Myasthenia gravis

Overview 
Theory 
Diagnosis 
Management 
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Last reviewed: 14 Jul 2025

Last updated: 14 Aug 2025

14 Aug 2025

Nipocalimab approved by FDA for treatment of generalized myasthenia gravis

Nipocalimab, a neonatal Fc receptor (FcRn) antagonist monoclonal antibody, has been approved by the Food and Drug Administration (FDA) for the treatment of generalized myasthenia gravis in adults and children ≥12 years who are positive for acetylcholine receptor (AChR) or muscle-specific tyrosine kinase (MuSK) antibodies. The approval follows FDA priority review designation and provides an alternative treatment option to offer sustained disease control for a broad range of patients with troublesome symptoms caused by myasthenia gravis.

The approval was based on results from Vivacity-MG3, a phase 3 trial of patients with generalized myasthenia gravis inadequately controlled with standard therapy. Nipocalimab added to standard care was associated with long-lasting reductions in total circulating IgG and AChR antibodies, and improvements in patient-reported outcomes, with a good safety profile.

See Management: approach

Original source of update

Myasthenia gravis (MG) is a chronic autoimmune disorder of the postsynaptic membrane at the neuromuscular junction in skeletal muscle.

MG is characterized by muscle weakness that increases with exercise (fatigue) and improves on rest. It commonly presents with drooping eyelids, double vision, oropharyngeal and/or appendicular weakness, and shortness of breath.

Elevated serum levels of antibodies against the acetylcholine receptor (AChR) or muscle-specific tyrosine kinase (MuSK) are usually present. Antibodies have also been identified to proteins located at the neuromuscular junction: low-density lipoprotein receptor-related protein 4 (LRP4), agrin, collagen Q, and cortactin. Patients with MG may have elevated levels of one or more of these antibodies.

Clinical electrophysiology shows decremental response on repetitive nerve stimulation or increased jitter on single-fiber study.

Treatments include the anticholinesterase inhibitor pyridostigmine and immunotherapy (a corticosteroid or other immunosuppressant). Thymectomy is required if thymoma is present. Thymectomy has also been shown to be effective in people with generalized MG without thymoma who are AChR antibody positive.

Newer therapies for patients with generalized MG with AChR antibodies include complement C5 inhibitors and neonatal Fc receptor (FcRn) antagonists.

Approximately 15% to 20% of patients with MG experience a myasthenic crisis, an exacerbation necessitating mechanical ventilation and acute treatment with intravenous immune globulin or plasma exchange.

Many patients with MG enjoy good quality of life and normal lifespan due to advances in diagnosis and in immunosuppressive and immunomodulatory treatment. However, some patients have a significant burden of disease.

Definition

MG is a chronic autoimmune disorder of the postsynaptic membrane at the neuromuscular junction in skeletal muscle. Circulating antibodies against the nicotinic acetylcholine receptor (AChR) or associated proteins impair neuromuscular transmission.[1][2][3]

Patients present with muscle weakness, which typically worsens with continued or repetitive activity (fatigue) and improves on rest. Severity varies from isolated eye muscle weakness to generalized muscle weakness to respiratory failure requiring mechanical ventilation.

History and exam

Key diagnostic factors

muscle strength fatigability
ptosis
diplopia
dysphagia
dysarthria
facial paresis
proximal limb weakness
shortness of breath

Full details

Risk factors

family history of autoimmune disorders
genetic markers
cancer-targeted therapy

Full details

Diagnostic tests

1st tests to order

serum acetylcholine receptor (AChR) antibody analysis
muscle-specific tyrosine kinase (MuSK) antibodies
serial pulmonary function tests

Full details

Tests to consider

striational receptor antibody assays
repetitive nerve stimulation
single-fiber EMG
CT of chest

Full details

Treatment algorithm

ACUTE

myasthenic crisis

ONGOING

mild to moderate disease (class I to III)

severe (class IV or V) or refractory disease

Contributors

Authors

David P. Richman, MD

Distinguished Professor

Professor of Neurology

University of California - Davis

Davis

Disclosures

DPR declares that he has no competing interests.

Acknowledgements

Dr David Richman would like to gratefully acknowledge Dr Robert Lisak, Dr Andrea Corse, and Dr Ami Mankodi, previous contributors to this topic.

Disclosures

AC and AM declare that they have no competing interests. RPL is a Data and Safety Monitoring Board Member for the COUR myasthenia gravis clinical trial. RPL is a site principal investigator for clinical trials and a co-author for the clinical trial reports for myasthenia gravis therapies for Alexion, Argenx, and UCB Ra. RPL's institution receives payment for the time spent on these clinical trials. RPL has received book royalties from Oxford University Press and Blackstone, and has carried out consultancy work for Avilar.

Peer reviewers

Vern C. Juel, MD

Associate Professor of Medicine (Neurology)

Duke University

Durham

Disclosures

VCJ declares that he has no competing interests.

References

Our in-house evidence and editorial teams collaborate with international expert contributors and peer reviewers to ensure that we provide access to the most clinically relevant information possible.

Key articles

Narayanaswami P, Sanders DB, Wolfe G, et al. International consensus guidance for management of myasthenia gravis: 2020 update. Neurology. 2021 Jan 19;96(3):114-22.Full text Abstract

Skeie GO, Apostolski S, Evoli A, et al. Guidelines for treatment of autoimmune neuromuscular transmission disorders. Eur J Neurol. 2010 Jul;17(7):893-902.Full text Abstract

Gronseth GS, Barohn R, Narayanaswami P. Practice advisory: thymectomy for myasthenia gravis (practice parameter update). Report of the Guideline Development, Dissemination, and Implementation Subcommittee of the American Academy of Neurology. Neurology. 2020 Apr 21;94(16):705-9.Full text Abstract

Elovaara I, Apostolski S, van Doorn P, et al. EFNS guidelines for the use of intravenous immunoglobulin in treatment of neurological diseases: EFNS task force on the use of intravenous immunoglobulin in treatment of neurological diseases. Eur J Neurol. 2008 Sep;15(9):893-908.Full text Abstract

Reference articles

A full list of sources referenced in this topic is available to users with access to all of BMJ Best Practice.

Differentials
- Lambert-Eaton myasthenic syndrome (LEMS)
- Botulism
- Penicillamine-induced myasthenia gravis
More Differentials
Guidelines
- International consensus guidance for management of myasthenia gravis: 2020 update
- Practice advisory: thymectomy for myasthenia gravis (practice parameter update)
More Guidelines
Patient information
Myasthenia gravis
More Patient information
Videos
Venepuncture and phlebotomy: animated demonstration
Peripheral intravascular catheter: animated demonstration
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Myasthenia gravis

Nipocalimab approved by FDA for treatment of generalized myasthenia gravis

Summary

Definition

History and exam

Key diagnostic factors

Risk factors

Diagnostic tests

1st tests to order

Tests to consider

Treatment algorithm

myasthenic crisis

mild to moderate disease (class I to III)

severe (class IV or V) or refractory disease

Contributors

Authors

David P. Richman, MD

Disclosures

Acknowledgements

Disclosures

Peer reviewers

Vern C. Juel, MD

Disclosures

References

Key articles

Reference articles

A full list of sources referenced in this topic is available to users with access to all of BMJ Best Practice.

Differentials

Guidelines

Patient information

Videos

Log in or subscribe to access all of BMJ Best Practice

Log in or subscribe to access all of BMJ Best Practice

Log in to access all of BMJ Best Practice