Thymectomy may not be associated with clinical improvement in MuSK myasthenia gravis
INTRODUCTION: A randomized trial demonstrated benefit from thymectomy in nonthymomatous acetylcholine receptor (AChR)-antibody positive myasthenia gravis (MG). Uncontrolled observational and histologic studies suggest thymectomy may not be efficacious in anti-muscle-specific kinase (MuSK)-MG. METHODS: The therapeutic impact of thymectomy was evaluated from data collected for a multicenter, retrospective blinded review of rituximab in MuSK-MG. RESULTS: Baseline characteristics were similar between thymectomy (n = 26) and nonthymectomy (n = 29) groups, including treatment with rituximab (42% vs. 45%). At last visit, 35% of thymectomy subjects reached the primary endpoint, a Myasthenia Gravis Foundation of America (MGFA) post-intervention status (PIS) score of minimal manifestations (MM) or better, compared with 55% of controls (P = 0.17). After controlling for age at onset of MG, rituximab, prednisone, and intravenous immunoglobulin/plasma exchange treatment, thymectomy was not associated with greater likelihood of favorable clinical outcome (odds ratio = 0.43, 95% confidence interval 0.12-1.53, P = 0.19). DISCUSSION: Thymectomy was not associated with additional clinical improvement in this multicenter cohort of MuSK-MG patients. Muscle Nerve 59:404-410, 2019.
Medical Subject Headings
Adolescent; Adult; Age of Onset; Aged; Child; Cohort Studies; Female; Humans; Immunoglobulins, Intravenous (therapeutic use); Male; Middle Aged; Myasthenia Gravis (genetics, therapy); Prednisone (therapeutic use); Receptor Protein-Tyrosine Kinases (genetics); Receptors, Cholinergic (genetics); Retrospective Studies; Rituximab (therapeutic use); Thymectomy; Treatment Outcome; Young Adult
Muscle & nerve
Digital Object Identifier (DOI)
Clifford, Katherine M.; Hobson-Webb, Lisa D.; Benatar, Michael; Burns, Ted M.; Barnett, Carolina; Silvestri, Nicholas J.; Howard, James F.; Visser, Amy; Crum, Brian A.; Nowak, Richard; Beekman, Rachel; Kumar, Aditya; Ruzhansky, Katherine; Chen, I-Hweii Amy; Pulley, Michael T.; Laboy, Shannon M.; Fellman, Melissa A.; Howard, Diantha B.; Kolb, Noah A.; Greene, Shane M.; Pasnoor, Mamatha; Dimachkie, Mazen M.; Barohn, Richard J.; and Hehir, Michael K., "Thymectomy may not be associated with clinical improvement in MuSK myasthenia gravis" (2019). Neurology. 1675.