Background: Myasthenia gravis (MG) is a rare autoimmune condition that impairs neuromuscular transmission, resulting in weakness. The therapeutic landscape has been rapidly expanding, and traditional treatments (acetylcholinesterase inhibitors [ACH], systemic immunosuppressants [SYS], and oral glucocorticoids [OG]) have been associated with adverse events (AEs).
Objectives: To examine the incidence and costs of AEs following initiation of MG treatment.
Methods: Patients aged ≥18 years with MG who initiated their first treatment between January 1, 2017 and September 30, 2023 (first treatment claim = index) were selected for this retrospective study using the Merative™ MarketScan® Research Databases. Incidence of AEs (metabolic, cardiovascular, gastrointestinal [GI], neurological, other) and AE-related medical costs were measured during a fixed 12-month follow-up period, in 2024 dollars.
Results: The analysis included 2,943 patients initiating MG treatment (mean [SD] age, 58.1 [15.7] years; 52.4% female) with a mean (SD) follow-up of 37.2 (21.4) months. The majority of patients (99.8%) were on traditional therapies (monotherapy, 79.0%; combination regimen, 21.0%) and 76.2% initiated treatment within six months of an MG diagnosis. Over 12 months of follow-up, metabolic AEs had the highest incidence (37.7%, including 25.9% with dyslipidemia), followed by cardiovascular AEs (24.3%, including 23.6% with hypertension), GI AEs (20.6%, including 18.6% with nausea, vomiting, and diarrhea), and neurological AEs (16.6%, including 9.5% with headache). Individual AEs with the highest mean costs over 12 months of follow-up included acute myocardial infarction ($76,355), severe infection ($47,379), acute heart failure ($43,325), ketoacidosis ($21,552), and GI perforation ($19,909).
Conclusions: Findings suggest that despite the availability of novel, safe and effective therapies, patients with MG often start on traditional medications. In addition, the incidence and costs of AEs during the first 12 months of follow-up can be substantial. This AE burden contributes to an increased overall disease burden and suggests that alternative treatment approaches should be considered.