Long-term safety and efficacy of zilucoplan in patients with generalized myasthenia gravis: interim analysis of the RAISE-XT open-label extension study
James F. Howard, Saskia Bresch, Constantine Farmakidis, Miriam Freimer, Angela Genge, Channa Hewamadduma, John L. Hinton, Yessar Hussain, Raúl Juntas‐Morales, Henry J. Kaminski, Angelina Maniaol, Renato Mantegazza, Masayuki Masuda, Richard J. Nowak, Kumaraswamy Sivakumar, Marek Śmiłowski, Kimiaki Utsugisawa, Tuan Vu, Michael D. Weiss, Małgorzata Zajda, Jos Bloemers, Babak Boroojerdi, Melissa Brock, Guillemette de la Borderie, Petra W. Duda, Mark Vanderkelen, Maria Isabel Leite, the RAISE-XT Study Team*
Abstract
Background: Generalized myasthenia gravis (gMG) is a chronic, unpredictable disease associated with high treatment and disease burdens, with a need for more effective and well-tolerated treatments. Objectives: To evaluate the long-term safety, tolerability, and efficacy of zilucoplan in a mild-to-severe, acetylcholine receptor autoantibody-positive (AChR+) gMG population. Design: Ongoing, multicenter, phase III open-label extension (OLE) study. Methods: Eligible patients had completed a qualifying randomized, placebo-controlled phase II or phase III zilucoplan study and received daily, self-administered subcutaneous 0.3 mg/kg zilucoplan. The primary endpoint was incidence of treatment-emergent adverse events (TEAEs). Secondary efficacy endpoints included change from baseline in Myasthenia Gravis Activities of Daily Living (MG-ADL) score. Results: = 49, 25%). In patients who received zilucoplan 0.3 mg/kg in the parent study, further improvements in MG-ADL score continued through to Week 24 (least squares mean change [95% confidence interval] from double-blind baseline -6.06 [-7.09, -5.03]) and were sustained through to Week 60 (-6.04 [-7.21, -4.87]). In patients who switched from placebo in the parent study, rapid improvements in MG-ADL score were observed at the first week after switching to zilucoplan; further improvements were observed at Week 24, 12 weeks after switching (-6.46 [-8.19, -4.72]), and were sustained through to Week 60 (-6.51 [-8.37, -4.65]). Consistent results were observed in other efficacy endpoints. Conclusion: Zilucoplan demonstrated a favorable long-term safety profile, good tolerability, and sustained efficacy through to Week 60 with consistent benefits in a broad AChR+ gMG population. Additional long-term data will be available in future analyses. Trial registration: ClinicalTrials.gov identifier: NCT04225871 (https://clinicaltrials.gov/ct2/show/NCT04225871).