[Pubmed] Clinical and laboratory remission with rituximab in anti-MuSK-positive myasthenia gravis

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Ir J Med Sci. 2024 Aug 1. doi: 10.1007/s11845-024-03763-w. Online ahead of print.

ABSTRACT

BACKGROUND: Increasing data are available on the use and efficacy of rituximab (RTX) in patients with anti-muscle-specific tyrosine kinase (MuSK)-positive myasthenia gravis (MG), especially those steroid-dependent or unresponsive to traditional immunotherapies.

AIMS: We aimed to evaluate the clinical characteristics and treatment responses of adult patients with generalized anti-MuSK-positive MG treated with RTX.

METHODS: We retrospectively recruited 16 patients who were on RTX, between January 2010 and September 2023. RTX was given 1000 mg/day intravenously twice, two weeks apart. Maintenance treatment was administered at intervals of 3-6 months based on clinical evaluation. The outcome was assessed by Myasthenia Gravis Foundation of America (MGFA) and Myasthenia Gravis Status and Treatment Intensity (MGSTI) scores. Additionally, anti-MuSK antibody levels were retested after treatment in all patients except one.

RESULTS: Twelve patients were female. The mean age at disease onset was 35.3 ± 17.3 years. The median duration between disease onset and RTX administration was 2.4 years (min-max: 0.5-36.5 years). The worst MGFA class before RTX was between IIIb-V. After RTX treatment, 81.3% of patients achieved MGFA minimal manifestations or better and MGSTI level 1 or better. Anti-MuSK antibodies became negative in 12 patients, while they remained positive in three. The changes in antibody levels seemed associated with clinical outcomes.

CONCLUSIONS: RTX is an effective treatment in anti-MuSK-positive MG. Furthermore, our results support the inhibition of antibody production by RTX and we recommend monitoring anti-MuSK antibody titers to follow disease progression and treatment response.

PMID:39088160 | DOI:10.1007/s11845-024-03763-w


Source: https://pubmed.ncbi.nlm.nih.gov/3908816 ... t9+e462414