Evaluating the Impact of Thrombopoietin Receptor Agonists Medications on Patient Outcomes and Quality of Life in Pediatric Immune Thrombocytopenia
Authors: Livingston Joel , Jackson Melanie , Alrajihi Ziyad , McGuire Catherine , Klaassen Robert J , Kirby -Allen Melanie 
Published: November 2021

Abstract

Introduction: The treatment of Immune Thrombocytopenia (ITP) in children has advanced significantly over the last decade with novel therapies and enhanced clinical care guidelines. Recent American Society of Hematology guidelines now recommend the use of thrombopoietin receptor agonist (TPO-RA) medications as the preferred second line therapy for children with ITP. Accompanying this change, recent ASH guidelines also put emphasis on quality of life in managing ITP, acknowledging the detrimental affect ITP and previous managements can have on patient's and family's quality of life. With this change in guidelines, evaluating the impact of these medications on patient reported outcomes outside of clinical trials is important to evaluate the efficacy of therapy. While there is data from adult studies to show that TPO-RAs improve patient's health related quality of life (HRQoL), results were not statistically significant in previous clinical trials in children. Thus, the goal of the present study is to address this gap and describe the real-world experience of using TPO-RAs in pediatric ITP including the impact on patient-reported HRQoL.
Methods: We reviewed all children aged 1-18 at our institution with a diagnosis of ITP and started on a TPO-RA medication after March 1, 2017 (date of TPO-RA for pediatric ITP licensure in Canada). A chart review was conducted to collect demographic data (e.g., age, associated diagnoses, previous therapies), TPO-RA data (e.g. dose(s), monitoring, side effects), outcome data (e.g., platelet count, need for emergency treatments). To explore the impact of TPO-RA use on patient-reported HRQoL, semi-structured interviews were conducted by phone with patients over age 7 and/or their guardians with topics including the effects of the TPO-RA on patient symptoms (e.g. bleeding, bruising, need for emergency treatment), activities (e.g. sports, hobbies, social events) mood (e.g. anxiety, stress, fatigue) and financial burden of treatment (e.g. coverage for medication). These interviews were conducted data in parallel to reviewing the Kids ITP Tool (KIT) questionnaire and a qualitative analysis of HRQoL was performed.
Results: We identified 25 patients on a TPO-RA medication for pediatric ITP, of these, 3 were on romiplostim, 20 were on eltrombopag and 2 had been on both romiplostim and eltrombopag at different times. The median age at start of TPO-RA was 9 years (range 1 - 16 years). 14/25 responded to TPO-RA medication by meeting platelet count criteria. The average number of treatments per patient in the 6 months prior to commencing a TPO-RA was 3.7 and in the 6 months post commencing a TPO-RA was 0.5. No significant side effects observed with TPO-RA use, although 2 patients had a transient rise in liver enzymes.
Of the 25 patients on a TPO-RA, 23 were eligible to participate in the semi-structured interviews (1 family having permanently relocated out of country and was not contactable; one family had a significant language barrier). With interviews ongoing, 11/23 patients and/or families have participated and results to date indicate that the majority (&gt;90%) have seen an improvement in quality of life. All participants interviewed at the time of abstract submission reported improvement in bleeding/bruising symptoms. The majority also noted a reduction in the frequency of emergency treatments and hematology clinic visits. Several participants reported on their ability to resume sports/activities once on a TPO-RA. While there was some reduction in parental stress/worry there was no clear benefit to patient fatigue/mood. Financial concerns about medication costs and duration of therapy were raised, and many parents expressed the cost of medication and source of ongoing funding a significant stressor. There were also concerns related to oral administration for younger children.
Discussion: To our knowledge, this is the first post-licensing study to look at the impact of TPO-RA medications on patient-reported HRQoL in children with ITP. At our institution, TPO-RA medications prescribed for pediatric ITP have had a positive impact on patient platelet count and resulted in a reduced need for emergency treatment with minimal noted side effects. There also appears to be a positive impact on patient reported HRQoL reported by the majority of patients and/or families, while issues with medication administration, cost and long-term duration of therapy remain a concern.

Disclosures
Klaassen: Agios Pharmaceuticals: Consultancy; Amgen: Membership on an entity's Board of Directors or advisory committees; Hoffman-La Roche: Consultancy; Novo Nordisk: Consultancy; Octapharma AG: Consultancy; Sanofi: Consultancy; Takeda: Consultancy.