Some people with well-controlled myasthenia gravis (MG) may be able to stop azathioprine or mycophenolate mofetil after a prolonged period of stable disease, though relapse remains possible, a small single-center real-world study suggests.

The study, “Prognosis After Discontinuation of Azathioprine or Mycophenolate Mofetil in Well-Controlled Myasthenia Gravis: A Retrospective Analysis,” was published in Muscle & Nerve.

MG is an autoimmune disease often treated with medications that calm the immune system, including corticosteroids. While steroids can be effective, long-term use can cause significant side effects, so many patients transition to steroid-sparing agents or conventional immunosuppressants, such as azathioprine (sold as Imuran and others) or mycophenolate mofetil (sold as CellCept and others).

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When patients and doctors consider tapering

These medications can help control MG symptoms and reduce the need for long-term steroids. But they can also carry risks, including infections, low white blood cell counts, liver problems, and, in some conditions, a higher risk for certain cancers. Because of these concerns, some patients and doctors may consider lowering the dose or stopping treatment once MG is well controlled.

There are no clear guidelines on when or how to safely taper these immunosuppressive therapies after MG stabilizes. Past studies have reported widely varying relapse rates after dose reduction or discontinuation, making it hard to predict who can stop treatment without symptoms returning.

To explore this question, researchers reviewed records from MG patients at a hospital outpatient clinic in Turkey who stopped azathioprine or mycophenolate mofetil between 2013 and 2023. They looked at how often relapses occurred and whether any clinical factors were linked to a higher risk of symptoms coming back.

The analysis included 32 patients (65.6% men). Of these, 28 had taken azathioprine, and four had taken mycophenolate mofetil. Most (71.9%) had previously used corticosteroids before switching to azathioprine or mycophenolate mofetil alone. At the time tapering began, none were taking corticosteroids or acetylcholinesterase inhibitors.

Overall, 34.3% of patients experienced a relapse after stopping treatment. Relapses were more common among those who had taken mycophenolate mofetil (three of four patients) than among those who had taken azathioprine (eight of 28). Most relapses occurred within the first year after stopping treatment.

Relapses were more common after stopping treatment abruptly

In 25 patients, treatment was gradually discontinued under a physician’s guidance, while seven stopped the medication abruptly on their own. Relapse occurred in 57% of patients who stopped treatment on their own, compared with 28% of those who discontinued therapy following medical advice. Among those who tapered, the dose-reduction period averaged about 14 months for azathioprine and 24 months for mycophenolate mofetil.

Most relapses happened without a clear trigger, but in three cases they followed an identifiable event: a dental infection, pregnancy, or botulinum toxin injection.

When relapses occurred, symptoms were generally manageable. All patients improved after restarting treatment, and four also required short-term intravenous immunoglobulin therapy.

Patients who were in pharmacological remission — meaning no symptoms or signs of MG for at least one year while on treatment — were significantly less likely to relapse than those with minimal manifestations, who still had some degree of muscle weakness while on treatment. This was the only factor clearly associated with relapse risk.

Overall, the researchers concluded that discontinuation of immunosuppressive therapy “may be safe and could be considered” in well-controlled MG patients, while emphasizing the importance of careful tapering and close follow-up.