Key takeaways

  • Imaavy (nipocalimab-aahu) is a brand-name medication prescribed to treat generalized myasthenia gravis (gMG) in adults and children ages 12 years and older who test positive for certain antibodies. It’s administered via intravenous (IV) infusion.
  • The dosage of Imaavy is determined by body weight, with an initial dose of 30 mg/kg, followed by maintenance doses of 15 mg/kg every 2 weeks.
  • Imaavy can cause mild to serious side effects ranging from muscle spasms and respiratory infections to severe, potentially life threatening allergic reactions. Side effects in children are similar to those seen in adults.

Specifically, the Food and Drug Administration (FDA) has approved Imaavy to treat generalized myasthenia gravis (gMG) in adults and children ages 12 years and older who are anti-acetylcholine receptor (AChR) or anti-muscle-specific tyrosine kinase (MuSK) antibody positive.

Drug details

You’ll find key information about Imaavy here:

  • Drug class: neonatal Fc receptor blocker
  • Drug form: intravenous (IV) infusion (an injection into a vein given over time)
  • Generic available? no
  • Prescription required? yes
  • Controlled substance? no
  • Accelerated approval? no

Imaavy is available only as a brand-name medication. It’s not currently available in generic form. (A generic drug contains an exact copy of the active ingredient in a brand-name medication but usually costs less.)

The Imaavy dosage your doctor prescribes will depend on several factors. These include:

  • the type and severity of the condition you’re using Imaavy to treat
  • your age
  • your body weight
  • other medical conditions you may have

The following information describes dosages that are commonly used or recommended. Your doctor will determine the best dosage to fit your needs.

Drug form and strengths

Imaavy comes as a liquid solution that’s diluted by a healthcare professional before being given as an intravenous (IV) infusion (an injection into a vein given over time).

The drug comes in two vial sizes measured in milligrams (mg) per milliliter (mL):

  • 300 mg/1.62 mL (185 mg/mL) in a single-dose vial
  • 1,200 mg/6.5 mL (185 mg/mL) in a single-dose vial

Dosage for gMG

Your doctor will determine your dosage of Imaavy based on your body weight in kilograms (kg). For reference, 1 kg equals approximately 2.2 pounds (lb).

The initial dosage of Imaavy is 30 mg per kg of body weight given as an IV infusion over the course of at least 30 minutes.

The ongoing (maintenance) dosage, which starts 2 weeks after the initial dose, is 15 mg/kg given via an IV infusion over the course of at least 15 minutes. This will continue every 2 weeks thereafter.

Children’s dosage

Imaavy is only approved for use in children ages 12 years and older.

The recommended dosage for children ages 12 to 18 years is the same as for adults: an initial dose of 30 mg/kg followed by 15 mg/kg every 2 weeks.

How it’s given

Imaavy is administered via IV infusion by a healthcare professional in a doctor’s office, clinic, or hospital.

The initial infusion is given over the course of at least 30 minutes. Subsequent maintenance infusions are given over the course of at least 15 minutes.

About taking Imaavy

You’ll find information about key dosage issues here:

  • If you miss a dose: If you miss an infusion, you should receive your next one as soon as possible and resume dosing every 2 weeks thereafter.
  • Length of use: Imaavy is meant to be a long-term treatment. If you and your doctor determine that Imaavy is safe and effective for you, you’ll likely receive it long term.
  • Length of time to work: According to the drug’s clinical trials, it took over 5 months of treatment for the full, intended benefit of Imaavy to be measured and confirmed. At this point there was significant improvement in people receiving Imaavy compared to those receiving a placebo.

Imaavy can cause mild to serious side effects. The following lists contain some of the key side effects that may occur while receiving Imaavy but do not include all possible side effects.

For more information about possible side effects of Imaavy, talk with your doctor or pharmacist. They can give you tips on how to manage any that are concerning or bothersome.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks and reviews side effects of the medication. Sharing your experience helps make medications safer for everyone by giving doctors and researchers more information about how the drug works in real life. If you develop a side effect while taking Imaavy and want to tell the FDA about it, visit MedWatch or call 800-FDA-1088.

Mild side effects

Here is a list of mild side effects of Imaavy. To learn about other mild side effects, talk with your doctor or pharmacist, or view Imaavy’s prescribing information.

Mild side effects of Imaavy can include:

Most of these side effects may go away within a few days to a couple of weeks. However, if they become severe or don’t go away, talk with your doctor or pharmacist.

Serious side effects

Serious side effects from Imaavy aren’t common, but they can occur.

Serious side effects can include:

  • serious infections, including the activation of dormant viruses, such as herpes zoster and Epstein-Barr
  • anaphylaxis (a severe allergic reaction)
  • angioedema (swelling of the face, lips, mouth, tongue, or throat)

Call your doctor right away if you have serious side effects. Call 911 or your local emergency phone number if your symptoms feel life threatening or you think you’re having a medical emergency.

Side effects in children

Side effects in children are typically the same as those seen in adults. In a study of children ages 12 to 16 years, adverse reactions were consistent with those observed in adult patients with gMG.

ALLERGIC REACTION

For some people, Imaavy can cause an allergic reaction.

In general, symptoms of an allergic reaction can be mild or serious.

Ways to manage

For mild allergic reaction symptoms, such as a mild rash, call your doctor right away. They may recommend treatments to help manage your symptoms. They’ll also let you know whether you should continue Imaavy treatment.

For severe allergic reaction symptoms, such as swelling or difficulty breathing, call 911 or your local emergency number right away. These symptoms require immediate medical care because they can become life threatening. If you’ve had a serious allergic reaction to Imaavy, your doctor will recommend a different medication instead.

Imaavy is prescribed for the treatment of generalized myasthenia gravis (gMG) in adults and children 12 years of age and older who are anti-acetylcholine receptor (AChR) or anti-muscle-specific tyrosine kinase (MuSK) antibody positive.

For this purpose, Imaavy may be prescribed on its own or with other drugs for gMG. Examples of other gMG drugs that doctors may prescribe with Imaavy include:

Imaavy and children

Imaavy has been shown to be safe and effective for treating gMG in children ages 12 years and older.

Imaavy can interact with several other medications. Before starting Imaavy, talk with your doctor and pharmacist. Tell them about all prescription, over-the-counter, and other drugs you take. Also tell them about any vitamins, herbs, and supplements you use. Sharing this information can help you avoid potential interactions.

Interactions with medications, foods, and supplements

If you have questions about drug interactions that may affect you, ask your doctor or pharmacist.

Medications that can interact with Imaavy

Here’s a list of medications that can interact with Imaavy. This list does not contain all drugs that may interact with Imaavy.

Drugs that bind to the human neonatal Fc receptor (FcRn) can interact with Imaavy. These include:

  • immunoglobulin products
  • monoclonal antibodies
  • antibody derivatives containing the human Fc domain of the IgG subclass (in other words, drugs shaped like the most common natural defense proteins in your blood)

Taking Imaavy with other IgG-based therapies (such as monoclonal antibodies) may lower the levels of those drugs in your system and reduce their effectiveness. This interaction does not apply to all medications but specifically to antibody-based treatments.

Lab tests or vaccines that can interact with Imaavy

Live vaccines are not recommended during treatment with Imaavy because Imaavy temporarily lowers your body’s main natural defense proteins. Since these proteins are reduced for a while, a live vaccine might not work as well, or it could potentially cause an infection instead of preventing one.

Foods, vitamins, and supplements that can interact with Imaavy

There are currently no known interactions between Imaavy and any foods, vitamins, or supplements. Talk with your doctor or pharmacist if you have questions or concerns about any substances you take during your treatment with this medication.

Alcohol interaction

Alcohol is not known to interact with Imaavy. It’s likely safe to consume alcohol during treatment with this medication. If you have questions about how much alcohol is safe to drink while receiving Imaavy, talk with your doctor or pharmacist.

As with all medications, the cost of Imaavy can vary. The actual price you’ll pay depends on your insurance plan, your location, and the pharmacy that’s used.

Financial and insurance assistance: If you need financial support to pay for Imaavy or help understanding your insurance coverage, the Imaavy withMe program may be able to assist you. For more information and to find out if you’re eligible for support, call 800-526-7736 or visit the program website.

Imaavy is not available in a generic form. (A generic drug contains an exact copy of the active ingredient in a brand-name medication but tends to cost less.)

Other drugs are available that can treat your condition. Some may be a better fit for you than others.

The following drugs are similar to Imaavy:

If you’re interested in exploring an alternative to Imaavy, talk with your doctor. They can tell you about other treatments that may work well for you.

If you can become pregnant, consider the following information about pregnancy, birth control, and breastfeeding.

Imaavy and pregnancy

There are risks to receiving Imaavy treatment during pregnancy. But there are also risks with having untreated generalized myasthenia gravis (gMG) while pregnant. (Imaavy is used to treat gMG.)

If you’re planning a pregnancy or can become pregnant, talk with your doctor about potential treatments for gMG. Together, you can consider the risks and benefits of your treatment options and decide whether or not you should take Imaavy during this time.

Imaavy and birth control

It’s not known whether Imaavy is safe to take during pregnancy. If you’re sexually active and you or your partner can become pregnant, talk with your doctor about your birth control options while receiving Imaavy.

Imaavy and breastfeeding

It’s not known whether Imaavy should be used while breastfeeding. If you’re currently breastfeeding or planning to do so, talk with your doctor before receiving Imaavy infusions.

Imaavy’s mechanism of action (how it works) is by interfering with your body’s natural system for protecting its most common defensive proteins called IgG antibodies.

With gMG, the immune system mistakenly creates harmful antibodies that attack muscle receptors. These antibodies are a specific type of IgG. The key to treating gMG is to reduce the number of harmful IgG antibodies circulating in your blood.

Typically, your body is constantly producing antibodies. It also has a special system that acts like a recycling center or security checkpoint called the neonatal Fc receptor (FcRn).

When the body’s natural antibodies (IgG) are circulating in your system, the FcRn receptor recognizes them, grabs them, and protects them from being broken down and destroyed. By doing this, the FcRn keeps your IgG antibody levels high, making them last longer in your system.

Imaavy acts as a blocker. It works by targeting and tightly binding to that FcRn “recycling center.” When Imaavy is attached to the FcRn, it blocks the center and prevents it from grabbing and recycling your natural IgG antibodies (both the protective ones and those that cause gMG).

Because the antibodies can no longer be recycled, the body’s normal processes break them down and destroy them much faster than usual. By stopping the recycling process, Imaavy causes a reduction in the total amount of IgG antibodies circulating in your blood, which lowers the levels of the harmful, disease-causing IgG antibodies in gMG. This leads to fewer attacks on your muscle receptors and results in an improvement in your gMG symptoms.

Before starting Imaavy, discuss your health history with your doctor. Imaavy may not be right for you if you have certain medical conditions or other factors affecting your health. Be sure to talk with your doctor if any of the following apply to you:

  • current (active) infection
  • history of serious hypersensitivity reaction to nipocalimab (the active ingredient in Imaavy) or any of the drug’s inactive ingredients: in this case, your doctor will not prescribe this medication for you
  • previous allergic reaction to this or a similar drug: in this case your doctor will determine whether Imaavy is a safe treatment option for you
  • pregnancy
  • breastfeeding

Note: For more information about the potential negative effects of Imaavy, see the “Imaavy side effects” section.

Disclaimer: Medical News Today has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.

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