Sustained Effectiveness, Tolerability, and Safety of Long-Term Prophylaxis with Lanadelumab in Hereditary Angioedema: The Prospective, Phase 4, Noninterventional EMPOWER Real-World Study

Introduction: Lanadelumab is approved for long-term prophylaxis of hereditary angioedema (HAE) attacks in patients aged ≥ 2 years in the USA and aged ≥ 12 years in Canada. The EMPOWER Study (NCT03845400) evaluated the real-world effectiveness and safety of lanadelumab in male and female patients with HAE due to C1 inhibitor deficiency type 1 or 2 from the USA and Canada. Here, we report final, up to 36-month, data. Methods: Patients aged ≥ 12 years were classified as newly treated with lanadelumab or established on lanadelumab (receiving < 4 and ≥ 4 lanadelumab doses at enrollment, respectively). The primary objective was effectiveness of lanadelumab as measured by HAE attack rate before and after lanadelumab initiation. Safety data were collected. Results: A total of 109 patients received ≥ 1 lanadelumab dose and had ≥ 1 post-baseline safety assessment. Patients were 40.9 (17.4) years of age (mean [standard deviation (SD)]), majority (72/109; 66.1%) female, 37/109 (33.9%) male, and over 90% white. Patients newly treated with and established on lanadelumab received lanadelumab for 737.7 (374.5) (mean [SD]) and 907.1 (469.3) days, respectively, during the study. In patients newly treated with lanadelumab, the mean (95% confidence interval) observed attack rate (attacks/month) decreased by 85% after lanadelumab initiation, from 1.42 (0.34–2.50) pre-lanadelumab to 0.20 (0.02–0.38) post-lanadelumab initiation (cumulative period). Patients established on lanadelumab had an observed attack rate of 0.20 (0.10–0.30) during 36 months’ follow-up. Of 154 treatment-emergent adverse events (TEAEs), no injection site reactions were reported and 6 (in 2 patients) were considered related to lanadelumab; no lanadelumab-related TEAEs were serious. Conclusion: Real-world data from EMPOWER showed marked HAE attack rate reduction up to 36 months after initiating lanadelumab in patients newly treated with lanadelumab and maintenance of low attack rates in patients established on lanadelumab. No new safety signals were identified. Trial Registration: ClinicalTrials.gov, identifier NCT03845400.