Myasthenia gravis is a lifelong (chronic) autoimmune condition, which means that the body’s immune system attacks its own healthy cells. Most people with generalized myasthenia gravis (gMG) have antibodies in their system that attack receptors in the neuromuscular junction, which is where the nerve and muscle cells communicate. This blocks signals between the cells and leads to muscle weakness.
Imaavy (Nipocalimab-aahu ), a neonatal Fc receptor (FcRn) blocker, has been approved by the FDA for treatment of generalized myasthenia gravis in adults and adolescents with anti-acetylcholine receptor (AChR) or anti-muscle-specific tyrosine kinase (MuSK) antibodies. It is given as an intravenous (IV) infusion once every two weeks. Rozanolixizumab-noli (Rystiggo) is another FcRn blocker that has previously been approved for the same use in adults and is given as a weekly injection under the skin.
Four other biologic drugs – the FcRn blocker efgartigimod alfa (Vyvgart, Vyvgart Hytrulo) and the complement inhibitors eculizumab (Soliris), ravulizumab (Ultomiris), and zilucoplan (Zilbrysq) – are approved for use in patients with anti-AChR antibodies.
How Does Imaavy Work for Myasthenia Gravis?
There is no cure for generalized myasthenia gravis (gMG). It causes muscle weakness that can affect various parts of the body. The more you use the muscles, the weaker they become. Common symptoms include the following and can be different from person to person.
- Drooping of one or both eyelids
- Changes in facial expressions due to weakness in your face, jaw, or mouth
- Weakness in your arms, legs, and hands
- A hard time swallowing
- Trouble speaking
In gMG, two of the harmful antibodies are called acetylcholine receptor (AChR) or muscle-specific tyrosine kinase (MuSK) receptor antibodies. These antibodies block receptors on muscle cells, preventing them from receiving signals from nerve cells. As a result, the immune system mistakenly attacks the body’s muscles.
Imaavy is a new treatment designed to reduce the harmful antibodies causing the symptoms of gMG. Imaavy targets a protein called the neonatal Fc receptor (FcRn). By binding to FcRn, Imaavy causes the body to remove the anti-AChR and anti-MuSK antibodies from the bloodstream. With fewer of these antibodies in the blood, there is less blockage of the nerve-to-muscle communication. This can lead to improved muscle strength and fewer MG symptoms for many people.
Can Anyone With Myasthenia Gravis Use Imaavy?
Imaavy is approved for people with generalized myasthenia gravis (gMG) who have certain types of antibodies in their blood, called anti-acetylcholine receptor or anti-muscle-specific tyrosine kinase antibodies. Although most (80%-90%) people with myasthenia gravis have one of these antibodies, not everyone does, so it is important to confirm that one of these antibodies is present. Imaavy may not help people who do not have these antibodies.
How Will I Receive This Medicine?
Imaavy is given as an intravenous (IV) infusion through a needle placed in your vein by a health care provider. The infusion is given once every two weeks. Each infusion lasts between 15 to 30 minutes. The first infusion is usually longer. Your health care provider may shorten future infusions to 15 minutes if your first infusion does not cause major side effects. Imaavy can cause IV-related reactions and allergic reactions, so your health care provider will monitor you for these side effects during and after your infusion. Your health care provider may slow or stop your infusion if you have a reaction.
How Was Imaavy Studied for Generalized Myasthenia Gravis?
The effectiveness and safety of Imaavy for generalized myasthenia gravis (gMG) was studied in a clinical trial called the Vivacity-MG3. Everyone in the trial had gMG and anti-acetylcholine receptor (AChR) or anti-muscle-specific tyrosine kinase (MuSK) antibodies, and most people (88%) had anti-AChR antibodies. To be included in the trial, participants had to be taking common treatments for gMG but still be having symptoms of gMG. The average age was about 52, and the average duration of disease was six years. About two-thirds of the people in the study were female (60%) and White (63%). About 32% were Asian, 1% were Black or African American, and less than 1% were American Indian or Alaska Native. Most people had mild (25%), or moderate (62%) disease based on the Myasthenia Gravis Foundation of America disease class, with 12% of the people having severe disease.
Here is some important information about the treatments that people were using when the trial started. These medicines were allowed to continue during the trial.
- Most people (85%) were using an anticholinesterase medicine, such as pyridostigmine bromide (Mestinon or Regonol).
- About two-thirds (66%) were taking a corticosteroid, such as dexamethasone, methylprednisolone, or prednisone.
- About half (54%) were taking an immunosuppressive medicine, such as azathioprine, ciclosporin, cyclophosphamide, mycophenolate mofetil or mycophenolic acid, methotrexate, or tacrolimus.
People in the trial were treated with an IV infusion of Imaavy or a placebo (containing no medicine) every two weeks for six months.
The trial measured the efficacy of Imaavy by rating each person’s symptoms using the following scales. A higher score in each scale means that symptoms are more severe.
- The Myasthenia Gravis Activities of Daily Living (MG-ADL) scale, which asks the person to rate how much their symptoms affect different activities in the day, like talking, chewing, swallowing, breathing, seeing clearly, and brushing their teeth and hair. The score ranges from 0 to 24.
- The Quantitative MG (QMG) score, which asks a health care provider to measure muscle strength in different parts of the body. The score ranges from 0 to 39. Higher scores indicate more muscle weakness. A lower score indicates that their symptoms are less likely to negatively affect these activities.
What Benefits of Imaavy Were Seen?
After six months of treatment, people treated with Imaavy had MG-ADL scores about 1.5 points lower than people who received placebo. People treated with Imaavy also had lower QMG scores compared to people who received placebo. This means that symptoms rated by the people in the trial and the health care providers improved more with Imaavy than placebo.
Your results may differ from what was seen in clinical studies.
How Long Does It Take to Work?
In the Vivacity-MG3 clinical trial, some people with generalized myasthenia gravis (gMG) who used Imaavy saw improvements in their gMG symptoms (less muscle weakness) as early as one or two weeks after the first dose. Other people in the trial took longer to start to see improvements in their muscle weakness.
Do not stop using this or any other medicines for myasthenia gravis without talking with your health care provider first, even if your symptoms have gotten better. Your symptoms may get worse again if you stop or change any of your medicines.
It is important to track your progress and review with your health care provider. Contact your health care provider if you do not see improvements or your symptoms are getting worse.
How Can I Prevent and Manage Side Effects?
The most common side effects of Imaavy are infections in the airways, fluid retention and swelling in the hands or lower legs (also called peripheral edema), and muscle spasms.
People who use Imaavy may get infections more often, especially infections of the airways. These include infections in the nose or throat, a sore throat, or common cold symptoms. The best way to prevent infection is to reduce your exposure to germs by washing your hands and avoiding people who are sick. You should also stay current on vaccinations, such as getting an annual flu vaccine. Before you start Imaavy, speak with your health care provider about whether you are due for any vaccines.
If your lower legs become swollen during treatment with Imaavy, elevate them on a stack of pillows for 15 to 30 minutes, two to four times a day. Compression socks and stockings can also be worn to help prevent and manage fluid buildup in the lower legs.
If you get muscle spasms, stretching or massaging the area might help. You can also apply heat or ice to the affected area. If the spasms are painful, over-the-counter pain medicines like Tylenol or Advil may help.
These are not all of the possible side effects. Talk with your health care provider if you are having symptoms that bother you. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088 (800-332-1088). In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.
What Types of Interactions Can Happen?
Imaavy works by blocking the neonatal Fc receptor (FcRn) receptor. It may lower the effects of other medicines that bind to the FcRn receptor. Tell your health care provider if you are using the following medicines.
- Immunoglobulin products, like intravenous immunoglobulin (IVIg)
- Monoclonal antibodies
- Medicines that use antibody derivatives containing the human Fc domain
This is not a complete list of medicines that may interact with Imaavy. Tell your pharmacist or health care provider about all the prescription or OTC medicines, vitamins/minerals, herbal products, or other supplements you take or have recently taken. This will help them find out if there are any interactions, or if you need a dosage adjustment.
Getting Your Medicine: What to Expect
You will receive Imaavy at an infusion center. The drugmaker has a program to help support the process for you and your health care provider. You can find out more at www.jnjwithme.com/hcp/imaavy/ or by calling 844-494-8463.
Insurance approval. Your insurance may require approval for using this medicine, also called a prior authorization. The insurance company reviews the prescription from your health care provider to make sure it is covered.
Finding an Imaavy Infusion Center. Imaavy infusions are given at certain hospitals and infusion centers in the United States. Talk to your health care provider about an infusion center near you or find out more information at www.2infuse.com.
Cost support. There is a cost support program from the drugmaker that may allow you to pay $0 for your prescription. For questions or more information, contact the drugmaker at 844-494-8463 or visit asset.jnjwithme.com/document/imaavy-withme-savings-program-overview.pdf.
