Myasthenia gravis (MG) has no cure, but in just the last few years, new and innovative treatments have become available that are helping to transform care for those with the disease.
“In the past, we would see patients come in repeatedly with respiratory failure, and their myasthenia was very difficult to control,” says Arjun Seth, MD, a neurologist and neuromuscular medicine specialist who treats MG at Northwestern Medicine in Chicago, IL. “Now, with these newer therapies, we are better able to manage MG and prevent deaths associated with it. We can help people live longer and happier lives, while their myasthenia gravis remains more quiet over the long run.”
Seth predicts that the new therapies — as well as drugs being studied now — will mean more than additional options to match patients’ needs. These innovative treatments will reshape how doctors learn about and treat MG.
“We’re very excited about where the field has moved,” he says. “We’ve known the basics of how the disease works and how it disrupts the communication between nerves and muscles, and now we’re figuring out how to block those areas where that disruption occurs.”
Two types of MG treatment have been developed in recent years: complement inhibitors and neonatal Fc receptor inhibitors.
Complement Inhibitors
In 2017, the FDA approved eculizumab (Soliris) for the treatment of adults with the most common form of MG: generalized myasthenia gravis that’s anti-AChR antibody positive. Generalized MG causes muscle weakness in your:
- Eyes
- Face
- Neck
- Throat
- Arms
- Legs
Eculizumab was the first MG treatment approved in 60 years. Earlier this year, the FDA expanded its approval to include people as young as 6.
The medication is a targeted therapy that belongs to a class of drugs called complement inhibitors. The complement system, part of your immune system, helps you to heal and to fight off bacterial infections and illnesses. But MG upsets how it works. Here’s a quick overview.
Your muscle membranes have receptors that receive nerve signals delivered via a chemical called acetylcholine. Those signals tell your muscles to contract. In MG, your immune system creates antibodies that attack and destroy those receptors, called AChR.
“You get degradation of the muscle membrane itself, and in the long run, there are fewer of those receptors there,” says Seth.
The result: Nerve signals can’t communicate with your muscles, and your muscles become weak. The complement system plays an important though not fully understood role in this destruction. Drugs like eculizumab target specific parts of the complement system in order to prevent that destruction.
There are three FDA-approved complement inhibitors for MG:
- Eculizumab (Soliris), approved in 2017
- Ravulizumab (Ultomiris), approved in 2022
- Zilucoplan (Zilbrysq), approved in 2023
Both eculizumab and ravulizumab are delivered via intravenous (IV) infusions. Zilucoplan is different. If you’re prescribed this drug, you will give yourself daily injections.
All three drugs increase your risk of meningococcal disease, a potentially fatal bacterial infection. You will need to be vaccinated against this disease at least two weeks before you take a complement inhibitor in order to reduce your risk.
If you need the medication sooner, says Seth, you will receive the vaccine as well as a course of the antibioticpenicillin to prevent meningococcal disease while you wait for the vaccine to become fully effective.
Neonatal Fc Receptor Inhibitors
An even newer type of targeted therapy, neonatal Fc receptor inhibitors first became an option for MG when the FDA approved
efgartigimod (Vyvgart) in 2021. This drug treats generalized myasthenia gravis that’s anti-AChR antibody positive. Since then, two other drugs in this class have been approved, both of which also treat a less common type of MG called anti-MuSK antibody positive MG. These drugs are:
- Rozanolixizumab (Rystiggo), approved in 2023
- Nipocalimab (Imaavy), approved in 2025
With one exception, these drugs are all given by IV infusion. In 2023, the FDA approved a self-injectable version of efgartigimod called Vyvgart Hyrtrulo.
Like complement inhibitors, neonatal Fc receptor inhibitors are what are called targeted therapies. That means they go after very specific mechanisms involved in MG. In this case, they block the neonatal Fc receptor.
Why is that important? This receptor helps preserve a type of antibody called immunoglobulin G (IgG), and most of the antibodies that cause MG symptoms are IgG antibodies. By blocking the neonatal Fc receptor, fewer of these antibodies can stick around to cause trouble.
Myasthenia gravis, says Seth, was the first disease for which this type of drug was tested. Researchers, he says, found that if you reduce the amount of IgG, MG patients had a significant improvement in their symptoms.
“That was really exciting,” says Seth, who adds that these drugs are now being studied in other autoimmune conditions.
Which New Drug Might Be Right for You?
Complement inhibitors and neonatal Fc receptor inhibitors appear to be equally effective, according to a recent study. Seth has found the same in his practice. However, when deciding between prescribing a complement inhibitor and a neonatal Fc receptor inhibitor, Seth says that he and most of his colleagues often opt for the latter. Why?
“We tend to use neonatal Fc receptor inhibitors because they don’t require vaccination,” he says.
Your preferences will play a big part in deciding which medication to try. Some of these drugs require IV infusions every few weeks. That means making regular trips to your doctor’s office or to an infusion center for treatment. However, in both classes, there’s one drug that you can administer yourself via injection.
“Some patients are happy to come in every two weeks for an injection, while others find that the injections make life easier and allow them to travel,” says Seth. “We try to make decisions based on their goals.”
One thing to keep in mind: These drugs don’t adequately manage symptoms for everyone who takes them. Researchers have found that both classes of drugs come up short in 20% to nearly 50% of patients. But if one does not work, that does not mean you will strike out with each of them.
“We usually give patients a trial of around three months to see how they respond,” says Seth. “If they do well, we will continue it. But if they don’t, we can switch them to another one of that class.”
Show Sources
Photo Credit: Moment/Getty Images
Sources:
Arjun Seth, MD, and neuromuscular medicine specialist, Northwestern Medicine, Chicago, Illinois.
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