Use of Thrombopoietin Receptor Agonists in Childhood Immune Thrombocytopenia

In Silico Identification and In Vitro Validation of Repurposed Compounds Targeting the RSV Polymerase

Respiratory Syncytial Virus (RSV) is the top cause of infant hospitalization globally, with no effective treatments available. Researchers have sought small molecules to target the RNA-dependent RNA Polymerase (RdRP) of RSV, which is essential for replication and transcription. Based on the cryo-EM structure of the RSV polymerase, in silico computational analysis including molecular docking and the protein-ligand simulation of a database, including 6554 molecules, is currently undergoing phases 1-4 of clinical trials and has resulted in the top ten repurposed compound candidates against the RSV polymerase, including Micafungin, Totrombopag, and Verubecestat. We performed the same procedure to evaluate 18 small molecules from previous studies and chose the top four compounds for comparison. Among the top identified repurposed compounds, Micafungin, an antifungal medication, showed significant inhibition and binding affinity improvements over current inhibitors such as ALS-8112 and Ribavirin. We also validated Micafungin's inhibition of the RSV RdRP using an in vitro transcription assay. These findings contribute to RSV drug development and hold promise for broad-spectrum antivirals targeting the non-segmented negative-sense (NNS) RNA viral polymerases, including those of rabies (RABV) and Ebola (EBOV).

Evidence-based clinical practice guideline for the management of primary immune thrombocytopenia (ITP) in pediatric population

Introduction: Primary immune thrombocytopenia (ITP) is the most common cause of thrombocytopenia in children, with a reported incidence of 1.1-12.5 cases per 100 000 children. However, currently, there are several definitions of ITP, as well as diagnostic and therapeutic approaches. Objective: To develop an evidence-based clinical practice guideline (CPG) to standardize the definition of ITP and, in this way, reduce the variability of its diagnosis, and to provide indications for the treatment of acute, persistent, and chronic ITP in patients under 18 years of age. Materials and methods: The CPG was prepared by a multidisciplinary group that followed the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) guidelines for developing CPGs, formulated PICO clinical questions, and conducted systematic reviews. GRADE evidence profiles were created and recommendations, with their corresponding level of evidence and strength, were made after a panel of experts assessed the benefit-risk balance, the quality of evidence, the patients’ values and preferences, and the context in which they should be implemented. Results: A total of 23 recommendations were made to pediatricians, hematologists, and health professionals working in emergency services for treating acute, persistent, and chronic ITP. Overall, the CPG has low quality of evidence, and the recommendations were made in order to improve the success rate of ITP treatment and the prognosis of children with this condition. Conclusions: Although ITP is the main cause of thrombocytopenia in pediatrics, to date there is not enough high-quality evidence that supports the recommendations presented here for its proper classification and treatment in children. Thus, further studies providing high-quality evidence on this issue are required.

Safety and Efficacy of Eltrombopag in Children and Adults with Immune Thrombocytopenia: A Systematic Review and Meta-Analysis

Immune thrombocytopenia is an immune condition where antibodies are produced against platelets. Eltrombopag is a thrombopoietin receptor agonist that stimulates and promotes platelet production approved for treating thrombocytopenia in patients with chronic immune thrombocytopenia, where other treatments such as corticosteroids, splenectomy or immunoglobulins are inadequate. The aim of this meta-analysis was to evaluate the efficacy and safety of the eltrombopag in adults and children with immune thrombocytopenia. We included 7 studies with a total of 765 patients (606 adults and 159 children). We evaluated the number of patients that achieved a post-treatment platelet count equal or above 50x10⁹/L (primary result-target) without the need of rescue treatment for at least 4 weeks. Our data showed that patients who received eltrombopag were almost 4 times more probable in achieving the primary target when compared to patients who received placebo (RR 3.84, 95% CI 2.39 to 6.14; I² = 46%). The number of patients needed rescue treatment and the number of bleeding incidents were reduced in the group that received eltrombopag when compared to those who received placebo (RR 0.40, 95% CI 0.25 to 0.62; I² = 40%) (RR 0.74, 95% CI 0.62 to 0.89; I² = 68%). The total number of side effects did not statistically differ between the two groups (RR 0.99, 95% CI 0.90 to 1.08; I² = 14%). Our findings were similar to previously published studies and confirm that eltrombopag is safe and efficient in immune thrombocytopenia. However, more clinical trials are needed in order to enhance our findings.

Efficacy and Safety of Avatrombopag in Patients With Thrombocytopenia: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background: Avatrombopag is a novel oral, nonpeptide thrombopoietin receptor agonist (TPO-RA). A few studies have shown that avatrombopag is effective against thrombocytopenia. However, no systematic review has been conducted on the efficacy and safety of avatrombopag. Therefore, the aim of this study was to comprehensively assess the efficacy and safety of avatrombopag patients with thrombocytopenia. Methods: Databases including Medline, PubMed, Embase, the Cochrane Library and ClinicalTrials.gov were searched for randomized controlled trials that compared avatrombopag with placebo in patients with thrombocytopenia. The deadline was March 2019. Results: In total, 743 patients were analyzed in five clinical trials. Patients treated with avatrombopag achieved higher platelet response (OR: 17.71, 95% CI [11.01 to 28.48], p < 0.00001) than with placebo. Avatrombopag produced an absolute increment in platelet count (WMD: 31.13%, 95% CI [22.27 to 39.99], p < 0.00001) unlike the placebo. In addition, the incidence of serious adverse events (RR: 1.18, 95% CI [0.72 to 1.93], p = 0.51) and deaths (RR: 0.93, 95% CI [0.19 to 4.45], p = 0.93) in patients treated with avatrombopag was not significantly different from that in patients treated with placebo. The incidence of adverse events in patients treated with avatrombopag was slightly higher than that in patients treated with placebo (RR: 1.25, 95% CI [1.05 to 1.49], p = 0. 01) after one trial with high heterogeneity was removed. Conclusions: This meta-analysis showed that avatrombopag was an effective treatment for thrombocytopenia, but there is sufficient evidence to indicate that adverse events may occur.

Successful resection of intrahepatic cholangiocarcinoma with idiopathic thrombocytopenic purpura using thrombopoietin receptor agonist: a case report

Background

Patients with idiopathic thrombocytopenic purpura (ITP) have low platelet counts and an increased risk of complications. Therefore, these patients generally require high-dose immunoglobulin therapy and platelet transfusion. However, thrombopoietin receptor agonists (TPO-RAs) have recently become available for use in the preoperative treatment strategy for intractable ITP. Recent studies have also reported radiofrequency ablation (RFA) or tissue biopsy as perioperative management for thrombocytopenia using TPO-RA. However, no report has described the use of TPO-RA in a case of hepatectomy.

Case presentation

A 76-year-old man presented with intrahepatic cholangiocarcinoma (IHCC) complicated with ITP. His platelet count was 3.5 × 10⁴/μL. To increase platelet levels prior to surgery, romiplostim was administered subcutaneously (70 μg per week for 3 weeks) and eltrombopag was administered orally (25 mg per day for 23 days), as TPO-RA. His platelet count increased to 14.1 × 10⁴/μL. The patient was successfully and safely treated with left hemi-hepatectomy and TPO-RA as preoperative platelet management.

Conclusions

This case suggests that TPO-RA can be effective, and could serve as a new treatment option in the preoperative management of ITP.

Efficacy and safety of thrombopoietin receptor agonists in children with chronic immune thrombocytopenic purpura: meta-analysis

Immune thrombocytopenic purpura (ITP) is an autoimmune disorder presenting with low platelet count <100 × 10⁹/L. The condition affects both adults and children. Thrombopoietin receptor agonists (TPO-RAs) are second-line of therapy that includes Romiplostim and Eltrombopag, which stimulate the production of normally functioning platelets. Although the biological effect of these drugs is well established, there has not been a meta-analysis in children. To estimate the efficacy and safety of Romiplostim and Eltrombopag, we performed a systematic review and meta-analysis in children with chronic ITP. Systematic literature search was conducted in the following database: PubMed, EMBASE, and Cochrane Central Register of Controlled Trials (CENTRAL). Review Manager 5.3 for Windows was used to analyze the data. Five randomized controlled trials with total of 261 pediatric patients from 1-17 years of age were included. The efficacy and safety analysis showed TPO-RA groups were superior over placebo, and there was no difference in adverse event occurrence between TPO-RA (Romiplostim and Eltrombopag) and placebo groups. The efficacy and safety of Eltrombopag did not differ significantly from those of Romiplostim. Both drugs were effective in treatment of children with chronic ITP. Our findings extend the currently available data on ITP treatment and is helpful for pediatric health providers and for the design of future clinical trials.

Eltrombopag For Immune Thrombocytopenic Children in a Single Region

Objective Child patients of chronic thrombocytopenic purpura with severe and resistant thrombocytopenia were evaluated to observe whether their clinical or laboratory states improve by one of the thrombomimetic therapeutic agent called Eltrombopag as in adults in a single center of different country from previous studies. Materials and Methods Nineteen patients with chronic immune thrombocytopenia were treated with Eltrombopag to dose in international guidelines. Results Approximately half (11/19:58%) of the patients benefitted from the treatment with Eltrombopag either by an increase of platelet levels at safe levels with a decrease in the frequency of bleedings which needed rescue treatment. Conclusion Thrombomimetic treatment options have strengthened the clinician's hand where the regular treatment options became insufficient.

Eltrombopag versus romiplostim in treatment of children with persistent or chronic immune thrombocytopenia: a systematic review incorporating an indirect-comparison meta-analysis

In absence of direct comparison, we conducted an indirect-comparison meta-analysis to evaluate the efficacy and safety of thrombopoietin-receptor agonists(TPO-RAs) in treatment of pediatric persistent or chronic immune thrombocytopenia(ITP). PubMed, Embase, Cochrane Library, Clinical Trials.gov, China National Knowledge Infrastructure, and Chinese Biomedical Literature Database were searched from their earliest records to May 2017. Randomized controlled trials comparing the TPO-RAs with placebo in pediatric ITP were included. Outcomes included overall response rate(primary), durable response, overall or clinically significant bleeding, the proportion of patients receiving rescue medication, and safety. Five randomized placebo-controlled studies(N = 261) were analyzed. The overall response[Risk Ratio(RR) 0.57, 95% confidence interval(CI) 0.21–1.56], the incidence of adverse events (RR 0.96, 95%CI 0.66–1.39), durable response(RR 2.48, 95%CI 0.31–19.97), and the proportion of patients receiving rescue treatment(RR 0.73, 95%CI 0.20–2.73) were similar between eltrombopag and romiplostim group. Nevertheless, eltrombopag might have lower risk of overall bleeding(RR 0.43, 95%CI 0.23–0.80) and clinically significant bleeding(RR 0.33, 95%CI 0.12–0.89) than romiplostim. This meta-analysis suggests that eltrombopag might be similar to romiplostim in efficacy and safety, but seems to reduce the risk of bleeding compared to romiplostim. Furthermore, cost of the treatment, comorbidity of patients and drug compliance should also be considered in clinical decision making.

Treatment of Children with Persistent and Chronic Idiopathic Thrombocytopenic Purpura: 4 Infusions of Rituximab and Three 4-Day Cycles of Dexamethasone

OBJECTIVES

To assess initial and long-term outcome of children with persistent/chronic idiopathic thrombocytopenic purpura (ITP) treated with 4 infusions of rituximab and three 4-day cycles of dexamethasone (4R+3Dex) including cohorts with most benefit and/or treatment associated toxicity.

STUDY DESIGN

All pediatric patients with ITP at Weill-Cornell who received 4R+3Dex were included in this retrospective study. Duration was median time from first rituximab infusion to treatment failure. Patient cohort included 33 children ages 1-18 years with persistent/chronic ITP; 19 were female, 10 of whom were adolescents. Every patient had failed more than 1 and usually several ITP treatments.

RESULTS

Children were treated with rituximab, 375 mg/m² weekly for 4 weeks and three 4-day courses of dexamethasone 28 mg/m² (40 mg max). Average age of nonresponders was 7.75 years, and initial responders averaged 12.7 years (P = .0073); 30% maintained continuing response at 60 months or last check-up. Eight of the 10 patients who underwent remission were female with ITP <24 months prior to initiating 4R+3Dex. All responding male patients except 2 relapsed.

CONCLUSIONS

Durable unmaintained ITP remission after 4R+3Dex was seen almost exclusively in female adolescents with <24 months duration of ITP. This provides a new therapeutic paradigm for a subpopulation with hard-to-treat chronic ITP. The pathophysiology of ITP underlying this distinction requires further elucidation.

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.

The Centenary of Immune Thrombocytopenia-Part 2: Revising Diagnostic and Therapeutic Approach

Primary immune thrombocytopenia (ITP) is the most common cause of thrombocytopenia in children and adolescents and can be considered as a paradigmatic model of autoimmune disease. This second part of our review describes the clinical presentation of ITP, the diagnostic approach and overviews the current therapeutic strategies. Interestingly, it suggests an algorithm useful for differential diagnosis, a crucial process to exclude secondary forms of immune thrombocytopenia (IT) and non-immune thrombocytopenia (non-IT), which require a different therapeutic management. Advances in understanding the pathogenesis led to new therapeutic targets, as thrombopoietin receptor agonists, whose role in treatment of ITP will be discussed in this work.

[Clinical study of pulsed high- dose dexamethasone treatment in 38 children with primary immune thrombocytopenic purpura]

目的

探讨大剂量地塞米松(HDD)静脉滴注，对原发免疫性血小板减少症(ITP)患儿的疗效及安全性。

方法

2013年9月至2014年9月38例一线治疗无效的ITP患儿接受HDD治疗。用药方案：地塞米松0.6 mg·kg⁻¹·d⁻¹×4 d(最大剂量40 mg/d)，冲击治疗每疗程间隔28 d，共6个疗程。

结果

①38例患儿中男26例，女12例，中位月龄为54(6~151)个月，中位病程为6(1~72)个月；新诊断ITP 9例，持续性ITP 13例，慢性ITP 16例；治疗前中位PLT为16.3(1.0~30.0)×10⁹/L。②中位随访时间180(90~554)d, 17例(44.7%)获得治疗反应[完全反应(CR)7例(18.4%)，有效(R)10例(26.3%)]，中位起效时间为80.5(23~245)d; 17例获得CR/R患儿中3例失效复发，中位反应持续时间为63(37~67)d; 21例(55.3%)无效(NR)，但其中18例(85.7%)患儿出血症状好转。③用药过程中仅1例患儿出现轻度可逆性不良反应。④CR/R组患儿外周血CD4⁺CD25⁺Foxp3⁺T细胞比例高于NR组[(7.54±1.50)％对(5.69±1.95)%，P=0.049]。单因素分析显示骨髓巨核细胞<300个患儿HDD疗效较好(P=0.049)。

结论

HDD冲击治疗是ITP患儿一种比较理想的二线治疗选择；骨髓巨核细胞计数<300个、CD4⁺CD25⁺Foxp3⁺T细胞比例高的患儿可能更适用于该疗法。

Advances in Diagnosis and Treatments for Immune Thrombocytopenia

Immune thrombocytopenia (ITP) is an acquired hemorrhagic condition characterized by the accelerated clearance of platelets caused by antiplatelet autoantibodies. A platelet count in peripheral blood <100 × 10⁹/L is the most important criterion for the diagnosis of ITP. However, the platelet count is not the sole diagnostic criterion, and the diagnosis of ITP is dependent on additional findings. ITP can be classified into three types, namely, acute, subchronic, and persistent, based on disease duration. Conventional therapy includes corticosteroids, intravenous immunoglobulin, splenectomy, and watch-and-wait. Second-line treatments for ITP include immunosuppressive therapy [eg, anti-CD20 (rituximab)], with international guidelines, including rituximab as a second-line option. The most recently licensed drugs for ITP are the thrombopoietin receptor agonists (TRAs), such as romiplostim and eltrombopag. TRAs are associated with increased platelet counts and reductions in the number of bleeding events. TRAs are usually considered safe, effective treatments for patients with chronic ITP at risk of bleeding after failure of first-line therapies. Due to the high costs of TRAs, however, it is unclear if patients prefer these agents. In addition, some new agents are under development now. This manuscript summarizes the pathophysiology, diagnosis, and treatment of ITP. The goal of all treatment strategies for ITP is to achieve a platelet count that is associated with adequate hemostasis, rather than a normal platelet count. The decision to treat should be based on the bleeding severity, bleeding risk, activity level, likely side effects of treatment, and patient preferences.

A Phase 3, Randomized, Double-Blind, Placebo-Controlled Study to Determine the Effect of Romiplostim on Health-Related Quality of Life in Children with Primary Immune Thrombocytopenia and Associated Burden in Their Parents

BACKGROUND

Chronic immune thrombocytopenia (ITP) in children can negatively impact their health-related quality of life (HRQoL) and impose a burden on their parents. This study sought to examine the effect of romiplostim on HRQoL and parental burden in children with primary ITP.

PROCEDURE

This was a phase 3, randomized, double-blind, placebo-controlled study. Children aged <18 years with ITP ≥6 months were randomly assigned to receive romiplostim or placebo for 24 weeks. The Kids' ITP Tool (KIT) was used to measure HRQoL and was administered to patients and/or their parents at baseline and weeks 8, 16, and 25. Mean KIT scores at each assessment and mean changes in KIT scores from baseline were calculated overall by treatment group and platelet response status. Psychometric properties of the KIT were evaluated and the minimally important difference (MID) was estimated for different KIT versions.

RESULTS

Sixty-two patients (42 romiplostim and 20 placebo) were enrolled. Changes in KIT scores by treatment group showed numerically greater and more often statistically significant improvements from baseline to each assessment for children receiving romiplostim versus placebo. Mixed-effects analysis demonstrated statistically significantly greater reduction in parental burden from baseline in the romiplostim group versus placebo. Ranges for the MID were estimated as 9-13 points for the Child Self-Report version and 11-13 points for the Parent Impact version.

CONCLUSIONS

The treatment with romiplostim may be associated with improved HRQoL in children with primary ITP and reduced burden to their parents.

The Centenary of Immune Thrombocytopenia - Part 1: Revising Nomenclature and Pathogenesis

The natural history of the immune thrombocytopenia (ITP) is interesting and intriguing because it traces different steps underlying autoimmune diseases. The review points out the main steps that have accompanied the stages of its history and the consequential changes related to its terminology. ITP is an autoimmune disease resulting from platelet antibody-mediated destruction and impaired megakaryocyte and platelet production. However, research advances highlight that a complex dysregulation of the immune system is involved in the pathogenesis of this condition. The review examines the role of the multiple immune components involved in the autoimmunity process, focusing on the more recent mechanisms, which could be new promising therapeutic targets for ITP patients.