Long-Term Prophylaxis for Hereditary Angioedema: Real-World Treatment Patterns in Selected US Allergy Clinics

Introduction Hereditary angioedema (HAE) is a rare genetic disorder which causes recurrent and unpredictable swelling attacks that pose high morbidity and risk of death. Long-term prophylactic (LTP) treatments are an important clinical management tool to reduce attack frequency. This study aims to assess real-world treatment patterns among US patients receiving LTP therapy. Methods The Patient Important Outcomes National Data Repository for Hereditary Angioedema (PIONEER) HAE registry contains structured and unstructured data for patients within the Consortium of Independent Immunology Clinics (CIIC). Eligibility criteria included diagnosis of HAE due to C1-inhibitor deficiency (HAE-C1NH), observation between April-2021 to March-2024 and record of a LTP therapy. Index therapy was defined as the earliest prophylactic therapy for which the patient had at least 180 days of medical history prior to initiation and 180 days of follow-up thereafter. Patients were observed for up to three years. Results This study included 179 patients; most had HAE-C1INH Type 1 (86%) with median age 38 years (IQR 25-53). Index therapy included kallikrein inhibitors (55%), C1-esterase inhibitors (37%), androgens (6%), and anti-fibrinolytic agents (2%); most often initiated in 2019 (21%). Eighty-three (46%, 83/179) discontinued index therapy, with a median 12 (IQR: 4.8-33) months to discontinuation. Discontinuations were most commonly due to lack of efficacy (29%, 76/83). Of those, 48/83 (58%) switched or restarted prophylactic therapy. Conclusion Nearly half of patients discontinued their index LTP at some point during the observation period, primarily due to efficacy, administration, or dosing challenges. Advanced understanding of unmet treatment needs and other important factors in the HAE treatment landscape will require more robust and detailed data on real-world treatment decision-making.