Romiplostim in children with newly diagnosed or persistent primary immune thrombocytopenia

Update on the Use of Thrombopoietin-Receptor Agonists in Pediatrics

This review summarizes the rationale and current data on the use of thrombopoietin receptor agonists (TPO-RAs) for treating severe thrombocytopenia in infants, children, and adolescents. It focuses on substances that have been approved by the U.S. Food and Drug Administration (FDA) and European Medicines Agency (EMA) for pediatric patients. Romiplostim and eltrombopag are already established as second-line treatment for persistent or chronic immune thrombocytopenia (ITP). As in adults, TPO-RAs are currently also evaluated in severe aplastic anemia (SAA), chemotherapy-induced thrombocytopenia (CIT), myelodysplastic syndromes (MDS), and poor engraftment after hematopoietic stem cell transplantation in pediatric and adolescent patients. Moreover, studies on the implication of TPO-RA in treating rare inherited thrombocytopenias, such as Wiskott-Aldrich syndrome (WAS), congenital amegakaryocytic thrombocytopenia (CAMT), or MYH9-associated thrombocytopenia, deserve future attention. Current developments include testing of avatrombopag and lusutrombopag that are approved for the treatment of thrombocytopenia associated with chronic liver disease (CLD) in adult patients. In pediatric and adolescent medicine, we expect in the near future a broader use of TPO-RAs as first-line treatment in primary ITP, thereby considering immunomodulatory effects that increase the rate of sustained remission off-treatment, and a selective use in rare inherited thrombocytopenias based on current clinical trials.

Recommendations for the management of acute immune thrombocytopenia in children. A Consensus Conference from the Italian Association of Pediatric Hematology and Oncology

BACKGROUND

Immune thrombocytopenia (ITP) is an acquired immune-mediated bleeding disorder characterized by isolated thrombocytopenia. Its estimated yearly incidence in the pediatric population is 1.9-6.4/100,000. ITP in children is usually a self-limiting and benign disorder. The clinical management of children with ITP often remains controversial, as robust randomized trials on the management of this disorder are lacking. Treatments vary widely in clinical practice and existing guidelines from hematology societies on clinical management offer indications based largely on expert opinion rather than strong evidence.

MATERIALS AND METHODS

The Coagulative Disorder Working Group of the Italian Association of Pediatric Hematology and Oncology (AIEOP) developed this document to collect shared expert opinions on the management of newly diagnosed ITP, updating previous guidelines and providing recommendations to pediatricians. Each statement has been given a score expressing the strength of evidence, appropriateness and agreement among participants.

RESULTS

Clear-cut definitions of the clinical phases of the disease and clinical response are stated. Recommendations are given regarding the classification of bleeding symptoms, evaluation of bleeding risk, diagnosis, and prognostic factors. Specific recommendations for treatment include indications for first-line (intravenous immunoglobulins, steroids) and second-line (combined therapy, thrombopoietin receptor agonists, immunosuppressive drugs, rituximab) therapeutic agents, as well as hemorrhagic emergency and supportive treatment, including emergency splenectomy. The optimal follow-up schedule, the relation between ITP and vaccines and health-related quality-of-life issues are also discussed.

DISCUSSION

The panel achieved broad consensus on issues related to how to treat children with newly diagnosed ITP, providing a comprehensive review of all relevant clinical aspects.

Can low-dose intravenous immunoglobulin be an alternative to high-dose intravenous immunoglobulin in the treatment of children with newly diagnosed immune thrombocytopenia: a systematic review and meta-analysis

Intravenous immunoglobulin (IVIg) is a first-line treatment for children with newly diagnosed immune thrombocytopenia (ITP). Higher doses of IVIg are associated with a more insupportable financial burden to pediatric patients' families and may produce more adverse reactions. Whether low-dose IVIg (LD-IVIg) can replace high-dose IVIg (HD-IVIg) has yet to be established. We conducted a comprehensive literature search from the establishment of the database to May 1, 2023, and eventually included 22 RCTs and 3 cohort studies compared different dosages of IVIg. A total of 1989 patients were included, with 991 patients in the LD-IVIg group and 998 patients in the HD-IVIg group. Our results showed no significant differences between the two groups in the effective rate (LD-IVIg: 91% vs. HD-IVIg: 93%; RR: 0.99; 95%CI: 0.96-1.02) and the durable remission rate (LD-IVIg: 65% vs. HD-IVIg: 67%; RR: 0.97; 95%CI: 0.89-1.07). Similar results were also found in the time of platelet counts (PC) starting to rise (MD: 0.01, 95%CI: -0.06-0.09), rising to normal (MD: 0.16, 95%CI: -0.03-0.35), and achieving hemostasis (MD: 0.11, 95%CI: -0.02-0.23) between the two groups. Subgroup analysis showed the effective rate of 0.6 g/kg was equal to 1 g/kg subgroup (91%) but higher than 0.8 g/kg subgroup (82%), and a combination with glucocorticoid may contribute to effect enhancement (combined with glucocorticoid: 91% vs. IVIg alone: 86%) whether combined with dexamethasone (92%) or methylprednisolone (91%). Besides, the incidence rate of adverse reactions in the LD-IVIg group (3%) was significantly lower than the HD-IVIg group (6%) (RR: 0.61; 95%CI: 0.38-0.98). So low-dose IVIg (≤ 1 g/kg) is effective, safe, and economical, which can replace high-dose IVIg (2 g/kg) as an initial treatment. This systematic review was registered in PROSPERO (CRD42022384604).

Low-dose intravenous immunoglobulin for children with newly diagnosed immune thrombocytopenia: protocol of a systematic review and meta-analysis

INTRODUCTION

Intravenous immunoglobulin (IVIg) is a first-line treatment for children with newly diagnosed immune thrombocytopenia (ITP). However, the cost of IVIg is high. Higher doses of IVIg are associated with a more insupportable financial burden to paediatric patients' families and may produce more adverse reactions. Whether low-dose IVIg can quickly stop bleeding and induce a durable response in treating children with newly diagnosed ITP is not yet established.

METHODS AND ANALYSIS

We will extensively search five English databases (PubMed, Embase, Web of Science, Cochrane Central Register of Controlled Trials, Cumulative Index of Nursing and Allied Health Literature) and three Chinese databases (CNKI, Wanfang and VIP). International Clinical Trials Registry Platform and ClinicalTrials.gov will also be searched as supplementary. Randomised controlled trials and prospective observational studies compared the efficacy of low-dose IVIg and high-dose or moderate-dose IVIg will be included. The primary outcome is the proportion of patients achieving durable response. Estimates of effect will be pooled with either a random-effect model or a fixed-effect model according to the heterogeneity of studies. If significant heterogeneity exists, we will conduct subgroup analysis and sensitivity analysis to explore the source of heterogeneity and evaluate the robustness of the results. Publication bias will also be assessed, if possible. The risk of bias will be assessed using the Risk of Bias 2 and Risk Of Bias In Non-randomised Studies of Interventions tools. The certainty of evidence will be evaluated using the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) system.

ETHICS AND DISSEMINATION

No ethical approval is required since this systematic review is based on previously published studies. The findings of this study will be presented at international conferences or published in a peer-reviewed journal.

PROSPERO REGISTRATION NUMBER

CRD42022384604.

Evaluating the impact of thrombopoietin receptor agonist medications on patient outcomes and quality of life in paediatric immune thrombocytopenia through semi-structured interviews

Over the last decade, treatment of immune thrombocytopenia (ITP) in children has advanced to include thrombopoietin receptor agonist (TPO-RA) medications. Concurrently, there has been an increased emphasis on patient-reported outcomes-especially quality of life-to guide treatment. Assessing the impact of TPO-RAs on quality of life in paediatric ITP is therefore a priority. In this single-centre integrative mixed-methods study, a cohort of children with ITP prescribed a TPO-RA was identified. These children and/or their caregivers were invited to participate in semi-structured interviews focussed on quality-of-life measures. Independently, a retrospective chart review collected ITP-related data (platelet count, bleeding events) and TPO-RA data (dosing, side effects). Among the 23 eligible patients, 20 were represented in interviews. On chart review, 11/20 patients responded to TPO-RA by meeting platelet count criteria of ≥50 × 10⁹ /L for six or more weeks in the absence of rescue therapy. In interviews with these children and/or their parents, 19/20 expressed the TPO-RA had 'worked', with 11/20 reporting benefit to mood and 11/20 reporting increased participation in activities/sports. Concerns were raised in interviews about TPO-RA medication cost (17/20), medication administration (10/20) and potential side effects (10/20). In conclusion, this study suggests that TPO-RA use in children with ITP improves quality of life.

[Expression of miR-106b-5p in children with primary immune thrombocytopenia and its correlation with T cells]

OBJECTIVES

To study the expression level of plasma miR-106b-5p in primary immune thrombocytopenia (ITP) and its correlation with the levels of T helper 17 cell (Th17) and regulatory T cell (Treg) and the Th17/Treg ratio.

METHODS

A total of 79 children with ITP (ITP group) and 40 healthy children (control group) were selected as subjects. According to the treatment response, the 79 children with ITP were divided into three groups: complete response (n=40), partial response (n=18), and non-response (n=21). Quantitative real-time PCR was used to measure the expression level of miR-106b-5p. Flow cytometry was used to measure the frequencies of Th17 and Treg, and the Th17/Treg ratio was calculated. The correlation of the expression level of plasma miR-106b-5p with the frequencies of Th17 and Treg and the Th17/Treg ratio was analyzed.

RESULTS

Compared with the control group, the ITP group had significantly higher levels of miR-106b-5p, Th17, and Th17/Treg ratio (P<0.05) and a significantly lower level of Treg (P<0.05). After treatment, the ITP group had significant reductions in the levels of miR-106b-5p, Th17, and Th17/Treg ratio (P<0.05) and a significant increase in the level of Treg (P<0.05). Compared with the partial response and non-response groups, the complete response group had significantly lower levels of miR-106b-5p, Th17, and Th17/Treg ratio (P<0.05) and a significantly higher level of Treg (P<0.05). The correlation analysis showed that in the children with ITP, the expression level of plasma miR-106b-5p was positively correlated with the Th17 level and the Th17/Treg ratio (r=0.730 and 0.816 respectively; P<0.001) and was negatively correlated with the Treg level (r=-0.774, P<0.001).

CONCLUSIONS

A higher expression level of miR-106b-5p and Th17/Treg imbalance may be observed in children with ITP. The measurement of miR-106b-5p, Th17, Treg, and Th17/Treg ratio during treatment may be useful to the evaluation of treatment outcome in children with ITP.