to acute myeloid leukemia. Iron overload (IO) is common in MDS due to chronic transfusion support and disease-related alterations in iron metabolism. IO has been conclusively associated with inferior outcomes among MDS patients. Despite lack of randomized trials showing a survival impact of iron chelation therapy (ICT), ICT is recommended by experts and guidelines for select MDS patients with IO and is often used. The availability of effective oral ICT agents has reignited the controversy regarding ICT use in patients with MDS and IO. Here we summarize the studies evaluating the value of ICT in MDS and suggest a practical approach for use of these therapies. We also highlight controversies regarding use of ICT in MDS and discuss some ongoing efforts to answer these questions.

The Use of Flow Cytometry in Myelodysplastic Syndromes: A Review

Myelodysplastic syndromes (MDSs) are a heterogeneous group of hematopoietic stem cell diseases categorized by dysplasia in one or more hematopoietic cell lineages, as well as cytopenia and functional abnormalities in bone marrow cells. Several MDS classification methods have been proposed to categorize the disease and help professionals better plan in patients’ treatment. The World Health Organization classification, released in 2008 and revised in 2016, is the currently and the most used classification method worldwide. Recent advances in MDS molecular biology and innovations in flow cytometry have enabled the development of new parameters for MDS diagnosis and classification. Several groups have published flow cytometry scores and guidelines useful for the diagnosis and/or prognosis of MDS, which are mostly based on detecting immunophenotypic abnormalities in granulocyte, monocyte, and lymphoid lineages. Here, we review the current literature and discuss the main parameters that should be analyzed by flow cytometry with the aim of refining MDS diagnosis and prognosis. Furthermore, we discuss the critical role of flow cytometry and molecular biology in MDS diagnosis and prognosis, as well as the current challenges and future perspectives involving these techniques.