Ravulizumab in Adults with Generalized Myasthenia Gravis: A Sub-Analysis of the Phase 3 CHAMPION MG Study According to Chronic IVIg Use at Study Entry
Vera Bril1, Jin-Hong Shin2, Nicholas Silvestri3, James Winkley4, Andrew Gordon5, Yasushi Suzuki6, Rasha Aguzzi7, Glen Frick7
1Toronto General Hospital, 2Pusan National University Yangsan Hospital, 3UBMD Neurology, 4Baptist Health Neurology, 5Northwest Neurology, 6National Hospital Organization Sendai Medical Center, 7Alexion, AstraZeneca Rare Disease
Objective:
To assess differences in response to ravulizumab in adults with anti-acetylcholine receptor antibody-positive (AChR Ab+) generalized myasthenia gravis (gMG), according to previous intravenous immunoglobulin (IVIg) treatment.
Background:
The long-acting terminal complement C5 inhibitor, ravulizumab, demonstrated sustained efficacy and was well tolerated in the phase 3 CHAMPION MG study in adults with AChR Ab+ gMG. While IVIg treatment was only allowed as rescue therapy during the CHAMPION MG study, many patients had a history of IVIg use prior to entering the study.
Design/Methods:
Subgroup analysis of all patients enrolled in a double-blind, placebo-controlled, phase 3 study (CHAMPION MG; NCT03920293) that assessed response to ravulizumab (administered every 8 weeks) in adults with AChR Ab+ gMG. Changes from baseline to Weeks 26 in Myasthenia Gravis-Activities of Daily Living (MG-ADL; primary endpoint) and Quantitative Myasthenia Gravis (QMG) total scores were analyzed according to IVIg use between MG diagnosis and study entry.
Results:
Of 175 patients enrolled in the study, 79 had no previous IVIg use (38 placebo; 41 ravulizumab) and 96 had received any (acute or chronic) IVIg (51 placebo; 45 ravulizumab). Forty-six patients (22 placebo; 24 ravulizumab) had received chronic IVIg therapy. There were no notable differences in baseline characteristics/demographics between the IVIg subgroups.
Least squares (LS) mean changes (95% confidence intervals [CI]) from baseline for ravulizumab vs placebo at Week 26 in MG-ADL total score were -2.1 (-3.6, -0.5), -1.3 (‑2.8, ‑0.6), and -1.1 (-2.6, -0.0) in patients with history of no, any or chronic IVIg use, respectively. LS mean change (CI) from baseline vs placebo at Week 26 in QMG total scores were -2.4 (-4.2, -0.7), -1.6 (-3.2, -0.0), and -2.3 (-4.6, 0.1), respectively.
Conclusions:
There were no differences in response to ravulizumab with respect to improvements in functional ability and muscle strength, in patients with AChR Ab+ gMG according to previous IVIg treatment.