Biologics

The goal of treating myasthenia gravis (MG) is to reduce or improve muscle weakness. Drugs like acetylcholinesterase (AChE) inhibitors, steroids, and other immunosuppressants are often tried first. However, these drugs do not always control symptoms.¹

Biologic drugs (biologics) are another option for generalized MG (gMG). There are several biologics now approved for gMG.^2-10

What are biologics?

Biologics are drugs made from natural and living sources — animal and plant cells, and microorganisms such as bacteria or yeast. They can be made of sugars, proteins, living cells, tissues, or a mix of these.¹¹

Most traditional drugs are made in a lab from chemicals. Biologics are more complex and harder to make.^11,12

How do biologics work?

The biologics used most often to treat MG are monoclonal antibodies. Antibodies are proteins that the immune system makes to fight germs. With autoimmune diseases, pathologic or “bad” antibodies attack healthy tissue instead of germs.^1,12

Monoclonal antibody drugs are lab-made molecules produced by living cells. Steroids tamp down the whole immune system, but a monoclonal antibody is designed to target one process in it. That targeting may mean better results, fewer side effects, and less need for other treatment pathways like long-term steroid treatment.^1,12

Examples

Each biologic is approved for a specific group of people with gMG. Your antibody type and your age decide which ones you can take:^2-10

• Eculizumab (Soliris®) – adults and children 6 years and older who are AChR antibody positive.
• Eculizumab-aeeb (Bkemv®) and eculizumab-aagh (Epysqli®) – biosimilars of Soliris, for adults who are AChR antibody positive.
• Ravulizumab-cwvz (Ultomiris®) – adults who are AChR antibody positive.
• Efgartigimod alfa (Vyvgart®) – adults with gMG.
• Efgartigimod alfa and hyaluronidase-qvfc (Vyvgart® Hytrulo) – adults with gMG.
• Rozanolixizumab-noli (Rystiggo®) – adults who are AChR or MuSK antibody positive.
• Inebilizumab-cdon (Uplizna®) – adults who are AChR or MuSK antibody positive.
• Nipocalimab-aahu (Imaavy™) – adults and children 12 years and older who are AChR or MuSK antibody positive.

One more biologic is used in MG but is not approved for it. Rituximab (Rituxan®) is sometimes prescribed for people with MuSK antibodies whose symptoms have not improved with other treatments. It is given as an IV infusion.^1,13

While not a true biologic, Zilucoplan (Zilbrysq®) is a complement inhibitor approved to treat gMG in adults who are AChR antibody positive.⁶

If you are unsure what type of MG you have, talk with your doctor.

What are the possible side effects?

Side effects can vary depending on the specific medication you are taking. Side effects may include:^2-10

• Fever or chills
• Headache
• Upper respiratory infection
• Nausea, vomiting, or diarrhea
• Swelling (edema)
• Muscle or joint pain
• Changes in white blood cell counts
• Infections, including respiratory tract and urinary tract infections
• Changes in potassium levels
• Changes in liver function
• Changes in cholesterol levels

People taking these drugs are watched for infections, which can sometimes be life-threatening. Before starting, tell your doctor if you have any signs of infection, including:^2-10

• Headache
• Fever
• Chills
• Muscle aches
• Cough
• Sore throat

Soliris, Bkemv, Epysqli, Ultomiris, and Zilbrysq block a part of the immune system called the complement system. All 5 carry a boxed warning, the strongest warning the FDA gives: people taking them have developed life-threatening meningococcal infections, which can be deadly if they are not treated quickly. All 5 are available only through a restricted safety program.^2-6

Get a meningococcal vaccine at least 2 weeks before your first dose of one of these 5 drugs. Your doctor may start sooner if waiting is riskier. You will need booster shots, and your doctor may also prescribe antibiotics.^3,6,14

Rituximab carries a boxed warning of its own, for different reasons: deadly infusion reactions, severe skin and mouth reactions, hepatitis B becoming active again, and a serious brain infection.¹³

These are not all the possible side effects of the biologics and other therapies mentioned. Talk to your doctor about what to expect when taking these medications. You also should call your doctor if you have any changes that concern you when taking them.

Other things to know

Each medication is different and has its own risks. Some raise the risk of cardiovascular, kidney, or pancreatic problems. Ask your doctor what to watch for.^2-10

Some biologics and other medications mentioned here can harm an unborn baby. If you can become pregnant, you may need to use birth control during treatment and for a time after your last dose with certain medications.^2-10

Some medications also affect which vaccines you can have. Tell your doctor about any vaccines you are scheduled to get.^2-10

Some therapies are given by IV at an infusion center. Others are a shot under the skin, and some of those you can give yourself after training. Allergic and infusion reactions can happen, so your doctor will watch for them. A severe reaction may mean stopping the drug.^2-10

Before beginning treatment for myasthenia gravis, tell your doctor about all your health conditions and any other drugs, vitamins, or supplements you take. This includes over-the-counter drugs.