Sustained minimal symptom expression in generalized myasthenia gravis: A 120-week post hoc analysis of RAISE-XT

Topic:

Clinical Trials

Poster Number: 228 M

Author(s):

Channa Hewamadduma, MBBS, FRCP (Neuro), FRCPE, PhD, Academic Neuroscience Unit, Sheffield Teaching Hospitals NHS FT, and SITraN, Univ. of Sheffield, UK, Saskia Bresch, MD, Service de Neurologie, Hospital Pasteur, Centre Hospitalier Universitaire de Nice, Nice, France, Miriam Freimer, MD, Ohio State University, Raul Juntas-Morales, MD, PhD, Department of Neurology, Vall d’Hebron University Hospital, Passeig de la Vall d’Hebron, Barcelona, M. Isabel Leite, University of Oxford, Angelina Maniaol, PhD, Department of Neurology, Oslo University Hospital, Oslo, Norway, Kimiaki Utsugisawa, Hanamaki General Hospital, Tuan Vu, MD, University of South Florida, Michael Weiss, MD, Department of Neurology, University of Washington Medical Center, Seattle, WA, USA, Babak Boroojerdi, MD, PhD, MBA, UCB, Monheim, Germany, Fiona Grimson, PhD, UCB, Slough, UK, Natasa Savic, MD, PhD, UCB, Bulle, Switzerland, James F. Howard Jr., MD, University of North Carolina

Introduction

Minimal symptom expression (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 (MG). This post hoc analysis of RAISE-XT (NCT04225871), a Phase 3, open-label extension study of the complement component 5 inhibitor zilucoplan, assessed the durability of MSE response.

Methods

Adults with anti-acetylcholine receptor antibody-positive generalized MG 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 0.3mg/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 cut-off: 11 November 2023).

Results

Of 200 patients enrolled in RAISE-XT, 183 received zilucoplan 0.3mg/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 0.3mg/kg/zilucoplan 0.3mg/kg and placebo/zilucoplan 0.3mg/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.

Conclusion

Zilucoplan demonstrated sustained efficacy, as shown by maintenance of MSE response up to 120 weeks of treatment.