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Long-term benefit of rituximab in MuSK autoantibody myasthenia gravis patients
  1. Benison Keung,
  2. Kimberly R Robeson,
  3. Daniel B DiCapua,
  4. Jennifer B Rosen,
  5. Kevin C O'Connor,
  6. Jonathan M Goldstein,
  7. Richard J Nowak
  1. Department of Neurology, Yale University School of Medicine, New Haven, Connecticut, USA
  1. Correspondence to Dr Richard J Nowak, Department of Neurology, Division of Neuromuscular Medicine, Yale University School of Medicine, PO Box 208018, 15 York Street, LCI 9th floor, New Haven, CT 06510, USA; richard.nowak{at}

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Despite the efficacy of standard immunotherapy, a subset of myasthenia gravis (MG) patients remains medically refractory. Muscle-specific kinase autoantibody positive (MuSK+) patients, in particular, do not respond well to treatment, exhibit more bulbar symptoms and have more frequent exacerbations as compared to acetylcholine receptor antibody positive (AChR+) patients.1 ,2 Autoreactive B cells are appropriate candidates for targeted drug therapy as they play an important role in the pathogenesis of MG.2–4 Rituximab, a chimeric monoclonal antibody that targets the CD20 antigen on B lymphocytes, is the only B cell–directed biologic currently approved for clinical use. Several groups, including our own, have observed the benefits of rituximab in both AChR+ and MuSK+ patients.2–7 The durability of this positive response has varied among different reports. One group reported sustained benefit after a mean follow-up of 31 months in the combined AChR+ and MuSK+ cohort and 40 months in the MuSK+ subpopulation.3

Here, we report our experience with the sustained effects of rituximab in nine refractory MuSK+ patients in a follow-up period ranging from 2 to 5.5 years.


A retrospective study was performed of generalised MuSK+ MG patients referred to our neuromuscular clinic from 2003 to 2011. Nine MuSK+ patients were identified with refractory disease and treated with rituximab. The group consisted of eight females and one male with a median age of 40. Patients were defined as refractory when they: (1) could not lower …

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  • BK and RJN contributed equally.

  • Contributors BK: Data collection, analysis, drafting and revision of manuscript. KRR: Data collection, analysis and revision of manuscript. DBD, JBR, KCO: Data analysis and revision of manuscript. JMG: Study conception and revision of manuscript. RJN: Study conception, data collection, analysis, drafting and revision of manuscript.

  • Competing interests None.

  • Ethics approval Approval to complete a retrospective chart review was provided by our institutional review board, Yale Human Investigation Committee.

  • Provenance and peer review Not commissioned; externally peer reviewed.