Impact of Prior Intravenous Immunoglobulin and Plasmapheresis on Eculizumab or Ravulizumab Treatment for Generalized Myasthenia Gravis: An Analysis of the MG SPOTLIGHT Registry

Objective The complement component 5 inhibitor therapies (C5ITs) eculizumab and ravulizumab are approved for the treatment of generalized myasthenia gravis (gMG). We evaluated the real‐world effectiveness and safety of eculizumab and ravulizumab in patients with gMG with or without prior intravenous immunoglobulin (IVIg) or plasma exchange (PLEX) treatment. Methods Data from enrollment up to January 1, 2024, were collected from the real‐world, multinational, observational MG SPOTLIGHT Registry (NCT04202341). Patients were grouped by the presence/absence of IVIg/PLEX use within 12 months prior to C5IT initiation. Myasthenia Gravis Activities of Daily Living (MG‐ADL) total scores and Myasthenia Gravis Foundation of America (MGFA) classification were assessed before and after C5IT initiation. Safety was assessed by the number of serious adverse events (SAEs). Results Data from 219 patients were included in this analysis: 106 had received IVIg/PLEX during the 12 months prior to eculizumab or ravulizumab initiation, and 113 had not. Demographics and disease characteristics at Registry enrollment were similar between the groups. For patients with and without prior IVIg/PLEX, mean (±SD) MG‐ADL total scores were 8.2 (±4.0) and 7.3 (±3.5), respectively, before eculizumab or ravulizumab treatment and 3.7 (±4.0; p < 0.0001) and 3.9 (±3.7; p < 0.0001) at last assessment. After initiation, both groups also showed increases in the proportion of patients with MGFA classification of 0–II. Safety profiles were similar in both groups, although fewer SAEs were observed in patients without prior IVIg/PLEX. Conclusion This MG SPOTLIGHT Registry analysis demonstrates the clinical benefit of eculizumab and ravulizumab in patients with gMG regardless of prior IVIg or PLEX therapy.