Tapering and Sustained Remission of Thrombopoietin Receptor Agonists (TPO-RAs): Is it Time for Paediatric ITP?

Thrombopoietin receptor agonists (TPO-Ras; romiplostim/eltrombopag/avatrombopag) have demonstrated high efficacy rates (59-88%) and a good safety profile in clinical trials with adult patients with immune thrombocytopenia (ITP). Similar efficacy and safety results have been observed with romiplostim and eltrombopag in paediatric cohorts. Continuous treatment with TPO-RAs has shown durable responses with long-term use, up to 3 years. The effect of TPO-RAs was generally considered transient, as platelet counts tended to drop to baseline values after a short period of time (about 2 weeks), unless treatment was maintained. Several groups have reported successful discontinuation of TPO-RAs without the need for concomitant treatments. This is referred to as sustained remission off treatment (SROT). Both short- and medium-term treatment with TPO-RAs may reduce costs to our healthcare systems and, more importantly, may reduce the potential side effects that may be associated with continuous TPO-RA treatment. The issue of tapering and discontinuation of TPO-RAs in paediatric patients with ITP has received little attention to date. Given that paediatric ITP has much higher rates of spontaneous remission than ITP in adults, we consider that the possibility of SROT of TPO-RAs in paediatric patients with ITP is a neglected but very relevant issue in this subtype of the disease.

Can Machine Learning Assist in Diagnosis of Primary Immune Thrombocytopenia? A Feasibility Study.

Primary Immune Thrombocytopenia (ITP) is a rare autoimmune disease characterised by the immune-mediated destruction of peripheral blood platelets in patients leading to low platelet counts and bleeding. The diagnosis and effective management of ITP are challenging because there is no established test to confirm the disease and no biomarker with which one can predict the response to treatment and outcome. In this work, we conduct a feasibility study to check if machine learning can be applied effectively for the diagnosis of ITP using routine blood tests and demographic data in a non-acute outpatient setting. Various ML models, including Logistic Regression, Support Vector Machine, k-Nearest Neighbor, Decision Tree and Random Forest, were applied to data from the UK Adult ITP Registry and a general haematology clinic. Two different approaches were investigated: a demographic-unaware and a demographic-aware one. We conduct extensive experiments to evaluate the predictive performance of these models and approaches, as well as their bias. The results revealed that Decision Tree and Random Forest models were both superior and fair, achieving nearly perfect predictive and fairness scores, with platelet count identified as the most significant variable. Models not provided with demographic information performed better in terms of predictive accuracy but showed lower fairness scores, illustrating a trade-off between predictive performance and fairness.

Fostamatinib effectiveness and safety for immune thrombocytopenia in clinical practice.

ABSTRACT: Fostamatinib, a recently approved Syk inhibitor used in adult primary immune thrombocytopenia (ITP), has been shown to be safe and effective in this disorder. However, clinical trial results may not be similarly reproduced in clinical practice. Here, 138 patients with ITP (both primary and secondary) from 42 Spanish centers who had been treated with fostamatinib were evaluated prospectively and retrospectively. The median age of our cohort (55.8% women) was 66 years (interquartile range [IQR], 56-80). The median time since ITP diagnosis at fostamatinib initiation was 51 months (IQR, 10-166). The median number of therapies before fostamatinib initiation was 4 (IQR, 2-5), including eltrombopag (76.1%), romiplostim (57.2%), and IV immunoglobulins (44.2%). Fifty-eight patients (42.0%) had signs/symptoms of bleeding in the month before treatment initiation. Seventy-nine percent of patients responded to fostamatinib with 53.6% complete responses (platelet count > 100 × 109/L). Eighty-three patients (60.1%) received fostamatinib monotherapy, achieving a high response rate (85.4%). The proportion of time in response during the 27-month period examined was 83.3%. The median time to platelet response was 11 days (IQR, 7-21). Sixty-seven patients (48.5%) experienced adverse events, mainly grade 1 to 2; the commonest of which were diarrhea (n = 28) and hypertension (n = 21). One patient had deep venous thrombosis, and one patient developed acute myocardial infarction. Fostamatinib was shown to be effective with good safety profile in patients with primary and secondary ITP across a wide age spectrum in this real-world study.

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.

Real-world use of thrombopoietin receptor agonists for the management of immune thrombocytopenia in adult patients in the United Kingdom: Results from the TRAIT study.

Few studies have reported the real-world use of both romiplostim and eltrombopag in immune thrombocytopenia (ITP). TRAIT was a retrospective observational study aimed to evaluate the platelet responses and adverse effects associated with the use of these thrombopoietin receptor agonists (TPO-RAs) in adult patients with ITP in the United Kingdom. Of 267 patients (median age at diagnosis, 48 years) with ITP (primary ITP [n = 218], secondary ITP [n = 49]) included in the study, 112 (42%) received eltrombopag and 155 (58%) received romiplostim as the first prescribed TPO-RA. A platelet count ≥30 × 109/L was achieved in 89% of patients with the first TPO-RA treatments, while 68% achieved a platelet count ≥100 × 109/L. Treatment-free response (TFR; platelet count ≥30 × 109/L, 3 months after discontinuing treatment) was achieved by 18% of the total patients. Overall, 61 patients (23%) switched TPO-RAs, most of whom achieved platelet counts ≥30 × 109/L with the second TPO-RA (23/25 who switched from eltrombopag to romiplostim [92%]; 28/36 who switched from romiplostim to eltrombopag [78%]). TFR was associated with secondary ITP, early TPO-RA initiation after diagnosis, the presence of comorbidity and no prior splenectomy or treatment with steroids or mycophenolate mofetil. Both TPO-RAs had similar efficacy and safety profiles to those reported in clinical studies.

Addressing thrombosis concerns in immune thrombocytopenia: the role of fostamatinib in immune thrombocytopenia management.

INTRODUCTION: Immune thrombocytopenia (ITP), a disease that commonly presents with an increased risk of bleeding, can also paradoxically produce an increased risk of thromboembolic events. The risk of thromboembolism can be associated with patient-related factors (e.g. co-morbidities, age and history of thrombosis), disease-related factors (e.g. a greater proportion of younger, more reactive platelets, and the presence of microparticles and pro-inflammatory cytokines) and treatment-related factors (e.g. splenectomy, thrombopoietin receptor agonists, and IVIg). AREAS COVERED: Aspects of the pathophysiology of ITP and the effects of treatment are discussed with emphasis on individualizing treatment based on the patient's thromboembolic risk, treatment options and preferences. EXPERT OPINION: An increased understanding of the pathophysiology of ITP has led to the development of new agents such as fostamatinib, a spleen tyrosine kinase inhibitor. Further research into the factors contributing to the risks for bleeding and thromboembolic events can contribute to the development of more specific therapies for ITP and allow greater individualization of therapy based on each patient's medical history and clinical status.

Concurrent coronary artery disease and immune thrombocytopenia: a systematic review.

Introduction: Coronary artery disease (CAD) management in the setting of immune thrombocytopenia (ITP) remains very challenging to clinicians as a reasonable balance between bleeding and thrombosis risks needs to be achieved, and the evidence guiding such management is scarce. Methods: We conducted a systematic review following the PRISMA guidelines to summarize the available literature on the management and outcomes of CAD coexisting with ITP. We searched PubMed and Embase for studies published in English exploring CAD and ITP management until 05 October 2022. Two independent reviewers screened and assessed the articles for inclusion. Patients' characteristics, CAD treatment modalities, ITP treatment, and complications were reported. Results: We identified 32 CAD cases, among which 18 cases were revascularized with percutaneous coronary intervention (PCI), 12 cases underwent coronary artery bypass graft surgery (CABG), and two cases were managed conservatively. More than 50% were men, with a mean age of 61 ± 13 years and a mean baseline platelet count of 52 ± 59 × 109/L. Irrespective of the revascularization modality, most patients were treated with either corticosteroids alone, intravenous immunoglobulins (IVIG) alone, or in combination. Among those who underwent PCI, two patients had bleeding events, and one patient died. Similarly, among those with CABG, one patient developed bleeding, and one patient died. Conclusion: We found that revascularization with either PCI or CABG with the concurrent use of corticosteroids and/or IVIG for ITP was feasible, with an existing non-negligible risk of bleeding and mortality.

The role of T cells and myeloid-derived suppressor cells in refractory immune thrombocytopenia.

Immune thrombocytopenia (ITP) is characterized by a dysregulated immune response against platelets, affecting both their destruction and production. A role for an abnormal T-cell compartment has been established in ITP pathogenesis and treatments that increase platelet counts in patients with ITP have shown improvements in T-cell profiles. On the other hand, patients who were refractory to treatment appear to retain the T-cell abnormalities as before. Myeloid-derived suppressive cells (MDSCs) are also emerging as key contributors to the immune pathology of ITP and response to treatment. In this review, we will discuss how various treatments affect the T-cell and MDSC compartments in ITP. The review will focus on studies that have examined the underlying mechanisms and/or genetic basis responsible for refractoriness to a given treatment and highlight remaining challenges in identifying factors and mechanisms to predict response to treatment.

Primary and secondary immune thrombocytopenia (ITP): Time for a rethink.

There are not many publications that provide a holistic view of the management of primary and secondary ITP as a whole, reflecting the similarities and differences between the two. Given the lack of major clinical trials, we believe that comprehensive reviews are much needed to guide the diagnosis and treatment of ITP today. Therefore, our review addresses the contemporary diagnosis and treatment of ITP in adult patients. With respect to primary ITP we especially focus on establishing the management of ITP based on the different and successive lines of treatment. Life-threatening situations, "bridge therapy" to surgery or invasive procedures and refractory ITP are also comprehensively reviewed here. Secondary ITP is studied according to its pathogenesis by establishing three major differential groups: Immune Thrombocytopenia due to Central Defects, Immune Thrombocytopenia due to Blocked Differentiation and Immune Thrombocytopenia due to Defective Peripheral Immune Response. Here we provide an up-to-date snapshot of the current diagnosis and treatment of ITP, including a special interest in addressing rare causes of this disease in our daily clinical practice. The target population of this review is adult patients only and the target audience is medical professionals.

Sustained Remission Off-Treatment (SROT) of TPO-RAs: The Burgos Ten-Step Eltrombopag Tapering Scheme.

Background and Objectives: TPO-RAs (romiplostim/eltrombopag/avatrombopag) have broadly demonstrated high efficacy rates (59-88%), durable responses (up to three years) and a satisfactory safety profile in clinical trials. The effect of TPO-RAs is classically considered to be transient because platelet numbers usually dropped rapidly to baseline unless therapy was maintained. However, several groups have reported the possibility of successfully discontinuing TPO-RAs in some patients without further need for concomitant treatments. This concept is usually referred as sustained remission off-treatment (SROT). Materials and Methods: Unfortunately, we still lack predictors of the response to discontinuation even after the numerous biological, clinical and in vitro studies performed to study this phenomenon. The frequency of successful discontinuation is matter of controversy, although a percentage in the range of 25-40% may probably be considered a consensus. Here, we describe all major routine clinical practice studies and reviews that report the current position on this topic and compare them with our own results in Burgos. Results: We report our Burgos ten-step eltrombopag tapering scheme with which we have achieved an elevated percentage rate of success (70.3%) in discontinuing treatment. Conclusions: We hope this protocol may help successfully taper and discontinue TPO-RAs in daily clinical practice.

Current Concepts in the Diagnosis and Management of Adult Primary Immune Thrombocytopenia: Our Personal View.

Primary immune thrombocytopenia (ITP) is an acquired blood disorder that causes a reduction in circulating platelets with the potential for bleeding. The incidence of ITP is slightly higher in adults and affects more women than men until 60 years, when males are more affected. Despite advances in basic science, primary ITP remains a diagnosis of exclusion. The disease is heterogeneous in its clinical behavior and response to treatment. This reflects the complex underlying pathophysiology, which remains ill-understood. Platelet destruction plays a role in thrombocytopenia, but underproduction is also a major contributing factor. Active ITP is a proinflammatory autoimmune disease involving abnormalities within the T and B regulatory cell compartments, along with several other immunological abnormalities. Over the last several years, there has been a shift from using immunosuppressive therapies for ITP towards approved treatments, such as thrombopoietin receptor agonists. The recent COVID-19 pandemic has hastened this management shift, with thrombopoietin receptor agonists becoming the predominant second-line treatment. A greater understanding of the underlying mechanisms has led to the development of several targeted therapies, some of which have been approved, with others still undergoing clinical development. Here we outline our view of the disease, including our opinion about the major diagnostic and therapeutic challenges. We also discuss our management of adult ITP and our placement of the various available therapies.

Thrombopoietin-receptor agonists for adult patients with immune thrombocytopenia: a narrative review and an approach for managing patients fasting intermittently.

Introduction: Thrombopoietin-receptor agonist (TPO-RAs) currently represent the state of art for treating immune thrombocytopenia. Their different molecular structures contribute to the difference in their pharmacodynamics and pharmacokinetics. This narrative review aims to provide an overview of the current TPO-RAs approved for primary immune thrombocytopenia (romiplostim, eltrombopag, avatrombopag) and the effect of intermittent fasting in adult patients receiving TPO-RAs. Areas covered: Literature was searched with no limits on date or language, using various combinations of keywords. Data on the pharmacokinetics, pharmacodynamics, efficacy, and safety of TPO-RAs and the effect of intermittent fasting were summarized. Expert opinion: Switching between TPO-RAs is a useful strategy to tackle some associated limitations. Romiplostim and avatrombopag have an advantage over eltrombopag as they do not require any dietary restrictions. In cases where romiplostim and avatrombopag are unavailable, patients should be educated on the appropriate administration, possible interactions, and dietary restrictions before initiating eltrombopag.

Incidence of adult primary immune thrombocytopenia in England-An update.

BACKGROUND: Adult primary immune thrombocytopenia (ITP) is a rare bleeding disorder of unknown cause. Recent estimates of its incidence and trend over time were acquired for England. METHOD: The primary ITP population (using ICD 10 code D693 and excluding secondary ITP cases; positive predictive value: 82.6%) was sourced from NHS Digital inpatient and outpatient. Incidence rate (IR) for England and by age groups, sex, and regions were calculated and trends were assessed using average annual percent change (AAPC). RESULTS: A total of 25 805 patients (mean age 59 years; females 57.8%) diagnosed between 2003 and 2014 was identified. IRs increased from 4.2/100 000 to 6.4/100 000 over this period (AAPC:4.3%). For all sex-specific age groups, the IRs significantly increased over time, except 18-29 years males. The greatest increase was among females aged 30-39 (AAPC:8.7%). In contrast, among ≥70 years, ITP was more common in males (highest IR among ≥80 years males: 23.9/100 000). England's average annual IR was 6.1/100 000 for 2010-14. An estimated 2.5/100 000 (based on UKITP Registry data) was estimated to require 1st line treatment whereas 2.4/100 000 would have 1st and 2nd line treatments within 6 months from diagnosis. IRs for London and East Midlands were the highest (6.5/100 000). CONCLUSIONS: This study found a rising incidence of primary ITP, with sharp increases among young women and elderly men. These findings put in context the impact of ITP on patients' lives and the healthcare services in England, especially with 17%-50% who may develop chronic ITP and require long-term care.

Investigational drugs for immune thrombocytopenia.

INTRODUCTION: Primary immune thrombocytopenia (ITP) is an acquired autoimmune disease of unknown cause. Autoantibodies, self-reactive T cells and other immune abnormalities, with impairment of platelet production, lead to a reduced platelet count. Until recently, therapy was largely empirical using immune suppressants (none of which have undergone randomized clinical trials). These therapies have variable efficacy and are associated with predictable unwanted effects which impact patient quality-of-life. With greater understanding of the underlying pathophysiology, better, more targeted therapies have been developed; however, there is still an urgent need for additional classes of treatment. AREAS COVERED: This article covers new TPO receptor agonists, Syk inhibitors, Fcγ receptor antagonists, BTK and complement inhibitors, and other therapies. Insights into the most promising therapies are offered. Novel ITP treatments currently in clinical trials and those recently approved come under the spotlight. EXPERT OPINION: Thrombopoietin receptor agonists remain the most effective treatment for ITP and have changed the ITP therapeutic landscape remarkably. Other new molecules such as Fcγ receptor blockers, Bruton tyrosine kinase, complement inhibitors, and others are unlikely to enjoy the same success rate as the TPO-RAs, but nonetheless they will find a place in the management of patients with ITP.

Proposal for a New Protocol for the Management of Immune Thrombocytopenia (ITP).

For many decades immune thrombocytopenia (ITP) was managed using therapies which had not undergone randomised clinical trials and included corticosteroids, immune suppression or splenectomy. These older therapies are associated with an increase in morbidity and mortality. These empirical therapies have variable efficacy and well-described side effects for many patients with minimal benefit to the patient. Over the past 10 years there has been a shift away from immune suppression and non-evidence-based therapies towards using treatments with reduced or no immune suppression with an increasing reliance on the recently developed and approved thrombopoietin receptor agonists. The recent COVID-19 pandemic has made it more urgent that we develop non-immune suppressive strategies for ITP. In this commentary we describe our proposal for a contemporary approach to the management of ITP in adults that is based on our hospital practices and published guidelines.

Recent advances in the mechanisms and treatment of immune thrombocytopenia.

Primary immune thrombocytopenia is an autoimmune disease associated with a reduced peripheral blood platelet count. The phenotype is variable with some patients suffering no bleeding whilst others have severe bleeding which may be fatal. Variability in clinical behaviour and treatment responses reflects its complex underlying pathophysiology. Historically the management has relied heavily on immune suppression. Recent studies have shown that the older empirical immune suppressants fail to alter the natural history of the disease and are associated with a poor quality of life for patients. Newer treatments, such as the thrombopoietin receptor agonists, have transformed ITP care. They have high efficacy, are well tolerated and improve patients' quality of life. A greater understanding of the underlying pathophysiology of this disorder has helped develop a number of new targeted therapies. These include inhibitors of the neonatal Fc receptor inhibitors, Bruton tyrosine kinase and complement pathway. Here we discuss the mechanisms underlying ITP and the new approach to ITP care.

Psychometric Evaluation of ITP Life Quality Index (ILQI) in a Global Survey of Patients with Immune Thrombocytopenia.

INTRODUCTION: Immune thrombocytopenia (ITP) is an autoimmune disorder caused by immunologic destruction of otherwise normal platelets. Patients and physicians differ in their views pertaining to the limitations imposed on patients' daily lives by ITP and its treatment. Poor understanding of ITP symptoms can result in misdiagnosis and complex treatment patterns, and affect patient health-related quality of life (HRQoL). The ITP Life Quality Index (ILQI) is a 10-item patient-reported outcome measure developed for clinical practice to aid discussions between patients and physicians. This research aimed to validate the psychometric properties of the ILQI using data collected in the ITP World Impact Survey (I-WISh). METHODS: I-WISh data containing responses to the ILQI from 1507 patients with ITP across 13 countries worldwide was subject to psychometric analysis to evaluate the structure, reliability and validity of the ILQI and assess scoring cut-offs. RESULTS: The ILQI has an overarching unidimensional structure, supporting a total score including all 10 items. Reliability was supported (Cronbach's alpha = 0.90). ILQI scores monotonically increased with ITP severity. ILQI scores correlated with measures of fatigue and emotional well-being, supporting construct validity. Differential item functioning (DIF) analyses showed that ILQI item responses were interpreted similarly between the USA and other Western countries. It was suggested that previous clinical cut-off score of 20 for "impaired HRQoL" was reduced to 17 and a cut-off of 23-25 (rather than 30) was suggested to assess "significantly impaired HRQoL". CONCLUSION: The validity and reliability of the ILQI to assess HRQoL of patients with ITP is supported. The revised cut-off scores for the ILQI will aid patient-centric decision-making.

Qualitative study to support the content validity of the immune thrombocytopenia (ITP) Life Quality Index (ILQI).

Immune thrombocytopenia (ITP) is an acquired immune-mediated disorder. Bleeding is the primary symptom that presents in varying severities. ITP has a negative impact on health-related quality of life (HRQoL). The ITP Life Quality Index (ILQI) was developed as a 10-item patient-reported outcome measure to assess impact on HRQoL in ITP. The objective of the present study was to confirm the content validity of the ILQI with a qualitative interview study in the UK involving 15 adult participants with ITP. Combined concept elicitation (CE) and cognitive debriefing (CD) interviews were conducted to explore the symptoms and impacts associated with ITP and confirm content validity of the draft ILQI. The CE phase elicited 14 ITP symptom concepts, including: bruising (all 15 patients, 100%), fatigue (14, 93·3%) and bleeding gums/blood blisters (13, 86·7%). Impacts included decreased ability to participate in sport (all 15 patients, 100%) and anxiety (12, 80%). The CD phase resulted in an adjustment to the ILQI recall period from 1 week to 'the past month'. Updates were made to improve relevance and response options. The qualitative interviews support the content validity of the ILQI and confirm that the concepts assessed are relevant and consistently understood and interpreted by adult patients with ITP.