Katherine M Clifford1, Lisa D Hobson-Webb2, Michael Benatar3, Ted M Burns4, Carolina Barnett5, Nicholas J Silvestri6, James F Howard7, Amy Visser8, Brian A Crum9, Richard Nowak10, Rachel Beekman10, Aditya Kumar10, Katherine Ruzhansky11, I-Hweii Amy Chen11, Michael T Pulley12, Shannon M Laboy12, Melissa A Fellman3, Diantha B Howard1, Noah A Kolb1, Shane M Greene1, Mamatha Pasnoor13, Mazen M Dimachkie13, Richard J Barohn13, Michael K Hehir1. 1. Larner College of Medicine, University of Vermont, 1 South Prospect Street, Burlington, Vermont 05401, USA. 2. Department of Neurology, Duke University School of Medicine, Durham, North Carolina, USA. 3. Department of Neurology, University of Miami Health System, Miami, Florida, USA. 4. Department of Neurology, University of Virginia School of Medicine, Charlottesville, Virginia, USA. 5. Department of Neurology, University of Toronto School of Medicine, Toronto, Ontario, Canada. 6. Department of Neurology, University at Buffalo Jacobs School of Medicine & Biomedical Sciences, Buffalo, New York, USA. 7. Department of Neurology, University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA. 8. Department of Neurology, Oregon Health & Science University, Portland, Oregon, USA. 9. Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA. 10. Department of Neurology, Yale School of Medicine, New Haven, Connecticut, USA. 11. Department of Neurology, Medical University of South Carolina, Charleston, South Carolina, USA. 12. Department of Neurology, University of Florida, Jacksonville, Florida, USA. 13. Department of Neurology, University of Kansas Medical Center, Kansas City, Kansas, USA.
Abstract
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.
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-MGpatients. Muscle Nerve 59:404-410, 2019.