Recent advances in the treatment of lower-risk non-del(5q) myelodysplastic syndromes (MDS)

Oral therapy for myelodysplastic syndromes/neoplasms and acute myeloid leukemia: a revolution in progress

INTRODUCTION

Patients with myeloid neoplasms such as myelodysplastic syndromes/neoplasms (MDS) and acute myeloid leukemia (AML) are generally older, and many are not eligible for curative intent intensive therapies and/or allogeneic hematopoietic stem cell transplantation. While lower intensity, hypomethylating agent (HMA)-based therapies such as azacitidine+venetoclax have improved patient outcomes significantly, responses are not durable, and most patients die from disease-related complications. The approvals of oral HMAs such as cedazuridine-decitabine (C-DEC) and oral azacitidine (CC-486) have kindled the hope that myeloid malignancies may soon be treated with total oral therapy.

AREAS COVERED

We review all-oral therapies including the approvals of C-DEC and CC-486 in MDS and AML, respectively, in addition to emerging all-oral therapies, both monotherapy and combination, in higher-risk (HR) MDS and AML.

EXPERT OPINION

Oral HMAs have the potential to be a convenient and efficacy-equivalent treatment option for patients with HR-MDS or AML and improve their quality of life by reducing clinic visits for medication administration. Total-oral therapy combinations, largely including an oral HMA 'backbone,' are in the early phases of clinical development, and it is our hope that well-designed trials employing these agents may soon allow the identification of optimal regimens that deliver effective disease-directed therapy with good tolerability.

Eltrombopag monotherapy can improve hematopoiesis in patients with low to intermediate risk-1 myelodysplastic syndrome

Myelodysplastic syndromes (MDS) are a group of clonal myeloid disorders characterized by low blood counts and a propensity to develop acute myeloid leukemia. The management of lowerrisk (LR) MDS with persistent cytopenias remains suboptimal. Eltrombopag, a thrombopoietin-receptor agonist, can improve platelet counts in LR-MDS and trilineage hematopoiesis in aplastic anemia. We conducted a phase II dose modification study to investigate the safety and efficacy of eltrombopag in LR-MDS. The eltrombopag dose was escalated from 50 mg/day to a maximum of 150 mg/day over a period of 16 weeks. The primary efficacy endpoint was hematologic response at 16-20 weeks. Eleven of 25 (44%) patients responded; five and six patients had uni- or bi-lineage hematologic responses, respectively. The predictors of response were presence of a paroxysmal nocturnal hemoglobinuria clone, marrow hypocellularity, thrombocytopenia, and elevated plasma thrombopoietin levels at study entry. The safety profile was consistent with that found in previous eltrombopag studies in aplastic anemia; no patients discontinued the drug due to adverse events. Three patients developed reversible grade 3 liver toxicity and one patient had increased reticulin fibrosis. Ten patients discontinued eltrombopag after achieving a robust response (median time 16 months); four of them reinitiated eltrombopag because of declining blood counts, and all attained a second robust response. Six patients had disease progression not associated with expansion of mutated clones and no patient progressed to develop acute myeloid leukemia on study. In conclusion, eltrombopag was well-tolerated and effective in restoring hematopoiesis in some patients with low or intermediate-1 risk MDS. This study was registered at clinicaltrials.gov as #NCT00932156.

Mesenchymal Stem Cells in Aplastic Anemia and Myelodysplastic Syndromes: The "Seed and Soil" Crosstalk

There is growing interest in the contribution of the marrow niche to the pathogenesis of bone marrow failure syndromes, i.e., aplastic anemia (AA) and myelodysplastic syndromes (MDSs). In particular, mesenchymal stem cells (MSCs) are multipotent cells that contribute to the organization and function of the hematopoietic niche through their repopulating and supporting abilities, as well as immunomodulatory properties. The latter are of great interest in MDSs and, particularly, AA, where an immune attack against hematopoietic stem cells is the key pathogenic player. We, therefore, conducted Medline research, including all available evidence from the last 10 years concerning the role of MSCs in these two diseases. The data presented show that MSCs display morphologic, functional, and genetic alterations in AA and MDSs and contribute to immune imbalance, ineffective hematopoiesis, and leukemic evolution. Importantly, adoptive MSC infusion from healthy donors can be exploited to heal the "sick" niche, with even better outcomes if cotransplanted with allogeneic hematopoietic stem cells. Finally, future studies on MSCs and the whole microenvironment will further elucidate AA and MDS pathogenesis and possibly improve treatment.

Myelo-deception: Luspatercept & TGF-Beta ligand traps in myeloid diseases & anemia

Myelodysplastic syndromes (MDS) encompass a clinically heterogenous group of diseases defined by a clonal bone marrow failure state. Patients with lower-risk MDS primarily suffer from the consequences of anemia, with a subset having increased risks of bleeding and infection. There are few good therapeutic options for this patient population, as patients are dependent on cytokine support to improve hematopoiesis. Our review will discuss luspatercept, a transforming growth factor (TGF)-Beta ligand trap, the first new Food & Drug Administration (FDA)-approved treatment in MDS in over a decade. We will explore the different TGF-Beta ligand traps that have been developed for a number of diseases, with a focus on myeloid malignancies.

Allogeneic Stem Cell Transplantation for Patients with Lower-Risk Myelodysplastic Syndrome

The indication for allogeneic stem cell transplantation (SCT) in patients with lower-risk myelodysplastic syndrome (MDS) is controversial. Here we report 60 patients with a low risk (n = 32) or intermediate risk (n = 28) classification according to the revised International Prognostic Scoring System (IPSS-R) who underwent allogeneic SCT with a reduced-intensity conditioning (n = 45) or myeloablative conditioning (n = 15) regimen from an HLA-identical sibling (n = 9), a matched unrelated donor (n = 36), or a mismatched unrelated donor (n = 15). The rates of grade II-IV and grade III-IV acute graft-versus-host disease were 32% and 7%, respectively, resulting in a transplantation-related mortality (TRM) of 17% at 3 years. The cumulative incidence of relapse at 5 years was only 7%, resulting in a 5-year disease-free survival of 72% and overall survival (OS) of 79%. Transplantation from a fully matched donor resulted in significantly improved OS at 5 years (91% versus 70%). Allogeneic SCT in lower-risk MDS (IPSS-R low or intermediate risk) from an HLA-matched donor resulted in excellent OS with a low risk of relapse.

Treatment of Anemia in Transfusion-Dependent and Non-Transfusion-Dependent Lower-Risk MDS: Current and Emerging Strategies

Myelodysplastic syndromes (MDS) are a heterogeneous group of bone marrow disorders with a highly diverse clinical course. For lower-risk MDS patients, therapeutic objectives aim to correct chronic anemia and improve/maintain health-related quality of life (HRQoL). However, disease burden is often insufficiently recognized, and although some patients do not respond/lose response to standard treatment, many are treated late. This is the case for non-transfusion-dependent patients with symptomatic anemia, in whom delayed treatment initiation may lead to unnecessary morbidity. Current active treatment options for lower-risk MDS are limited. Standard care for lower-risk 5q deletion [del(5q)] MDS patients with anemia remains supportive, consisting of red blood cell (RBC) transfusions, iron chelation therapy, and treatment with erythropoiesis-stimulating agents (ESAs) in the case of low serum erythropoietin levels. Response rates to ESAs range from 15% to 63%, whereas 56% to 67% of patients with del(5q) MDS achieve RBC transfusion independence with lenalidomide. Treatment options for patients’ refractory to ESAs and/or lenalidomide, however, are limited. Frequent transfusions are associated with profound clinical, HRQoL, and economic consequences for transfusion-dependent patients. This review focuses on the multiple unmet clinical needs that exist in the treatment of anemia associated with lower-risk MDS and the current and future treatment options that may improve disease management and patient outcomes.

Activin receptor ligand traps in chronic kidney disease

PURPOSE OF REVIEW

Sotatercept and luspatercept are recombinant soluble activin type-II receptor-IgG-Fc fusion proteins that are tested in clinical trials for the treatment of various types of anemias, including renal anemia. The mechanism of the action of the novel drugs is incompletely understood, but it seems to be based on the inactivation of soluble proteins of the transforming growth factor-ß (TGFß) family. This review considers pros and cons of the clinical use of the drugs in reference to the current therapy with recombinant erythropoiesis-stimulating agents (ESAs).

RECENT FINDINGS

One or more activin type-II receptor (ActRII) ligands appear to inhibit erythroid precursors, for example growth and differentiation factor 11. Trapping of these ligands by the recombinant ActRII fusion proteins, sotatercept and luspatercept increases red blood cell numbers and hemoglobin levels in humans. Reportedly, the novel compounds were well tolerated in trials on healthy volunteers and patients suffering from anemia due to chronic kidney disease or malignancies. On approval, the drugs may prove particularly useful in patients suffering from ineffective erythropoiesis, such as in myelodysplastic syndrome, multiple myeloma or ß-thalassemia, where ESAs are of little use. Independent of their effect on erythropoiesis, ActRII ligand traps were found to exert beneficial effects on renal tissue in experimental animals.

SUMMARY

ESAs are likely to remain standard of care in renal anemia. There is a need for a better understanding of the effects of ActRII ligand traps on TGFß-like proteins. The novel drugs have not been approved for sale as therapeutics so far. Their long-term efficacy and safety still needs to be proven, particularly with respect to immunogenicity. Antifibrotic effects may be worthy to be investigated in humans.

Epoetin alfa for the treatment of myelodysplastic syndrome-related anemia: A review of clinical data, clinical guidelines, and treatment protocols

Myelodysplastic syndromes (MDS) are characterized by ineffective hematopoiesis, leading to hematopoietic precursor cell apoptosis and peripheral blood cytopenias. Anemia is the most frequently experienced cytopenia and is the main cause of MDS symptoms, with fatigue and dyspnea contributing to reduced quality of life and increased morbidity. As MDS disease course and prognosis is influenced by disease factors, prognostic scoring systems have been developed for MDS to aid clinical and therapeutic decisions following diagnosis. Erythropoiesis- stimulating agents (ESAs) have been used for many years to treat anemia in patients with lower-risk MDS without chromosomal abnormalities. The use of ESAs is recommended by international clinical practice guidelines, due to the large body of evidence demonstrating their effectiveness in lower-risk MDS. In March 2017, the European Medicines Agency approved epoetin alfa for the treatment of anemia in lower-risk MDS patients, based on the results from a Phase 3 clinical trial and three European registry studies. The effectiveness of biosimilar epoetin alfa (Binocrit^®, Sandoz) to correct anemia in lower-risk MDS patients has also been demonstrated in a retrospective, single-center, observational study. The recent approval of epoetin alfa by the EMA in this setting will provide clinicians with a welcome, approved treatment option for lower-risk MDS.

Clinical effectiveness and safety of erythropoietin-stimulating agents for the treatment of low- and intermediate-1-risk myelodysplastic syndrome: a systematic literature review

Many patients with lower-risk myelodysplastic syndrome (MDS) experience anaemia, which has negative consequences. Erythropoiesis-stimulating agents (ESAs) and their biosimilars are used to treat anaemia in MDS and, currently, epoetin alfa and darbepoetin alfa are commonly used and recommended by clinical guidelines. To better understand the evidence available on the use of ESAs for anaemia in lower-risk MDS, we conducted a systematic literature review to identify randomized and nonrandomized prospective studies reporting on clinical efficacy/effectiveness, patient-reported quality of life (QoL), and safety. We extended our review to include retrospective studies for darbepoetin alfa specifically and to ascertain the feasibility of completing an indirect network meta-analysis comparing epoetin and darbepoetin alfa. Overall, 53 articles reporting on 35 studies were included. The studies indicated a clinical benefit of ESAs, with benefits observed across key clinical outcomes. ESAs showed consistent improvement in erythroid response rates (ESA-naïve, 45-73%; previous ESA exposure, 25-75%) and duration of response. Comparative studies demonstrated similar progression to acute myeloid leukaemia and several showed improved overall survival and QoL. Limited safety concerns were identified. This analysis confirmed ESA therapy should be the foremost first-line treatment of anaemia in most patients with lower-risk MDS who lack the 5q deletion.

Prognostic Significance of Platelet Recovery in Myelodysplastic Syndromes With Severe Thrombocytopenia

Severe thrombocytopenia is a serious condition that frequently arises in patients with myelodysplastic syndrome (MDS) and is associated with poor prognosis. Few studies have investigated the prognostic significance of platelet recovery in patients with MDS having thrombocytopenia. We retrospectively analyzed 117 patients with de novo MDS complicated with thrombocytopenia (platelet count [PLT] < 100 × 10⁹/L). Patients received decitabine treatment (schedule A) or decitabine followed by allogeneic hematopoietic stem cell transplantation (allo-HSCT; schedule B). Severe thrombocytopenia (PLT < 20 × 10⁹/L), identified in 31 (26.5%) patients, was associated with poor survival. The PLT increased significantly after decitabine treatment in the 2 groups. Patients with thrombocytopenia treated with schedule B showed a superior prognosis compared to those treated with schedule A. On analysis of overall survival by platelet response in patients with severe thrombocytopenia, a significant survival advantage was observed in patients who achieved a platelet response, who would further benefit from allo-HSCT following decitabine therapy. The results indicate a potentially favorable prognostic impact of platelet response achieved with decitabine. Patients with MDS having severe thrombocytopenia may benefit from the effective recovery of platelets and further allo-HSCT following decitabine therapy.

Normal and pathological erythropoiesis in adults: from gene regulation to targeted treatment concepts

Pathological erythropoiesis with consequent anemia is a leading cause of symptomatic morbidity in internal medicine. The etiologies of anemia are complex and include reactive as well as neoplastic conditions. Clonal expansion of erythroid cells in the bone marrow may result in peripheral erythrocytosis and polycythemia but can also result in anemia when clonal cells are dysplastic and have a maturation arrest that leads to apoptosis and hinders migration, a constellation typically seen in the myelodysplastic syndromes. Rarely, clonal expansion of immature erythroid blasts results in a clinical picture resembling erythroid leukemia. Although several mechanisms underlying normal and abnormal erythropoiesis and the pathogenesis of related disorders have been deciphered in recent years, little is known about specific markers and targets through which prognosis and therapy could be improved in anemic or polycythemic patients. In order to discuss new markers, targets and novel therapeutic approaches in erythroid disorders and the related pathologies, a workshop was organized in Vienna in April 2017. The outcomes of this workshop are summarized in this review, which includes a discussion of new diagnostic and prognostic markers, the updated WHO classification, and an overview of new drugs used to stimulate or to interfere with erythropoiesis in various neoplastic and reactive conditions. The use and usefulness of established and novel erythropoiesis-stimulating agents for various indications, including myelodysplastic syndromes and other neoplasms, are also discussed.

Myelodysplastic syndromes current treatment algorithm 2018

Myelodysplastic syndromes (MDS) include a group of clonal myeloid neoplasms characterized by cytopenias due to ineffective hematopoiesis, abnormal blood and marrow cell morphology, and a risk of clonal evolution and progression to acute myeloid leukemia (AML). Because outcomes for patients with MDS are heterogeneous, individual risk stratification using tools such as the revised International Prognostic Scoring System (IPSS-R) is important in managing patients-including selecting candidates for allogeneic hematopoietic stem cell transplantation (ASCT), the only potentially curative therapy for MDS. The IPSS-R can be supplemented by molecular genetic testing, since certain gene mutations such as TP53 influence risk independent of established clinicopathological variables. For lower risk patients with symptomatic anemia, treatment with erythropoiesis-stimulating agents (ESAs) or lenalidomide (especially for those with deletion of chromosome 5q) can ameliorate symptoms. Some lower risk patients may be candidates for immunosuppressive therapy, thrombopoiesis-stimulating agents, or a DNA hypomethylating agent (HMA; azacitidine or decitabine). Among higher risk patients, transplant candidates should undergo ASCT as soon as possible, with HMAs useful as a bridge to transplant. Non-transplant candidates should initiate HMA therapy and continue if tolerated until disease progression. Supportive care with transfusions and antimicrobial drugs as needed remains important in all groups.

The impact of anaemia, transfusion dependency, comorbidities and polypharmacy in elderly patients with low-risk myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are heterogeneous clonal disorders ranging from indolent conditions with a near-normal life expectancy to forms approaching acute myeloid leukaemia. Comorbid conditions have rarely been systematically studied among patients with MDS. Older age per se has a negative impact on survival of MDS patients, in particular of those with lower risk. However, age indirectly affects also the survival of higher-risk patients by limiting their eligibility to intensive treatments. In addition, ageing is associated with an increasingly high risk of developing comorbidity, and a high prevalence of comorbid diseases has indeed been reported in MDS patients. The impact of multi-morbidities/comorbidities and polypharmacy in patients with low-risk MDS patients is a poorly explored topic. We focused on medications, multi-morbidities and comorbidities of 155 low-risk MDS patients followed in the haematological outpatients clinics or in medical/oncology wards of our University Hospital. One or more comorbidities were present at diagnosis in 24 younger patients with MDS syndromes (31%), whereas 56 older patients with MDS (75%) presented 1 or more comorbidities (P < 0.001).The most frequent comorbidity was cardiac comorbidity 18% in younger patients and 25% in older patients. With no statistical significance between older and younger patients, congestive heart failure was the most frequent observed disease. Our study has shown a statistical correlation between transfusion dependency and polypathology (P = 0.0014). These data were also confirmed in a subanalysis of the younger group of patients. Our study has shown that comorbidity is very common among patients with MDS, potentially affecting the clinical course and outcome of MDS patients.

Hypomethylating agents (HMA) treatment for myelodysplastic syndromes: alternatives in the frontline and relapse settings

INTRODUCTION

Hypomethylating agents (HMA) have played a pivotal role for treating myelodysplastic syndromes (MDS) over the past decade, inducing sustained hematological responses and delaying progression to leukemia. However, a vast majority of patients will experience treatment failure within 2 years, with poor prognoses and limited options, and management of this growing patient population remains unclear. Areas covered: With the introduction of new agents in the MDS field, a better understanding of the biology of MDS, and updated information on standard of care options (including allogeneic transplantation), we re-evaluate the global treatment strategy in MDS via novel agents, focusing in particular on investigational approaches for patients who fail to respond to HMA when applicable. This review aims to address two questions: what are reasonable alternatives to HMA in MDS, and what strategies can be used for patients experiencing HMA failure. Expert opinion/commentary: HMA therapy remains a mainstay of treatment, even if additional research is still warranted to maximize its benefits for the different groups of patients. The outcome of patients experiencing HMA failure remains grim, without standard of care, but several new approaches seem promising, as there is an increasing focus on studying treatments for patients refractory to HMA treatment.

Increasing the effectiveness of hematopoiesis in myelodysplastic syndromes: erythropoiesis-stimulating agents and transforming growth factor-β superfamily inhibitors

Patients with lower-risk myelodysplastic syndromes (MDS) are mainly affected by chronic anemia and fatigue. Treatment strategies aim to improve anemia and quality of life, as well as iron overload due to red blood cell transfusion support. To promote proliferation and differentiation of erythropoiesis, erythropoiesis-stimulating agents (ESAs) such as erythropoietin (EPO) and mimetics are applied as first-line therapy in a large fraction of lower-risk MDS patients. In general, ESAs yield favorable responses in about half of the patients, although responses are often short-lived. In fact, many ESA-refractory patients harbor defects in late-stage erythropoiesis downstream of EPO action. Novel transforming growth factor (TGF)-β superfamily inhibitors sotatercept and luspatercept represent a promising approach to alleviate anemia by stimulating erythroid differentiation.

Techniques for detecting chromosomal aberrations in myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are a group of heterogeneous hematologic diseases. Chromosomal aberrations are important for the initiation, development, and progression of MDS. Detection of chromosomal abnormalities in MDS is important for categorization, risk stratification, therapeutic selection, and prognosis evaluation of the disease. Recent progress of multiple techniques has brought powerful molecular cytogenetic information to reveal copy number variation, uniparental disomy, and complex chromosomal aberrations in MDS. In this review, we will introduce some common chromosomal aberrations in MDS and their clinical significance. Then we will explain the application, advantages, and limitations of different techniques for detecting chromosomal abnormalities in MDS. The information in this review may be helpful for clinicians to select appropriate methods in patient-related decision making.

Splicing factor mutations in MDS RARS and MDS/MPN-RS-T

Spliceosomal mutations, especially mutations in SF3B1, are frequently (>80%) identified in patients with refractory anemia with ringed sideroblasts (RARS) and myelodysplastic/myeloproliferative neoplasms with ringed sideroblasts and thrombocytosis (MDS/MPN-RS-T; previously known as RARS-T), and SF3B1 mutations have a high positive predictive value for disease phenotype with ringed sideroblasts. These observations suggest that SF3B1 mutations play important roles in the pathogenesis of these disorders and formation of ringed sideroblasts. Here we will review recent insights into the molecular mechanisms of mis-splicing caused by mutant SF3B1 and the pathogenesis of RSs in the context of congenital sideroblastic anemia as well as RARS with SF3B1 mutations. We will also discuss therapy of SF3B1 mutant MDS, including novel approaches.