Anifrolumab Study for Treatment Effectiveness in the Real World (ASTER) among patients with systemic lupus erythematosus: protocol for an international observational effectiveness study.

Introduction: Systemic lupus erythematosus (SLE) is a chronic autoimmune disease with a diverse clinical presentation that involves multiple organ systems and may lead to organ damage and increased risk of mortality. SLE is associated with a high burden of disease that can include loss of productivity and employment and reduced health-related quality of life. The current standard of care for SLE is primarily based on immunosuppression and glucocorticoids and is associated with risk of toxicities and poor tolerability. Anifrolumab, a human monoclonal antibody to type I interferon receptor subunit 1, was recently approved as a new treatment for patients with moderate-to-severe SLE.

Methods And Analysis: Here, we report the study design of the ongoing, multinational Anifrolumab Study for Treatment Effectiveness in the Real World (ASTER) that includes 3-years of follow-up beginning with the first infusion of anifrolumab and 1 year of retrospective baseline data. ASTER aims to enrol 500 adult patients receiving anifrolumab for SLE in Europe and Canada. The key study objective is to describe the real-world effectiveness of anifrolumab in routine clinical practice, including clinician-reported disease activity and patient-reported outcomes collected via mobile application. This mobile application also includes a medication diary, where patients report their prescription and non-prescription medication use for SLE on a weekly basis; these data will lend insights on treatment patterns for the study population.

Ethics And Dissemination: The design of the ASTER study was informed through consultations with patients with SLE who provided important insights to help maximise patient engagement, retention and the collection of key, patient-relevant endpoints. ASTER enrolment began in February 2023 and the study is expected to finish in 2029.

Trial Registration Number: NCT05637112.