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OTTAWA — Established treatments such as thymectomy and steroids remain mainstays in the management of myasthenia gravis (MG), according to a presentation at the Canadian Neurological Sciences Federation (CNSF) Congress 2025.

Hans Katzberg, MD, professor of medicine at the University of Toronto and head of Neurology at University Health Network, Toronto, described an analysis that found an increased risk for all-cause mortality, cancer, and autoimmune disease among patients who underwent thymus removal.

“This was a study of health consequences in thymus removal in adults. It was not an MG-specific population,” said Katzberg. These adverse events have not been observed in large MG practices. “MG cohort data do not support these risks.”

A case-control study suggested that the benefits of thymectomy outweigh the risks for patients with MG. The authors’ suggestion “was that the benefits of thymectomy are still clear for MG patients, but incidental thymectomy should be avoided,” said Katzberg.

Use of Steroids

Steroids are no longer given to patients with MG in the high doses that historically were used. “In the early 1960s, doses of up to 100 mg or more were used,” said Katzberg, noting that a paradoxical and temporary worsening of disease has been observed in some patients who received high-dose steroids.

In a formal consensus on the management of MG, an international group of experts called for minimal effective dosing to reduce adverse effects. “The steroid doses that we’ve used are lower, 1 mg/kg, and sometimes higher, trying to get to that minimal, effective dosing strategy,” said Katzberg, referring to the 2016 guidance.

Ocular MG appears to respond to steroid treatment. One randomized, controlled trial found prednisone (15 mg/d) to be associated with control of symptoms after 6 weeks. “Steroids are still probably one of the best treatments for ocular MG,” said Katzberg.

But clinicians who manage MG recognize the complications associated with steroid use and have made efforts to develop strategies to curb them. Consensus guidance from the American Association of Neuromuscular and Electrodiagnostic Medicine task force has called for the monitoring of neuromuscular patients who are being treated with glucocorticoids. The guidance “is a nice effort to provide recommendations on mitigating some of the difficulties in bone health, endocrine effects, and infection risks,” said Katzberg. 

Steroid-sparing agents represent a treatment option in patients who are not responding to steroids as monotherapy. The primary agents are azathioprine and mycophenolate mofetil. Cyclophosphamide is a good choice in low-resource countries, according to Katzberg. A cohort study of 51 patients suggested that cyclophosphamide can induce remission.

“Some of the new therapies may not always be available and accessible for everyone, and really you have to use what you can, particularly in high-risk patients,” said Katzberg. 

Intravenous immunoglobulin and plasma exchange are immunomodulatory therapies that have been used for more than a decade to manage acute MG. Immunoglobulin, administered either intravenously or subcutaneously, recently has been adopted for chronic treatment of MG, noted Katzberg.

Emerging MG Treatments

Newer agents — such as neonatal FC receptor (FcRn) inhibitors and complement inhibitors — to manage MG that fails to respond to first-line therapies and steroid-sparing agents are changing the landscape of MG management. These treatments provide rapid onset of action and sustained impact, said Katzberg. Still other advanced options include chimeric antigen receptor T-cell therapy and immune checkpoint inhibitors.

Zaeem Siddiqui, MD, PhD, professor of neurology at the University of Alberta in Edmonton, who chaired the session, noted that FcRn inhibitors and complement inhibitors appear to have equal efficacy in treating MG. The potential absence of a reliable supply of immunoglobulin is a limitation in the chronic use of immunoglobulin for MG management, he noted. “There can be shortages of blood products,” said Siddiqui.

Katzberg is a consultant for Grifols, CSL Behring, Octapharma, Takeda Pharmaceuticals, Pfizer, Biogen, Alexion Pharmaceuticals, Terumo, UCB, Argenx, Dyne Therapeutics, Merz Pharma, Annexon Biosciences, Cour Pharma, BioCryst Pharmaceuticals, Johnson and Johnson, AstraZeneca, and Alnylam Pharmaceuticals. He conducts research for Grifols, CSL Behring, Takeda Pharmaceuticals, Argenx, Alexion Pharmaceuticals, UCB, Octapharma, and Syneos Health. Siddiqui is a consultant for Alexion Pharmaceuticals, Argenx, UCB, and Johnson and Johnson and is a speaker for Alexion Pharmaceuticals and Argenx.