Long-term outcomes after splenectomy in children with immune thrombocytopenia: an update on the registry data from the Intercontinental Cooperative ITP Study Group

What is in a name: defining pediatric refractory ITP

ABSTRACT

There are no agreed upon terminology to define "refractory" pediatric immune thrombocytopenia (ITP). Guidelines are therefore limited to arbitrary and outdated definitions. The Pediatric ITP Consortium of North America held a meeting in 2023 to define this entity. With 100% agreement, the faculty established that pediatric ITP that is refractory to emergent therapy could be defined as no platelet response after treatment with all eligible emergent pharmacotherapies. With 100% agreement, the working group established that pediatric patients with ITP that continue to demonstrate high disease burden and/or no platelet response despite treatment with multiple classes of disease-modifying therapies represent a challenging subset of ITP. These patients are at higher risk of ongoing disease burden and merit additional investigation as well as consideration for clinical trials or novel therapies. Future efforts to define disease burden and disease response will be completed in collaboration with the ITP International Working Group.

Generic romiplostim for children with persistent or chronic immune thrombocytopenia: Experience from a tertiary care centre in North India

Thrombopoietin receptor agonists are important therapeutic option in children with immune thrombocytopenia (ITP). We evaluated the response, efficacy, safety of a generic form of romiplostim manufactured in India for treating children with persistent/chronic ITP at our centre. Study of 45 children with persistent/chronic ITP was conducted of which 5 discontinued and 40 were included between 2019-2020. Patients received romiplostim for 20 weeks, at a dose of 5 mcg/kg/week. Platelet count at week 1, 3, 20 and 26 was assessed. Predesigned algorithm was used for dose adjustment. After 20 weeks, patients who had platelet count of 50 × 109/L or above were tapered off medication and monitored till 26 weeks. Median platelet count at enrolment was 11 x 109/L (IQR 23 X 109/L). 13/40 children had received >/= three lines of prior ITP therapy. Platelet response (platelet count rise to more than 50×109/L without rescue medications) observed in 26 (65%) patients at week 20. Rescue medication was used in 12/40 children. Sustained platelet response after tapering and stopping romiplostim observed in 22/40 children. No adverse events were considered serious or led to discontinuation of treatment. Our data demonstrated generic romiplostim is well tolerated and efficacious in children with persistent/chronic ITP.

Determinants of splenectomy long-term outcomes in pediatric autoimmune cytopenias

Splenectomy is effective in ~70-80% of pediatric chronic immune thrombocytopenia (cITP) and few data exist in autoimmune hemolytic anemia (AIHA) and Evans syndrome (ES). Because of the irreversibility of the procedure and the lack of predictor of long-term outcomes, splenectomy decision is difficult to take in children. We report here factors associated with splenectomy outcomes from the OBS'CEREVANCE cohort, which prospectively includes French children with autoimmune cytopenia (AIC) since 2004. The primary outcome was failure-free survival (FFS), defined as the time from splenectomy to the initiation of a second-line treatment (other than steroids and intravenous immunoglobulins) or death. We included 161 patients (cITP n = 120, AIHA n = 19, ES n = 22) with a median (min-max) follow-up of 6.8 years (1.0-33.3) after splenectomy. AIC subtype was not associated with FFS. We found that immunopathological manifestations (IMs) were strongly associated with unfavorable outcomes. Diagnosis of an IM before splenectomy was associated with a lower FFS (hazard ratio [HR] 0.39, 95% confidence interval [CI] 0.21-0.72, p = 0.003, adjusted for AIC subtype). Diagnosis of an IM at any timepoint during follow-up was associated with an even lower FFS (HR 0.22, 95% CI 0.12-0.39, p = 2.8x10-7, adjusted for AIC subtype) as well as with higher risk of recurrent or severe bacterial infections and thrombosis. In conclusion, our results support the search for associated IMs when considering a splenectomy to refine the risk-benefit ratio. After the procedure, monitoring IMs helps to identify patients with higher risk of unfavorable outcome.

An Update on Pediatric Immune Thrombocytopenia (ITP): Differentiating Primary ITP, IPD, and PID

Immune thrombocytopenia (ITP) is the most common acquired thrombocytopenia in children and is caused by both immune-mediated decreased platelet production and increased platelet destruction. In the absence of a diagnostic test, ITP must be differentiated from other thrombocytopenic disorders, including inherited platelet disorders (IPD). In addition, a diagnosis of secondary ITP due to a primary immune deficiency (PID) with immune dysregulation may not be apparent at diagnosis but can alter management and should be considered in an expanding number of clinical scenarios. The diagnostic evaluation of children with thrombocytopenia will vary based on the clinical history and laboratory features. Access to genotyping has broadened the ability to specify the etiology of thrombocytopenia, while increasing access to immunophenotyping, functional immunologic and platelet assays, and biochemical markers has allowed for more in-depth evaluation of patients. With this greater availability of testing, diagnostic algorithms in patients with thrombocytopenia have become complex. In this article, we highlight the diagnostic evaluation of thrombocytopenia in children with a focus on ITP, including consideration of underlying genetic and immune disorders, and utilize hypothetical patient cases to describe disease manifestations and strategies for treatment of pediatric ITP.

Primary Immune Thrombocytopenia: Novel Insights into Pathophysiology and Disease Management

Immune thrombocytopenia (ITP) is an autoimmune disorder defined by a significantly reduced number of platelets in blood circulation. Due to low levels of platelets, ITP is associated with frequent bruising and bleeding. Current evidence suggests that low platelet counts in ITP are the result of multiple factors, including impaired thrombopoiesis and variations in immune response leading to platelet destruction during pathological conditions. Patient outcomes as well as clinic presentation of the disease have largely been shown to be case-specific, hinting towards ITP rather being a group of clinical conditions sharing common symptoms. The most frequent characteristics include dysfunction in primary haemostasis and loss of immune tolerance towards platelet as well as megakaryocyte antigens. This heterogeneity in patient population and characteristics make it challenging for the clinicians to choose appropriate therapeutic regimen. Therefore, it is vital to understand the pathomechanisms behind the disease and to consider various factors including patient age, platelet count levels, co-morbidities and patient preferences before initiating therapy. This review summarizes recent developments in the pathophysiology of ITP and provides a comprehensive overview of current therapeutic strategies as well as potential future drugs for the management of ITP.

A risk score for predicting hospitalization for community-acquired pneumonia in ITP using nationally representative data

Infection is one of the primary causes of death from immune thrombocytopenia (ITP), and the lungs are the most common site of infection. We identified the factors associated with hospitalization for community-acquired pneumonia (CAP) in nonsplenectomized adults with ITP and established the [corrected] (ACPA) prediction model to predict the incidence of hospitalization for CAP. This was a retrospective study of nonsplenectomized adult patients with ITP from 10 large medical centers in China. The derivation cohort included 145 ITP inpatients with CAP and 1360 inpatients without CAP from 5 medical centers, and the validation cohort included the remaining 63 ITP inpatients with CAP and 526 inpatients without CAP from the other 5 centers. The 4-item ACPA model, which included age, Charlson Comorbidity Index score, initial platelet count, and initial absolute lymphocyte count, was established by multivariable analysis of the derivation cohort. Internal and external validation were conducted to assess the performance of the model. The ACPA model had an area under the curve of 0.853 (95% confidence interval [CI], 0.818-0.889) in the derivation cohort and 0.862 (95% CI, 0.807-0.916) in the validation cohort, which indicated the good discrimination power of the model. Calibration plots showed high agreement between the estimated and observed probabilities. Decision curve analysis indicated that ITP patients could benefit from the clinical application of the ACPA model. To summarize, the ACPA model was developed and validated to predict the occurrence of hospitalization for CAP, which might help identify ITP patients with a high risk of hospitalization for CAP.