Sustained Minimal Symptom Expression in Generalized Myasthenia Gravis: A 120-week Post Hoc Analysis of RAISE-XT
James F. Howard Jr.1, Saskia Bresch2, Miriam Freimer3, Raul Juntas-Morales4, M. Isabel Leite5, Angelina Maniaol6, Kimiaki Utsugisawa7, Tuan Vu8, Michael D. Weiss9, Babak Boroojerdi10, Fiona Grimson10, Natasa Savic10, Channa Hewamadduma11
1Department of Neurology, The University of North Carolina at Chapel Hill, 2Service de Neurologie, Hospital Pasteur, Centre Hospitalier Universitaire de Nice, 3Department of Neurology, The Ohio State University Wexner Medical Center, 4Department of Neurology, Vall d’Hebron University Hospital, 5Nuffield Department of Clinical Neurosciences, University of Oxford, 6Department of Neurology, Oslo University Hospital, 7Department of Neurology, Hanamaki General Hospital, 8Department of Neurology, University of South Florida Morsani College of Medicine, 9Department of Neurology, University of Washington Medical Center, 10UCB, 11Academic Neuromuscular Unit, Sheffield Teaching Hospitals NHS Foundation Trust
Objective:
A post hoc analysis to assess the durability of minimal symptom expression (MSE) response during treatment with zilucoplan in patients with generalized myasthenia gravis (gMG).
Background:
MSE, defined as a Myasthenia Gravis Activities of Daily Living (MG-ADL) score of 0 or 1, is a rigorous measure of therapeutic efficacy in myasthenia gravis. RAISE-XT (NCT04225871) is a Phase 3, open-label extension study of the complement component 5 inhibitor zilucoplan.
Design/Methods:
Adults with anti-acetylcholine receptor antibody-positive gMG who completed a qualifying double-blind, placebo-controlled study (NCT03315130/NCT04115293 [RAISE]) could opt to enter RAISE-XT and self-administer once-daily subcutaneous injections of zilucoplan 0.3 mg/kg. The cumulative proportion of patients who achieved MSE (MG-ADL score of 0 or 1 without rescue therapy) at any time during zilucoplan treatment up to Week 120 and the proportion of time spent in MSE up to Week 120 were assessed post hoc (interim data cutoff: November 11, 2023).
Results:
Of 200 patients enrolled in RAISE-XT, 183 received zilucoplan 0.3 mg/kg or placebo in the double-blind studies. The cumulative proportion of patients who achieved MSE at any time from the start of zilucoplan treatment up to Week 120 in the zilucoplan 0.3 mg/kg/zilucoplan 0.3 mg/kg and placebo/zilucoplan 0.3 mg/kg groups was 61% and 64%, respectively. After first achieving MSE during zilucoplan treatment, patients maintained their MSE response for a median (range) of 80.8% (0.8–100.0%) of their remaining time in the study up to Week 120. Treatment-emergent adverse events were experienced by 97.0% (n=194/200) of patients; most were mild or moderate.
Conclusions:
Zilucoplan demonstrated sustained efficacy, as shown by maintenance of MSE response up to 120 weeks of treatment.
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