Imaavy
Pronunciation: im-AH-vee
Generic name: nipocalimab-aahu
Dosage form: injection (300 mg/1.62 mL, 1,200 mg/6.5 mL)
What is Imaavy?
Imaavy (nipocalimab-aahu) is a new FDA-approved medication used to treat generalized myasthenia gravis (gMG) that is anti-AChR or anti-MuSK antibody positive. Imaavy improves myasthenia gravis symptoms and daily function by decreasing harmful levels of immunoglobulin G (IgG) antibodies. Imaavy works by blocking the receptor FcRn, which increases the breakdown of IgG antibodies, so there are fewer IgG antibodies causing damage to the nervous system.
Imaavy is given as an intravenous infusion every 2 weeks by your healthcare professional.
Imaavy FDA approval was granted on April 30, 2025, for the treatment of generalized myasthenia gravis (gMG) in patients 12 years of age and older who are anti-acetylcholine receptor (AChR) or anti-muscle-specific tyrosine kinase (MuSK) antibody positive. Imaavy FDA approval is based on positive results from the Phase 3 Vivacity-MG3 study (NCT04951622) and the ongoing Phase 2/3 Vibrance-MG study (NCT05265273).
What is myasthenia gravis?
Myasthenia gravis is a long-term (chronic) autoimmune disease that causes muscle weakness, leading to symptoms of double vision, drooping eyelids, trouble talking, breathing, and trouble walking. Myasthenia gravis is caused by antibodies from your immune system attacking proteins between nerves and muscles (neuromuscular junction), which makes it harder for the muscles to contract. Many patients with myasthenia gravis have antibodies that attack the nicotinic acetylcholine receptors (AChR); these patients are called AChR antibody positive (AChR-Ab+). Other patients have antibodies that attack muscle-specific tyrosine kinase [MuSK], and they are called anti-MuSK antibody positive.
Usually, the first and main symptom of MG is painless weakness of specific muscles that gets worse towards the end of the day. It may also become worse during physical activity and then improve after rest. MG symptoms often start with eye weakness; then, over a period of time, they may progress to a severe generalized form, with weakness in arms and legs or in muscles involved in swallowing and breathing.
How does Imaavy work?
IgG autoantibodies are part of the immune system that attack proteins between nerves and muscles and cause symptoms of myasthenia gravis. The more IgG autoantibodies there are, the more damage is done. Imaavy decreases the level of IgG antibodies, so there is less damage to the neuromuscular junction, and this improves MG symptoms.
Imaavy works by blocking FcRn, a protein responsible for recycling IgG antibodies and keeping IgG levels high. Once Imaavy blocks FcRn, the IgG antibodies are broken down, levels are reduced, and myasthenia gravis symptoms improve.
Imaavy is a neonatal Fc receptor (FcRn) blocker monoclonal antibody. Imaavy's active ingredient is nipocalimab-aahu.
How well does Imaavay work?
The Vivacity-MG3 clinical trial demonstrated that Imaavy patients had a:
- 75% reduction in autoantibody levels throughout 24 weeks of monitoring
- Superior disease control throughout 24 weeks as measured by improvement in the MG-ADL* score, meaning patients had improvements in daily functions, such as chewing, swallowing, speaking, and breathing.
This study compared patients using Imaavy plus standard of care to patients using a placebo plus standard of care over 24 weeks.
*Myasthenia Gravis–Activities of Daily Living (MG-ADL) score measures the severity of myasthenia gravis. The score is the result of 8 questions related to symptoms and the ability to perform functional activities related to daily living. The total score ranges from 0 (no symptoms) to 24 (severe symptoms). In clinical trials, the MG-ADL score is measured at the start of the trial and end of the trial.
Imaavy side effects
Common Imaavy side effects
The most common Imaavy side effects were respiratory tract infections (18%), swelling of feet, hands, or extremities (12%), and muscle spasms (12%). These side effects occurred in 10% or more of patients who took every 2 weeks for at least 6 months in Study 1 (NCT04951622).
Serious side effects
Serious infections. This medicine may cause serious side effects, including serious infections (7%). Tell your healthcare provider right away if you have any of the following symptoms of infection:
- Fever
- Chills
- Shivering
- Cough
- Sore throat
- Fever blisters
- Burning or pain when you urinate.
Allergic (hypersensitivity) reactions. Allergic reactions can occur during or up to a few weeks after your infusion. Get emergency medical help right away if you get any of these symptoms during or after your infusion, which may be part of a serious allergic reaction:
- Swelling of your face, lips, mouth, tongue, or throat
- Difficulty swallowing or breathing
- Itchy rash (hives)
- Chest pain or tightness.
Infusion-related reactions. Tell your healthcare provider right away if you get any of the following symptoms during or a few days after your infusion:
- Headache
- Rash
- Nausea
- Fatigue
- Dizziness
- Chills
- Flu-like symptoms
- Redness of skin
This is not a complete list of side effects, and others may occur. Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
What to avoid
You should not have live vaccines while receiving Imaavy.
Before taking this medicine
Do not use this medicine if you have ever had an allergic reaction to Imaavy or any of the inactive ingredients. Allergic reactions, including angioedema and anaphylaxis, have occurred in patients taking this medicine.
Do not use Imaavy if you:
- Have or have had any recent infections or have any symptoms of infection
- Have recently received or are scheduled to receive an immunization (vaccine) - you should not receive live vaccines while being treated with Imaavy.
Pregnancy
Tell your healthcare provider if you are pregnant or plan to become pregnant, as it is not known whether Imaavy will harm your unborn baby.
There is a pregnancy safety study for Imaavy if this medicine is given during pregnancy or you become pregnant while receiving this medicine. Your healthcare provider should report exposure by contacting Janssen at 1-800-526-7736 or www.IMAAVY.com.
Breastfeeding
Tell your healthcare provider if you are breastfeeding or planning to breastfeed, as this medicine can pass into your breastmilk, and it is not known whether Imaavy will harm your baby. Talk to your healthcare provider about the best way to feed your baby if you receive this medicine.
How will I receive this medicine?
Imaavy is given through a needle placed into your vein (intravenous [IV] infusion) every 2 weeks by your healthcare provider. Your first infusion usually takes at least 30 minutes, then if all goes well, your next infusions usually take at least 15 minutes. If you have a reaction during your infusion, your healthcare provider may decide to give your infusion more slowly or to stop your infusion.
Missed dose
If you miss a scheduled infusion, you should receive your next dose as soon as possible.
Imaavy dose information
Initial dosage: 30 mg/kg once via intravenous infusion over at least 30 minutes.
Maintenance dose: 15 mg/kg via intravenous infusion over at least 15 minutes, and continue every two weeks thereafter.
General dosing information
The maintenance dose starts two weeks after the initial dose.
Must be diluted with 0.9% sodium chloride injection before administration.
Administer the diluted Imaavy solution immediately after preparation.
Evaluate the need to administer age-appropriate vaccines according to immunization guidelines before starting this medicine.
Interactions
Tell your healthcare provider about all of the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements.
Your doctor will closely monitor for reduced effectiveness of medications if you take medications that bind to the human neonatal Fc receptor, (e.g., immunoglobulin products, monoclonal antibodies, or antibody derivatives containing the human Fc domain of the IgG subclass).
Not all possible interactions are listed here and other drugs may interact with this medicine, including prescription and over-the-counter medicines, vitamins, and herbal products.
Storage
Unopened Vials
- Store vials refrigerated at 2ºC to 8ºC (36ºF to 46ºF) in the original carton to protect from light until the time of use.
- Do not freeze.
- Do not shake.
Diluted Solution
Diluted Imvaay solution should be used immediately if possible. If it is not used immediately:
- Protect from light.
- Store refrigerated at 2°C to 8°C (36°F to 46°F) for no more than 24 hours.
- Do not freeze.
- After preparation or removal from the refrigerator, use or discard the diluted Imaavy solution within 12 hours, including infusion time. During these 12 hours, store under ambient light at 15°C to 30°C (59°F to 86°F).
Ingredients
Active ingredient: nipocalimab-aahu
Inactive ingredients: arginine hydrochloride, histidine, L-histidine monohydrochloride monohydrate, methionine, polysorbate 80, sucrose, and water for injection.
Company
Imaavy Janssen Biotech, Inc., Horsham, PA 19044, USA
Further information
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.