Introduction: Immune thrombocytopenia (ITP) is a rare autoimmune disorder characterised by abnormally high platelet destruction and impaired platelet production. Thrombopoietin-receptor agonists (TPO-RAs) are standard care for ITP patients who have failed on initial first-line immunosuppressive therapy. There is limited evidence quantifying patient attitudes towards TPO-RAs, with a specific emphasis on product characteristics such as method of administration, food restrictions, monitoring requirements and safety. We describe the methodology of a study aiming to investigate how TPO-RAs are used in the ITP population, and patients’ perceptions and preferences regarding specific attributes of existing options.

Design and methods: TRAPeze (Thrombopoietin Receptor Agonist Patient experience survey) is a cross-sectional observational study on TPO-RAs use in the ITP population and patient perceptions towards existing therapies. The study will be administered via online survey of ITP patients (n~150) who have been recently treated with a TPO-RA. In the first part, data on ITP disease characteristics, work and productivity, family impact and the utilisation of healthcare services will be collected for context. Current and prior treatment, and overall satisfaction with therapy, will first be explored with open and closed questions. More detailed patient preferences towards TPO-RA product attributes will be elicited using a discrete choice experiment (DCE). Participants will be presented with multiple scenarios of hypothetical treatment options and asked to select a product preference based on attributes relevant to the patient perspective. The experimental design aims for the most orthogonal and balanced design whilst presenting participants with the minimal number of scenarios.

Conclusion: We believe this is the first online use of DCE to explore patient perspectives in ITP care. Combined with a broader online questionnaire, such methodology may generate robust evidence from the patient perspective on treatment preferences, patterns and burden and hence may facilitate improved ITP management.