LANADELUMAB EFFICACY AFTER SWITCHING FROM PLACEBO: RESULTS FROM THE HELP AND HELP OPEN-LABEL EXTENSION STUDIES

Introduction Lanadelumab significantly reduced hereditary angioedema (HAE) attack rates versus placebo over 26 weeks in the phase 3 double-blind (DB) HELP Study (NCT02586805). Patients who completed the DB continued into the ongoing open-label extension study (OLE; NCT02741596). This interim analysis of data from 26May2016-01Sept2017 evaluated lanadelumab efficacy in the OLE among patients who received placebo in the DB. Methods Patients from the DB placebo group received a single 300 mg lanadelumab dose on Day 1 of the OLE. Following their first attack, they received lanadelumab 300 mg every 2 weeks. Results 33 patients from the DB placebo group entered the OLE. Their median time on study in the OLE was 8.6 months (range 6.6-12.6 months); all patients completed ≥6 months’ time on study, and 14 (42.4%) patients completed ≥9 months. During the DB run-in and treatment periods, patients had a median attack rate of 2.90 and 1.82 attacks/month, respectively (Figure). During the OLE, the median attack rate was 0.10 attacks/month. The median change in attack rate between the DB and OLE treatment periods was −1.38 attacks/month (−98.5%). Conclusions Consistent with the DB results, there was a significant reduction in attack rate with lanadelumab treatment among patients who previously received placebo. Attack rates in the DB and OLE studies