Eltrombopag versus placebo for low-risk myelodysplastic syndromes with thrombocytopenia (EQoL-MDS): phase 1 results of a single-blind, randomised, controlled, phase 2 superiority trial

Management of the Older Patient with Myelodysplastic Syndrome

No two diagnoses of myelodysplastic syndrome are genuinely alike, owing to differing and dynamic mutational topography and epigenetic aberrancy. Consequently, no two patients with myelodysplastic syndrome are identical and disease-specific and patient-specific factors are considered in formulating the optimal treatment, which includes few that are disease modifying. Age itself should not be an absolute contraindication to therapy, including intensive therapy such as allogeneic hematopoietic stem cell transplantation, which is the only curative therapy. However, age associates with an increased prevalence of frailty and comorbidities that must be considered and may preclude a path to cure. Palliative therapies are the mainstay for many patients with myelodysplastic syndrome, which is a disease of older adults with the majority of patients diagnosed at age ≥ 75 years. The older patient requires heightened attention to end organ function/reserve and drug-drug interactions as well as insurance, income, cost, and socioeconomic and psychosocial issues that influence management. Many prior studies have included relatively younger populations or have not specifically performed high-quality subgroup analyses of older patients. In this review, we discuss the available standard-of-care therapies for myelodysplastic syndrome as they specifically relate to the older population and assess the emerging therapeutics that may further the pursuit for personalized treatment and improve both the outcomes and quality of life of the older patient with myelodysplastic syndrome.

Myelodysplastic Syndromes: A New Decade

Myelodysplastic syndromes (MDS) are a group of heterogeneous clonal hematopoietic stem cell disorders. The 2020 Surveillance, Epidemiology, and End Results data demonstrates the incidence rate of MDS increases with age especially in those greater than 70 years of age. Risk stratification that impact prognosis, survival, and rate of acute myeloid leukemia (AML) transformation in MDS is largely dependent on revised International Prognostic Scoring System along with molecular genetic testing as a supplement. Low risk MDS typically have a more indolent disease course in which treatment is only initiated to ameliorate symptoms of cytopenias. In many, anemia is the most common cytopenia requiring treatment and erythroid stimulating agents, are considered first line. In contrast, high risk MDS tend to behave more aggressively for which treatment should be initiated rapidly with Hypomethylating Agents (HMA) being in the frontline. In those with high risk MDS and eligible, evaluation for allogeneic stem cell transplant should be considered as this is the only potential curative option for MDS. With the use of molecular genetic testing, a personalized approach to therapy in MDS has ensued. As the treatment landscape in MDS continues to flourish with novel targeted agents, we ambitiously seek to improve survival rates especially among the relapsed/refractory and transplant ineligible.

Current challenges and unmet medical needs in myelodysplastic syndromes

Myelodysplastic syndromes (MDS) represent a heterogeneous group of myeloid neoplasms that are characterized by ineffective hematopoiesis, variable cytopenias, and a risk of progression to acute myeloid leukemia. Most patients with MDS are affected by anemia and anemia-related symptoms, which negatively impact their quality of life. While many patients with MDS have lower-risk disease and are managed by existing treatments, there currently is no clear standard of care for many patients. For patients with higher-risk disease, the treatment priority is changing the natural history of the disease by delaying disease progression to acute myeloid leukemia and improving overall survival. However, existing treatments for MDS are generally not curative and many patients experience relapse or resistance to first-line treatment. Thus, there remains an unmet need for new, more effective but tolerable strategies to manage MDS. Recent advances in molecular diagnostics have improved our understanding of the pathogenesis of MDS, and it is becoming clear that the diverse nature of genetic abnormalities that drive MDS demands a complex and personalized treatment approach. This review will discuss some of the challenges related to the current MDS treatment landscape, as well as new approaches currently in development.

Preclinical evaluation of eltrombopag in a PDX model of myelodysplastic syndromes

Preclinical research of myelodysplastic syndromes (MDSs) is hampered by a lack of feasible disease models. Previously, we have established a robust patient-derived xenograft (PDX) model for MDS. Here we demonstrate for the first time that this model is applicable as a preclinical platform to address pending clinical questions by interrogating the efficacy and safety of the thrombopoietin receptor agonist eltrombopag. Our preclinical study included n = 49 xenografts generated from n = 9 MDS patient samples. Substance efficacy was evidenced by FACS-based human platelet quantification and clonal bone marrow evolution was reconstructed by serial whole-exome sequencing of the PDX samples. In contrast to clinical trials in humans, this experimental setup allowed vehicle- and replicate-controlled analyses on a patient–individual level deciphering substance-specific effects from natural disease progression. We found that eltrombopag effectively stimulated thrombopoiesis in MDS PDX without adversely affecting the patients’ clonal composition. In conclusion, our MDS PDX model is a useful tool for testing new therapeutic concepts in MDS preceding clinical trials.

Eltrombopag for myelodysplastic syndromes or chronic myelomonocytic leukaemia with no excess blasts and thrombocytopenia: a French multicentre retrospective real-life study

Despite a moderate prevalence in low-risk myelodysplastic syndromes (MDS) and chronic myelomonocytic leukaemia (CMML), thrombocytopenia remains a risk of severe bleeding and therapeutic options are still limited. There are only a few studies with eltrombopag (ELT), a thrombopoietin receptor agonist, in those patients. In this retrospective multicentre study, ELT was used in 50 patients with MDS and 11 with CMML, with no excess of marrow blasts and platelet counts of <50 × 10⁹ /l in a 'real-life' situation. Platelet response occurred in 47 (77%) patients. The median (range) duration of response was 8 (0-69) months. None of the eight still responders who discontinued ELT had relapsed, at a median (range) of 16 (6-23) months after ELT discontinuation. Although 36% of the patients were anti-coagulated or anti-aggregated only 10% of patients had Grade ≥3 bleeding events. Thrombotic events were observed in six (10%) patients, who all but one had a medical history of arterial or venous thrombosis. Progression to acute myeloid leukaemia occurred in four (7%) patients. In this first 'real-life' study, ELT was effective and generally well tolerated in patients with MDS/CMML without excess blasts.

Targeting health-related quality of life in patients with myelodysplastic syndromes - Current knowledge and lessons to be learned

Using a range of health-related quality of life (HRQoL) instruments, most - but not all - studies of myelodysplastic syndromes (MDS) have reported that lower hemoglobin levels and red blood cell transfusion dependency are associated with worse HRQoL. In addition, some MDS treatments may significantly improve HRQoL, particularly among those patients who respond to therapy; however, the majority of these studies were underpowered for this secondary endpoint. Furthermore, decreased HRQoL has been associated with worse survival outcomes, and HRQoL scores can be used to refine classical prognostic systems. Despite the subjective nature of HRQoL, the importance and validity of measuring it in trials and clinical practice are increasingly being recognized, but properly validated MDS-specific instruments are required. We describe what is currently known about HRQoL in patients with MDS, and the limitations of measuring HRQoL, and we provide some recommendations to improve the measurement of this outcome in future trials.

Current Therapy of the Patients with MDS: Walking towards Personalized Therapy

Myelodysplastic syndromes (MDS) are characterized by ineffective hematopoiesis, dysplasia and peripheral cytopenias. Nowadays, MDS therapy is selected based on risk. The goals of therapy are different in low-risk and high-risk patients. In low-risk MDS, the goal is to decrease transfusion needs and to increase the quality of life. Currently, available drugs for newly diagnosed low-risk MDS include growth factor support, lenalidomide and immunosuppressive therapy. Additionally, luspatercept has recently been added to treat patients with MDS with ring sideroblasts, who are not candidates or have lost the response to erythropoiesis-stimulating agents. Treatment of high-risk patients is aimed to improve survival. To date, the only currently approved treatments are hypomethylating agents and allogeneic stem cell transplantation. However, the future for MDS patients is promising. In recent years, we are witnessing the emergence of multiple treatment combinations based on hypomethylating agents (pevonedistat, magrolimab, eprenetapopt, venetoclax) that have proven to be effective in MDS, even those with high-risk factors. Furthermore, the approval in the US of an oral hypomethylating agent opens the door to exclusively oral combinations for these patients and their consequent impact on the quality of life of these patients. Relapsed and refractory patients remain an unmet clinical need. We need more drugs and clinical trials for this profile of patients who have a dismal prognosis.

Eligibility for clinical trials is unsatisfactory for patients with myelodysplastic syndromes, even at a tertiary referral center

Participation in clinical trials may allow patients with MDS to gain access to therapies not otherwise available. However, access is limited by strict inclusion and exclusion criteria, reflecting academic or regulatory questions addressed by the respective studies. We performed a simulation in order to estimate the average proportion of MDS patients eligible for participation in a clinical trial. The simulation drew upon 1809 patients in the Düsseldorf MDS Registry whose clinical data allowed eligibility screening for a wide range of clinical trials. This cohort was assumed to be alive and available for study participation. The simulation also posited that all MDS trials (n = 47) conducted in our center between 1987 and 2016 were open for recruitment. In addition, study activities in the year 2016 were analyzed to determine the proportion of patients eligible for at least one of the 9 MDS trials open at that time. On average, each clinical trial was suitable for about 18 % of patients in the simulation cohort. Conversely, 34 % of the patients were eligible for at least one of the 9 clinical studies in 2016. Inclusion/exclusion criteria of studies initiated by the pharmaceutical industry excluded more than twice the fraction of patients compared with investigator initiated trials (potential inclusion of 10 % vs. 21 %, respectively). Karyotype (average exclusion rate 58 %), comorbidities (40 %), and prior therapies (55 %) were the main reasons for exclusion. We suggest that in- and exclusion criteria should be less restrictive, in order to meet the needs of the real-life population of elderly MDS patients.

Sample size calculation of clinical trials in geriatric medicine

A preliminary step when planning a randomized clinical trial (RCT) is the sample size calculation. This is the determination of the optimal number of patients which ensures an adequate power to the study to detect as statistically significant a certain between-arms difference, if any, in the frequency/magnitude of a specific endpoint. The sample size calculation is performed by specific calculators requiring as input variables the expected effect size, the alpha error (α), the beta error (β) and the allocation ratio, this latter being the ratio between the number of participants allocated to the arms of a RCT. Herein, we provide a series of examples of sample size calculation in the context of superiority RCTs in elderly.

Risk-Adapted, Individualized Treatment Strategies of Myelodysplastic Syndromes (MDS) and Chronic Myelomonocytic Leukemia (CMML)

Myelodysplastic syndrome (MDS) and chronic myelomonocytic leukemia (CMML) are two distinct blood cancers with a variable clinical symptom burden and risk of progression to acute myeloid leukemia. Management decisions should be guided by individual patient and disease characteristics and based on validated risk stratification tools. While supportive care with red blood cell transfusions, erythropoiesis-stimulating agents, and iron chelation remains the mainstay of therapy for lower-risk (LR)-MDS patients, luspatercept has recently been approved for transfusion-dependent anemic LR-MDS patients ending a decade without any new drug approvals for MDS. For higher-risk patients, allogeneic hematopoietic cell transplant (allo-HCT) remains the only curative therapy for both MDS and CMML but most patients are not eligible for allo-HCT. For those patients, the hypomethylating agents (HMA) azacitidine and decitabine remain standard of care with azacitidine being the only agent that has shown an overall survival benefit in randomized trials. Although early results from novel molecularly driven agents such as IDH1/2 inhibitors, venetoclax, magrolimab, and APR-246 for MDS as well as tagraxofusp, tipifarnib, and lenzilumab for CMML appear encouraging, confirmatory randomized trials must be completed to fully assess their safety and efficacy prior to routine clinical use. Herein, we review the current management of MDS and CMML and conclude with a critical appraisal of novel therapies and general trends in this field.

Phase III, Randomized, Placebo-Controlled Trial of CC-486 (Oral Azacitidine) in Patients With Lower-Risk Myelodysplastic Syndromes

PURPOSE

Treatment options are limited for patients with lower-risk myelodysplastic syndromes (LR-MDS). This phase III, placebo-controlled trial evaluated CC-486 (oral azacitidine), a hypomethylating agent, in patients with International Prognostic Scoring System LR-MDS and RBC transfusion-dependent anemia and thrombocytopenia.

METHODS

Patients were randomly assigned 1:1 to CC-486 300-mg or placebo for 21 days/28-day cycle. The primary end point was RBC transfusion independence (TI).

RESULTS

Two hundred sixteen patients received CC-486 (n = 107) or placebo (n = 109). The median age was 74 years, median platelet count was 25 × 10⁹/L, and absolute neutrophil count was 1.3 × 10⁹/L. In the CC-486 and placebo arms, 31% and 11% of patients, respectively, achieved RBC-TI (P = .0002), with median durations of 11.1 and 5.0 months. Reductions of ≥ 4 RBC units were attained by 42.1% and 30.6% of patients, respectively, with median durations of 10.0 and 2.3 months, and more CC-486 patients had ≥ 1.5 g/dL hemoglobin increases from baseline (23.4% v 4.6%). Platelet hematologic improvement rate was higher with CC-486 (24.3% v 6.5%). Underpowered interim overall survival analysis showed no difference between CC-486 and placebo (median, 17.3 v 16.2 months; P = .96). Low-grade GI events were the most common adverse events in both arms. In the CC-486 and placebo arms, 90% and 73% of patients experienced a grade 3-4 adverse event. Overall death rate was similar between arms, but there was an imbalance in deaths during the first 56 days (CC-486, n = 16; placebo, n = 6), most related to infections; the median pretreatment absolute neutrophil count for the 16 CC-486 patients was 0.57 × 10⁹/L.

CONCLUSION

CC-486 significantly improved RBC-TI rate and induced durable bilineage improvements in patients with LR-MDS and high-risk disease features. More early deaths occurred in the CC-486 arm, most related to infections in patients with significant pretreatment neutropenia. Further evaluation of CC-486 in MDS is needed.

Challenges and Advances in Managing Thrombocytopenic Cancer Patients

Cancer patients have varying incidence, depth and duration of thrombocytopenia. The mainstay of managing severe chemotherapy-induced thrombocytopenia (CIT) in cancer is the use of platelet transfusions. While prophylactic platelet transfusions reduce the bleeding rate, multiple unmet needs remain, such as high residual rates of bleeding, and anticancer treatment dose reductions/delays. Accordingly, the following promising results in other settings, antifibrinolytic drugs have been evaluated for prevention and treatment of bleeding in patients with hematological malignancies and solid tumors. In addition, Thrombopoeitin receptor agonists have been studied for two major implications in cancer: treatment of severe thrombocytopenia associated with myelodysplastic syndrome and acute myeloid leukemia; primary and secondary prevention of CIT in solid tumors in order to maintain dose density and intensity of anti-cancer treatment. Furthermore, thrombocytopenic cancer patients are often prescribed antithrombotic medication for indications arising prior or post cancer diagnosis. Balancing the bleeding and thrombotic risks in such patients represents a unique clinical challenge. This review focuses upon non-transfusion-based approaches to managing thrombocytopenia and the associated bleeding risk in cancer, and also addresses the management of antithrombotic therapy in thrombocytopenic cancer patients.

Treatment options for lower-risk myelodysplastic syndromes. Where are we now?

Myelodysplastic syndromes (MDS) are a spectrum of clonal stem-cell disorders characterized clinically by bone-marrow failure. Resultant cytopenias are responsible for significant mortality and decreased quality of life in patients with MDS. In patients with low-risk MDS (LR-MDS), anemia is the most common cytopenia and erythropoiesis-stimulating agents (ESA) are usually used as first-line therapy. Those patients who become refractory to ESA have a poor survival. Available treatment options such as lenalidomide, hypomethylating agents, and immunosuppressive therapy can provide some hematologic response among selected subsets of patients, however durable responses are limited, and these agents can carry significant adverse effects. Chronic transfusions help to alleviate symptoms of anemia but still carry risks associated with transfusion and iron overload. Luspatercept, recently approved for those LR-MDS with ring sideroblasts refractory to ESA, was found to have an improvement in transfusion independence with a well-tolerated safety profile. While anemia is the most common cytopenia, thrombocytopenia and neutropenia management is challenging and the co-occurrence of these cytopenias with anemia may dictate the choice of therapy. In this article, we review LR-MDS and discuss the optimal use of current treatment options and explore new therapeutic options on the horizon.

Hypoplastic Myelodysplastic Syndromes: Just an Overlap Syndrome?

Simple Summary

Hypoplastic myelodysplastic syndromes (hMDS) represent a diagnostic conundrum. They share morphologic and clinical features of both MDS (dysplasia, genetic lesions and cytopenias) and aplastic anemia (AA; i.e., hypocellularity and autoimmunity) and are not comprised in the last WHO classification. In this review we recapitulate the main clinical, pathogenic and therapeutic aspects of hypo-MDS and discuss why they deserve to be distinguished from normo/hypercellular MDS and AA. We conclude that hMDS may present in two phenotypes: one more proinflammatory and autoimmune, more similar to AA, responding to immunosuppression; and one MDS-like dominated by genetic lesions, suppression of immune surveillance, and tumor escape, more prone to leukemic evolution.

Abstract

Myelodysplasias with hypocellular bone marrow (hMDS) represent about 10–15% of MDS and are defined by reduced bone marrow cellularity (i.e., <25% or an inappropriately reduced cellularity for their age in young patients). Their diagnosis is still an object of debate and has not been clearly established in the recent WHO classification. Clinical and morphological overlaps with both normo/hypercellular MDS and aplastic anemia include cytopenias, the presence of marrow hypocellularity and dysplasia, and cytogenetic and molecular alterations. Activation of the immune system against the hematopoietic precursors, typical of aplastic anemia, is reckoned even in hMDS and may account for the response to immunosuppressive treatment. Finally, the hMDS outcome seems more favorable than that of normo/hypercellular MDS patients. In this review, we analyze the available literature on hMDS, focusing on clinical, immunological, and molecular features. We show that hMDS pathogenesis and clinical presentation are peculiar, albeit in-between aplastic anemia (AA) and normo/hypercellular MDS. Two different hMDS phenotypes may be encountered: one featured by inflammation and immune activation, with increased cytotoxic T cells, increased T and B regulatory cells, and better response to immunosuppression; and the other, resembling MDS, where T and B regulatory/suppressor cells prevail, leading to genetic clonal selection and an increased risk of leukemic evolution. The identification of the prevailing hMDS phenotype might assist treatment choice, inform prognosis, and suggest personalized monitoring.

Current and emerging strategies for management of myelodysplastic syndromes

Myelodysplastic syndromes (MDS) are characterized by ineffective hematopoiesis with varying degrees of dysplasia and peripheral cytopenias. MDS are driven by structural chromosomal alterations and somatic mutations in neoplastic myeloid cells, which are supported by a tumorigenic and a proinflammatory marrow microenvironment. Current treatment strategies for lower-risk MDS focus on improving quality of life and cytopenias, while prolonging survival and delaying disease progression is the focus for higher-risk MDS. Several promising drugs are in the horizon, including the hypoxia-inducible factor stabilizer roxadustat, telomerase inhibitor imetelstat, oral hypomethylating agents (CC-486), TP53 modulators (APR-246 and ALRN-6924), and the anti-CD47 antibody magrolimab. Targeted therapies approved for acute myeloid leukemia treatment, such as isocitrate dehdyrogenase inhibitors and venetoclax, are also being studied for use in MDS. In this review, we provide a brief overview of pathogenesis and current treatment strategies in MDS followed by a discussion of newer agents that are under clinical investigation.

Therapy for lower-risk MDS

Lower-risk myelodysplastic syndromes (MDS) are characterized by the presence of dysplasia, low bone marrow blast percentage, low number and depth of cytopenia(s), and relatively good-risk karyotpic and molecular abnormalities. A score of ≤3.5 on the Revised International Prognostic Scoring System classifies patients as lower-risk MDS. Information from a mutational profile of the MDS at time of diagnosis (and over serial time points) can be reassuring for predicted behavior of lower-risk MDS compared with one expected to progress more rapidly (higher-risk MDS). Supportive care continues to be the crux of treatment, although the options to reduce transfusion needs have improved in 2020. Erythropoiesis stimulating agents, lenalidomide, and luspatercept address the most frequent (and symptomatic) cytopenia (anemia) and are started only when patients are transfusion dependent. Patients can derive long-term benefits (years) from these approaches but will often progress to higher-risk MDS. Interestingly, some patients with lower-risk MDS can present with an isolated thrombocytopenia for which thrombopoietin receptor analogs such as romiplostim and eltrombopag are options (as long as blast counts are low). The presence of pancytopenia and or intensifying and unremitting clinical symptoms are often treated with hypomethylating agents or (anti-thymocyte globulin if hypocellular MDS is of concern). Targeted therapies are emerging for small subsets of MDS patients with specific somatic mutations (ie, TP53, IDH1/2, FLT3), although currently, there are no approved, mutation-directed medications to treat MDS.

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.

Safety and Efficacy of Eltrombopag and Romiplostim in Myelodysplastic Syndromes: A Systematic Review and Meta-Analysis

Background and Aim

Many studies indicated that eltrombopag and romiplostim could improve hematopoietic function in patients with myelodysplastic syndromes (MDS), but their toxicity and efficacy were not known. This meta-analysis aimed to investigate the safety and efficacy of eltrombopag and romiplostim in MDS.

Methods

A full-scale search strategy was used to search relevant published studies in PubMed, Embase, Web of Science, ClinicalTrials.gov and the Cochrane Library until January 2020 using a random-effects model and the pooled risk ratio (RR) with 95% confidence interval as the effect indicator. Statistical analyses were performed using RevMan 5.3.

Results

This meta-analysis included eight studies comprising 1047 patients. A lower RR of overall response rate (ORR) (RR: 0.65; 95% CI, 0.47–0.9) and grade ≥3 bleeding events (RR: 0.36; 95% CI, 0.36–0.92) were observed after romiplostim and eltrombopag treatment compared with placebo. The pooled RR for the ORR and grade ≥3 bleeding events were 0.58 (95% CI: 0.41–0.83, P = 0.003) and 0.6 (95% CI: 0.37–0.96, P = 0.03) in eltrombopag, respectively. A lower ORR in intermediate- or high-risk MDS (RR: 0.63; 95% CI: 0.45–0.88, P = 0.006) was observed. No difference in mortality, serious adverse events, platelet transfusion, hematologic improvement, and AML transformation was observed.

Conclusions

Thrombopoietin receptor agonists (TPO-RAs) romiplostim and eltrombopag were effective in reducing bleeding events, especially grade ≥3 bleeding events. However, it might reduce the ORR of MDS, especially in eltrombopag treatment group or high-risk MDS group. Due to the limited treatment of MDS and the poor response to the drug, this may be a selection method for MDS combined with fatal bleeding, although further research is needed to confirm the effectiveness of this approach.

Myelodysplastic syndromes: 2021 update on diagnosis, risk stratification and management

DISEASE OVERVIEW

The myelodysplastic syndromes (MDS) are a very heterogeneous group of myeloid disorders characterized by peripheral blood cytopenias and increased risk of transformation to acute myelogenous leukemia (AML). Myelodysplastic syndromes occur more frequently in older males and in individuals with prior exposure to cytotoxic therapy.

DIAGNOSIS

Diagnosis of MDS is based on morphological evidence of dysplasia upon visual examination of a bone marrow aspirate and biopsy. Information obtained from additional studies such as karyotype, flow cytometry and molecular genetics is usually complementary and may help refine diagnosis.

RISK-STRATIFICATION

Prognosis of patients with MDS can be calculated using a number of scoring systems. In general, all these scoring systems include analysis of peripheral cytopenias, percentage of blasts in the bone marrow and cytogenetic characteristics. The most commonly accepted system is the Revised International Prognostic Scoring System (IPSS-R). Somatic mutations can help define prognosis and therapy.

RISK-ADAPTED THERAPY

Therapy is selected based on risk, transfusion needs, percent of bone marrow blasts, cytogenetic and mutational profiles, comorbidities, potential for allogeneic stem cell transplantation (alloSCT) and prior exposure to hypomethylating agents (HMA). Goals of therapy are different in lower-risk patients than in higher-risk individuals and in those with HMA failure. In lower-risk MDS, the goal is to decrease transfusion needs and transformation to higher risk disease or AML, as well as to improve survival. In higher-risk disease, the goal is to prolong survival. In 2020, we witnessed an explosion of new agents and investigational approaches. Current available therapies include growth factor support, lenalidomide, HMAs, intensive chemotherapy and alloSCT. Novel therapeutics approved in 2020 are luspatercept and the oral HMA ASTX727. At the present time, there are no approved interventions for patients with progressive or refractory disease particularly after HMA-based therapy. Options include participation in a clinical trial, cytarabine-based therapy or alloSCT.

Considerations for Managing Patients With Hematologic Malignancy During the COVID-19 Pandemic: The Seattle Strategy

In January 2020, the first documented patient in the United States infected with severe acute respiratory syndrome coronavirus 2 was diagnosed in Washington State. Since that time, community spread of coronavirus disease 2019 (COVID-19) in the state has changed the practice of oncologic care at our comprehensive cancer center in Seattle. At the Seattle Cancer Care Alliance, the primary oncology clinic for the University of Washington/Fred Hutchinson Cancer Consortium, our specialists who manage adult patients with hematologic malignancies have rapidly adjusted clinical practices to mitigate the potential risks of COVID-19 to our patients. We suggest that our general management decisions and modifications in Seattle are broadly applicable to patients with hematologic malignancies. Despite a rapidly changing environment that necessitates opinion-based care, we provide recommendations that are based on best available data from clinical trials and collective knowledge of disease states.

The thrombopoietin mimetic JNJ-26366821 increases megakaryopoiesis without affecting malignant myeloid proliferation

Thrombocytopenia remains a challenge in myeloid malignancies, needing safer and more effective therapies. JNJ-26366821, a pegylated synthetic peptide thrombopoietin (TPO) mimetic not homologous to endogenous TPO, has an in-vitro EC50 of 0.2 ng/mL for the TPO receptor and dose dependently elevates platelets in volunteers. We demonstrate that JNJ-26366821 increases megakaryocytic differentiation and megakaryocytic colony formation in healthy controls and samples from myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). JNJ-26366821 had no effect on proliferation of malignant myeloid cell lines at doses up to 1000 ng/mL and malignant patient-derived mononuclear cells showed no increased cell growth or leukemic colony formation capacity at concentrations between 0.2 ng/mL and 10 ng/mL. Furthermore, JNJ-26366821 did not enhance in-vivo engraftment of leukemic cells in an AML xenotransplantation murine model. Our results show that JNJ-26366821 stimulates megakaryopoiesis without causing proliferation of the malignant myeloid clones in MDS/AML and provides the rationale for clinical testing of JNJ-26366821 in myeloid malignancies.

Myelodysplastic syndromes: a review of therapeutic progress over the past 10 years

INTRODUCTION

Myelodysplastic syndromes (MDS) represent a range of bone marrow disorders, with patients affected by cytopenias and risk of progression to AML. There are limited therapeutic options available for patients, including hypomethylating agents (azacitidine/decitabine), growth factor support, lenalidomide, and allogeneic stem cell transplant.

AREAS COVERED

This review provides an overview of the progress made over the past decade for emerging therapies for lower- and higher-risk MDS (MDS-HR). We also cover advances in prognostication, supportive care, and use of allogeneic SCT in MDS.

EXPERT OPINION

While there have been no FDA-approved therapies for MDS in the past decade, we anticipate the approval of luspatercept based on results from the MEDALIST trial for patients with lower-risk MDS (MDS-LR) and ringed sideroblasts who have failed or are ineligible for erythropoiesis stimulating agents (ESAs). With growing knowledge of the biologic and molecular mechanisms underlying MDS, it is anticipated that new therapies will be approved in the coming years.

A sequential two-stage dose escalation study of eltrombopag in patients with myelodysplastic syndrome and thrombocytopenia after hypomethylating agent failure

Thrombocytopenia occurs frequently in patients with myelodysplastic syndromes (MDS), and the survival of patients after failure of hypomethylating agents (HMAs) is poor. We conducted a trial of eltrombopag in patients with MDS, MDS/myeloproliferative neoplasm (MPN) or acute myeloid leukemia (AML) with 20-30% myeloblasts after HMA failure and mean baseline platelet count ≤ 50 × 10⁹/L. Eltrombopag was escalated from 50 mg daily up to 200 mg daily. The primary objective was to determine the maximally tolerated dose (MTD). 37 patients were enrolled, and MTD was not reached. Responses were observed in 9 patients (24%), 2 achieving marrow CR with hematologic improvement (HI), 1 marrow CR without HI, and 6 HI. Median overall survival was 7.5 months. Eltrombopag was well-tolerated and yielded modest responses in heavily treated, predominantly higher-risk MDS patients after HMA failure. Future studies should focus on determining characteristics that predict response.

In vitro effect of eltrombopag alone and in combination with azacitidine on megakaryopoiesis in patients with myelodysplastic syndrome

Thrombocytopenia is a severe complication for patients with myelodysplastic syndrome (MDS). Eltrombopag increases platelet count in MDS patients but its combination with azacitidine elicited controversial results. We aimed to quantify the colony forming units of megakaryocytes (CFU-Mk) obtained from CD34+ bone marrow cells isolated from patients with MDS and from healthy donors that were cultured in vitro in the presence or absence of azacitidine and with or without the sequential addition of eltrombopag to the culture medium. CD34+ bone marrow cells from 6 MDS patients and 3 controls were expanded in vitro and cultured for 3 days with or without azacitidine. Subsequently, a CFU-Mk assay was performed in presence or absence of eltrombopag. The addition of eltrombopag in the CFU-Mk assay after mock treatment of CD34+ cells increased the number of CFU-Mk in both controls and patients. On the contrary, using azacitidine pretreated CD34+ cells, eltrombopag minimally increased CFU-Mk in controls and produced heterogeneous response in MDS patients with no change in two patients and CFU-Mk increase in four patients. In vitro CFU-Mk assay suggest that some MDS patients are likely to benefit from the sequential addition of eltrombopag after azacitidine treatment, in the context of a personalized medicine.

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.

Evolving therapies for lower-risk myelodysplastic syndromes

The development in the therapeutic landscape of myelodysplastic syndromes (MDS) has substantially lagged behind other hematologic malignancies with no new drug approvals for MDS for 13 years since the approval of decitabine in the United States in 2006. While therapeutic concepts for MDS patients continue to be primarily defined by clinical-pathologic risk stratification tools such as the International Prognostic Scoring System (IPSS) and its revised version IPSS-R, our understanding of the genetic landscape and the molecular pathogenesis of MDS has greatly evolved over the last decade. It is expected that the therapeutic approach to MDS patients will become increasingly individualized based on prognostic and predictive genetic features and other biomarkers. Herein, we review the current treatment of lower-risk MDS patients and discuss promising agents in advanced clinical testing for the treatment of symptomatic anemia in lower-risk MDS patients such as luspatercept and imetelstat. Lastly, we review the clinical development of new agents and the implications of the wider availability of mutational analysis for the management of individual MDS patients.

Lowering the boom on lower-risk myelodysplastic syndromes

Lower-risk myelodysplastic syndromes are defined using prognostic scoring systems that incorporate data on bone marrow blast percentage, degree and numbers of cytopenias, and cytogenetic abnormalities. Increasingly, these are incorporating molecular abnormalities to further refine risk. Therapy is geared toward predominating cytopenias, with erythropoiesis-stimulating agents luspatercept and lenalidomide used to ameliorate anemia, romiplostim and eltrombopag tackling thrombocytopenia, and hypomethylating agents and antithymocyte globulin palliating pancytopenia. Newer agents on the horizon are abrogating the downstream sequelae of specific molecular mutations. One challenge for the future is in further modifying response criteria to align with improvements that are clinically meaningful to patients.

Mechanisms and therapeutic prospects of thrombopoietin receptor agonists

The second-generation thrombopoietin (TPO) receptor agonists eltrombopag and romiplostim are potent activators of megakaryopoiesis and represent a growing treatment option for patients with thrombocytopenic hematological disorders. Both TPO receptor agonists have been approved worldwide for the treatment of children and adults with chronic immune thrombocytopenia. In the EU and USA, eltrombopag is approved for the treatment of patients with severe aplastic anemia who have had an insufficient response to immunosuppressive therapy and in the USA for the first-line treatment of severe aplastic anemia in combination with immunosuppressive therapy. Eltrombopag has also shown efficacy in several other disease settings, for example, chemotherapy-induced thrombocytopenia, selected inherited thrombocytopenias, and myelodysplastic syndromes. While both TPO receptor agonists stimulate TPO receptor signaling and enhance megakaryopoiesis, their vastly different biochemical structures bestow upon them markedly different molecular and functional properties. Here, we review and discuss results from preclinical and clinical studies on the functional and molecular mechanisms of action of this new class of drug.

How we manage adults with myelodysplastic syndrome

The prognosis in Myelodysplastic syndromes (MDS), although recently refined by molecular studies, remains largely based on conventional prognostic scores [International Prognostic Scoring System (IPSS), revised IPSS], classifying patients into "lower risk" MDS (LR-MDS) and "higher risk" MDS (HR-MDS). In LR-MDS, treatment mainly aims at improving cytopenias, principally anaemia, while in HR-MDS it aims at delaying disease progression and prolonging survival. In LR-MDS without deletion 5q, anaemia is generally treated first by erythropoietic stimulating factors, while second line treatments are currently not approved [lenalidomide, hypomethylating agents (HMA), luspatercept] or rarely indicated (antithymocyte globulin). Lenalidomide has major efficacy in LR-MDS with deletion 5q. Allogeneic stem cell transplantation (allo-SCT) is sometimes considered in LR-MDS, and iron chelation can be considered when multiple red blood cell transfusions are required. Allo-SCT is the only potentially curative treatment for HR-MDS; however, it is rarely applicable. It is generally preceded by intensive chemotherapy (IC) or HMA in patients with excess of marrow blasts (especially if >10%). In other patients, HMA can improve survival. The role of new drugs, including venetoclax or, in case of specific mutations, IDH1 or IDH2 inhibitors, is investigated. IC is mainly indicated as a bridge to allo-SCT, in the absence of unfavourable karyotype.

Eltrombopag in Immune Thrombocytopenia, Aplastic Anemia, and Myelodysplastic Syndrome: From Megakaryopoiesis to Immunomodulation

Eltrombopag is an orally available thrombopoietin receptor agonist indicated for the treatment of immune thrombocytopenia (ITP). Beyond the effect on megakaryopoiesis, the drug also showed a stimulating effect on the hematopoietic stem cell with consistent clinical efficacy in aplastic anemia (AA) and myelodysplastic syndromes (MDS). Eltrombopag is highly effective in ITP and less so in AA and MDS. This observation underlines the importance of residual normal hematopoiesis, which is maximal in ITP, minimal/absent in AA, and dysregulated in MDS. In ITP, the drug at 50-75 mg daily induced up to 85% responses both in clinical trials and real-life studies, with the possibility of tapering and discontinuation. In AA, eltrombopag at 150 mg daily was effective in about 40% of cases relapsed/refractory to standard immunosuppression or ineligible for bone marrow transplant. In MDS, the drug seems less effective, with responses in about a quarter of patients at various schedules. The efficacy of eltrombopag in ITP, AA, and MDS suggests the existence of common immune-pathological mechanisms in these diseases, including autoimmunity against peripheral blood cells and bone marrow precursors, as well as a possible evolution of one condition into the other. Additional mechanisms of action emerging from the clinical use of eltrombopag include modulation of T-regulatory cells, restoration of Fc-γ receptor balance in phagocytes, and an iron-mobilizing effect. In this review, we analyzed the most recent literature on eltrombopag use and efficacy in patients with ITP, AA, and MDS, exploring the basis for different dosing, combined treatments, and discontinuation in each context.

Novel therapies in low- and high-risk myelodysplastic syndrome

Introduction: Myelodysplastic syndromes (MDS) comprise a heterogeneous group of myeloid neoplasms with diverse clinical courses. The revised version of the international prognostic scoring system (IPSS-R) provides risk stratification into 5 different groups. Areas covered: For lower-risk patients, red blood cell transfusions and iron chelation are the backbone of supportive care. In addition, erythropoiesis-stimulating agents (ESA) are used to ameliorate anemia. Lenalidomide is approved for the treatment of lower-risk patients with del(5q) who are transfusion-dependent. Patients with higher-risk disease should be offered allogeneic stem cell transplantation whenever possible. If they are unfit for transplantation or an appropriate donor cannot be found, hypomethylating agents may be used. Expert opinion: New therapeutic options for lower-risk patients include thrombopoietin analogues, the TGF-beta family ligand trapping drug Luspatercept, and the telomerase inhibitor Imetelstat. Combinations of hypomethylating agents (HMA) with other compounds, and inhibitors of bcl2, such as venetoclax are being developed for higher-risk patients. Finally, hypomethylating agents in combination with donor lymphocytes may lead to long-term remission following molecular or hematological relapse after allogeneic SCT.

Eltrombopag for the treatment of inherited thrombocytopenias: a phase II clinical trial

Patients with inherited thrombocytopenias often require platelet transfusions to raise their platelet count before surgery or other invasive procedures; moreover, subjects with clinically significant spontaneous bleeding may benefit from an enduring improvement of thrombocytopenia. The hypothesis that thrombopoietin-mimetics can increase platelet count in inherited thrombocytopenias is appealing, but evidence is scarce. We conducted a prospective, phase II clinical trial to investigate the efficacy of the oral thrombopoietin-mimetic eltrombopag in different forms of inherited thrombocytopenia. We enrolled 24 patients affected by MYH9-related disease, ANKRD26-related thrombocytopenia, X-linked thrombocytopenia/ Wiskott-Aldrich syndrome, monoallelic Bernard-Soulier syndrome, or ITGB3-related thrombocytopenia. The average pre-treatment platelet count was 40.4 ×10⁹/L. Patients received a 3- to 6-week course of eltrombopag in a dose-escalated manner. Of 23 patients evaluable for response, 11 (47.8%) achieved a major response (platelet count >100 ×10⁹/L), ten (43.5%) had a minor response (platelet count at least twice the baseline value), and two patients (8.7%) did not respond. The average increase of platelet count compared to baseline was 64.5 ×10⁹/L (P<0.001). Four patients with clinically significant spontaneous bleeding entered a program of long-term eltrombopag administration (16 additional weeks): all of them obtained remission of mucosal hemorrhages, with the remission persisting throughout the treatment period. Treatment was globally well tolerated: five patients reported mild adverse events and one patient a moderate adverse event. In conclusion, eltrombopag was safe and effective in increasing platelet count and reducing bleeding symptoms in different forms of inherited thrombocytopenia. Despite these encouraging results, caution is recommended when using thrombopoietinmimetics in inherited thrombocytopenias predisposing to leukemia. ClinicalTrials.gov identifier: NCT02422394.

Hematologic recovery induced by eltrombopag in Japanese patients with aplastic anemia refractory or intolerant to immunosuppressive therapy

Eltrombopag, an oral thrombopoietin-receptor agonist, stimulates hematopoiesis in patients with acquired aplastic anemia (AA) and has higher exposure in patients of East Asian origin. We evaluated the pharmacokinetics, efficacy, and safety of eltrombopag in Japanese patients with AA refractory or intolerant to immunosuppressive therapy (IST). Twenty-one patients (15 with non-severe AA, six with severe AA) with platelet counts < 30,000/µL received eltrombopag in a dose-escalation fashion (25, 50, 75, or 100 mg once daily) depending on individual platelet responses; the responders continued eltrombopag treatment beyond 6 months. The primary endpoint was hematologic response at 6 months, defined as improvements in blood counts or transfusion requirements. Ten (48%) patients achieved hematologic responses in at least one lineage at 6 months. Six patients achieved tri- and/or bi-lineage responses with continuation of eltrombopag treatment, with two patients no longer requiring eltrombopag treatment. The most common adverse events were nasopharyngitis and abnormal hepatic function, with the majority being grade 1 or 2. Cytogenetic abnormalities were observed in three patients; however, no progression to myelodysplastic syndrome/other malignancy was observed. Eltrombopag can safely restore multi-lineage hematopoiesis in Japanese patients with AA refractory or intolerant to IST.Clinical Trial registration NCT02148133.

[Management of myelodysplastic syndromes in 2019: An update]

Myelodysplastic syndromes are a heterogeneous group of clonal myeloid disorders characterized by peripheral cytopenias and an increased risk of progression to acute myeloid leukemia. Inflammatory, auto-immune or syndromic symptoms can make the diagnosis difficult. Diagnosis is currently based on bone marrow cytology but cytogenetics and molecular features are currently overpassing their initial prognostic function (allowing early diagnosis and prediction of therapeutic response). The prognostic classification is based on the Revised International Prognostic Scoring System, which also provides guidance for therapeutic management. The treatment of low-risk myelodysplastic syndromes is based on the correction of cytopenias (erythropoiesis stimulating agents, transfusions, lenalidomide, etc.), whereas in high-risk group, the goal is the control of the leukemic clone (hypomethylating agents, allograft of hematopoietic stem cell transplantation). Other molecules are used to manage complications of cytopenias or transfusion (anti-infectious prophylaxis and treatments, martial chelation). New molecules are being studied with some interesting results (luspatercept, venetoclax). This article aims to provide an update on the knowledge that an internist should know for the practical management of myelodysplastic syndromes in 2019.

Treatment optimization and genomic outcomes in refractory severe aplastic anemia treated with eltrombopag

Eltrombopag (EPAG) received approval from the US Food and Drug Administration for the treatment of refractory severe aplastic anemia (rSAA) based on treatment of 43 patients with doses escalating from 50 to 150 mg daily for 12 weeks. Response kinetics suggested that more prolonged administration of EPAG at a dose of 150 mg could speed and improve response rates. We enrolled 40 patients with rSAA in a study of EPAG 150 mg daily, with a primary end point of response at 24 weeks. Twenty (50%) of 40 patients responded at 24 weeks; 5 (25%) of 20 would have been deemed nonresponders at 12 weeks, the end point of the previous study. Fifteen of the 19 responding patients continuing on EPAG had drug discontinued for robust response; 5 of the 15 required EPAG re-initiation for relapse, with all recovering response. To analyze risk of clonal progression, we combined long-term data from the 83 patients with rSAA enrolled in both studies. Evolution to an abnormal karyotype occurred in 16 (19%), most within 6 months of EPAG initiation. Targeted deep sequencing/whole-exome sequencing was performed pre-EPAG and at primary response end point and/or time of clonal evolution or longest follow-up. Cytogenetic evolution did not correlate with mutational status, and overall mutated allele fractions of myeloid cancer genes did not increase on EPAG. In summary, extended administration of EPAG at a dose of 150 mg for 24 weeks rescued responses in some patients with rSAA not responding at 12 weeks. The temporal relationship between clonal evolution and drug exposure suggests that EPAG may promote expansion of dormant preexisting clones with an aberrant karyotype. The studies were registered at www.clinicaltrials.gov as #NCT00922883 and #NCT01891994.

Infection control in patients with myelodysplastic syndromes who are candidates for active treatment: Expert panel consensus-based recommendations

The improvement in supportive care and the introduction of new therapeutic agents, including lenalidomide and hypomethylating agents, in myelodysplastic syndromes have improved patients' outcomes; however, at the same time, the frequency and epidemiology of infections have changed. Therefore, the great strides in the indications and use of new treatment strategies for myelodysplastic syndromes need a parallel progress in the best approach to prophylaxis and supportive therapy for infections. Based on the recognition that the above issues represent an unmet clinical need in myelodysplastic syndromes, an Italian expert panel performed a review of the literature and composed a framework of the best recommendations for optimal infection control in patient candidates to receive active treatment for myelodysplastic syndromes. In this consensus document we report the outcomes of that review and of the consensus meetings held during 2017. The issues tackled in the project dealt with: information to be collected from candidates for active treatment for myelodysplastic syndromes; how to monitor the risk of infection; antimicrobial prophylaxis; the role of iron chelation and antiviral/antibacterial vaccinations. For each of these issues, practice recommendations are provided.

Eltrombopag treatment during induction chemotherapy for acute myeloid leukaemia: a randomised, double-blind, phase 2 study

BACKGROUND

Patients with acute myeloid leukaemia frequently have thrombocytopenia during induction chemotherapy. Eltrombopag, an oral thrombopoietin receptor agonist, stimulates platelet production by a similar mechanism to endogenous thrombopoietin. This study investigated safety and efficacy of eltrombopag versus placebo during anthracycline-based induction treatment of patients with acute myeloid leukaemia.

METHODS

In this randomised, double-blind, phase 2 study, treatment-naive patients were recruited from clinical centres across 10 countries (Australia, Belgium, Canada, Greece, Hungary, Israel, South Korea, Poland, Russia, and the USA). Patients with acute myeloid leukaemia of any subtype except M3 and M7 were stratified by antecedent malignant haematological disorder (yes or no) and age (18-60 years or >60 years) and were then randomly assigned (1:1) using an automated interactive voice-response system randomisation schedule. Investigators and patients were blinded to study treatment. Starting on day 4, patients received standard induction chemotherapy (daunorubicin bolus intravenous infusion on days 1-3 [90 mg/m² for patients aged 18-60 years or 60 mg/m² for patients aged >60 years], plus cytarabine continuous intravenous infusion on days 1-7 [100 mg/m²]), with eltrombopag 200 mg (100 mg for east Asians) or placebo once daily, until platelet counts were 200 × 10⁹/L or higher, until remission, or after 42 days from the start of induction chemotherapy. The primary objective of the study was safety and tolerability assessed by adverse events, changes in left ventricular ejection fraction (LVEF), and clinical laboratory parameters in all treated patients. This study has been completed and is registered with ClinicalTrials.gov, number NCT01890746.

FINDINGS

Between Sept 7, 2013, and Jan 30, 2015, 149 patients were assessed for eligibility and 148 were then randomly assigned to receive eltrombopag (n=74) and placebo (n=74). Groups were matched in mean (SD) age (56·7 years [12·3] in the eltrombopag group vs 56·6 years [11·6] in the placebo group), mean (SD) initial platelet count (59·5 × 10⁹/L [43·3] vs 63·7 × 10⁹/L [48·0]), and poor-risk karyotype (16 [22%] of 74 patients in both groups). The most common grade 3-4 adverse events (≥10% in either group) were febrile neutropenia (31 [42%] vs 28 [39%]), decreased white blood cell count (8 [11%] vs 5 [7%]), and hypophosphataemia (3 [4%] vs 9 [13%]). Serious adverse events occurred in 24 (32%) patients in the eltrombopag group compared with 14 (20%) patients in the placebo group. 39 (53%) patients in the eltrombopag group died versus 29 (41%) patients in the placebo group. Thromboembolic events (5 [7%] vs 4 [6%]) and mean (SD) change in LVEF (-2·5% [7·8] vs -4·3% [8·5]) were similar.

INTERPRETATION

Data from this trial do not support combining eltrombopag with induction chemotherapy in patients with acute myeloid leukaemia.

FUNDING

Novartis Pharma AG.

Eltrombopag for post-transplant cytopenias due to poor graft function

Persistent cytopenia due to poor graft function (PoGF) is a relatively common complication which may affect up to 20% of patients undergoing allogeneic hematopoietic stem cell transplantation (HSCT). Treatment options for PoGF remain limited, and reinfusion of additional HSC is often the only way to rescue hematopoiesis. Here we describe a retrospective single-center experience with the thrombopoietin-mimetic agent eltrombopag for the treatment of PoGF. Thirteen patients have received eltrombopag for either PoGF (n = 12) or primary graft failure (n = 1). In the 12 PoGF patients eltrombopag was started at the median time of 79 days after HSCT, due to persistent thrombocytopenia, with concomitant anemia and neutropenia in 7 and 3 patients, respectively. The treatment was started at the dose of 50 mg per day, and eventually increased up to 150 mg in case of lack of response. Hematological response was seen in 7 patients, with 6 complete responses. Hematological responses were seen both in patients with evidence of immune-mediated pathophysiology, and with possible infectious/iatrogenic causes. In responding patients, eltrombopag was discontinued in 6/7 patients without further relapse. These results suggest that eltrombopag is safe and possibly effective in the setting of the treatment of PoGF, and pave the way for future prospective studies.

Treatment of MDS

The heterogeneous nature of myelodysplastic syndromes (MDS) demands a complex and personalized variety of therapeutic approaches. Among them, allogeneic hematopoietic stem cell transplantation remains the only potentially curative option and is accessible to only a small number of fit patients. For the majority of patients with MDS, treatment strategies are nonintensive and risk-adapted (by the revised version of the International Prognostic Scoring System), ranging from iron chelation and growth factors to lenalidomide and hypomethylating agents. These approaches are noncurative and aimed instead at improving cytopenias and quality of life and delaying disease progression. These limitations underpin the need for more translational research-based clinical trials in well-defined subgroups of patients with MDS. Indeed, much progress has been made over the past decade in understanding the complex molecular mechanisms underlying MDS. Unfortunately, this has not yet translated into approval of novel treatment options. There is a particularly urgent medical need in patients failing current first-line therapies, such as with erythropoiesis-stimulating or hypomethylating agents. Nevertheless, actual developments are expected to pave the way for exciting novel therapeutic opportunities. This review provides an overview of the current therapeutic landscape in MDS focusing on recent advances in clinical and translational research.

What are the most promising new agents in myelodysplastic syndromes?

PURPOSE OF REVIEW

Myelodysplastic syndromes (MDS) are a diverse group of clonal disorders of hematopoietic stem or progenitor cells that represent the most common class of acquired bone marrow failure syndromes in adults. Despite significant improvement in the pathologic insight into this group of disorders, therapeutic options remain limited and allogeneic hematopoietic stem-cell transplantation is the only treatment that can induce long-term remission in patients with MDS. The goals of therapy for MDS are based on disease prognostication, with a focus of minimizing transfusion dependence and preserving quality of life in low-risk groups and preventing progression of disease to acute myeloid leukemia in high-risk groups. Given the dearth of approved treatment options, there is a marked need for novel therapies across the board, and there are several novel agents currently in the pipeline.

RECENT FINDINGS

Among the promising agents with preclinical and early phase efficacy in higher risk MDS, apoptosis targeting with BCL-2 inhibitors have been a standout. There is also a keen interest in immunotherapy, and targeted agents (genetic, signaling pathways, bispecific antibodies, antibody-drug conjugates, and others described in this review).

SUMMARY

In this review, we will highlight some of the promising new agents currently under investigation for the management of MDS.