Patient leaflet - Imaavy 185 mg/ml concentrate for solution for infusion
1 What Imaavy is and what it is used for
What Imaavy is
Imaavy contains the active substance nipocalimab. Nipocalimab binds to a protein in the body called FcRn. By binding to FcRn, nipocalimab decreases the level of IgG autoantibodies. IgG autoantibodies are proteins of the immune system that attack parts of the person’s own body by mistake.
What Imaavy is used for
Imaavy is used together with standard therapy to treat adult and adolescent patients aged 12 years and older with generalised Myasthenia Gravis (gMG), an autoimmune disease that causes muscle weakness. gMG can affect multiple muscle groups throughout the body. The condition can also lead to shortness of breath, extreme fatigue and difficulties swallowing.
In patients with gMG, IgG autoantibodies attack and damage certain proteins on the nerves called acetylcholine receptors. Because of this damage, the nerves are not able to make the muscles contract as well as normal, leading to muscle weakness and difficulty moving. By binding to the FcRn protein and reducing autoantibody levels, Imaavy can improve the ability of muscles to contract and reduce the symptoms of the disease and their impact on daily activities.
2 What you need to know before you use Imaavy
Do not use Imaavy
- if you are allergic to nipocalimab or any of the other ingredients of this medicine (listed in section 6).
Warnings and precautions
Infusion reactions and allergic reactions
Imaavy contains a protein that can cause reactions such as headache, nausea, rash, tiredness, chills, reddening of the skin and dizziness in some people. You will be monitored for signs of an infusion or serious allergic (anaphylactic) reaction during and for at least 30 minutes after treatment. Signs of a serious allergic reaction include: swelling of the face, lips, throat or tongue which makes it difficult to swallow or breathe, shortness of breath, feeling of loss of consciousness, or skin rash. If you experience any of these symptoms tell your doctor immediately. Infections
Imaavy treatment may reduce your natural resistance to infections. Before starting or during treatment with this medicine, inform your doctor if you have any symptoms of infection (such as fever, chills or shivering, cough or sore throat).
Imaavy treatment may allow herpes zoster infection (shingles) to come back. Tell your doctor if you get a painful skin rash with blisters as these can be signs of shingles.
Additional monitoring tests
Your doctor will carry out blood tests to check your blood fat (cholesterol) levels after Imaavy treatment (see section 4). Vaccinations
Please inform your doctor if you have received a vaccine in the last 4 weeks, or if you plan to be vaccinated in the near future (within a couple of weeks).
Children
Imaavy is not for use in children less than 12 years of age, because it has not been studied in these patients.
Other medicines and Imaavy
Tell your doctor if you are using, have recently used or might use any other medicines.
Taking Imaavy with other medicines such as therapeutic antibodies or immunoglobulins may decrease their effectiveness. Other interventions such as plasma exchange (plasmapheresis), may impair the effect of Imaavy.
Pregnancy, breast-feeding and fertility
There is limited information about the use of Imaavy in pregnancy or while breast‑feeding. If you are pregnant or breast‑feeding, think you may be pregnant or are planning to have a baby, ask your doctor or pharmacist for advice before taking this medicine.
Driving and using machines
Imaavy is not expected to influence the ability to drive or use machines.
Imaavy contains polysorbate
This medicine contains 0.97 mg (300 mg vial) or 3.9 mg (1200 mg vial) of polysorbate 80 in each single‑use vial which is equivalent to 0.60 mg/mL. Polysorbates may cause allergic reactions. Tell your doctor if you have any known allergies.
3 How to use Imaavy
The treatment will be given by your doctor or other healthcare provider.
What dose of Imaavy you will receive and how often
The dose you receive will depend on your bodyweight and will be given directly into your blood as an infusion (drip) given into a vein every 2 weeks.
If you receive more Imaavy than you should
The dose of this medicine will be carefully calculated by your doctor. If you suspect that you have accidentally been given a higher dose of Imaavy than prescribed, please contact your doctor for advice.
If you forget an appointment to receive Imaavy
If you forget an appointment, please contact your doctor immediately for advice and see section below “If you stop using Imaavy”.
If you stop using Imaavy
Interrupting or stopping treatment with Imaavy may cause your gMG symptoms to come back. Please speak to your doctor before stopping Imaavy. Your doctor will discuss the possible side effects and risks with you. Your doctor may also want to monitor you closely. If you have any further questions on the use of this medicine, ask your doctor.
4 Possible side effects
Like all medicines, this medicine can cause side effects, although not everybody gets them.
Your doctor will discuss the possible side effects with you and explain the risks and benefits of Imaavy with you prior to treatment. Very common (may affect more than 1 in 10 people)
- high level of lipids (fats) or cholesterol in the blood
- decreases in the level of ‘albumin’ (a protein) in the blood
- muscle spasms
- swollen hands, ankles or feet (peripheral oedema)
Common (may affect up to 1 in 10 people)
- urinary tract infection (may cause pain or a burning sensation during urination)
- chest infection (such as pneumonia or bronchitis)
- shingles (herpes zoster virus infection)
- difficulty sleeping (insomnia)
- feeling dizzy
- diarrhoea
- belly (abdominal) pain
- nausea
- fever
Reporting of side effects
If you get any side effects, talk to your doctor, pharmacist or nurse. This includes any possible side effects not listed in this leaflet. You can also report side effects directly via the Yellow Card Scheme at: www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store. By reporting side effects, you can help provide more information on the safety of this medicine.
5 How to store Imaavy
Keep this medicine out of the sight and reach of children. Do not use this medicine after the expiry date which is stated on the carton and on the label after “EXP”. The expiry date refers to the last day of that month.
Store in a refrigerator (2 °C ‑ 8 °C).
Do not freeze.
Store in the original package in order to protect from light. Do not throw away any medicines via wastewater or household waste. Ask your pharmacist how to throw away medicines you no longer use. These measures will help protect the environment.
6 Contents of the pack and other information
What Imaavy contains
The active substance is nipocalimab.
‑ Each vial of 1.62 mL contains 300 mg of nipocalimab (185 mg/mL). ‑ Each vial of 6.5 mL contains 1200 mg of nipocalimab (185 mg/mL).
- The other ingredients are: arginine hydrochloride, histidine, histidine monohydrochloride monohydrate, methionine, polysorbate 80 (E433), sucrose, and water for injections.
What Imaavy looks like and contents of the pack
Imaavy is presented as a sterile concentrate for solution for infusion (300 mg or 1200 mg in a vial – pack size of 1).
Imaavy is a liquid. It is colourless to slightly brownish, clear to slightly opalescent.
Marketing Authorisation Holder
Janssen‑Cilag Ltd
50‑100 Holmers Farm Way
High Wycombe
Buckinghamshire
HP12 4EG
UK
Manufacturer
Janssen Biologics B.V.
Einsteinweg 101
Leiden, 2333 CB
The Netherlands
For information in large print, tape, CD or Braille, telephone 0800 7318450. This leaflet was last revised in 11/2025
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