Long-Term Efficacy and Safety of Ravulizumab in Adults With Anti-Acetylcholine Receptor Antibody-Positive Generalized Myasthenia Gravis: Final Results From the Phase 3 CHAMPION MG Open-Label Extension

Abstract

Background: Ravulizumab, an anti-complement C5 monoclonal antibody, was efficacious with acceptable safety in the randomized controlled period (RCP) and interim open-label extension (OLE) periods of the CHAMPION MG phase 3 trial in adults with anti-acetylcholine receptor antibody-positive (AChR-Ab+) generalized myasthenia gravis (gMG). Here, we report final results from the OLE. Methods: Patients who completed the 26-week RCP could enter the OLE and receive ravulizumab for up to 4 years. Efficacy and safety were assessed throughout the OLE. Results: Among all ravulizumab-treated patients (n = 169; median [range] ravulizumab treatment, 759.0 [14.0, 1265.0] days), 161 entered the OLE (ravulizumab-ravulizumab: n = 78; placebo-ravulizumab: n = 83). Sustained improvements were observed in Myasthenia Gravis Activities of Daily Living (MG-ADL) total scores (ravulizumab-ravulizumab, least squares mean [95% CI] change from RCP baseline at week 164: −4.0 [−5.3, −2.8]; p < 0.0001; placebo-ravulizumab, change from OLE baseline after 138 weeks of treatment: −2.1 [−3.3, −0.9]; p = 0.0005). One hundred and forty-one out of 160 (88.1%) patients achieved a ≥ 2-point improvement in MG-ADL total score, and 59/141 (41.8%) achieved a score of 0 or 1; once achieved, 32/59 (54.2%) sustained this status for > 50% of their remaining time in the study. Similar improvements were observed in Quantitative Myasthenia Gravis and Myasthenia Gravis Quality of Life-15 revised scores, and Neurological Quality of Life Fatigue subscale scores. Clinical deterioration event rates were reduced in the OLE versus placebo in the RCP. Corticosteroid usage was reduced in the OLE. Ravulizumab was well tolerated; no meningococcal infections were reported. Conclusion: Ravulizumab demonstrated clinically meaningful and durable efficacy and safety in adults with AChR-Ab+ gMG.