Longer-term benefit of luspatercept in transfusion-dependent lower-risk myelodysplastic syndromes with ring sideroblasts

Treatment of Myelodysplastic Syndromes for Older Patients: Current State of Science, Challenges, and Opportunities

PURPOSE OF REVIEW

Myelodysplastic syndromes/neoplasms (MDS) represent a diverse group of pathologically distinct diseases with varying prognoses and risks of leukemia progression. This review aims to discuss current treatment options for elderly patients with MDS, focusing on patients ineligible for intensive chemotherapy or allogenic hematopoietic stem cell transplantation (HSCT). The challenges associated with treatment in this population and emerging therapeutic prospects are also explored.

RECENT FINDINGS

Recent advancements in molecular diagnostics have enhanced risk stratification by incorporating genetic mutations, notably through the molecular International Prognostic Scoring System (IPSS-M). Lower-risk MDS (LR-MDS) treatment ranges from observation to supportive measures and erythropoiesis-stimulating agents (ESAs), with emerging therapies like luspatercept showing promise. High-risk MDS (HR-MDS) is treated with hypomethylating agents (HMAs) or allogenic HSCT, but outcomes remain poor. Elderly MDS patients, often diagnosed after 70, pose challenges in treatment decision-making. The IPSS-M aids risk stratification, guiding therapeutic choices. For LR-MDS, supportive care, ESAs, and novel agents like luspatercept are considered. Treatment of HR-MDS involves HMAs or allogenic HSCT. Emerging treatments, including oral HMAs and novel agents targeting FLT3, and IDH 1/2 mutations, show promise. Future research should refine treatment strategies for this elderly population focusing on quality-of-life improvement.

Accelerated DNA replication fork speed due to loss of R-loops in myelodysplastic syndromes with SF3B1 mutation

Myelodysplastic syndromes (MDS) with mutated SF3B1 gene present features including a favourable outcome distinct from MDS with mutations in other splicing factor genes SRSF2 or U2AF1. Molecular bases of these divergences are poorly understood. Here we find that SF3B1-mutated MDS show reduced R-loop formation predominating in gene bodies associated with intron retention reduction, not found in U2AF1- or SRSF2-mutated MDS. Compared to erythroblasts from SRSF2- or U2AF1-mutated patients, SF3B1-mutated erythroblasts exhibit augmented DNA synthesis, accelerated replication forks, and single-stranded DNA exposure upon differentiation. Importantly, histone deacetylase inhibition using vorinostat restores R-loop formation, slows down DNA replication forks and improves SF3B1-mutated erythroblast differentiation. In conclusion, loss of R-loops with associated DNA replication stress represents a hallmark of SF3B1-mutated MDS ineffective erythropoiesis, which could be used as a therapeutic target.

Next-generation therapy for lower-risk MDS

Myelodysplastic syndromes (MDS) are malignant myeloid neoplasms characterized by ineffective clonal hematopoiesis leading to peripheral blood cytopenia and a variable risk of transformation to acute myeloid leukemia. In lower-risk (LR) MDS, as defined by prognostic scoring systems recently updated with the addition of a mutation profile, therapeutic options aim to reduce cytopenia, mainly anemia. Although options for reducing the transfusion burden have recently been improved, erythropoiesis-stimulating agents (ESAs), lenalidomide, hypomethylating agents, and, more recently, luspatercept have shown efficacy in rarely more than 50% of patients with a duration of response often far inferior to the patient's life expectancy. Nevertheless, several new therapies are currently under investigation aiming at improving cytopenia in patients with LR-MDS, mostly by targeting different biological pathways. Targeting ligands of the transforming growth factor β pathway has led to the approval of luspatercept in LR-MDS with ring sideroblasts or SF3B1 mutation, potentially replacing first-line ESAs in this population. Here, we also discuss the evolving standard of care for the treatment of LR-MDS and explore some of the most promising next-generation agents under investigation.

Treatment Considerations of Myelodysplastic Syndromes/Neoplasms for Pathologists

The diagnosis of myelodysplastic syndromes/neoplasms (MDS) has evolved over the years with the incorporation of genetic abnormalities to establish a diagnosis, their impact on risk stratification, prognostication, and therapeutic options. Hematopathologists are the cornerstone to establish an accurate diagnosis and ensure patients receive the best available treatment option. Hematopathologists and clinicians must work closely together to establish the best disease subclassification, by combining pathologic findings with the clinical presentation. This will ensure patients receive the best therapeutic approach by better understanding the disease entity. In this review, we discuss how we approach a bone marrow biopsy report in the management of MDS.

Novel potential therapeutics to modify iron metabolism and red cell synthesis in diseases associated with defective erythropoiesis

Under normal conditions, iron metabolism is carefully regulated to sustain normal cellular functions and the production of hemoglobin in erythroid cells. Perturbation to the erythropoiesis-iron metabolism axis can result in iron imbalances and cause anemia or organ toxicity. Various congenital and acquired diseases associated with abnormal red cell production are characterized by aberrant iron absorption. Several recent studies have shown that improvements in red blood cell production also ameliorate iron metabolism and vice versa. Many therapeutics are now under development with the potential to improve a variety of hematologic diseases, from β-thalassemia and iron-refractory iron deficiency anemia to anemia of inflammation and polycythemia vera. This review summarizes selected mechanisms related to red cell production and iron metabolism and describes potential therapeutics and their current uses. We also consider the potential application of the discussed therapeutics on various diseases, alone or in combination. The vast repertoire of drugs under development offers new opportunities to improve the clinical care of patients suffering from congenital or acquired red blood cell disorders with limited or no treatment options.

Management of Patients with Lower-Risk Myelodysplastic Neoplasms (MDS)

Myelodysplastic neoplasms (MDS) are a heterogenous group of clonal hematologic disorders characterized by morphologic dysplasia, ineffective hematopoiesis, and cytopenia. In the past year, the classification of MDS has been updated in the 5th edition of the World Health Organization (WHO) Classification of Haematolymphoid Tumours and the International Consensus Classification (ICC) of Myeloid Neoplasms and Acute Leukemia with incorporation of morphologic, clinical, and genomic data. Furthermore, the more comprehensive International Prognostic Scoring System-Molecular (IPSS-M) allows for improved risk stratification and prognostication. These three developments allow for more tailored therapeutic decision-making in view of the expanding treatment options in MDS. For patients with lower risk MDS, treatment is aimed at improving cytopenias, usually anemia. The recent approval of luspatercept and decitabine/cedazuridine have added on to the current armamentarium of erythropoietic stimulating agents and lenalidomide (for MDS with isolated deletion 5q). Several newer agents are being evaluated in phase 3 clinical trials for this group of patients, such as imetelstat and oral azacitidine. This review provides a summary of the classification systems, the prognostic scores and clinical management of patients with lower risk MDS.

Advances in myelodysplastic syndromes: promising novel agents and combination strategies

INTRODUCTION

Myelodysplastic syndromes (MDS) are heterogeneous group of clonal hematopoietic stem cell neoplasms that have limited approved treatment options. Multiple novel agents are currently being tested in a clinical trial setting. From a therapeutic perspective, MDS is generally divided into lower-risk and higher-risk disease. In this review, we summarize some of the most prominent novel agents currently in development.

AREAS COVERED

This review focuses on select clinical trials in both lower- and higher-risk MDS, elucidating the mechanisms of action and rationale for drug combinations and summarizing early safety and efficacy data using novel agents in MDS.

EXPERT OPINION

Advances in understanding the innate immune system, telomere biology, as well as genomic drivers of the disease have led to the development of multiple novel agents that are currently in late stages of clinical development in MDS. Imetelstat is being tested in lower-risk disease and the phase III clinical trial recently completed accrual. Magrolimab, sabatolimab, and venetoclax in addition to novel oral hypomethylating agents (HMA) are being investigated in higher-risk MDS. These advances will hopefully bring better treatment options to patients and lead to a shift in the treatment paradigm. Post HMA therapy remains an area of dire unmet need.

How I Manage Transplant Ineligible Patients with Myelodysplastic Neoplasms

Myelodysplastic neoplasms, formerly known as myelodysplastic syndromes (MDS), represent a group of clonal disorders characterized by a high degree of clinical and molecular heterogeneity, and an invariable tendency to progress to acute myeloid leukemia. MDS typically present in the elderly with cytopenias of different degrees and bone marrow dysplasia, the hallmarks of the disease. Allogeneic hematopoietic stem cell transplant is the sole curative approach to date. Nonetheless, given the disease’s demographics, only a minority of patients can benefit from this procedure. Currently used prognostic schemes such as the Revised International Prognostic Scoring System (R-IPSS), and most recently the molecular IPSS (IPSS-M), guide clinical management by dividing MDS into two big categories: lower- and higher-risk cases, based on a cut-off score of 3.5. The main clinical problem of the lower-risk group is represented by the management of cytopenias, whereas the prevention of secondary leukemia progression is the goal for the latter. Herein, we discuss the non-transplant treatment of MDS, focusing on current practice and available therapeutic options, while also presenting new investigational agents potentially entering the MDS therapeutic arsenal in the near future.

TGF-beta signal transduction: biology, function and therapy for diseases

The transforming growth factor beta (TGF-β) is a crucial cytokine that get increasing concern in recent years to treat human diseases. This signal controls multiple cellular responses during embryonic development and tissue homeostasis through canonical and/or noncanonical signaling pathways. Dysregulated TGF-β signal plays an essential role in contributing to fibrosis via promoting the extracellular matrix deposition, and tumor progression via inducing the epithelial-to-mesenchymal transition, immunosuppression, and neovascularization at the advanced stage of cancer. Besides, the dysregulation of TGF-beta signal also involves in other human diseases including anemia, inflammatory disease, wound healing and cardiovascular disease et al. Therefore, this signal is proposed to be a promising therapeutic target in these diseases. Recently, multiple strategies targeting TGF-β signals including neutralizing antibodies, ligand traps, small-molecule receptor kinase inhibitors targeting ligand-receptor signaling pathways, antisense oligonucleotides to disrupt the production of TGF-β at the transcriptional level, and vaccine are under evaluation of safety and efficacy for the forementioned diseases in clinical trials. Here, in this review, we firstly summarized the biology and function of TGF-β in physiological and pathological conditions, elaborated TGF-β associated signal transduction. And then, we analyzed the current advances in preclinical studies and clinical strategies targeting TGF-β signal transduction to treat diseases.