A randomized, double-blind, placebo-controlled phase 2 study evaluating the efficacy and safety of romiplostim treatment of patients with low or intermediate-1 risk myelodysplastic syndrome receiving lenalidomide

Effect of thrombopoietin receptor agonist on health-related quality of life and platelet transfusion burden for patients with myelodysplastic syndromes: a systematic review and meta-analysis

Thrombocytopenia is a common and unsolved problem in myelodysplastic syndrome (MDS) patients; we aimed to summarize the evidence of TPO-RA treatment for heath-related quality of life (HRQoL) and platelet transfusion burden of MDS patients. We searched Pubmed, Web of Science, EMBASE, and CENTRAL for randomized clinical trials (RCTs) comparing TPO-RA to placebo in MDS published until July 31, 2021. A random-effect model was used. Eight RCTs with 908 patients were identified. Only three RCTs involving eltrombopag reported HRQoL, and all three studies treated HRQoL as a secondary outcome. In these three RCTs, the HRQoL instruments used in each study were different. However, this outcome cannot be meta-analyzed because some studies did not provide complete data. Subsequent clinical trials should pay more attention to this. Compared to placebo, TPO-RA did not affect platelet transfusion incidence 0.83 (95% CI 0.60-1.15). There was no evidence for subgroup differences in the analyses of different types of TPO-RA, different additional agent, and different types of MDS risk groups. However, platelet transfusion units (RR = 0.68, 95% CI 0.53 to 0.84) were significantly decreased. The RR of patients who did not require platelet transfusion for 56 or more consecutive days was not different between groups (RR = 0.98, 95% CI 0.41 to 2.34). TPO-RA may decrease platelet transfusion units in MDS patients with thrombocytopenia. But the significance of this finding should be interpreted with caution, because too few studies were meta-analyzed.

Off-Label Use of Thrombopoietin Receptor Agonists: Case Series and Review of the Literature

Since their license in 2008, studies on thrombopoietin receptor agonists (TPO-RAs) are proceeding at a fast pace. Their favorable efficacy and safety profile makes them good candidates for the management of thrombocytopenia in different settings, even beyond their current indications. In the last 10 years, we faced patients with refractory thrombocytopenia that required treatment with off-label TPO-RA, despite the paucity of data in the literature and the possible risks, particularly that of thrombosis. We hereby report our 10-year real-life single-center experience of TPO-RA used off-label. Fourteen patients were divided into three groups according to the etiology of thrombocytopenia: myelodysplastic syndromes, post-transplantation, and lymphoproliferative diseases. Clinical features and results are reported within each group. Overall, TPO-RA proved effective in all these conditions achieving responses also in heavily pretreated patients. The overall response rate (ORR) was 100% in patients with thrombocytopenia after transplantation and in those with lymphoproliferative diseases and 75% in patients with myelodysplastic syndromes. The median duration of therapy was 285 days (range 93–1,513 days). Four patients (29%) discontinued treatment because of lack of response (n=2) or a sustained response (n=2). No grade 3–4 adverse events occurred, particularly no thrombosis. In our real-life experience, TPO-RAs were effective and safe and proved of value in the challenging management of patients with refractory thrombocytopenia associated with different conditions.

Radiation countermeasures for hematopoietic acute radiation syndrome: growth factors, cytokines and beyond

PURPOSE

The intent of this article is to report the status of some of the pharmaceuticals currently in late stage development for possible use for individuals unwantedly and acutely injured as a result of radiological/nuclear exposures. The two major questions we attempt to address here are: (a) What medicinals are currently deemed by regulatory authorities (US FDA) to be safe and effective and are being stockpiled? (b) What additional agents might be needed to make the federal/state/local medicinal repositories more robust and useful in effectively managing contingencies involving radiation overexposures?

CONCLUSIONS

A limited number (precisely four) of medicinals have been deemed safe and effective, and are approved by the US FDA for the 'hematopoietic acute radiation syndrome (H-ARS).' These agents are largely recombinant growth factors (e.g. rhuG-CSF/filgrastim, rhuGM-CSF/sargramostim) that target and stimulate myeloid progenitors within bone marrow. Romiplostim, a small molecular agonist that enhances platelet production via stimulation of bone marrow megakaryocytes, has been recently approved and indicated for H-ARS. It is critical that additional agents for other major sub-syndromes of ARS (gastrointestinal-ARS) be approved. Future success in developing such medicinals will undoubtedly entail some form of a polypharmaceutical strategy, or perhaps novel, bioengineered chimeric agents with multiple, radioprotective/radiomitigative functionalities.

Repurposing Pharmaceuticals Previously Approved by Regulatory Agencies to Medically Counter Injuries Arising Either Early or Late Following Radiation Exposure

The increasing risks of radiological or nuclear attacks or associated accidents have served to renew interest in developing radiation medical countermeasures. The development of prospective countermeasures and the subsequent gain of Food and Drug Administration (FDA) approval are invariably time consuming and expensive processes, especially in terms of generating essential human data. Due to the limited resources for drug development and the need for expedited drug approval, drug developers have turned, in part, to the strategy of repurposing agents for which safety and clinical data are already available. Approval of drugs that are already in clinical use for one indication and are being repurposed for another indication is inherently faster and more cost effective than for new agents that lack regulatory approval of any sort. There are four known growth factors which have been repurposed in the recent past as radiomitigators following the FDA Animal Rule: Neupogen, Neulasta, Leukine, and Nplate. These four drugs were in clinic for several decades for other indications and were repurposed. A large number of additional agents approved by various regulatory authorities for given indications are currently under investigation for dual use for acute radiation syndrome or for delayed pathological effects of acute radiation exposure. The process of drug repurposing, however, is not without its own set of challenges and limitations.

Clinical spectrum, outcome and management of immune thrombocytopenia associated with myelodysplastic syndromes and chronic myelomonocytic leukemia

Myelodysplastic syndromes (MDS) and chronic myelomonocytic leukemia (CMML) are associated with systemic inflammatory or autoimmune diseases in 10-20 % of cases. Among them, immune thrombocytopenia (ITP) has been reported but large studies assessing this association are missing. Whether such patients have a particular phenotype and require particular management is unclear. This study analyzes the clinical spectrum, outcome and therapeutic management of patients with ITP associated with MDS or CMML, in comparison (i) to patients with primary ITP without MDS/CMML and (ii) to patients with MDS/CMML without ITP. Forty-one MDS/CMML-associated ITP patients were included, with chronic ITP in 26 (63%) patients, low-risk myelodysplasia in 30 (73%) patients and CMML in 24 (59%) patients. An associated autoimmune disease was noted in 10 (24%) patients. In comparison to primary ITP patients, MDS/CMML-associated ITP patients had a higher occurrence of severe bleeding despite similar platelet counts at diagnosis. First-line treatment consisted of glucocorticoids (98%) and intravenous immunoglobulin (IVIg) (56%). Response achievement with IVIg was more frequent in primary ITP than in MDS/CMML-associated ITP patients. Response rates to second-line therapies were not statistically different between primary ITP and MDS/CMMLassociated ITP patients. Ten percent (n=4) of patients with MDS/CMML-associated ITP had multirefractory ITP versus none in primary ITP controls. After a median follow-up of 60 months, there was no difference in overall survival between MDS/CMML-associated ITP and primary ITP patients. Leukemia-free-survival was significantly better in MDS/CMMLassociated ITP patients than in MDS/CMML without ITP MDS/CMML-associated ITP have a particular outcome with more severe bleeding and multirefractory profile than primary ITP, similar response profile to primary ITP therapy except for IVIg, and less progression toward acute myeloid leukemia than MDS/CMML without ITP.

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.

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.

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: 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.

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.

Pharmacological management of ionizing radiation injuries: current and prospective agents and targeted organ systems

Introduction: There is a limited array of currently available medicinals that are useful for either the prevention, mitigation or treatment of bodily injuries arising from ionizing radiation exposure.Area covered: In this brief article, the authors review those pharmacologic agents that either are currently being used to counter the injurious effects of radiation exposure, or those that show promise and are currently under development.Expert opinion: Although significant, but limited progress has been made in the development and fielding of safe and effective pharmacotherapeutics for select types of acute radiation-associated injuries, additional effort is needed to broaden the scope of drug development so that overall health risks associated with both short- and long-term injuries in various organ systems can be reduced and effectively managed. There are several promising radiation countermeasures that may gain regulatory approval from the government in the near future for use in clinical settings and in the aftermath of nuclear/radiological exposure contingencies.

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.

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.

Avatrombopag for the treatment of immune thrombocytopenia and thrombocytopenia of chronic liver disease

Avatrombopag is an orally-administered small molecule thrombopoietin receptor agonist. It was the third thrombopoietin receptor agonist approved for the treatment of immune thrombocytopenia and the first approved to treat periprocedural thrombocytopenia in patients with chronic liver disease (thereby providing an alternative to blood transfusions for these patients). Unlike eltrombopag, avatrombopag does not require a 4 hr food-restricted window around its use and it has not been associated with hepatotoxicity in ITP patients or portal vein thrombosis in patients with chronic liver disease. In ITP patients it can often be dosed less frequently than once daily. It is overall well-tolerated with a side-effect profile similar to placebo in randomized clinical trials. This article will review the clinical development, efficacy, safety, and pharmacology of avatrombopag for use in patients with ITP and thrombocytopenia of chronic liver disease.

Treatment of Lymphoid and Myeloid Malignancies by Immunomodulatory Drugs

Thalidomide and its derivatives (lenalidomide, pomalidomide, avadomide, iberdomide hydrochoride, CC-885 and CC-90009) form the family of immunomodulatory drugs (IMiDs). Lenalidomide (CC5013, Revlimid®) was approved by the US FDA and the EMA for the treatment of multiple myeloma (MM) patients, low or intermediate-1 risk transfusion-dependent myelodysplastic syndrome (MDS) with chromosome 5q deletion [del(5q)] and relapsed and/or refractory mantle cell lymphoma following bortezomib. Lenalidomide has also been studied in clinical trials and has shown promising activity in chronic lymphocytic leukemia (CLL) and non-Hodgkin lymphoma (NHL). Lenalidomide has anti-inflammatory effects and inhibits angiogenesis. Pomalidomide (CC4047, Imnovid® [EU], Pomalyst® [USA]) was approved for advanced MM insensitive to bortezomib and lenalidomide. Other IMiDs are in phases 1 and 2 of clinical trials. Cereblon (CRBN) seems to have an important role in IMiDs action in both lymphoid and myeloid hematological malignancies. Cereblon acts as the substrate receptor of a cullin-4 really interesting new gene (RING) E3 ubiquitin ligase CRL4CRBN. This E3 ubiquitin ligase in the absence of lenalidomide ubiquitinates CRBN itself and the other components of CRL4CRBN complex. Presence of lenalidomide changes specificity of CRL4CRBN which ubiquitinates two transcription factors, IKZF1 (Ikaros) and IKZF3 (Aiolos), and casein kinase 1α (CK1α) and marks them for degradation in proteasomes. Both these transcription factors (IKZF1 and IKZF3) stimulate proliferation of MM cells and inhibit T cells. Low CRBN level was connected with insensitivity of MM cells to lenalidomide. Lenalidomide decreases expression of protein argonaute-2, which binds to cereblon. Argonaute-2 seems to be an important drug target against IMiDs resistance in MM cells. Lenalidomide decreases also basigin and monocarboxylate transporter 1 in MM cells. MM cells with low expression of Ikaros, Aiolos and basigin are more sensitive to lenalidomide treatment. The CK1α gene (CSNK1A1) is located on 5q32 in commonly deleted region (CDR) in del(5q) MDS. Inhibition of CK1α sensitizes del(5q) MDS cells to lenalidomide. CK1α mediates also survival of malignant plasma cells in MM. Though, inhibition of CK1α is a potential novel therapy not only in del(5q) MDS but also in MM. High level of full length CRBN mRNA in mononuclear cells of bone marrow and of peripheral blood seems to be necessary for successful therapy of del(5q) MDS with lenalidomide. While transfusion independence (TI) after lenalidomide treatment is more than 60% in MDS patients with del(5q), only 25% TI and substantially shorter duration of response with occurrence of neutropenia and thrombocytopenia were achieved in lower risk MDS patients with normal karyotype treated with lenalidomide. Shortage of the biomarkers for lenalidomide response in these MDS patients is the main problem up to now.

CC-486 (oral azacitidine) in patients with myelodysplastic syndromes with pretreatment thrombocytopenia

Thrombocytopenia is among the strongest predictors of decreased survival for patients with myelodysplastic syndromes (MDS) across all prognostic risk groups. The safety and efficacy of CC-486 (oral azacitidine) was investigated in early-phase studies; we assessed clinical outcomes among subgroups of MDS patients from these studies, defined by presence or lack of pretreatment thrombocytopenia (≤75 × 10⁹/L platelet count). Patients received CC-486 300 mg once-daily for 14 or 21 days of repeated 28-day cycles. Overall, 81 patients with MDS, median age 72 years, comprised the Low Platelets (n = 45) and High Platelets (n = 36) cohorts. Pretreatment median platelet counts were 34 × 10⁹/L and 198 × 10⁹/L, respectively. Grade 3-4 bleeding events occurred in 2 patients in the Low Platelets and 1 patient in the High Platelets groups; events resolved without sequelae. Treatment-related mortality was reported for 7 patients, 5 of whom had pretreatment platelet values <25 × 10⁹/L. Overall response rates were 38% and 46% in the Low Platelets and High Platelets groups, respectively. Five thrombocytopenic patients attained complete remission and 9 attained platelet hematologic improvement. In both cohorts, platelet counts dropped during the first CC-486 treatment cycle, then increased thereafter. Extended CC-486 dosing was generally well tolerated and induced hematologic responses in these patients regardless of pretreatment thrombocytopenia.

Thrombocytopenia in Patients with Myelodysplastic Syndromes: Still an Unsolved Problem

The myelodysplastic syndromes (MDS) are a group of clonal bone marrow (BM) stem cell disorders, characterized by ineffective hematopoiesis, peripheral cytopenias, and hematologic cellular dysfunction, as well as potential transformation to acute leukemia. Thrombocytopenia is common in MDS and is associated with bleeding complications, occasionally life-threatening. Low platelet count (PLT), as well declining PLT also serves as a prognostic marker. Understanding thrombopoiesis led to the cloning of thrombopoietin, resulting in the development of platelet stimulating agents, thrombomimetics, romiplostim and eltrombopag. Both agents have been shown to increase PLT, decrease the need for platelet transfusions and reduce the number of bleeding episodes, with a reasonable tolerance. They are already approved for immune thrombocytopenia and thrombocytopenia related to liver disease. Romiplostim and eltrombopag have proven efficacy in lower- and higher-risk MDS with thrombocytopenia, as monotherapy, as well as a part of a combination, either with lenalidomide, and mainly combined with hypomethylating agents. However, safety concerns have been raised: while several trials have been completed with no evidence of disease progression, others have been early terminated due to an increased number of BM blasts and possible leukemic transformation in treated-patients. The jury is still out regarding this safety concern, although recent publications are more encouraging.

Long-term follow-up for up to 5 years on the risk of leukaemic progression in thrombocytopenic patients with lower-risk myelodysplastic syndromes treated with romiplostim or placebo in a randomised double-blind trial

BACKGROUND

Treatment options for thrombocytopenia in myelodysplastic syndromes are scarce. As described previously in a randomised phase 2 study (n=250), 58 weeks of romiplostim treatment in patients with International Prognostic Scoring System (IPSS)-defined lower-risk (low-risk or intermediate-1 risk) myelodysplastic syndromes led to reduced platelet transfusions (p<0·0001) and increased International Working Group-defined haematological improvement-platelet rates (p<0·0001) versus placebo. However, the study drug was discontinued because of the potential risk for progression to or incorrect diagnosis or treatment for acute myeloid leukaemia, based on an acute myeloid leukaemia interim hazard ratio (HR) of 2·5; the subsequent 58-week acute myeloid leukaemia HR was 1·2 (95% CI 0·4-3·8).

METHODS

This study is a 5-year follow-up of a phase 2, multicentre, double-blind trial of romiplostim treatment in patients with lower-risk myelodysplastic syndromes. Eligible patients were recruited at 109 centres in North America, Europe, Russia, and Australia, were aged 18-90 years, and had platelets of 20 × 10⁹ per L or less with or without a history of bleeding or 50 × 10⁹ platelets per L or less with a history of bleeding. Patients were randomly assigned by interactive voice response system with stratification by baseline platelet count (≥20 × 10⁹ per L or <20 × 10⁹ per L) and IPSS risk (low or intermediate-1) to receive either placebo or 750 μg romiplostim subcutaneously once per week for 58 weeks. The primary outcomes for this long-term follow-up were survival and progression to acute myeloid leukaemia. Progression to acute myeloid leukaemia was defined as either 20% blasts or more after 4 weeks from romiplostim discontinuation; as per pathology; or by initiation of antileukaemia treatment. The primary outcome was assessed per protocol in all patients with available data. This study is registered with ClinicalTrials.gov, NCT00614523.

FINDINGS

Patients were recruited from July 21, 2008, to Dec 16, 2010. 167 patients were assigned to receive romiplostim treatment and 83 were assigned to receive placebo. 210 (84%) of 250 patients entered the 5-year long-term follow-up (139 patients in the romiplostim group and 83 in the placebo group). At the end of follow-up, proportions of patients with acute myeloid leukaemia (20 [12%] of 167 in the romiplostim group vs nine [11%] of 83 in the placebo group; HR 1·06 [95% CI 0·48-2·33]; p=0·88) and proportions who died (93 [56%] vs 54 [54%]; HR 1·03 [0·72-1·47]; p=0·89) were not significantly different between the two groups.

INTERPRETATION

Following the decision to stop the study drug, 5-year long-term follow-up HRs for transformation to acute myeloid leukaemia and HRs for death did not differ between patients treated with romiplostim and those treated with placebo, indicating that use of romiplostim is probably not associated with any increased risk of acute myeloid leukaemia or death, despite initial concerns.

FUNDING

Amgen Inc.

The bone-marrow niche in MDS and MGUS: implications for AML and MM

Several haematological malignancies, including multiple myeloma (MM) and acute myeloid leukaemia (AML), have well-defined precursor states that precede the development of overt cancer. MM is almost always preceded by monoclonal gammopathy of undetermined significance (MGUS), and at least a quarter of all patients with myelodysplastic syndromes (MDS) have disease that evolves into AML. In turn, MDS are frequently anteceded by clonal haematopoiesis of indeterminate potential (CHIP). The acquisition of additional genetic and epigenetic alterations over time clearly influences the increasingly unstable and aggressive behaviour of neoplastic haematopoietic clones; however, perturbations in the bone-marrow microenvironment are increasingly recognized to have key roles in initiating and supporting oncogenesis. In this Review, we focus on the concept that the haematopoietic neoplasia-microenvironment relationship is an intimate rapport between two partners, provide an overview of the evidence supporting a role for the bone-marrow niche in promoting neoplasia, and discuss the potential for niche-specific therapeutic targets.

Thrombopoietin mimetics for patients with myelodysplastic syndromes

BACKGROUND

Myelodysplastic syndrome (MDS) is one of the most frequent haematologic malignancies of the elderly population and characterised by progenitor cell dysplasia with ineffective haematopoiesis and a high rate of transformation to acute myeloid leukaemia (AML). Thrombocytopenia represents a common problem for patients with MDS. ranging from mild to serious bleeding events and death. To manage thrombocytopenia, the current standard treatment includes platelet transfusion, unfortunately leading to a range of side effects. Thrombopoietin (TPO) mimetics represent an alternative treatment option for MDS patients with thrombocytopenia. However, it remains unclear, whether TPO mimetics influence the increase of blast cells and therefore to premature progression to AML.

OBJECTIVES

To evaluate the efficacy and safety of thrombopoietin (TPO) mimetics for patients with MDS.

SEARCH METHODS

We searched for randomised controlled trials in the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (January 2000 to August 2017), trials registries (ISRCTN, EU clinical trials register and clinicaltrials.gov) and conference proceedings. We did not apply any language restrictions. Two review authors independently screened search results, disagreements were solved by discussion.

SELECTION CRITERIA

We included randomised controlled trials comparing TPO mimetics with placebo, no further treatment or another TPO mimetic in patients with MDS of all risk groups, without gender, age or ethnicity restrictions. Additional chemotherapeutic treatment had to be equal in both arms.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data and assessed the quality of trials, disagreements were resolved by discussion. Risk ratio (RR) was used to analyse mortality during study, transformation to AML, incidence of bleeding events, transfusion requirement, all adverse events, adverse events >= grade 3, serious adverse events and platelet response. Overall survival (OS) and progression-free survival (PFS) have been extracted as hazard ratios, but could not be pooled as results were reported in heterogenous ways. Health-related quality of life and duration of thrombocytopenia would have been analysed as standardised mean differences, but no trial reported these outcomes.

MAIN RESULTS

We did not identify any trial comparing one TPO mimetic versus another. We analysed six eligible trials involving 746 adult patients. All trials were reported as randomised and double-blind trials including male and female patients. Two trials compared TPO mimetics (romiplostim or eltrombopag) with placebo, one trial evaluated eltrombopag in addition to the hypomethylating agent azacitidine, two trials analysed romiplostim additionally to a hypomethylating agent (azacitidine or decitabine) and one trial evaluated romiplostim in addition to the immunomodulatory drug lenalidomide. There are more data on romiplostim (four included, completed, full-text trials) than on eltrombopag (two trials included: one full-text publication, one abstract publication). Due to small sample sizes and imbalances in baseline characteristics in three trials and premature termination of two studies, we judged the potential risk of bias of all included trials as high.Due to heterogenous reporting, we were not able to pool data for OS. Instead of that, we analysed mortality during study. There is little or no evidence for a difference in mortality during study for thrombopoietin mimetics compared to placebo (RR 0.97, 95% confidence interval (CI) 0.73 to 1.27, N = 6 trials, 746 patients, low-quality evidence). It is unclear whether the use of TPO mimetics induces an acceleration of transformation to AML (RR 1.02, 95% CI 0.59 to 1.77, N = 5 trials, 372 patients, very low-quality evidence).Thrombopoietin mimetics probably improve the incidence of all bleeding events (RR 0.92, 95% CI 0.86 to 0.99, N = 5 trials, 390 patients, moderate-quality evidence). This means that in the study population, 713 out of 1000 in the placebo arm will have a bleeding event, compared to 656 of 1000 (95% CI 613 to 699) in the TPO mimetics arm. There is little or no evidence for a difference that TPO mimetics significantly diminish the rate of transfusion requirement (RR 0.83, 95% CI 0.66 to 1.05, N = 4 trials, 358 patients, low-quality evidence). No studies were found that looked at quality of life or duration of thrombocytopenia.There is no evidence that patients given TPO mimetics suffer more all adverse events (RR 1.01, 95% CI 0.96 to 1.07, N = 5 trials, 390 patients, moderate-quality evidence). There is uncertainty whether the number of serious adverse events decrease under therapy with TPO mimetics (RR 0.89, 95% CI 0.54 to 1.46, N = 4 trials, 356 patients, very low-quality evidence).We identified one ongoing study and one study marked as completed (March 2015), but without publication of results for MDS patients (only results reported for AML and MDS patients together). Both studies evaluate MDS patients receiving eltrombopag in comparison to placebo.

AUTHORS' CONCLUSIONS

No trial evaluated one TPO mimetic versus another.Six trials including adult patients analysed one TPO mimetic versus placebo, sometimes combined with standard therapy in both arms. Given the uncertainty of the quality of evidence, meta-analyses show that there is little or no evidence for a difference in mortality during study and premature progress to AML. However, these assumptions have to be further explored. Treatment with TPO mimetics resulted in a lower number of MDS patients suffering from bleeding events.There is no evidence for a difference between study groups regarding transfusion requirement. Enlarged sample sizes and a longer follow-up of future trials should improve the estimate of safety and efficacy of TPO mimetics, moreover health-related quality of life should be evaluated. As two ongoing studies currently investigate eltrombopag (one already completed, but without published results), we are awaiting results for this drug.

Beyond immune thrombocytopenia: the evolving role of thrombopoietin receptor agonists

Since its discovery, the thrombopoietin (TPO) pathway has been an important pharmaceutical target for the treatment of thrombocytopenia. The first generation of TPO mimetics included peptide agents sharing homology with endogenous TPO, but these introduced a risk of antibody formation to endogenous TPO and were not successful. However, second-generation TPO mimetics or TPO receptor agonists (RAs) are currently being used to treat thrombocytopenia associated with a number of conditions, such as immune thrombocytopenia (ITP), severe aplastic anaemia (SAA), and hepatitis C virus-associated chronic liver disease. Accumulating efficacy and safety data suggest that the role of TPO-RAs in the treatment of thrombocytopenia may evolve in the near future with broader use of these agents in ITP and SAA, as well as approval in other indications, potentially including myelodysplastic syndromes, chemotherapy-associated thrombocytopenia, and post-transplant thrombocytopenia. This review provides an overview of clinical data on the efficacy and safety of TPO-RAs, emphasising recent findings that may expand their clinical utility.

Treatment of low-risk myelodysplastic syndromes

The majority of myelodysplastic syndrome (MDS) patients belong to the International Prognostic Scoring System (IPSS) and IPSS-revised (IPSS-R) lower-risk categories. Their precise diagnostics and prognostic stratification is often a challenge, but may ensure the optimization of therapy. The availability of diverse treatment options has significantly improved the quality of life and survival of this group of patients. Anemia is the most relevant cytopenia in terms of frequency and symptoms in lower-risk MDS, and may be treated successfully with erythropoietic stimulating agents, provided a careful selection is performed on the basis of IPSS-R, endogenous erythropoietin levels, and transfusion independence. Doses and duration of therapy of erythropoietic-stimulating agents (ESAs) are critical to determine efficacy. In case a patient fails ESA treatment, the available options may include lenalidomide (approved for del5q positive cases), hypomethylating agents, and a rather large number of experimental agents, whose clinical trials should be offered to a larger number of MDS patients. The choice for second-line treatment must take into account biologic, cytogenetic, and molecular-identified characteristics of individual patients, as well as frailty and comorbidities. Other cytopenias are less frequently presenting as isolated. Specific therapy for thrombocytopenia has been proposed in experimental clinical trials with thrombomimetic agents that have shown good efficacy, but raised some safety concern. Although neutropenia is targeted symptomatically with growth factor supportive care, the immunosuppressive treatments are indicated mainly for pancytopenic, hypoplastic lower-risk MDS; they are not widely used because of their toxicity, despite the fact that they may induce responses. Finally, hematopoietic stem cell transplant is the curative option also for lower-risk MDS and timing should be carefully evaluated, balancing toxicity and the possibility of survival advantage. Finally, even when considered suitable for lower-risk MDS, transplant application is limited to the rarer fit and younger MDS patient.

Alternative agents to prophylactic platelet transfusion for preventing bleeding in people with thrombocytopenia due to chronic bone marrow failure: a meta-analysis and systematic review

BACKGROUND

People with thrombocytopenia due to bone marrow failure are vulnerable to bleeding. Platelet transfusions have limited efficacy in this setting and alternative agents that could replace, or reduce platelet transfusion, and are effective at reducing bleeding are needed.

OBJECTIVES

To compare the relative efficacy of different interventions for patients with thrombocytopenia due to chronic bone marrow failure and to derive a hierarchy of potential alternative treatments to platelet transfusions.

SEARCH METHODS

We searched for randomised controlled trials (RCTs) in the Cochrane Central Register of Controlled Trials (the Cochrane Library 2016, Issue 3), MEDLINE (from 1946), Embase (from 1974), CINAHL (from 1937), the Transfusion Evidence Library (from 1980) and ongoing trial databases to 27 April 2016.

SELECTION CRITERIA

We included randomised controlled trials in people with thrombocytopenia due to chronic bone marrow failure who were allocated to either an alternative to platelet transfusion (artificial platelet substitutes, platelet-poor plasma, fibrinogen concentrate, recombinant activated factor VII (rFVIIa), desmopressin (DDAVP), recombinant factor XIII (rFXIII), recombinant interleukin (rIL)6 or rIL11, or thrombopoietin (TPO) mimetics) or a comparator (placebo, standard of care or platelet transfusion). We excluded people undergoing intensive chemotherapy or stem cell transfusion.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened search results, extracted data and assessed trial quality. We estimated summary risk ratios (RR) for dichotomous outcomes. We planned to use summary mean differences (MD) for continuous outcomes. All summary measures are presented with 95% confidence intervals (CI).We could not perform a network meta-analysis because the included studies had important differences in the baseline severity of disease for the participants and in the number of participants undergoing chemotherapy. This raised important concerns about the plausibility of the transitivity assumption in the final dataset and we could not evaluate transitivity statistically because of the small number of trials per comparison. Therefore, we could only perform direct pairwise meta-analyses of included interventions.We employed a random-effects model for all analyses. We assessed statistical heterogeneity using the I2 statistic and its 95% CI. The risk of bias of each study included was assessed using the Cochrane 'Risk of bias' tool. The quality of the evidence was assessed using GRADE methods.

MAIN RESULTS

We identified seven completed trials (472 participants), and four ongoing trials (recruiting 837 participants) which are due to be completed by December 2020. Of the seven completed trials, five trials (456 participants) compared a TPO mimetic versus placebo (four romiplostim trials, and one eltrombopag trial), one trial (eight participants) compared DDAVP with placebo and one trial (eight participants) compared tranexamic acid with placebo. In the DDAVP trial, the only outcome reported was the bleeding time. In the tranexamic acid trial there were methodological flaws and bleeding definitions were subject to significant bias. Consequently, these trials could not be incorporated into the quantitative synthesis. No randomised trial of artificial platelet substitutes, platelet-poor plasma, fibrinogen concentrate, rFVIIa, rFXIII, rIL6 or rIL11 was identified.We assessed all five trials of TPO mimetics included in this review to be at high risk of bias because the trials were funded by the manufacturers of the TPO mimetics and the authors had financial stakes in the sponsoring companies.The GRADE quality of the evidence was very low to moderate across the different outcomes.There was insufficient evidence to detect a difference in the number of participants with at least one bleeding episode between TPO mimetics and placebo (RR 0.86, 95% CI 0.56 to 1.31, four trials, 206 participants, low-quality evidence).There was insufficient evidence to detect a difference in the risk of a life-threatening bleed between those treated with a TPO mimetic and placebo (RR 0.31, 95% CI 0.04 to 2.26, one trial, 39 participants, low-quality evidence).There was insufficient evidence to detect a difference in the risk of all-cause mortality between those treated with a TPO mimetic and placebo (RR 0.74, 95%CI 0.52 to 1.05, five trials, 456 participants, very low-quality evidence).There was a significant reduction in the number of participants receiving any platelet transfusion between those treated with TPO mimetics and placebo (RR 0.76, 95% CI 0.61 to 0.95, four trials, 206 participants, moderate-quality evidence).There was no evidence for a difference in the incidence of transfusion reactions between those treated with TPO mimetics and placebo (pOR 0.06, 95% CI 0.00 to 3.44, one trial, 98 participants, very low-quality evidence).There was no evidence for a difference in thromboembolic events between TPO mimetics and placebo (RR 1.41, 95%CI 0.39 to 5.01, five trials, 456 participants, very-low quality evidence).There was no evidence for a difference in drug reactions between TPO mimetics and placebo (RR 1.12, 95% CI 0.83 to 1.51, five trials, 455 participants, low-quality evidence).No trial reported the number of days of bleeding per participant, platelet transfusion episodes, mean red cell transfusions per participant, red cell transfusion episodes, transfusion-transmitted infections, formation of antiplatelet antibodies or platelet refractoriness.In order to demonstrate a reduction in bleeding events from 26 in 100 to 16 in 100 participants, a study would need to recruit 514 participants (80% power, 5% significance).

AUTHORS' CONCLUSIONS

There is insufficient evidence at present for thrombopoietin (TPO) mimetics for the prevention of bleeding for people with thrombocytopenia due to chronic bone marrow failure. There is no randomised controlled trial evidence for artificial platelet substitutes, platelet-poor plasma, fibrinogen concentrate, rFVIIa, rFXIII or rIL6 or rIL11, antifibrinolytics or DDAVP in this setting.

Alternatives, and adjuncts, to prophylactic platelet transfusion for people with haematological malignancies undergoing intensive chemotherapy or stem cell transplantation

BACKGROUND

Platelet transfusions are used in modern clinical practice to prevent and treat bleeding in people with thrombocytopenia. Although considerable advances have been made in platelet transfusion therapy since the mid-1970s, some areas continue to provoke debate especially concerning the use of prophylactic platelet transfusions for the prevention of thrombocytopenic bleeding.

OBJECTIVES

To determine whether agents that can be used as alternatives, or adjuncts, to platelet transfusions for people with haematological malignancies undergoing intensive chemotherapy or stem cell transplantation are safe and effective at preventing bleeding.

SEARCH METHODS

We searched 11 bibliographic databases and four ongoing trials databases including the Cochrane Central Register of Controlled Trials (CENTRAL, 2016, Issue 4), MEDLINE (OvidSP, 1946 to 19 May 2016), Embase (OvidSP, 1974 to 19 May 2016), PubMed (e-publications only: searched 19 May 2016), ClinicalTrials.gov, World Health Organization (WHO) ICTRP and the ISRCTN Register (searched 19 May 2016).

SELECTION CRITERIA

We included randomised controlled trials in people with haematological malignancies undergoing intensive chemotherapy or stem cell transplantation who were allocated to either an alternative to platelet transfusion (artificial platelet substitutes, platelet-poor plasma, fibrinogen concentrate, recombinant activated factor VII, desmopressin (DDAVP), or thrombopoietin (TPO) mimetics) or a comparator (placebo, standard care or platelet transfusion). We excluded studies of antifibrinolytic drugs, as they were the focus of another review.

DATA COLLECTION AND ANALYSIS

Two review authors screened all electronically derived citations and abstracts of papers identified by the review search strategy. Two review authors assessed risk of bias in the included studies and extracted data independently.

MAIN RESULTS

We identified 16 eligible trials. Four trials are ongoing and two have been completed but the results have not yet been published (trial completion dates: April 2012 to February 2017). Therefore, the review included 10 trials in eight references with 554 participants. Six trials (336 participants) only included participants with acute myeloid leukaemia undergoing intensive chemotherapy, two trials (38 participants) included participants with lymphoma undergoing intensive chemotherapy and two trials (180 participants) reported participants undergoing allogeneic stem cell transplantation. Men and women were equally well represented in the trials. The age range of participants included in the trials was from 16 years to 81 years. All trials took place in high-income countries. The manufacturers of the agent sponsored eight trials that were under investigation, and two trials did not report their source of funding.No trials assessed artificial platelet substitutes, fibrinogen concentrate, recombinant activated factor VII or desmopressin.Nine trials compared a TPO mimetic to placebo or standard care; seven of these used pegylated recombinant human megakaryocyte growth and differentiation factor (PEG-rHuMGDF) and two used recombinant human thrombopoietin (rhTPO).One trial compared platelet-poor plasma to platelet transfusion.We considered that all the trials included in this review were at high risk of bias and meta-analysis was not possible in seven trials due to problems with the way data were reported.We are very uncertain whether TPO mimetics reduce the number of participants with any bleeding episode (odds ratio (OR) 0.40, 95% confidence interval (CI) 0.10 to 1.62, one trial, 120 participants, very low quality evidence). We are very uncertain whether TPO mimetics reduce the risk of a life-threatening bleed after 30 days (OR 1.46, 95% CI 0.06 to 33.14, three trials, 209 participants, very low quality evidence); or after 90 days (OR 1.00, 95% CI 0.06 to 16.37, one trial, 120 participants, very low quality evidence). We are very uncertain whether TPO mimetics reduce platelet transfusion requirements after 30 days (mean difference -3.00 units, 95% CI -5.39 to -0.61, one trial, 120 participants, very low quality evidence). No deaths occurred in either group after 30 days (one trial, 120 participants, very low quality evidence). We are very uncertain whether TPO mimetics reduce all-cause mortality at 90 days (OR 1.00, 95% CI 0.24 to 4.20, one trial, 120 participants, very low quality evidence). No thromboembolic events occurred for participants treated with TPO mimetics or control at 30 days (two trials, 209 participants, very low quality evidence). We found no trials that looked at: number of days on which bleeding occurred, time from randomisation to first bleed or quality of life.One trial with 18 participants compared platelet-poor plasma transfusion with platelet transfusion. We are very uncertain whether platelet-poor plasma reduces the number of participants with any bleeding episode (OR 16.00, 95% CI 1.32 to 194.62, one trial, 18 participants, very low quality evidence). We are very uncertain whether platelet-poor plasma reduces the number of participants with severe or life-threatening bleeding (OR 4.00, 95% CI 0.56 to 28.40, one trial, 18 participants, very low quality evidence). We found no trials that looked at: number of days on which bleeding occurred, time from randomisation to first bleed, number of platelet transfusions, all-cause mortality, thromboembolic events or quality of life.

AUTHORS' CONCLUSIONS

There is insufficient evidence to determine if platelet-poor plasma or TPO mimetics reduce bleeding for participants with haematological malignancies undergoing intensive chemotherapy or stem cell transplantation. To detect a decrease in the proportion of participants with clinically significant bleeding from 12 in 100 to 6 in 100 would require a trial containing at least 708 participants (80% power, 5% significance). The six ongoing trials will provide additional information about the TPO mimetic comparison (424 participants) but this will still be underpowered to demonstrate this level of reduction in bleeding. None of the included or ongoing trials include children. There are no completed or ongoing trials assessing artificial platelet substitutes, fibrinogen concentrate, recombinant activated factor VII or desmopressin in people undergoing intensive chemotherapy or stem cell transplantation for haematological malignancies.

Effects of Designer Hyper-Interleukin 11 (H11) on Hematopoiesis in Myelosuppressed Mice

The incidence of cancer is constantly increasing. Chemo/radiotherapy is one of major methods of treating cancer. Although adverse chemo/radiotherapy events, such as anemia and neutropenia, can be successfully cured, thrombocytopenia is still problematic. We constructed the Hyper-IL11 (H11) cytokine by linking soluble interleukin 11 receptor alpha (sIL-11Ralpha) with IL-11. In vivo H11 activity was examined in myelosuppressed mice. Myelosuppression was induced by either i) sublethal irradiation and carboplatin administration or ii) sublethal irradiation. A dose of 100 μg/kg of H11 or IL-11 was administered subcutaneously for 7 days. IL-11 and H11 accelerated leukocyte, hematocrit and platelet recovery. The effect on the attenuation of thrombocytopenia was significant. Moreover, both cytokines increased the cellularity and numbers of megakaryocyte, erythroid, and granulocyte/macrophage progenitors in the bone morrow and spleen compared with the control. Although H11 was administered at a molar concentration that was three times lower, its effects were comparable with or better than those of IL-11; thus, the activity of H11 was superior to that of IL-11. Because no toxicity was observed after the intravenous administration of H11, this hyper-cytokine may be potentially useful for treatment of thrombocytopenia and other IL-11-dependent disorders.

Comparative efficacy and cost effectiveness of splenectomy and thrombopoietin prior to peginterferon and ribavirin therapy with compensatory cirrhosis associated with hepatitis C and thrombocytopenia

The aim of the present study was to evaluate and compare the treatment efficacy and cost of two therapies, splenectomy and thrombopoietin, in order to optimize the treatment plans for patients with HCV-associated cirrhosis. A prospective randomized controlled trial was conducted on 69 patients with a platelet count <60,000/mm³ that were enrolled between 2009 and 2013, including 38 cases as the research group and 31 cases as the observed group. The study included two stages: A 4-week initial treatment and a 48-week antiviral treatment, during which a number of parameters were evaluated, including platelet count, liver stiffness measure, albumin, total bilirubin, alanine aminotranferase and treatment cost-effectiveness. Of the 38 patients, 21 underwent a splenectomy and their platelet counts increased to 60,000/mm³ after the 4-week initial treatment. The patients then started a 48-week P-R antiviral treatment, and 18 cases completed the treatment. In addition, 17/38 patients received thrombopoietin as a drug therapy. The platelet counts in 15 cases increased to >60,000/mm³ and the patients received antiviral treatment, among which 9 cases completed the second treatment stage. The expense of the splenectomy group treatment was higher compared with that received by the thrombopoietin group. The results of the present study indicated that splenectomy was more effective at increasing platelet count. More splenectomy patients completed the full course of antiviral treatment and presented a sustained virologic response, compared with the thrombopoietin group. Therefore, splenectomy may be more expensive compared with thrombopoietin; however, the improved efficacy suggests that on balance it is the preferable treatment option.

Thrombocytopenia in MDS: epidemiology, mechanisms, clinical consequences and novel therapeutic strategies

Thrombocytopenia is commonly seen in myelodysplastic syndrome (MDS) patients, and bleeding complications are a major cause of morbidity and mortality. Thrombocytopenia is an independent factor for decreased survival and has been incorporated in newer prognostic scoring systems. The mechanisms of thrombocytopenia are multifactorial and involve a differentiation block of megakaryocytic progenitor cells, leading to dysplastic, hypolobated and microscopic appearing megakaryocytes or increased apoptosis of megakaryocytes and their precursors. Dysregulated thrombopoietin (TPO) signaling and increased platelet destruction through immune or nonimmune mechanisms are frequently observed in MDS. The clinical management of patients with low platelet counts remains challenging and approved chemotherapeutic agents such as lenalidomide and azacytidine can also lead to a transient worsening of thrombocytopenia. Platelet transfusion is the only supportive treatment option currently available for clinically significant thrombocytopenia. The TPO receptor agonists romiplostim and eltrombopag have shown clinical activity in clinical trials in MDS. In addition to thrombopoietic effects, eltrombopag can inhibit leukemic cell proliferation via TPO receptor-independent effects. Other approaches such as treatment with cytokines, immunomodulating drugs and signal transduction inhibitors have shown limited activity in selected groups of MDS patients. Combination trials of approved agents with TPO agonists are ongoing and hold promise for this important clinical problem.

[Management of myelodysplastic syndromes]

Myelodysplastic syndromes are heterogeneous diseases whose molecular characteristics have only been identified in recent years. Better identification of prognostic factors, larger access to allogeneic stem cell transplantation and the advent of new drugs notably hypomethylating agents (azacitidine, decitabine) and lenalidomide have improved patient outcome.

Risk of thromboembolism with thrombopoietin receptor agonists in adult patients with thrombocytopenia: Systematic review and meta-analysis of randomized controlled trials

BACKGROUND AND OBJECTIVE

Romiplostim and eltrombopag are thrombopoietin receptor (TPOr) agonists that promote megakaryocyte differentiation, proliferation and platelet production. In 2012, a systematic review and meta-analysis reported a non-statistically significant increased risk of thromboembolic events for these drugs, but analyses were limited by lack of statistical power. Our objective was to update the 2012 meta-analysis examining whether TPOr agonists affect thromboembolism occurrence in adult thrombocytopenic patients.

MATERIALS AND METHODS

We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs). Updated searches were conduced on PubMed, Cochrane Central, and publicly available registries (up to December 2014). RCTs using romiplostim or eltrombopag in at least one group were included. Relative risks (RR), absolute risk ratios (ARR) and number needed to harm (NNH) were estimated. Heterogeneity was analyzed using Cochran's Q test and I(2) statistic.

RESULTS

Fifteen studies with 3026 adult thrombocytopenic patients were included. Estimated frequency of thromboembolism was 3.69% (95% CI: 2.95-4.61%) for TPOr agonists and 1.46% (95% CI: 0.89-2.40%) for controls. TPOr agonists were associated with a RR of thromboembolism of 1.81 (95% CI: 1.04-3.14) and an ARR of 2.10% (95% CI: 0.03-3.90%) meaning a NNH of 48. Overall, we did not find evidence of statistical heterogeneity (p=0.43; I(2)=1.60%).

CONCLUSIONS

Our updated meta-analysis suggested that TPOr agonists are associated with a higher risk of thromboemboembolic events compared with controls, and supports the current recommendations included in the European product information on this respect.

Thrombocytopenia in cancer patients

Thrombocytopenia is a frequent complication of cancer and its treatment. The causes of thrombocytopenia in cancer patients can be diverse and multifactorial. Systemic chemotherapy is the most frequent cause of thrombocytopenia. The degree and duration thrombocytopenia depends upon whether the chemotherapeutic treatment is myeloablative, as used in stem cell transplants, or non-myeloablative, as typically used in solid non-hematologic malignancies. Additional causes of significant thrombocytopenia include tumor involvement of bone marrow and spleen; microangiopathic disorders such as disseminated intravascular coagulation, thrombotic thrombocytopenic purpura or hemolytic uremia syndrome. Lymphoproliferative malignancies can also be associated with secondary immune thrombocytopenia. Due to the broad differential diagnosis associated with cancer related thrombocytopenia, a careful diagnostic evaluation is indicated. The goal of treatment should be to maintain a safe platelet count to allow effective treatment of the underlying malignancy, prevent bleeding complications and to minimize the use of platelet product transfusion.

Clinical utility of lenalidomide in the treatment of myelodysplastic syndromes

Myelodysplastic syndromes (MDS) represent a heterogeneous group of acquired clonal hematopoietic disorders characterized by peripheral blood cytopenias, paradoxical BM hypercellularity, ineffective hematopoiesis, and increased risk of leukemic transformation. Risk stratification, using different prognostic scores and markers, is at the core of MDS management. Deletion 5q [del(5q)] MDS is a distinct class of MDS characterized by the haploinsufficiency of specific genes, microRNAs, and proteins, which has been linked to increased sensitivity to the drug lenalidomide. Phase II and III clinical trials have demonstrated the efficacy of lenalidomide in improving clinical outcomes of patients with del(5q) MDS, including reduction in red blood cell transfusion requirements and improvements in quality of life. Lenalidomide has also demonstrated some activity in non-del(5q) lower-risk MDS as well as higher-risk MDS, especially in combination with other agents. In this paper, we review the pathogenesis of del(5q) MDS, the proposed mechanisms of action of lenalidomide, the major clinical trials that documented the activity of lenalidomide in different MDS populations, potential predictors of benefit from the drug and suggested mechanisms of resistance, and the use of combination strategies to expand the clinical utility of lenalidomide in MDS.

Treatment of myelodysplastic syndrome with thrombomimetic drugs

Myelodysplastic syndromes (MDS) are clinically, genetically, and molecularly heterogeneous neoplastic diseases characterized by ineffective hematopoiesis leading to peripheral cytopenias. The severity of cytopenias influences oucome and is considered in prognostic scoring systems; thrombocytopenia, although not the most frequently observed at disease onset, is estimated to affect 40%-80% of MDS patients. As thrombocytopenia in MDS is determined by premature marrow destruction and programmed cell death, the use of thrombomimetic agents has been proposed in order to stimulate megakaryocyte differentation and proliferation. After early attempts of therapy of thrombocytopenic MDS patients with thrombopoietin and interleukin (IL)-11, clinical trials testing the activity of romiplostim and eltrombopag have been recently designed and have demonstrated good tolerability and efficacy in re-inducing megakaryocytopoiesis and in lowering the number of hemorragic events. The number of MDS patients receiving such treatments is still limited and a broader evaluation of the long-term effects and safety of these agents is ongoing.

Resuscitating a dying marrow: the role of hematopoietic growth factors

The treatment landscape for myelodysplastic syndromes (MDS) has evolved over the last two decades, with a better understanding of the disease pathophysiology and the use of newer or combination therapies. For lower-risk MDS patients, hematopoietic growth factors have continued to be the mainstay of therapy. However, better patient selection criteria and decision tools to predict responses have made these therapies more beneficial to patients. As the range of newer drugs continues to expand in our treatment armamentarium for lower-risk MDS, questions still remain regarding the safety of these drugs with long-term use. This review will discuss the role of growth factors in MDS, focusing on dosing and combination strategies to improve responses, selecting the appropriate patient population, and recognizing the safety profile based on evidence from published literature.

Are adverse drug reaction patterns different between romiplostim and eltrombopag? 2009-2013 French PharmacoVigilance assessment

BACKGROUND

Romiplostim and eltrombopag, the two marketed thrombopoietin receptor agonists (TPO-RAs), have distinct binding sites and might have distinct pharmacodynamic mechanisms. The aim of this study was to compare their adverse drug reaction (ADR) patterns.

METHODS

We selected in the French PharmacoVigilance Database all ADRs associated with TPO-RAs from TPO-RA marketing until the 31st of December 2013. Medical charts were reviewed. We conducted disproportionality analyses comparing romiplostim exposure in the reports of a given ADR pattern (thrombosis, neurological, cutaneous, gastrointestinal or hematological) to romiplostim exposure in all other TPO-RA-related ADR reports. Reporting Odds Ratios (RORs) were adjusted for age and gender. We also compared the number of reports of a given ADR pattern per million daily defined doses (DDDs) dispensed in France during the study period.

RESULTS

We described 45 reports (53 ADRs) with romiplostim and 26 reports (37 ADRs) with eltrombopag. There were 19 venous thromboses. At least one other risk factor was present in 83.3% of the cases. Ten (55.6%) patients had been splenectomized previously. There were eight arterial thromboses. Another risk factor was noticed in all cases. There was no signal for an excess risk of thrombosis with romiplostim versus eltrombopag (ROR: 1.45, 95% CI [0.48-4.45]). There was a signal for a higher risk of gastrointestinal ADRs with eltrombopag (ROR: 30.28, 95% CI [3.23-383.86]) and of hematological ADRs with romiplostim (ROR: 14.36, 95% CI [1.73-119.08]). Dispensing data-adjusted comparisons led to similar results.

CONCLUSIONS

This study suggests different ADR patterns between romiplostim and eltrombopag.

Intermittent granulocyte colony-stimulating factor for neutropenia management in patients with relapsed or refractory multiple myeloma treated with lenalidomide plus dexamethasone

Neutropenia is a major dose-limiting toxicity associated with lenalidomide in relapsed/refractory multiple myeloma (MM). The optimal dosing schedule of granulocyte colony-stimulating factor (G-CSF) is unclear. We developed an intermittent G-CSF schedule (4-6 doses per cycle) initiated upon onset of grade 3-4 neutropenia. Of 216 patients with relapsed/refractory MM treated at our center with lenalidomide/dexamethasone on an Expanded Access Program, there was a high incidence of grade 3-4 neutropenia (61%) and grade 3-4 infections (37%). Despite intermittent G-CSF use in 117 patients, recurrent grade 3-4 neutropenia was common (59%), and dose reductions were required in 40% of G-CSF recipients, most due to thrombocytopenia. G-CSF recipients had a longer duration on therapy and achieved a higher rate and depth of response. Intermittent G-CSF may be an effective approach for lenalidomide dose-preservation, which may lead to improved outcomes, although it does not prevent infections or thrombocytopenia-related dose limitations.

Results of a randomized, double-blind study of romiplostim versus placebo in patients with low/intermediate-1-risk myelodysplastic syndrome and thrombocytopenia

BACKGROUND

Thrombocytopenia in patients with myelodysplastic syndrome (MDS) is associated with shortened survival and an increased risk of evolution to acute myeloid leukemia (AML). In this study, the authors evaluated the efficacy of romiplostim in patients who had thrombocytopenia with low-risk/intermediate-1–risk MDS.

METHODS

Patients who had thrombocytopenia with low-risk/intermediate-1–risk MDS (N = 250) were randomized 2:1 to receive romiplostim or placebo weekly for 58 weeks.

RESULTS

The primary endpoint— the number of clinically significant bleeding events (CSBEs) per patient—had a hazard ratio for romiplostim:placebo of 0.83 (95% confidence interval, 0.66-1.05; P = .13). CSBEs were reduced significantly in the romiplostim group for patients who had baseline platelet counts ≥20 × 10⁹/L (P < .0001). For patients who had baseline platelet counts <20 × 10⁹/L, there was no difference in the number of CSBEs, but the platelet transfusion rates were higher in the placebo group (P < .0001), which may have affected the overall CSBE results in this group with severe thrombocytopenia. The incidence of bleeding events was reduced significantly in the romiplostim group (relative risk, 0.92), as were protocol-defined platelet transfusions (relative risk, 0.77). Platelet response rates according to 2006 International Working Group criteria were higher for the group that received romiplostim (odds ratio, 15.6). On the basis of interim data, an independent data monitoring committee advised halting study drug because of concerns regarding excess blasts and AML rates with romiplostim (interim hazard ratio, 2.51). At 58 weeks, the AML rates were 6% in the romiplostim group and 4.9% in the placebo group (hazard ratio, 1.20; 95% confidence interval, 0.38-3.84), and the overall survival rates were similar.

CONCLUSIONS

Romiplostim treatment in patients with low-risk/intermediate-1–risk MDS increased platelet counts and decreased the number of bleeding events and platelet transfusions. Although study drug was discontinued because of an initial concern of AML risk, survival and AML rates were similar with romiplostim and placebo.

Clinical indications for thrombopoietin and thrombopoietin-receptor agonists

Thrombocytopenia is a common hematologic disorder. Stimulation of thrombopoiesis may reduce the risk for thrombocytopenia-induced bleeding, prevent severe thrombocytopenia, and reduce the need for platelet transfusion. The key cytokine is thrombopoietin (TPO). It regulates proliferation and maturation of megakaryocytes as well as platelet production. TPO is synthesized in the liver. Development of TPO from the laboratory into a therapeutic tool has turned out to be an unexpected challenge. Clinical trials on first-generation thrombopoietic growth factors were stopped in 2001. At present, second-generation thrombopoiesis-stimulating agents have only been approved as orphan drugs for third-line therapy of patients with chronic immune thrombocytopenia. Larger groups in need are patients with myelodysplastic syndrome, chemotherapy-induced thrombocytopenia, other forms of hereditary and acquired bone marrow failure, hepatitis C infections, or liver cirrhosis.

Pathophysiology and management of thrombocytopenia in bone marrow failure: possible clinical applications of TPO receptor agonists in aplastic anemia and myelodysplastic syndromes

Aplastic anemia is a bone marrow failure syndrome that causes pancytopenia and can lead to life-threatening complications. Bone marrow transplantation remains the standard of care for younger patients and those with a good performance status but many patients may not have a suitable donor. Immunosuppressive therapy is able to resolve cytopenias in a majority of patients with aplastic anemia but relapses are not uncommon and some patients remain refractory to this approach. Patients may require frequent blood and platelet transfusion support which is expensive and inconvenient. Life-threatening bleeding complications still occur despite prophylactic platelet transfusion. Thrombopoietin (TPO) mimetics, such as romiplostim and eltrombopag, were developed to treat patients with refractory immune thrombocytopenia but are now being investigated for the treatment of bone marrow failure syndromes. TPO is the main regulator for platelet production and its receptor (c-Mpl) is present on megakaryocytes and hematopoietic stem cells. Trilineage hematopoietic responses were observed in a recent clinical trial using eltrombopag in patients with severe aplastic anemia refractory to immunosuppression suggesting that these agents can provide a new therapeutic option for enhancing blood production. In this review, we discuss these recent results and ongoing investigation of TPO mimetics for aplastic anemia and other bone marrow failure states like myelodysplastic syndromes. Clonal evolution or progression to acute myeloid leukemia remains a concern when using these drugs in bone marrow failure and patients should only be treated in the setting of a clinical trial.

How we treat lower-risk myelodysplastic syndromes

Lower-risk myelodysplastic syndromes (MDSs) are defined as having low or intermediate 1 risk by the International Prognostic Scoring System and are characterized mainly by anemia in most cases. Supportive care--primarily red blood cell transfusions--remains an important component of their treatment, but exposes patients to insufficient correction of anemia, alloimmunization, and organ iron overload (for which the role of iron chelation remains debated). Treatment aimed at preventing anemia recurrence should therefore be used whenever possible. Erythropoiesis stimulating agents remain the first-line treatment of anemia in most lower-risk MDS without del(5q), whereas anemia of low-risk MDS with del 5q responds to lenalidomide in two-thirds of the cases, but this drug should be used cautiously because profound cytopenias may occur initially. Treatment after failure of those first-line therapies are disappointing overall, with many patients eventually requiring long-term transfusions, but encouraging results have been reported with hypomethylating agents and lenalidomide. Selected patients respond to antithymocyte globulins, and thrombopoietin receptor agonists are under investigation in lower-risk MDS with thrombocytopenia. Some patients, while remaining at a "lower risk" MDS level, have severe cytopenias and/or poor prognostic factors, found using newer prognostic parameters, or resistance to treatment, making them urgent candidates for more intensive approaches, including allogeneic stem cell transplantation.