What immunosuppressants are used for myasthenia gravis?

October 17, 2025 •

4 min read

Myasthenia gravis (MG) affects up to 200 people per million and is an autoimmune disorder where the immune system mistakenly attacks healthy neuromuscular junctions. When initial symptomatic treatments are insufficient, a variety of immunosuppressants are used for myasthenia gravis to modulate the immune response, offering long-term management and symptom control.

Quick Summary

Overview of immunosuppressant therapies for myasthenia gravis, including traditional options like corticosteroids and azathioprine, as well as newer targeted biologics. Covers mechanisms, effectiveness, common side effects, and considerations for treatment selection based on disease type and severity.

Key Points

Broad vs. Targeted Therapies: Myasthenia gravis treatment includes both traditional, broad immunosuppressants like steroids and newer, highly targeted biologics.
Steroid-Sparing Agents: Non-steroidal drugs such as azathioprine and mycophenolate mofetil are used to minimize the long-term side effects of corticosteroids.
FcRn Inhibitors: Novel agents like efgartigimod and rozanolixizumab work by specifically targeting the neonatal Fc receptor to reduce levels of pathogenic IgG antibodies.
Complement Pathway Blockade: Drugs like eculizumab, ravulizumab, and zilucoplan inhibit the complement system, which is involved in neuromuscular junction damage in anti-AChR positive MG.
Anti-MuSK Antibody MG: For patients with the anti-MuSK subtype, B-cell depletion therapy with rituximab is a key treatment option.
Individualized Treatment: The best immunosuppressant is chosen based on an individual patient's specific subtype of MG, disease severity, and response to previous treatments.
Risk of Infection: All immunosuppressive therapies increase the risk of infection, necessitating careful patient education and monitoring.

Immunosuppressants are a cornerstone of myasthenia gravis (MG) management, targeting the root cause of the disease by suppressing the overactive immune system that attacks acetylcholine receptors at the neuromuscular junction. While symptom-management drugs like pyridostigmine offer short-term relief, immunosuppressive therapies are essential for long-term control, especially in more severe cases. The selection of therapy depends on disease severity, antibody status (e.g., anti-AChR or anti-MuSK), and patient-specific factors like age and comorbidities.

Traditional and Non-Steroidal Immunosuppressants

For decades, clinicians have relied on a range of immunosuppressive drugs to manage MG, often starting with broad-acting agents and adding steroid-sparing medications to minimize side effects over the long term.

Corticosteroids

Often used as an initial immunosuppressive agent, corticosteroids like prednisone work by reducing inflammation and suppressing the immune system to decrease antibody production. They act relatively quickly compared to other immunosuppressants, often showing effect within weeks. However, their use, particularly at high doses, is limited by numerous side effects, prompting the use of other agents to reduce the necessary dose.

Common Side Effects: Long-term use can lead to weight gain, high blood pressure, diabetes, osteoporosis, cataracts, and mood changes.

Non-Steroidal Immunosuppressants (NSISTs)

These agents, also known as steroid-sparing agents, are often used in combination with corticosteroids to enable dose reduction over time.

Azathioprine (Imuran®): One of the most frequently used NSISTs for MG, it inhibits the proliferation of lymphocytes. It has a slow onset, with full effect taking up to a year, and requires regular monitoring of blood counts and liver function.
Mycophenolate Mofetil (CellCept®): This drug selectively inhibits an enzyme crucial for lymphocyte proliferation. It is commonly used as a second-line agent, though clinical trial evidence supporting its efficacy is mixed. It is not recommended during pregnancy.
Calcineurin Inhibitors: This class includes cyclosporine (Neoral®) and tacrolimus (Prograf®). They inhibit T-cell activation and have a faster onset than azathioprine. However, their use is limited by potential nephrotoxicity (kidney damage) and other side effects like hypertension.
Cyclophosphamide (Cytoxan®): A potent alkylating agent reserved for severe, refractory MG due to its high risk of serious side effects, including malignancies and infertility.
Methotrexate: Sometimes used as a third-line steroid-sparing option, particularly in patients who do not tolerate other immunosuppressants.

Targeted Therapies: The New Generation of Immunosuppressants

In recent years, research has led to the development of highly specific biologic agents that target precise immune pathways involved in MG, offering better-tolerated options, particularly for those with refractory disease.

Neonatal Fc Receptor (FcRn) Inhibitors

These drugs bind to the FcRn receptor, leading to the breakdown and reduced recycling of harmful IgG autoantibodies.

Efgartigimod (Vyvgart®): The first FcRn inhibitor approved for anti-AChR positive generalized MG, administered intravenously or subcutaneously.
Rozanolixizumab (Rystiggo®): Approved for both anti-AChR and anti-MuSK antibody-positive MG, administered subcutaneously.

Complement Inhibitors

This class of drugs blocks the complement cascade, a part of the immune system that plays a key role in the destruction of the neuromuscular junction in anti-AChR positive MG.

Eculizumab (Soliris®): A monoclonal antibody that inhibits complement protein C5, reserved for refractory anti-AChR positive MG.
Ravulizumab (Ultomiris®): A long-acting C5 inhibitor, similar to eculizumab but with a less frequent dosing schedule.
Zilucoplan (Zilbrysq®): A daily self-administered subcutaneous peptide that inhibits C5.

B-Cell Depletion Therapies

These treatments target B cells, which produce the pathogenic antibodies in MG.

Rituximab (Rituxan®): A monoclonal antibody that depletes CD20-expressing B cells. It is often considered earlier in the treatment course for anti-MuSK positive MG.

Choosing the Right Immunosuppressant

Treatment decisions for MG are highly individualized and require a careful assessment of several factors. A common approach is a stepwise escalation of therapy, starting with symptomatic relief and adding immunosuppressants as needed. Traditional immunosuppressants are often used as first-line, long-term options, but newer biologics are increasingly used for refractory cases or specific subtypes of MG, particularly those resistant to conventional therapies.

Comparison of Immunosuppressants for Myasthenia Gravis


Drug Class	Examples	Mechanism of Action	Onset of Action	Primary Target	Potential Role	Adverse Events
Corticosteroids	Prednisone	Systemic immunosuppression and inflammation reduction.	Weeks.	Broad suppression of immune cells.	First-line for moderate-to-severe MG, often combined with steroid-sparing agents.	Weight gain, osteoporosis, hypertension, mood changes.
Antimetabolites	Azathioprine (Imuran®), Mycophenolate Mofetil (CellCept®)	Inhibits lymphocyte proliferation.	Months (6-12 months for full effect).	T-cells and B-cells.	Long-term, steroid-sparing therapy.	Blood count abnormalities, liver toxicity, GI upset.
Calcineurin Inhibitors	Cyclosporine (Neoral®), Tacrolimus (Prograf®)	Inhibits T-cell activation.	Months (2-3 months).	T-cells.	Second- or third-line for patients unresponsive to other NSISTs.	Nephrotoxicity, hypertension, tremor.
B-Cell Depletion	Rituximab (Rituxan®)	Targets CD20, depleting B-cells.	Months.	B-cells.	Refractory anti-AChR positive MG, or earlier for anti-MuSK positive MG.	Infusion reactions, increased infection risk.
FcRn Inhibitors	Efgartigimod (Vyvgart®), Rozanolixizumab (Rystiggo®)	Blocks neonatal Fc receptor, reducing IgG levels.	Weeks.	Pathogenic IgG antibodies.	Anti-AChR positive and anti-MuSK positive (Rystiggo®) generalized MG.	Injection site reactions, headache, nasopharyngitis.
Complement Inhibitors	Eculizumab (Soliris®), Ravulizumab (Ultomiris®)	Blocks C5, preventing membrane attack complex formation.	Weeks.	Complement protein C5.	Refractory anti-AChR positive MG.	Risk of meningococcal infection (requires vaccination), headache.

Long-Term Monitoring and Patient Safety

Long-term use of any immunosuppressant requires careful monitoring to manage side effects and ensure patient safety. Regular blood work is essential to check for complications like bone marrow suppression and liver or kidney function abnormalities. Patients on these medications have a heightened risk of infection and must take precautions, such as keeping vaccinations up-to-date and practicing good hygiene.

Conclusion

Immunosuppressants are vital for controlling the autoimmune attack in myasthenia gravis, providing long-term relief and stability for many patients. Treatment strategies have evolved from broad-acting agents like corticosteroids and non-steroidal drugs to highly targeted biologics that offer improved efficacy and tolerability for specific patient populations. The selection of the most appropriate immunosuppressant is a complex decision, and ongoing patient monitoring is essential for safe and effective management.

This article provides a general overview of immunosuppressants used for myasthenia gravis and is not a substitute for professional medical advice. Always consult with your physician to determine the most appropriate treatment for your specific condition.

Frequently Asked Questions

Traditional immunosuppressants, such as corticosteroids and azathioprine, act broadly to suppress the immune system, often leading to more widespread side effects. Targeted therapies, like biologics (e.g., efgartigimod, eculizumab), block specific immune pathways involved in MG, potentially offering better efficacy with fewer systemic side effects.

The onset of action varies by drug. Corticosteroids may show effects within a few weeks, while non-steroidal agents like azathioprine can take several months to a year to achieve their full effect. Newer biologics may start working within a few weeks.

Yes, some therapies are more effective for specific subtypes of MG. For example, rituximab is often a preferred option for anti-MuSK positive MG, while complement inhibitors are effective for anti-AChR positive MG but not MuSK-related disease.

Long-term immunosuppression carries risks, including an increased risk of infection, bone marrow suppression, liver or kidney problems, and potential long-term issues like osteoporosis with prolonged steroid use. Specific side effects depend on the medication used.

No, there is currently no cure for myasthenia gravis. Immunosuppressants help manage the underlying autoimmune process and control symptoms, but they do not eliminate the disease entirely. Most patients require long-term treatment.

Close and regular monitoring, including blood tests and check-ups, is crucial to track the drug's effects, monitor for potential side effects (like blood count changes or organ toxicity), and adjust the dosage as needed.

FcRn inhibitors, like efgartigimod, target the neonatal Fc receptor to promote the degradation and clearance of pathogenic IgG antibodies. Complement inhibitors, like eculizumab, block the complement cascade, which is a key part of the immune attack on the neuromuscular junction in AChR-positive MG.