Patterns Of Treatment And Retreatment Of Acute Attacks Of Hereditary Angioedema (Hae) With Standard Of Care (Soc) On-Demand Medication: Results From The Apex-2 Study

Berotralstat (BCX7353), administered orally once daily, is an inhibitor of plasma kallikrein in development for prophylaxis of HAE. Efficacy over a 24-week period was evaluated in the Phase 3, randomized, double-blind, placebo-controlled APeX-2 study (NCT03485911). This exploratory analysis evaluated use of SOC on-demand medications. Subjects with HAE Type 1/2 and ≥2 attacks in the 14-56 day baseline period were randomized 1:1:1 to berotralstat 110mg:berotralstat 150mg:placebo daily for 24 weeks. Subjects were to treat HAE attacks according to their usual treatment plan. Retreatment was defined as use of >1 dose of SOC on-demand medication to treat an attack. SOC on-demand medications were used in 87.2% of attacks. Of these, Firazyr® SC, Berinert® IV, Cinryze® IV, and Ruconest® IV were used first-line in 53.0%, 29.3%, 10.8%, and 6.9% of attacks, respectively. Overall, 17.3% of attacks were retreated with the same or another SOC on-demand medication (11.4%, 14.5%, and 24.2% of attacks in the 110mg, 150mg, and placebo arms, respectively). Retreatment was most common when Firazyr was used first-line, with 26.9% of attacks retreated. Firazyr was the most frequently used SOC on-demand medication for HAE attacks and had the highest rate of retreatment. The percentage of attacks retreated with SOC on-demand medications was lower for the daily oral 110mg and 150mg berotralstat arms than in the placebo arm, suggesting reduced attack severity on berotralstat.