Multicentre, randomised phase III study of the efficacy and safety of eltrombopag in Chinese patients with chronic immune thrombocytopenia

Platelet Disorders and Medication Strategies

Platelets are among the most abundant cells in the body and play important roles in coagulation and immunity. Platelets are formed when hematopoietic stem cells proliferate and differentiate into megakaryocytes via the regulation of various cytokines. After the megakaryocytes mature in the bone marrow cavity, proplatelets are released into the blood circulation where they eventually remodel into mature platelets. Given that the production and functions of platelets involve the regulation of many factors-such as hematopoietic stem cells, the hematopoietic microenvironment, and cytokines-the causes and mechanisms of platelet-related diseases are diverse, often involving platelet production, clearance, and distribution. In this review, we examined the regulation of platelet production and summarized common disorders affecting platelet quantity, namely, thrombocytopenia and thrombocytosis. In addition, we reviewed previous clinical studies and summarized the medication strategies commonly used for the treatment of different platelet disorders in different clinical scenarios.

Efficacy and safety and analysis of thrombopoietin receptor agonists for the treatment of immune thrombocytopenia in adults: analysis of a systematic review and network meta-analysis of randomized controlled trials and results of real-world safety data

This study aimed to compare the efficacy and safety of thrombopoietin receptor agonists (TPO-RA) in the treatment of immune thrombocytopenia (ITP) in adults. A systematic review was conducted using network meta-analysis and a disproportionality analysis based on the FDA Adverse Event Reporting System (FAERS) database to evaluate hemorrhagic and thrombotic events of clinical concern. Our network meta-analysis included 14 randomized controlled trials (RCTs) involving 1,454 patients. The results indicated that, in terms of efficacy, romiplostim [odds ratio (OR), 0.04; 95% confidence interval (CI), 0 to 0.68] was the most effective, followed by avatrombopag, hetrombopag, and eltrombopag. Regarding safety, there were no significant differences in the safety profiles of the four TPO-RA compared to placebo. According to the surface under the cumulative ranking curve (SUCRA), avatrombopag exhibited the highest safety ranking at 23.8%. Within the FAERS database, we identified 982 cases of TPO-RA-related hemorrhagic and thrombotic events. The highest number of preferred terms (PTs) associated with romiplostim was 26, followed by 18 for eltrombopag and 7 for avatrombopag. The findings of this study suggest that romiplostim exhibits significant efficacy, whereas avatrombopag presents a superior safety profile. In the context of clinical second-line treatment, the selection of the most suitable TPO-RA should be guided by the specific circumstances of each patient. Systematic review registration: https://www.crd.york.ac.uk/PROSPERO/#recordDetails.

Real-world evidence of avatrombopag for the treatment of immune thrombocytopenia intolerant or ineffective to eltrombopag/hetrombopag

Due to the limited real-world research on the application of avatrombopag (AVA) for immune thrombocytopenia (ITP) in China, we evaluated the effectiveness and safety of AVA in clinical practice. We included 121 adult ITP patients treated with AVA across three medical centres. Based on the reasons for choosing AVA, these patients were divided into eltrombopag (ELT)/hetrombopag (HET) intolerance group (IG), and ELT/HET unresponsive group (UG). Compared with UG, more patients in IG had a history of liver disease and received fewer treatments before AVA. Amongst all patients, 83% had platelet response (≥30 × 109/L) after AVA and 62% achieved complete response (≥100 × 109/L, CR). Sixty-two percent in IG and 56% in UG were able to discontinue more than one concomitant ITP medication. A total of 17 patients underwent multiple switches of thrombopoietin receptor agonists (TPO-RAs), resulting in an 88% platelet response rate. Sixty-three patients discontinued AVA, 27% were due to unaffordability. AVA was well tolerated in most patients. In the ITP population, AVA proved effective and safe, particularly in patients intolerant or unresponsive to ELT/HET. Patients benefited from TPO-RAs switches, particularly those undergoing multiple switches. However, many patients struggled with the long-term financial burden of AVA.

The effect of hetrombopag combined with conventional treatment on immune function and quality of life in patients with severe aplastic anemia

This study aimed to investigate the effect of hetrombopag combined with conventional treatment on immune function in patients with severe aplastic anemia (SAA). Patients were categorized into the control group (n = 50, receiving conventional treatment only) and experimental group (n = 50, receiving hetrombopag combined with conventional treatment). Before treatment and at weeks 18, 24, and 52 after treatment, the two groups were compared in routine blood test indicators, natural killer (NK) cell activity, and peripheral blood inflammatory factor levels. The overall remission rate and incidence of adverse events were also compared between the two groups. Outpatient or telephone follow-up was performed before treatment and at weeks 18, 24, and 52 after treatment to observe patients' immune function, treatment outcome, quality of life, and adverse events. Hemoglobin (Hb), and platelet count (PLT) (P < 0.05), and a rise in NK cell activity (P < 0.05). Interleukin (IL-10) levels were significantly higher, while IL-6 levels were significantly lower in the experimental group compared to the control group (P < 0.05). After receiving the treatment, all scores of SF-36 domains in both groups were higher than before treatment, particularly with higher scores in the experimental group (P < 0.05). Hetrombopag combined with conventional treatment improved the immune function and hematopoiesis of patients with SAA.

Extension of impurity profiling on eltrombopag olamine to in-silico predictions: An effort to exploit correlated forced degradation products and known drug-related substances in drug discovery

The recent pandemic has highlighted the impact of diseases on global health and the economy. The rapid discovery of new hit molecules remains a tough challenge. Pharmaceutical impurity profiling can be linked to drug discovery through the identification of new hits from compounds identified during the analytical profiling. The present study demonstrates this linkage through the extension of the impurity (forced degradation) profiling of eltrombopag (ELT) olamine, a thrombopoietin (TPO) receptor agonist. The drug was exposed to standard degradation and the degradation products were primarily resolved and identified by UPLC-ESI-MS. This led to the identification of five forced degradation products (FDP). Thirty-three other known related substances (RS) of ELT, identified in the literature, were also considered. Molecular similarity checks were performed using Tanimoto/Jaccard's similarity searches. A set of structurally and topologically similar molecules, including ELT and 15 RS, was established and subjected to in-silico toxicity-, absorption-, distribution-, metabolism-, and elimination (ADME) predictions. The RS, predicted with similar or lower toxicity than ELT and a comparable ADME profile, were subjected to molecular docking to trace changes in TPO receptor affinity. The results indicated that five RS had a high Jaccard's similarity with ELT and higher or comparable docking scores. These compounds, along with few other impurities were predicted to have lower toxicity, better or comparable absorption, distribution, metabolism, and also a better excretion profile than ELT. This justifies their entry as potential novel TPO receptor agonists in drug discovery.

The immune thrombocytopenia paradox: Should we be concerned about thrombosis in ITP?

Despite the predisposition to bleeding, patients with immune thrombocytopenia (ITP) may also have an increased risk of arterial and venous thrombosis, which can contribute to significant morbidity. The risk of thrombosis increases with age and the presence of cardiovascular risk factors. This narrative review explores the multifactorial nature of thrombosis in ITP, focusing on new pathological mechanisms, emerging evidence on the association between established treatments and thrombotic risk, the role of novel treatment approaches, and the challenges in assessing the balance between bleeding and thrombosis in ITP. The review also explores the challenges in managing acute thrombotic events in ITP, since the platelet count does not always reliably predict either the risk of bleeding or thrombosis and antithrombotic strategies lack specific guidelines for ITP. Notably, second-line therapeutic options, such as splenectomy and thrombopoietin receptor agonists (TPO-RAs), exhibit an increased risk of thrombosis especially in older individuals or those with multiple thrombotic risk factors or previous thrombosis, emphasizing the importance of careful risk assessment before treatment selection. In this context, it is important to consider second-line therapies such as rituximab and other immunosuppressive agents, dapsone and fostamatinib, which are not associated with increased thrombotic risk. In particular, fostamatinib, an oral spleen tyrosine kinase inhibitor, has promisingly low thrombotic risk. During the current era of the emergence of several novel ITP therapies that do not pose additional risks for thrombosis, it is critical to outline evidence-based strategies for the prevention and treatment of thrombosis in ITP patients.

Efficacy and safety of avatrombopag in Chinese children with persistent and chronic primary immune thrombocytopenia: A multicentre observational retrospective study in China

Avatrombopag (AVA) is a novel thrombopoietin receptor agonist (TPO-RA) that has been recently approved as a second-line therapy for immune thrombocytopenia (ITP) in adults; however, its safety and efficacy data in children are lacking. Here, we demonstrated the efficacy and safety of AVA as second-line therapy in children with ITP. A multicentre, retrospective, observational study was conducted in children with persistent or chronic ITP who did not respond to or relapsed from previous treatment and were treated with AVA for at least 12 weeks between August 2020 and December 2022. The outcomes were the responses (defined as achieving a platelet count ≥30 × 109/L, twofold increase in platelet count from baseline and absence of bleeding), including rapid response within 4 weeks, sustained response at weeks 12 and 24, bleeding control and adverse events (AEs). Thirty-four (18 males) patients with a mean age of 6.3 (range: 1.9-15.3) years were enrolled. The median number of previous treatment types was four (range: 1-6), and 41.2% patients switched from other TPO-RAs. Within 4 weeks, overall response (OR) was achieved in 79.4% patients and complete response (CR, defined as a platelet count ≥100 × 109/L and the absence of bleeding) in 67.7% patients with a median response time of 7 (range: 1-27) days. At 12 weeks, OR was achieved in 88.2%, CR in 76.5% and sustained response in 44% of patients. At 24 weeks, 22/34 (64.7%) patients who achieved a response and were followed up for 24 weeks were evaluated; 12/22 (54.55%) achieved a sustained response. During AVA therapy, median platelet counts increased by week 1 and were maintained throughout the treatment period. The proportion of patients with grade 1-3 bleeding decreased from 52.95% at baseline to 2.94% at 12 weeks, while concomitant ITP medications decreased from 36.47% at baseline to 8.82% at 12 weeks, with only 9 (26.47%) patients receiving rescue therapy 23 times within 12 weeks. There were 61.8% patients with 59 AEs: 29.8% with Common Terminology Criteria for Adverse Events grade 1 and the rest with grade 2. These findings show that AVA could achieve a rapid and sustained response in children with persistent or chronic ITP as a second-line treatment, with good clinical bleeding control and reduction of concomitant ITP therapy, without significant AEs.

A practical guide to the management of immune thrombocytopenia co-existing with acute coronary syndrome

Introduction

Immune thrombocytopenia (ITP) management with co-existing acute coronary syndrome (ACS) remains challenging as it requires a clinically relevant balance between the risk and outcomes of thrombosis and the risk of bleeding. However, the literature evaluating the treatment approaches in this high-risk population is scarce.

Methods and Results

In this review, we aimed to summarize the available literature on the safety of ITP first- and second-line therapies to provide a practical guide on the management of ITP co-existing with ACS. We recommend holding antithrombotic therapy, including antiplatelet agents and anticoagulation, in severe thrombocytopenia with a platelet count < 30 × 109/L and using a single antiplatelet agent when the platelet count falls between 30 and 50 × 109/L. We provide a stepwise approach according to platelet count and response to initial therapy, starting with corticosteroids, with or without intravenous immunoglobulin (IVIG) with a dose limit of 35 g, followed by thrombopoietin receptor agonists (TPO-RAs) to a target platelet count of 200 × 109/L and then rituximab.

Conclusion

Our review may serve as a practical guide for clinicians in the management of ITP co-existing with ACS.

Thrombopoietin receptor agonists use and risk of thrombotic events in patients with immune thrombocytopenic purpura: A systematic review and meta‑analysis of randomized controlled trials

Thrombopoietin receptor agonists (TPO-RAs) have a role in second-line immune thrombocytopenic purpura (ITP) treatment, binding to and activating thrombopoietin receptors on megakaryocyte membranes in the bone marrow. This promotes megakaryocyte maturation and increases platelet production. Despite a 2-6% incidence of thrombotic events during TPO-RA treatment, it remains uncertain whether TPO-RAs elevate thrombosis rates. A comprehensive search of electronic databases was conducted using the relevant search criteria. To assess the risk of bias, the included studies were assessed using the revised Cochrane Risk of Bias Assessment Tool 2.0, and a meta-analysis was performed using RevMan 5.4.1. A total of 1,698 patients with ITP were included from randomized controlled trials (RCTs). There were 26 thromboembolic events in the TPO-RAs group and 4 in the control group. However, there was no significant difference in the incidence of thrombotic events between the two groups [odds ratio (OR)=1.76, 95% confidence interval (CI): 0.78-4.00, P=0.18], even if the duration of treatment was >12 weeks (OR=2.46, 95% CI: 0.81-7.43, P=0.11). Subgroup analysis showed that none of the four drugs significantly increased the incidence of thrombotic events (romiplostim: OR=0.92, 95% CI: 0.14-6.13, P=0.93; eltrombopag: OR=2.32, 95% CI: 0.64-8.47, P=0.20; avatrombopag: OR=4.15, 95% CI: 0.20-85.23, P=0.36; and hetrombopag: OR=0.76, 95% CI: 0.03-18.76, P=0.87). There was also no significant difference in the results of the double-blinded placebo-controlled RCTs (OR=1.21, 95% CI: 0.41-3.58, P=0.73). Compared to patients with ITP who did not receive TPO-RA treatment, those receiving TPO-RA treatment did not exhibit a significantly increased risk of thrombotic events.

Spotlight on eltrombopag concentration in pediatric immune thrombocytopenia: A single-center observational study in China

Importance

Eltrombopag has been recommended for pediatric immune thrombocytopenia (ITP). Response and adverse drug reactions (ADRs) varied widely between individuals, even at the same dose of eltrombopag. The appropriate eltrombopag concentration in ITP has not been reported.

Objective

This study aims to explore the appropriate eltrombopag concentration in pediatric ITP.

Methods

This was a single-center, prospective cohort study. Children diagnosed with refractory persistent/chronic ITP and platelet count < 30×109/L were treated with eltrombopag and followed up for at least 2 months. Concentration was detected by high-performance liquid chromatography-mass spectrometry at least 2 weeks after eltrombopag. The clinical characteristics-concentration, concentration-response, and concentration-ADRs were analyzed.

Results

A total of 30 patients were enrolled, comprising 13 males and 17 females, with a median age of 72 (45‒94) months. The median dose and concentration were 1.39 (1.09‒1.56) mg/kg and 2.70 (2.25‒4.13) mg/L, respectively. Of the enrolled patients, 14 responded to treatment, whereas 16 did not. Additionally, five experienced adverse drug reactions. No linear correlation was observed between eltrombopag concentration and clinical characteristics. The concentration was lower in the response group than in the nonresponse group, but there was no significant difference (t = 0.755, P = 0.457). Patients who experienced ADRs had a higher concentration than those without ADRs (t = 2.538, P = 0.017). The area under the receiver operating characteristic curve of ADRs was 0.78 (95% confidence interval: 0.56‒1.00). Youden's index identified the cutoff point as 4.33 mg/L, with a sensitivity of 88% and a specificity of 60%. Logistic regression analysis demonstrated that a higher platelet count before eltrombopag predicted a favorable response.

Interpretation

Eltrombopag proves efficacious and well-tolerated for treating pediatric ITP. However, prolonged and high-dose administration may increase the likelihood of ADRs. Thus, examining the appropriate eltrombopag concentration assists in directing individualized management of pediatric ITP.

Efficacy and safety of eltrombopag in Chinese patients with refractory or relapsed severe aplastic anemia

For patients with severe aplastic anemia (SAA) in China who have had an insufficient response to the first-line treatment with hematopoietic stem cell transplantation or immunosuppressive therapy, there is no established standard of care other than transfusion support and treatment of infections. This non-randomized, open-label, Phase II multicenter trial investigated the efficacy and safety of eltrombopag in 20 adult Chinese patients with refractory or relapsed (r/r) SAA. The primary endpoint of hematologic response rate at Week 26, defined as the proportion of patients who met any of the International Working Group criteria, was observed in 70% (14/20) of patients, with more than 50% of these having at least bi-lineage response. Reduced red blood cell and platelet transfusion at Week 26 were observed in 57% (8/14) and 80% (8/10) of patients, respectively. Safety findings were consistent with the established safety profile of eltrombopag and no new safety signals were reported. None of the patients discontinued eltrombopag because of safety concerns. Although the sample size was small, this is the first prospective study to show that eltrombopag is efficacious and has a favorable safety profile in a Chinese patient population with r/r SAA.Trial registration: This trial is registered on ClinicalTrials.gov (NCT03988608); registered 17 June 2019.

Avatrombopag for adult chronic primary immune thrombocytopenia: a randomized phase 3 trial in China

Background

Immune thrombocytopenia (ITP) is an autoimmune disorder with decreased platelet counts and increased bleeding risk.

Objectives

To evaluate the efficacy and safety of avatrombopag, a second-generation oral thrombopoietin receptor agonist, for the treatment of Chinese patients with chronic primary ITP.

Methods

This multicenter, randomized, double-blind, placebo-controlled phase 3 study (CTR20210431) consisted of a 6-week double-blind core treatment phase followed by a 20-week, open-label extension phase. Chinese adults with chronic primary ITP for at least 12 months and a platelet count <30 × 109/L were randomized (2:1) to receive avatrombopag (initial dose of 20 mg/day) or matched placebo. The primary endpoint was the proportion of subjects with a platelet count ≥50 × 109/L at week 6 of the core treatment phase in absence of rescue therapy.

Results

In total, 74 patients were randomized (avatrombopag: N = 48; placebo: N = 26) between March 5, 2021, and August 6, 2021; all of whom entered the extension phase (72 received avatrombopag up to 26 weeks). At week 6 of the core study, the platelet response (≥50 x 109/L) rate was significantly higher in the avatrombopag group (77.1%; 95% CI, 62.7, 88.0) vs placebo (7.7%; 95% CI, 1.0, 25.1); the treatment difference was 69.4% (95% CI, 56.2, 86.3; P < .0001). During the 6-week core study, treatment-emergent adverse events were reported in 41 (85.4%) and 20 (76.9%) patients in the avatrombopag and placebo groups, respectively. The most common avatrombopag-related treatment-emergent adverse events were upper respiratory tract infection (14/48 [29.2%]), increased platelet count (13/48 [27.1%]) and headache (7/48 [14.6%]).

Conclusion

Avatrombopag was efficacious and generally well tolerated in Chinese patients with chronic primary ITP, with comparable efficacy and safety to previous reports in Western patients.

Safety of non‑peptide thrombopoietin receptor agonists in patients with immune thrombocytopenia: A systematic review and meta‑analysis of short‑term double‑blind randomized clinical trials

The aim of the present study was to analyze the safety of non-peptide thrombopoietin receptor agonists (TPO-RAs) for immune thrombocytopenia (ITP) treatment. All studies reporting adverse events (AEs) in relation to ITP treatment with eltrombopag, avatrombopag, and hetrombopag were retrieved from PubMed, Web of Science, and Embase databases. RevMan 5.4.1 was used for meta-analysis, heterogeneity and bias analyses. A total of 1,078 patients from seven eligible studies were enrolled. In the enrolled clinical trials, the double-blind period was between 6 weeks and 6 months. The results revealed that the chances of any AEs [relative risk (RR)=1.16; 95% confidence interval (CI), 0.90-1.51; I²=78%; P=0.26], grade 3/4 AEs (RR=1.07; 95% CI, 0.63-1.80; I²=0%; P=0.81), elevated transaminase levels (RR=1.09; 95% CI, 0.68-1.74; I²=0%; P=0.72), thrombosis (RR=1.92; 95% CI, 0.55-6.66; I²=0%; P=0.31) and cataracts (RR=0.83; 95% CI, 0.38-1.83; I²=0%; P=0.65) were not significantly higher in patients with ITP that received non-peptide TPO-RAs compared with patients with ITP treated with a placebo. The present study indicated that non-peptide TPO-RAs were relatively safe for patients with ITP, at least within 6 months of administration.

Risk of thrombotic events in immune thrombocytopenia patients treated with thrombopoietic agents: a systematic review and meta-analysis

BACKGROUND

Immune thrombocytopenia (ITP), which is a well-known hemorrhagic disorder characterized by low platelet counts, has been shown to be associated with the risk of thrombosis. Thrombopoietic agents (TAs) are extensively used as second-line treatments for ITP, effectively reducing the risk of hemorrhage. However, thrombosis, a potential adverse effect of TAs, raises clinical challenges.

METHODS

The MEDLINE(PubMed), Embase, and the Cochrane Library databases were systematically searched for relevant studies, including both single-arm trials and randomized controlled trials (RCTs), without language restrictions.

RESULTS

A total of 17 RCTs comprising 2,105 patients and 29 single-arm trials comprising 3,227 patients were included. In the single-arm meta-analysis, the pooled rate of overall thrombotic events in ITP patients receiving TAs was 2.2% (95% CI 1.0% - 3.7%). In RCTs, a higher incidence of thrombosis (33/1425 vs. 4/680) and higher risk ratios (RR) of overall, arterial, and venous thrombotic events (1.73, 95% CI [0.88, 3.39], P = 0.113; RR 1.98, 95% CI [0.80, 4.92], P = 0.141; RR 1.06, 95% CI [0.46, 2.41], P = 0.895, respectively) were observed in the TAs group than in the control group, although the differences were not significant. Subgroup analysis demonstrated that hetrombopag was the only TA with no increased thrombotic risk (rate 0.3% 95% CI [0.0 - 1.5%]; RR 0.76, 95% CI [0.03, 18.41], P = 0.864) compared to eltrombopag, avatrombopag, romiplostim, and rhTPO. Subgroup analyses also revealed that ITP patients with advanced age (3.7% vs. 1.3%, P = 0.132) or with a thrombotic history (3.0% vs. 1.4%, P = 0.257), and patients who received TAs therapy for a long duration (4.7% vs. 0.1%, P < 0.001) had an increased risk of thrombosis.

CONCLUSION

Our findings suggest ITP patients treated with TAs have a nonsignificantly higher risk of overall, arterial, and venous thrombotic events. Furthermore, hetrombopag is the recommended TA to avoid thrombophilia. Patients receiving long-term TAs, as well as elderly ITP patients or those with a history of thrombosis, face an increased thrombotic risk. In general, clinicians should consider potential thrombotic risks, address underlying risk factors, and ensure ongoing monitoring and follow-up when treating ITP patients with TAs.

Eltrombopag for Adults and Children with Immune-Refractory Thrombocytopenic Purpura: A Systematic Review

Eltrombopag is an agonist that binds to the membrane-bound domain of the thrombopoietin receptor used in immune thrombocytopenic purpura (ITP). We conducted a meta-analysis of randomized controlled trials to assess the efficacy and safety of eltrombopag in adults and children with refractory ITP. Adults who received eltrombopag had a significantly better platelet response (relative risk [RR], 3.65; 95% confidence interval [CI], 2.39-5.55), but there were no differences in the incidence of bleeding (RR, 0.8; 95% CI, 0.52-1.22) and adverse effects (RR, 0.99; 95% CI, 0.55-1.78) compared with the placebo. In children, there was no difference between eltrombopag and placebo for a platelet response >50,000/mm3 (RR, 3.93; 95% CI, 0.56-27.79) and the number of adverse events (RR, 0.99; 95% CI, 0.25-1.49); however, a lower incidence of bleeding was observed (RR, 0.47; 95% CI, 0.27-0.83). Treatment with eltrombopag protected adults and children from severe disease and death.

[Maintenance of efficacy and its predictors after discontinuation of eltrombopag in adults with primary immune thrombocytopenia]

Objective: To determine the efficacy of eltrombopag for primary immune thrombocytopenia (ITP) in adults and the predictive factors for treatment-free response (TFR) . Methods: Clinical data of adults with ITP who received eltrombopag from June 14, 2013 to May 31, 2021 in the Hematology Department of Ruijin Hospital affiliated with Shanghai Jiao Tong University Medical College were retrospectively analyzed. The initial dose of eltrombopag was 25 mg/d, and the maximum dose was 75 mg/d; the dose was adjusted to maintain the platelet count to within 50-150×10(9)/L. Treatment was discontinued according either to the protocol, on the patient's wishes or doctor's judgment (prescription medication), or based on clinical trials. The efficacy of eltrombopag and factors for TFR among patients who achieved complete response and those who discontinued treatment were analyzed. Results: Overall, 106 patients with ITP (33 men and 73 women) were included in the study. The median age of patients was 50 (18-89) years. There were 2, 10, and 94 cases of newly diagnosed, persistent, and chronic ITP, respectively. The complete response rate was 44.3% (47/106), the response rate was 34.0% (36/106), and the overall response rate was 78.3% (83/106). Meanwhile, 83 patients who responded to treatment discontinued eltrombopag; of these, 81 patients were evaluated. Additionally, 17 patients (21.0%) achieved TFR. The median follow-up duration of patients who achieved TFR was 126 (30-170) weeks. The recurrence rate was 17.6% (3/17), and the relapse-free survival rate was 76.5%. The results of univariate analysis revealed that non-recurrence after discontinuation of other treatments for ITP (P=0.001), and platelet count and eltrombopag dose of ≥100×10(9)/L (P=0.007) and ≤25 mg/d (P=0.031), respectively, upon discontinuation of eltrombopag were predictors of TFR; these effects were attributed to prolonged effective duration of eltrombopag. Multivariate analysis showed that there was a correlation between non-recurrence and prolonged effective duration after discontinuation of other treatments for ITP (P=0.002) . Conclusion: Eltrombopag is effective for patients with ITP as it can result in TFR. Predictors for TFR include non-recurrence after discontinuation of concomitant ITP treatment, and platelet count and eltrombopag dose of ≥100 × 10(9)/L and ≤25 mg/d upon discontinuation of treatment, respectively.

Relationship between CYP2C8, UGT1A1, and ABCG2 gene polymorphisms and the exposure, efficacy, and toxicity of eltrombopag in the treatment of refractory aplastic anemia

PURPOSE

Eltrombopag (ELT) is an effective drug for relapsed/refractory aplastic anemia (AA). Our previous study showed that ELT concentration was correlated with the effects of ELT. However, the factors affecting ELT concentration in patients with relapsed/refractory AA were not clarified. Therefore, we aimed to evaluate correlations between drug disposition-related gene polymorphisms and the concentration, efficacy, and toxicity of ELT.

METHODS

Forty-five patients who underwent ELT administration from January 2018 to January 2019 at Peking Union Medical Colleague Hospital (PUMCH) were included. The corresponding clinical information was also collected. ELT plasma concentrations were detected by high-performance liquid chromatography-mass spectrometry (HPLC/MS). CYP2C8, (UGT)1A1, and ABCG21 were genotyped by polymerase chain reaction (PCR). The influence of gene polymorphisms on the plasma concentration, efficacy, and toxicity of ELT was analyzed.

RESULTS

The mean dose required to obtain the optimal effects was significantly lower in the UGT1A1*6 variant carriers than in the UGT1A1*6 WT carriers. There was a significant correlation between the (UGT)1A1*6 polymorphism and higher ELT plasma concentrations (> 11.2 μg/mL). By logistic regression analysis, the efficacy of ELT was related to plasma concentration and a combined genotype of (UGT)1A1*6 and ABCG2. There were no significant associations between genotypes and adverse drug reactions (ADRs) or ELT concentrations and ADRs.

CONCLUSION

UGT1A1*6 is a predictor of the ELT plasma concentration and may help to determine the initial therapeutic dose in relapsed/refractory AA patients. Both drug exposure and patient genotype should be considered for better responses to ELT.

Thrombopoietin receptor agonist discontinuation rates and reasons among patients with immune thrombocytopenia: a study of administrative claims linked with medical chart review

Administrative claims provide a rich data source for retrospective studies of real-world clinical practice, yet some important data may be inconsistent or unavailable. This study explored factors influencing discontinuation of thrombopoietin receptor agonists (TPO-RAs) among patients with immune thrombocytopenia (ITP), by adding medical chart abstraction for additional details. Adult (≥ 18 years) patients with continuous commercial or Medicare Advantage with Part D health insurance coverage were included. Inclusion criteria were ≥ 1 claim for eltrombopag or romiplostim and ≥ 2 diagnoses of ITP between December 31, 2017, and January 1, 2020. Providers were asked to provide access to medical charts for abstraction. The analyses included only patients who discontinued TPO-RA and described patient characteristics, treatment patterns, platelet values, and reasons for discontinuation. Among 207 ITP patients treated with a TPO-RA, 137 (66%) discontinued treatment during the observation period. The mean TPO-RA treatment duration was 185 days. Mean platelet count at the time of discontinuation was 197 × 10⁹/L. The most common reason for discontinuation was improvement of the patient's condition (42%). Other reasons included worsening of ITP/lack of response (12%), adverse events (12%), and cost-related or social reasons (23%). No reason was reported for 10%. Notably 26% of patients who discontinued remained off all ITP therapy for the remainder of the study, with a mean treatment-free period of 262 days. These results emphasize that some patients with ITP are able to discontinue TPO-RA therapy and achieve durable treatment-free periods.

Management of immune thrombocytopenia: 2022 update of Korean experts recommendations

Despite the availability of therapies to treat patients with immune thrombocytopenia (ITP), there is currently little data from randomized trials to assist clinicians in managing patients. The evidence-based guidelines of the Korean Society of Hematology Aplastic Anemia Working Party (KSHAAWP) are intended to support patients and physicians in the management of ITP. Experts from the KSHAAWP discussed and described this guideline according to the current treatment situation for ITP in Korea and finalized the guidelines. The expert panel recommended the management of ITP in adult and pediatric patients with newly diagnosed, persistent, and chronic disease refractory to first-line therapy with minor bleeding. Management approaches include observation and administration of corticosteroids, intravenous immunoglobulin, anti-D immunoglobulin, and thrombopoietin receptor agonists. Currently, evidence supporting strong recommendations for various management approaches is lacking. Therefore, a large focus was placed on shared decision-making, especially regarding second-line treatment.

Dose tapering to withdrawal stage and long-term efficacy and safety of hetrombopag for the treatment of immune thrombocytopenia: Results from an open-label extension study

BACKGROUND

The efficacy of hetrombopag in Chinese patients with immune thrombocytopenia (ITP) has been demonstrated in a randomized, double-blind, placebo-controlled, multicenter, phase III trial (NCT03222843).

OBJECTIVE

This study aimed to report comprehensive data on a ≤6-week dose tapering to withdrawal (Stage 3) and an additional 24-week long-term extension period (Stage 4) in this phase III trial.

PATIENTS/METHODS

Patients who fulfilled the screening criteria were eligible to enter Stage 3 or 4. During Stage 3, hetrombopag was gradually tapered to withdrawal. During Stage 4, hetrombopag treatment was initiated at 2.5, 3.75, 5, or 7.5 mg once daily. The efficacy endpoints during Stage 3 or 4 and the safety profile during the entire treatment period were reported.

RESULTS

Among 194 patients who entered Stage 3, 171 (88.1%) relapsed. The median time to the first relapse since the start of Stage 3 was 15.0 days (95% CI, 14.0-16.0). In Stage 4, 144 (42.5%) patients responded at ≥75% of their assessments and 254 (74.9%) patients achieved platelet count ≥30 × 109 /L at least once, which was at least twice their baseline platelet count in the hetrombopag group (n = 339). The most common adverse events were upper respiratory tract infection (53.1%), thrombocytopenia (27.1%), and urinary tract infection (21.2%) in the hetrombopag group.

CONCLUSION

The majority of patients who experienced dose tapering to withdrawal experienced a relapse. Long-term treatment with hetrombopag was effective in increasing and maintaining platelet count within the desired range in Chinese adults with ITP. Hetrombopag was well tolerated.

Clinical Trial Diversity: An Opportunity for Improved Insight into the Determinants of Variability in Drug Response

Although the number of countries participating in pivotal trials submitted to enable drug registration has nearly doubled over the past 25 years, there has not been a substantial increase in the diversity of clinical trial populations. In parallel, our understanding of factors that influence medicine response and variability has continued to evolve. The notion of intrinsic and extrinsic sources of variability has been embedded into different regulatory guidelines, including the recent guideline on the importance of enhancing the diversity of clinical trial populations.

In addition to presenting the clinical and scientific reasons for ensuring that clinical trial populations represent the demographics of patient populations, this overview outlines the efforts of regulatory agencies, patient advocacy groups and clinical researchers to attain this goal through strategies to meet representation in recruitment targets and broaden eligibility criteria. Despite these efforts, challenges to participation in clinical trials remain, and certain groups continue to be underrepresented in development programmes. These challenges are amplified when the representativeness of specific groups may vary across countries and regions in a global clinical programme.

Whilst enhanced trial diversity is a critical step towards ensuring that results will be representative of patient populations, a concerted effort is required to characterise further the factors influencing interindividual and regional differences in response for global populations. Quantitative clinical pharmacology principles should be applied to allow extrapolation of data across groups or regions as well as provide insight into the effect of patient‐specific characteristics on a medicine's dose rationale and efficacy and safety profiles.

Repurposing Eltrombopag as an Antimicrobial Agent Against Methicillin-Resistant Staphylococcus aureus

Because of the excessive use of antibiotics, methicillin-resistant Staphylococcus aureus (MRSA) has become prevalent worldwide. Moreover, the formation of S. aureus biofilms often cause persistence and relapse of infections. Thus, the discovery of antibiotics with excellent antimicrobial and anti-biofilm activities is urgently needed. In the present study, eltrombopag (EP), a classic thrombopoietin receptor agonist, exhibited potential antimicrobial activity against S. aureus and its biofilms. Through our mechanistic studies, EP was found to interfere with proton motive force in S. aureus. The in vivo anti-infective efficacy of EP was further confirmed in the wound infection model, thigh infection model and peritonitis model by MRSA infection. In addition, the cytotoxicity of EP against mammalian cells and the in vivo toxicity of EP in animal models were not observed at the tested concentrations. Collectively, these results indicate that EP could be considered a potential novel antimicrobial agent against recalcitrant infections caused by MRSA.

Risk of thrombosis with thrombopoietin receptor agonists for ITP patients: a systematic review and meta-analysis

One possible side effect of thrombopoietin receptor agonists in immune thrombocytopenia is thrombosis. Our aim is to systematically review whether patients with ITP that were treated with a TPO-RA have an increased risk for thrombosis as compared to ITP patients without TPO-RA. Patients in the intervention group were required to receive TPO-RA therapy. The primary outcome was the incidence of thromboembolic events. Eleven studies were included in the pooled analysis. More thromboembolic events were noted in the TPO-RA group than in the control group: 25 compared to 4. Ten out of 11 studies showed a relative risk greater than 1. However, none of these individual risk ratios was statistically significant. The meta-analysis showed a RR of 1.82 [95% CI 0.78-4.24]. Our findings indicate there is a non-significant higher chance of thrombosis in ITP patients with TPO-RA treatments versus ITP patients without TPO-RA treatment.

The structure, function, and clinical use of the thrombopoietin receptor agonist avatrombopag

Thrombopoietin regulates platelet production through activation of the thrombopoietin receptor (TPO-R). TPO-R agonists (TPO-RAs) are available to treat thrombocytopenia in chronic immune thrombocytopenia (ITP), chronic liver disease (CLD) patients who are undergoing a procedure, severe aplastic anemia (SAA), and hepatitis C virus (HCV) infection. There are four TPO-RAs approved in the US and Europe: romiplostim (ITP), eltrombopag (ITP, SAA, HCV), avatrombopag (ITP, CLD), and lusutrombopag (CLD). It is important to understand pharmacological characteristics of these agents when evaluating treatment options. Avatrombopag interacts with the transmembrane domain of the TPO-RA and does not compete with endogenous thrombopoietin for TPO-R binding. Structural differences between avatrombopag and other TPO-RAs may impart differential downstream effects on cell signaling pathways, potentially resulting in clinically relevant differences in outcome. Avatrombopag has a favorable pharmacological profile with similar exposure in Japanese, Chinese, or Caucasian patients and no drug-drug interactions, food interactions, or potential for chelation.

Spotlight on eltrombopag in pediatric ITP in China: a long-term observational study in real-world practice

Immune thrombocytopenia (ITP) is an autoimmune bleeding disorder with isolated thrombocytopenia and risk of hemorrhage. Treatment with eltrombopag increases and maintains hemostatic platelet counts; however, to date, long-term data are lacking on the outcome of children with ITP who are treated with eltrombopag. This prospective, observational, longitudinal cohort study evaluated the efficacy and safety of eltrombopag in pediatric patients with persistent or chronic ITP. For the 116 pediatric patients enrolled, duration of eltrombopag treatment was at least 3 months. Median effective dose was 25 mg/day, 50 mg/day, and 50 mg/day, respectively, for children age 5 years or younger, 6 to 11 years, or 12 years or older. In all, 89 patients (76.7%) achieved overall response, 53 (45.7%) achieved complete response, and 36 (31.0%) achieved response. Median platelet counts increased by week 1 and were sustained throughout the treatment period. During treatment with eltrombopag, the proportion of patients with grade 1 to 4 bleeding symptoms decreased from 83.61% at baseline to 9.88% at 6 months when only grade 1 was reported. Forty-three patients (37.1%) reported using concomitant medications at study entry, which was reduced to 1 patient (2.5%) who needed concomitant medications at 12 months. All adverse events were grade 1 or 2 according to Common Terminology Criteria for Adverse Events. No serious adverse events, cataracts, malignancies, or thromboses were reported during the study. Long-term treatment with eltrombopag was generally safe, well tolerated, and effective in maintaining platelet counts and reducing bleeding in most pediatric patients with persistent or chronic ITP. Combined with future studies, these findings will help establish how eltrombopag should best be used in the management of pediatric patients with East Asian ancestry.

A multicentre double-blind, double-dummy, randomised study of recombinant human thrombopoietin versus eltrombopag in the treatment of immune thrombocytopenia in Chinese adult patients

We performed a double-blind, double-dummy controlled study to compare the efficacy between recombinant human thrombopoietin (rhTPO) and eltrombopag in rapidly increasing the platelet counts in Chinese patients with immune thrombocytopenia (ITP). A total of 96 patients diagnosed with ITP for ≥6 months who had baseline platelet counts of <30 × 10⁹ /l were randomly assigned (1:1 ratio) to receive eltrombopag 25 mg/day or rhTPO 300 u/kg for 2 weeks. Compared with the eltrombopag group, a significantly higher proportion of patients in the rhTPO group achieved platelet counts of ≥50 × 10⁹ /l [75·00% (36/48) vs. 43·75% (21/48), P = 0·003] or complete response (64·58% vs. 25·00%) on day 15. Moreover, a higher proportion of patients in the rhTPO group either had platelet counts that rapidly increased to twice that of baseline and with platelet counts of ≥30 × 10⁹ /l, or reached ≥50 × 10⁹ /l at least once when analysed on day 9, 12, and 15. However, upon discontinuation of the treatment, the platelet counts reduced to the baseline within 1 week in the rhTPO group, but on the fourth week in the eltrombopag group. Adverse events were similar in patients given rhTPO and eltrombopag. To conclude, rhTPO is superior to eltrombopag at 25 mg/day in rapidly increasing platelet counts in patients with ITP (ClinicalTrials.gov Identifier: NCT03771378).

Comparative Efficacy and Safety of Thrombopoietin Receptor Agonists in Adults With Thrombocytopenia: A Systematic Review and Network Meta-analysis of Randomized Controlled Trial

Thrombopoietin receptor agonists (TPO-RAs) play a crucial role in stimulating thrombopoiesis. However, conventional meta-analyses have shown inconsistent results regarding the efficacy of thrombopoietin receptor agonists versus placebo. Therefore, we performed a network meta-analysis to assess the effects of five TPO-RAs via indirect comparison. For this network meta-analysis, we considered randomized trials that included any of the following interventions: avatrombopag, lusutrombopag, eltrombopag, romiplostim, recombinant human thrombopoietin (rhTPO). We searched the Medline, PubMed, Embase, the Cochrane Library, and Web of Science databases for randomized controlled clinical trials from inception to January 31, 2021. We use randomized controlled clinical trials of TPO-RAs for treatment of immune thrombocytopenia in adults. The primary outcome was the number of patients achieving platelet response which was defined as the achievement of a platelet count of more than 30 or 50 cells × 10⁹/L in the absence of rescue therapy, and the secondary outcome was the therapy-related serious adverse events and incidence of bleeding episodes. To obtain the estimates of efficacy and safety outcomes, we performed a random-effects network meta-analysis. These estimates were presented as odds ratios with 95% confidence intervals. We use surface under the cumulative ranking probabilities to rank the comparative effects and safety of all drugs against the placebo. In total, 2,207 patients were analyzed in 20 clinical trials. All preparations improved the point estimates of platelet response when compared with the placebo. Avatrombopag and lusutrombopag had the best platelet response compared to the placebo, the former had a non-significant advantage compared to the latter [odds ratio (OR) = 1.91 (95% confidence interval: 0.52, 7.05)]. The treatments were better than eltrombopag, romiplostim, rituximab, and rhTPO + rituximab, with corresponding ORs of 3.10 (1.01, 9.51), 9.96 (2.29, 43.29), 33.09 (8.76, 125.02), and 21.31 (3.78, 119.98) for avatrombopag and 1.62 (0.63, 4.17), 5.21 (1.54, 17.62), 17.34 (5.15, 58.36), and 11.16 (2.16, 57.62) for lusutrombopag. Regarding bleeding, the placebo group had the highest probability of bleeding, whereas lusutrombopag had the lowest risk of bleeding when compared to the placebo. Adverse events were slightly higher in patients receiving rituximab than in those receiving placebo or other treatments. Overall, this meta-analysis showed that avatrombopag may yield the highest efficacy because it has the most favorable balance of benefits and acceptability.

A multicenter, randomized phase III trial of hetrombopag: a novel thrombopoietin receptor agonist for the treatment of immune thrombocytopenia

Background

Hetrombopag, a novel thrombopoietin receptor agonist, has been found in phase I studies to increase platelet counts and reduce bleeding risks in adults with immune thrombocytopenia (ITP). This phase III study aimed to evaluate the efficacy and safety of hetrombopag in ITP patients.

Methods

Patients who had not responded to or had relapsed after previous treatment were treated with an initial dosage of once-daily 2.5 or 5 mg hetrombopag (defined as the HETROM-2.5 or HETROM-5 group) or with matching placebo in a randomized, double-blind, 10-week treatment period. Patients who received placebo and completed 10 weeks of treatment switched to receive eltrombopag, and patients treated with hetrombopag in the double-blind period continued hetrombopag during the following open-label 14-week treatment. The primary endpoint was the proportion of responders (defined as those achieving a platelet count of ≥ 50 × 10⁹/L) after 8 weeks of treatment.

Results

The primary endpoint was achieved by significantly more patients in the HETROM-2.5 (58.9%; odds ratio [OR] 25.97, 95% confidence interval [CI] 9.83–68.63; p < 0.0001) and HETROM-5 (64.3%; OR 32.81, 95% CI 12.39–86.87; p < 0.0001) group than in the Placebo group (5.9%). Hetrombopag was also superior to placebo in achieving a platelet response and in reducing the bleeding risk and use of rescue therapy throughout 8 weeks of treatment. The durable platelet response to hetrombopag was maintained throughout 24 weeks. The most common adverse events were upper respiratory tract infection (42.2%), urinary tract infection (17.1%), immune thrombocytopenic purpura (17.1%) and hematuria (15%) with 24-week hetrombopag treatment.

Conclusions

In ITP patients, hetrombopag is efficacious and well tolerated with a manageable safety profile.

Trial registration Clinical trials.gov NCT03222843, registered July 19, 2017, retrospectively registered.

Eltrombopag Effectiveness and Tolerability in Chronic Immune Thrombocytopenia: A Meta-Analysis

Eltrombopag is an orally administered, non-peptide, thrombopoietin receptor agonist which initiates thrombopoietin signaling and stimulates the production of normally functioning platelet. We aimed to do a systematic review and meta-analysis of currently available published data to verify whether eltrombopag treatment in patients with chronic immune-mediated thrombocytopenia can prolong survival. We searched for published, randomized, controlled trials in PubMed, Cochrane and Scopus databases using the following search strategy ("Eltrombopag" OR "Benzoates" OR "Hydrazines") AND ("Idiopathic Thrombocytopenic Purpura" OR "immune thrombocytopenia" OR "Idiopathic Thrombocytopenic Purpuras" OR "Immune Thrombocytopenia" OR "Autoimmune Thrombocytopenia" OR "Werlhof"). The pooled relative risk (RR) showed that eltrombopag group has significantly higher overall platelet response than placebo group (MD = 3.42, 95% CI [2.51, 4.65], P > .0001); pooled results were homogenous (P = .27, I2 = 22%). The pooled relative risk showed that eltrombopag group has lower incidence of any bleeding than placebo group (MD = 0.65, 95% CI [0.48, 0.87], P = .003); pooled results were heterogenous (P = .001, I2 = 75%) and the detected heterogeneity was best resolved after excluding Bussel et al (P = .10). Homogeneous results were still favored eltrombopag group (MD = 0.75, 95% CI [0.60, 0.93], P = .008).

Correlation of the Plasma Concentration of Eltrombopag With Efficacy in the Treatment of Refractory Aplastic Anemia: A Single-Centre Study in China

Background and purpose: Eltrombopag (ELT) can be effective in the treatment of relapse/refractory aplastic anemia (AA) patients. Responses and adverse drug reactions (ADRs) differed greatly among individuals treated at the same dosage of ELT.

Methods: Patients diagnosed with nonsevere aplastic anemia (NSAA) between January 2018 and January 2019 in Peking Union Medical Colleague Hospital who were refractory to immunosuppressive therapy were treated with ELT and followed up for at least 6 months. Plasma concentrations of ELT were detected by high-performance liquid chromatography-mass spectrometry after at least two months of ELT treatment and treatment at the same dosage for at least 2 weeks. The dose-concentration, concentration-response and concentration-ADR relationships were evaluated.

Results: Among the 72 patients treated with ELT during the study period, 44 patients with complete data were enrolled. Six (13.6%) were males, and 38 were females (86.4%), with a median age of 54 years [interquartile range (IQR): 38.5–63]. At the time the ELT plasma concentration was detected, the median dosage of ELT was 75 (IQR 50–100) mg/d, the median time of total ELT exposure was 3 (IQR 2.0–6.0) months, and 37 (70.5%) patients had responded to ELT. The median concentration of ELT was 10.4 μg/ml (IQR 3.7–24.4 μg/ml). The concentration of ELT was positively correlated with the daily dose of ELT (r = 0.68, p < 0.001). Multivariate logistic regression analysis showed that the risk of inefficacy of ELT at a concentration between 11.2 and 15.2 μg/ml was 0.028-fold (95% CI: 0.001–0.864; p = 0.041) of that at a concentration between 3.2 and 7.2 μg/ml. The cutoff value for the concentration of ELT showing efficacy was 12.50 μg/ml according to the receiver operation characteristic curve. A higher risk of ADR was related to a longer total exposure to ELT (p = 0.012). Although the correlation was not significant, the odds ratio increased with the ELT concentration, suggesting that it was possible that an elevated risk of ADR was correlated with the ELT blood concentration.

Conclusion: ELT is effective for the treatment of NSAA and has acceptable side effects. The plasma concentration of ELT was correlated with the dose and the effects of ELT.

Eltrombopag as first-line treatment for thrombocytopenia among paediatric patients after allogeneic haematopoietic stem cell transplantation

AIMS

The purpose of this study is to examine the safety and efficacy of eltrombopag as first-line treatment for thrombocytopenia among paediatric patients after haematopoietic stem cell transplantation (HSCT).

METHODS

Forty-three childhood patients with thrombocytopenia after HSCT who received eltrombopag were retrospectively analysed.

RESULT

Eltrombopag was began at the median of 27 days after HSCT and lasted for 24 days. Thirty-five children responded to eltrombopag therapy, and the cumulative platelet recovery rate was 88.9%. The cumulative incidence of platelet recovery was lower (83.9 vs 100%; P = .035) in patients with decreased numbers of megakaryocytes before starting eltrombopag than in those with normal. Factors associated with a significantly elevated response to eltrobopag from univariate analysis were donor type. Results from the multiple regression analysis found that weight (hazard ratio [HR] = 0.7, 95% confidence interval [CI] 0.5-0.9, P = .022), platelet engraftment time (HR = 1.0, 95%CI 1.0-1.0, P = .012) and bone marrow megakaryocytes (HR = 8.0, 95%CI 1.5-43.3, P = .016) before starting eltrombopag were the independent risk factors. Based on Youden's index algorithm in the receiver-operating characteristic curve, the optimal cut-off value of the maintenance dose of eltrombopag in predicting nonresponders was 4 mg/kg. The area under the receiver-operating characteristic curve was 0.923 with sensitivity of 97.8%, specificity of 87.9%, positive predictive value of 72.3%, and negative predictive value of 92%. None of the paediatric patients stopped using eltrombopag due to side effect or intolerability.

CONCLUSION

Eltrombopag is effective and safe in paediatric patients with thrombocytopenia after HSCT. The number of megakaryocytes in bone marrow before eltrombopag treatment may serve as a predictor of the response to eltrombopag. We recommend that the maintenance dose of eltrombopag should not exceed 4 mg/kg/d.

Efficacy and safety of eltrombopag in Chinese patients with chronic immune thrombocytopenia: stage 2 results from a multicenter phase III study

This phase III, randomized, placebo-controlled study conducted in three stages (6-week, randomized, placebo-controlled stage 1; 24-week, open-label stage 2; and continuous extension stage 3) assessed the long-term efficacy and safety of eltrombopag use in Chinese patients with chronic immune thrombocytopenia (ITP). This article presents the results from stage 2. Overall, 150 patients (placebo-eltrombopag [P-E], 50; eltrombopag-eltrombopag [E-E], 100) received open-label eltrombopag. The median platelet count was maintained between 41 × 10⁹/L and 80 × 10⁹/L. Most patients in both groups (P-E, 90.0%; E-E, 81.8%) achieved platelet counts ≥30 × 10⁹/L and ≥2 times the baseline platelet count at least once with eltrombopag treatment. Overall, 32% of patients achieved platelet counts ≥50 × 10⁹/L in ≥75% of platelet count assessments. Both groups showed a decreased tendency to infrequent bleeding and clinically significant bleeding events during stage 2 compared with baseline. Among patients who received ≥1 ITP medication at baseline, 70.4% in the P-E group and 40.8% in the E-E group reduced or permanently stopped ≥1 of their ITP medications. The stage 2 results further demonstrated a sustainable long-term efficacy and good tolerability of eltrombopag with a favorable benefit-risk ratio in Chinese chronic ITP patients.Trial registration: Clinicaltrials.gov NCT01762761. Registered 8 January 2013, https://clinicaltrials.gov/ct2/show/NCT01762761.

First-in-patient study of hetrombopag in patients with chronic idiopathic thrombocytopenic purpura

BACKGROUND

Idiopathic thrombocytopenic purpura (ITP) especially refractory and (or) relapsed ITP, is a serious and global health burden and its clinical treatment is far from being satisfied. Hetrombopag is a novel, small-molecule thrombopoietin receptor agonist for the treatment of chronic idiopathic thrombocytopenic purpura (CITP).

OBJECTIVES

This first-in-patient study aimed to investigate the safety, pharmacokinetics, and anticipated therapeutic dose of hetrombopag in CITP patients.

METHODS

In this multicenter, first-in-patient study, CITP patients received hetrombopag in a dose escalation (2.5 mg/day, 5 mg/day, or 7.5 mg/day) cohort. All patients received hetrombopag in fasting condition once daily for 2 weeks.

RESULTS

Of 44 patients screened, 32 were enrolled and treated. Most adverse events were graded 1 to 2 (ie, mild to moderate), and the incidence and severity were similar for three study cohorts. The pharmacokinetics of hetrombopag were found to be nonlinear with greater than dose-proportional: 12.5% of patients (1/8) in the 2.5 mg/d cohort, 58.3% of patients (7/12) in the 5 mg/d cohort, 66.7% of patients (8/12) in the 7.5 mg/d cohort reached the primary study endpoint of a platelet count exceeding 50 × 109 /L on day 28.

CONCLUSION

Hetrombopag was well tolerated and preliminarily efficacious. Efficacy, safety, and pharmacokinetic data suggest that 7.5 mg hetrombopag once daily was the anticipated therapeutic dose of hetrombopag in CITP patients and has been recommended for investigation in a later confirmatory clinical study of hetrombopag.

Rescue treatment with eltrombopag in refractory cytopenias after allogeneic stem cell transplantation

Background:

Patients with post-transplant cytopenias due to poor graft function or primary engraftment failure show poor prognosis with a high mortality rate mainly because of graft versus host disease (GVHD), infection and/or bleeding. Treatment options are scarce and a CD34+ stem cell boost or a second bone marrow transplantation may be required to restore adequate haematopoiesis.

Methods:

In the present study patients with primary engraftment failure (n = 1) and refractory poor graft function (n = 11) were treated with eltrombopag in a single centre. The reason for eltrombopag treatment was trilineage cytopenia in six patients, bilineage cytopenia in three patients and single lineage cytopenia in three patients. Eltrombopag was initiated at a median of 214 (range: 120–877) days after haematopoietic stem cell transplantation (HCST) and administered for a median time of 114 (range: 12 days to >490) days. In 8/12 patients eltrombopag was introduced at a dose of 75 mg/day and then increased to 150 mg/day after 1 week; 1 patient was given 50 mg eltrombopag per day, and 3 patients received 75 mg daily.

Results:

In 10/12 patients eltrombopag significantly enhanced blood count values and patients became transfusion independent. Once stable haematological response was obtained, treatment was tapered until final discontinuation in 9/10 responding patients. No grade 3 or 4 toxicities were observed. At time of last follow up, 3/12 patients were dead, 2 due to disease relapse, 1 due to GVHD and pneumonia. All patients except one maintained their complete response and remain transfusion independent at a median of 858 (range: 429–1119) days.

Conclusion:

These preliminary data confirm that eltrombopag is able to rescue multilineage haematopoiesis in patients with treatment-refractory cytopenias after allogeneic HSCT.

American Society of Hematology 2019 guidelines for immune thrombocytopenia

BACKGROUND

Despite an increase in the number of therapies available to treat patients with immune thrombocytopenia (ITP), there are minimal data from randomized trials to assist physicians with the management of patients.

OBJECTIVE

These evidence-based guidelines of the American Society of Hematology (ASH) are intended to support patients, clinicians, and other health care professionals in their decisions about the management of ITP.

METHODS

In 2015, ASH formed a multidisciplinary guideline panel that included 8 adult clinical experts, 5 pediatric clinical experts, 2 methodologists with expertise in ITP, and 2 patient representatives. The panel was balanced to minimize potential bias from conflicts of interest. The panel reviewed the ASH 2011 guideline recommendations and prioritized questions. The panel used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach, including evidence-to-decision frameworks, to appraise evidence (up to May 2017) and formulate recommendations.

RESULTS

The panel agreed on 21 recommendations covering management of ITP in adults and children with newly diagnosed, persistent, and chronic disease refractory to first-line therapy who have non-life-threatening bleeding. Management approaches included: observation, corticosteroids, IV immunoglobulin, anti-D immunoglobulin, rituximab, splenectomy, and thrombopoietin receptor agonists.

CONCLUSIONS

There was a lack of evidence to support strong recommendations for various management approaches. In general, strategies that avoided medication side effects were favored. A large focus was placed on shared decision-making, especially with regard to second-line therapy. Future research should apply standard corticosteroid-dosing regimens, report patient-reported outcomes, and include cost-analysis evaluations.

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.

Romiplostim and Eltrombopag in Immune Thrombocytopenia as a Second-Line Treatment

Immune thrombocytopenia (ITP) is an autoimmune disorder characterized by platelet count less than 100×10⁹/L and an increased risk of bleeding. The risk of bleeding increases in proportion with the degree of thrombocytopenia. Although several medications are used for primary thrombocytopenia treatment, refractoriness remains a concern. Romiplostim and eltrombopag, two relatively new drugs, have been shown to be successful in ITP treatment after standard treatment failure. The current guidelines recommend their use as a second-line treatment. In this article, we have tried to compare which of these two medications is the best option considering clinical effectiveness, cost-effectiveness, adverse effects, and the possibility of switching between them in case of ineffectiveness. The studies used in this article were found in the PubMed database. All the studies are limited to adults. Based on these studies, both medications seem to be a largely effective, safe option. Romiplostim appears to have slightly fewer adverse effects and higher costs. Switching between thrombopoietin receptor agonists (TRAs) is a successful way to overcome adverse effects and inadequacy according to the currently available literature. We believe that more detailed studies are needed to determine which of these drugs should be considered the first choice, to report long term efficacy and adverse effects, and to determine if treatment guidelines can change regarding the use of TRAs as first-line treatment.

Thrombopoietin receptor agonists for the treatment of primary immune thrombocytopenia: a meta-analysis and systematic review

Previous meta-analyses reported discordant results on the efficacy and safety of thrombopoietin receptor agonists (TPO-RA) as second-line treatment in patients with immune thrombocytopenia (ITP). We conducted a meta-analysis of primary ITP treatment with the TPO-RA Romiplostim, Eltrombopag and Avatrombopag, including additional studies and relevant endpoints. We searched MEDLINE, EMBASE and CENTRAL for randomized clinical trials (RCTs) and cohort studies on TPO-RA in ITP published until December 31, 2018. The primary endpoints were: risk ratio (RR) of treatment failure and bleeding of WHO grade ≥2; rate of remission after discontinuation of treatment. The principal safety outcome was RR and incidence of thrombotic events and liver damage. From 1044 identified records we selected 16 RCTs and 19 cohort studies. RCTs included 909 patients assigned to TPO-RA and 427 to the control arm. Treatment failure was observed in 21% TPO-RA-treated patients and 47% control arm patients (RR = 0.42, 95% CI 0.33-0.53) in RCTs during a median follow-up of 13 weeks, and in 29% TPO-RA-treated patients in cohort studies, during a median follow-up of 69 weeks. The incidence of remission after TPO discontinuation was 18% (5-36%). RR of WHO grade ≥2 bleeding was 0.58 (0.38-0.86) in TPO-RA-treated patients, compared to control arm patients. Adverse events were rare and not significantly different in the two groups of patients. All-cause mortality was significantly lower with TPO-RA (RR 0.21, 95% CI, 0.06-0.68). In conclusion, TPO-RA are effective and safe in patients with ITP, even in the long term.

Sirolimus as Rescue Therapy for Refractory/Relapsed Immune Thrombocytopenia: Results of a Single-Center, Prospective, Single-Arm Study

Immune thrombocytopenia (ITP) is an autoimmune disease which arises due to self-destruction of circulating platelets. Failure to respond or maintain a response to first-line treatment can lead to refractory/relapsed (R/R) ITP. The mechanism remains complicated and lacks a standard clinical treatment. Sirolimus (SRL) is a mammalian target of rapamycin (mTOR) inhibitor that has been demonstrated to inhibit lymphocyte activity, indicating potential for SRL in treatment of ITP. Activation of the mTOR pathway in autoimmune diseases suggests that SRL might be a useful agent for treating ITP. Accordingly, we initiated an open-label, prospective clinical trial using SRL for patients with R/R ITP (ChiCTR-ONC-17012126). The trial enrolled 86 patients, each dosed with 2-4 mg/day of SRL. By the third month, 40% of patients (34 of 86) achieved complete remission (CR) and 45% of patients (39 of 86) achieved partial remission (PR), whereby establishing an overall response rate (ORR) of 85%. By 6 months of treatment, 41% of patients (32 of 78) achieved CR and 29% of patients (23 of 78) achieved PR, establishing an ORR of 70% without serious side effects. After 12 months follow-up, the ORR remained at 65%. We also found that SRL treatment exhibited higher efficacy in achieving CR in ITP patients who were younger than 40 years old or steroid dependent by univariate analysis. Importantly, in patients who responded, SRL treatment was associated with a reduction in the percentage of Th2, Th17 cells, and increase in the percentage of M-MDSCs and Tregs, indicating that SRL may reestablish peripheral tolerance. Taken together, Sirolimus demonstrated efficacy as a second-line agent for R/R ITP.

Effect of postdose fasting duration on hetrombopag olamine pharmacokinetics and pharmacodynamics in healthy volunteers

AIMS

Hetrombopag olamine is a novel small-molecule, nonpeptide thrombopoietin receptor agonist developed for immune thrombocytopenia treatment. This study aims to determine the safety and the effect of fasting duration after administration of hetrombopag on pharmacokinetics and pharmacodynamics in Chinese healthy subjects.

METHODS

A randomized, open-label, single-dose, 3-period crossover, self-control trial was conducted. 15 eligible subjects were enrolled and received hetrombopag 7.5 mg at day 1 of each period followed by a standard meal 4 hours postdose (treatment A/fasting condition), or a high-calorie, high-fat meal 1 hour postdose (treatment B), or a high-calorie, high-fat meal 2 hours postdose (treatment C). The plasma concentrations of hetrombopag were determined by validated liquid chromatography-tandem mass spectrometry, platelet counts were quantified by blood test. Analysis was performed using a mixed model, including treatment, period as fixed effects and participant as a random effect.

RESULTS

Compared with treatment A, peak concentration and area under concentration-time curve extrapolated to infinity decreased by 56 and 74.6%, and 44 and 61% in treatments B and C, respectively. The mean platelet number on day 6 increased by 15.8, 6.96 and 10.26%, respectively, in treatments A, B and C in comparison with baseline platelet level. No severe adverse events happened in any of the 3 treatments.

CONCLUSION

Hetrombopag was well tolerated in healthy male subjects under fasted/fed conditions. The shorter fasting duration resulted in lower hetrombopag exposure, corresponding to a lower level of platelet elevation. Therefore, we recommended oral administration of hetrombopag on an empty stomach (fasting condition) or at least 2 hours before a meal to achieve maximum bioavailability.

Updated international consensus report on the investigation and management of primary immune thrombocytopenia

Over the last decade, there have been numerous developments and changes in treatment practices for the management of patients with immune thrombocytopenia (ITP). This article is an update of the International Consensus Report published in 2010. A critical review was performed to identify all relevant articles published between 2009 and 2018. An expert panel screened, reviewed, and graded the studies and formulated the updated consensus recommendations based on the new data. The final document provides consensus recommendations on the diagnosis and management of ITP in adults, during pregnancy, and in children, as well as quality-of-life considerations.

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.

Treatment efficacy for adult persistent immune thrombocytopenia: a systematic review and network meta-analysis

Persistent immune thrombocytopenia (ITP) patients require second-line treatments, for which information on clinical outcomes are lacking. A systematic review and network meta-analysis (NMA) were conducted. Only randomised controlled trials (RCT) of second-line drugs in adult persistent ITP patients with platelet response, platelet count, any bleeding or serious adverse events (SAE) outcome were eligible. Twelve RCTs (n = 1313) were included in NMA. For platelet response outcome, eltrombopag and romiplostin were the best relative to placebo; the former had a non-significant advantage [risk ratio (RR) = 1·10 (95% confidence interval: 0·46, 2·67)]. Both treatments were superior to rituximab and recombinant human thrombopoietin (rhTPO)+rituximab, with corresponding RRs of 4·56 (1·89, 10·96) and 4·18 (1·21, 14·49) for eltrombopag; 4·13 (1·56, 10·94) and 3·79 (1·02, 14·09) for romiplostim. For platelet count, romiplostim ranked highest, followed by eltrombopag, rhTPO+rituximab, and rituximab. For bleeding, rituximab had lowest risk, followed by eltrombopag and romiplostim. For SAEs, rhTPO+rituximab had highest risk, followed by rituximab, eltrombopag and romiplostim. From clustered ranking, romiplostim had the best balance between short-term efficacy and SAEs, followed by eltrombopag. In conclusion, romiplostim and eltrombopag may yield high efficacy and safety. Rituximab may not be beneficial due to lower efficacy and higher complications compared with the thrombopoietin receptor agonists. RCTs with long-term clinical outcomes are required.

Primary immune thrombocytopenia (ITP) treated with romiplostim in routine clinical practice: retrospective study from the United Kingdom ITP Registry

BACKGROUND

Romiplostim is a thrombopoietin-mimetic peptibody for adult refractory chronic immune thrombocytopenia (ITP). We aimed to describe ITP patients receiving romiplostim, platelet counts and romiplostim usage in UK clinical practice.

METHODS

This was a retrospective cohort study of patients in the UKITP Registry who received romiplostim between October 2009 and January 2015, including data up to 6 months before romiplostim initiation through follow-up.

RESULTS

Of 1440 patients in the UKITP Registry, 118 adults with primary ITP were eligible. Before romiplostim, 22% had splenectomy, 12% received platelet transfusion, 97% received ≥ 1 different ITP medication and 77% received ≥ 3. Most patients (73%) initiated romiplostim ≥ 1 year after ITP diagnosis (chronic phase). The mean duration of romiplostim treatment was 5.7 (SE 0.9) months, and the median was 1.4 months (IQR: 0.2, 6.5). Mean platelet count before romiplostim was 38 × 10⁹ /L, rising to 103 × 10⁹ /L within 1 month, and remaining 50-150 × 10⁹ /L through up to 3 years of follow-up. After romiplostim, 4% of patients had splenectomy, 6% received platelet transfusion, and 57% received just one ITP medication other than romiplostim.

CONCLUSION

The study provides valuable insights into the real-world use of romiplostim in primary ITP in routine practice and highlighted the timing of romiplostim initiation at different ITP disease phases.

Therapeutic options for adult patients with previously treated immune thrombocytopenia - a systematic review and network meta-analysis

OBJECTIVES

The great majority of adult patients with immune thrombocytopenia (ITP) who fail to respond to first-line medication or who relapse following response require additional treatment. Although broad guidelines currently exist for second-line and subsequent therapies, none to date have been prescriptive. The purpose of this systematic review and network meta-analysis was to establish a clinically relevant ranking of the efficacy and safety of medications for adults (≥18 years old) with previously treated ITP.

METHODS

Relevant publications from Medline, Embase, and the Cochrane database were searched from their inceptions through July 31, 2018. The primary outcome was the overall response (OR, defined as a platelet count ≥50 × 10⁹/L at the end of treatment without rescue therapy), while the secondary endpoints included early response (ER; i.e. a platelet count ≥50 × 10⁹/L at week 2 after initiation of treatment) and therapy-related severe adverse events (AEs).

RESULTS

Thirteen randomized controlled trials (1,202 patients) were included in this study. According to pooled results, romiplostim appears to be the most suitable treatment in terms of OR, followed by avatrombopag, eltrombopag, fostamatinib, and rituximab. Avatrombopag produced more satisfactory outcomes than romiplostim, eltrombopag, and rituximab in terms of ER; severe AEs profiles were similar across all treatment arms.

CONCLUSION

Romiplostim appears to be the best option for patients who fail to respond to prior treatment or relapse thereafter, while avatrombopag and eltrombopag are reasonable alternatives. Rituximab monotherapy is not recommended, as it produces the lowest OR and ER rates.

Eltrombopag is an effective and safe therapy for refractory thrombocytopenia after haploidentical hematopoietic stem cell transplantation

Refractory thrombocytopenia is a frequent and severe complication after haploidentical allogeneic hematopoietic stem cell transplantation (haplo-HSCT) and lacks effective treatment strategies. Eltrombopag has shown promising results in several thrombocytopenia disorders. We report 38 patients treated with eltrombopag for refractory thrombocytopenia after haplo-HSCT. Eight patients had delayed platelet engraftment, 15 patients had secondary failure of platelet recovery, and 15 patients had poor graft function (PGF). Eltrombopag was initiated at 25 or 50 mg daily, and the dosage was adjusted to a maximum of 50-100 mg daily to maintain platelet between 50 × 10⁹/L and 100 × 10⁹/L. The cumulative incidence of platelet recovery to transfusion independence was 63.2% and to ≥50 × 10⁹/L without transfusion support was 52.3%. Furthermore, neutrophil counts and hemoglobin were also increased in the nine responders with PGF. Nineteen (79.2%) of the 24 responders were able to taper off eltrombopag, and the remaining 5 patients were able to begin a taper. The median duration of treatment was 64 (range 14-195) days. The presence of megakaryocyte before initiation was the only independent factor influencing the efficacy of eltrombopag (P = 0.044). Eltrombopag was well tolerated in all patients. In summary, eltrombopag was a safe and effective therapy for refractory thrombocytopenia after haplo-HSCT.

Comparison of treatments for persistent/chronic immune thrombocytopenia: a systematic review and network meta-analysis

Recent studies have indicated that medical options without splenectomy, such as rituximab (RTX) or thrombopoietin receptor agonists (TPO-RAs), can be effective to treat persistent or chronic primary immune thrombocytopenia (ITP). However, it remains to be determined which of these strategies should be the first choice after the first-line treatment for newly diagnosed ITP. We performed a systematic review and network meta-analysis to establish a clinically meaningful hierarchy of the efficacy and safety of medical treatments for persistent or chronic ITP in adults. Randomized controlled trials (RCTs) evaluating medical treatments were included. Reviewers independently extracted data and assessed the risk of bias. The main outcome was the overall response (platelet≥ 50 × 10⁹/L); incidence of bleeding episodes, necessity of rescue treatments, and therapy-related adverse events including thrombosis were the secondary endpoints. A total of 12 randomized controlled trials (N= 1306) were included in this study. Our main finding was an improved overall response in TPO-RA arms (both Eltrombopag and Romiplostim) compared with that of RTX or placebo. There were no significant differences between Eltrombopag and Romiplostim. Moreover, clinically significant bleeding episodes were decreased in TPO-RA arm compared with placebo. Therapy-related adverse events showed similar profiles, and were tolerable in all treatment arms. In conclusion, TPO-RAs can be first choices for the treatment of persistent and chronic ITP, rather than RTX, as alternatives to splenectomy. Future head-to-head trials including TPO-RAs vs. RTX or Eltrombopag vs. Romiplostim are necessary to validate our study findings and determine the most suitable therapy for persistent/chronic ITP.

Evidence-based management of immune thrombocytopenia: ASH guideline update

In 1996 and 2011, the American Society of Hematology (ASH) supported efforts to create guidelines for the diagnosis and management of patients with immune thrombocytopenia (ITP). These guidelines used different approaches to arrive at recommendations for testing and treatment. Despite differences in methodology, in both cases there was a paucity of randomized trials to inform recommendations. As data on the diagnosis and management of ITP expands, the ASH Committee on Quality is dedicated to maintaining updated guidelines representing recent evidence and guideline methodology. Here, we will review the updated ASH guidelines on ITP with a focus on recommendations with new understanding and future research to close knowledge gaps.