Mavacamten

Brand name: Camzyos (kam-zai-ōs)
Dosage form: capsules (2.5mg, 5mg, 10mg, 15mg)
Drug class: Miscellaneous cardiovascular agents

Medically reviewed by Melisa Puckey, BPharm. Last updated on Jul 24, 2024.

What is mavacamten?

Mavacamten (Camzyos) is a prescription medicine for obstructive hypertrophic cardiomyopathy (HCM) to help improve shortness of breath and the ability to be active. Mavacamten allows the heart muscles to relax so the heart can fill with more blood, and your heart can pump blood around your body more effectively. In obstructive hypertrophic cardiomyopathy (HCM), the walls of the heart become excessively thickened and stiff, this blocks or reduces blood flow from the heart to your body, which causes your symptoms. Mavacamten relaxes the heart muscles, which reduces the obstruction, so it improves your symptoms and your ability to be active.

What causes obstructive HCM?

In your heart muscle, two proteins called myosin and actin join together to make your heart contract and then release to allow your heart to relax, and this pumps blood around your body. In obstructive HCM, too many myosin and actin connect, making the heart contract too much and unable to relax properly, reducing blood flow from the heart.

How does mavacamten work?

Mavacamten works by binding to myosin, which means less myosin is available for actin proteins to connect to. As a result, the heart muscle relaxes, the heart fills with more blood, and it is able to pump more effectively.

Mavacamten mechanism of action is as an allosteric and reversible inhibitor selective for cardiac myosin. Mavacamten binds to myosin protein in the cardiac muscle which reduces left ventricular outflow tract obstruction and improves cardiac filling pressures.

Who can use mavacamten?

Mavacamten is indicated for the treatment of adults with symptomatic New York Heart Association (NYHA) class II-III obstructive hypertrophic cardiomyopathy (HCM) to improve functional capacity and symptoms. Camzyos brand of mavacamten became an FDA-approved medicine on April 28, 2022.

Mavacamten side effects

Common mavacamten side effects include dizziness (27%) or fainting (6%).

Serious mavacamten side effects

Get emergency medical help if you have signs of an allergic reaction, such as hives, difficulty breathing, or swelling of your face, lips, tongue, or throat.

Mavacamten may cause serious side effects. Call your doctor at once if you have:

• heart failure symptoms, e.g., shortness of breath, chest pain, tiredness, swelling in your legs, rapid weight gain, or racing or pounding heartbeats.

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.

Camzyos side effects (more detail)

Related/similar drugs

Camzyos REMS program

Mavacamten is only available through the Camzyos REMS program, which is required by the FDA to monitor the safe use of this medication. The REMS (Risk Evaluation and Mitigation Strategy) program is required as this medicine can cause the heart muscles to become too relaxed, which increases the risk of heart failure. Your doctor will review and discuss the REMS Patient Brochure with you and talk to you about how to enroll in the program.

Warnings

Mavacamten may cause serious side effects and carries a Boxed Warning for heart failure.

Heart failure:

Heart failure is a condition where the heart cannot pump with enough force. Heart failure is a serious condition that can lead to death. You must have echocardiograms before you take the first dose and also during your treatment with this medicine. This is important to help your healthcare provider understand how your heart is responding to this medicine. People who develop a serious infection or irregular heartbeat have a greater risk of heart failure during treatment.

Call your doctor at once if you have shortness of breath, chest pain, tiredness, swelling in your legs, rapid weight gain, or racing or pounding heartbeats.

The risk of heart failure is also increased when Camzyos is taken with certain other medicines. Tell your healthcare provider about the medicines you take, both prescribed and obtained over-the-counter, before and during treatment.

Because of the serious risk of heart failure, this medicine is only available through a restricted program called the Camzyos Risk Evaluation and Mitigation Strategy (REMS) Program.

See mavacamten side effects for information about side effects.

It is not known if this medicine is safe and effective in children.

Before taking this medicine

Some drugs should not be used with mavacamten. Your treatment plan may change if you also use:

• nefazodone;
• St. John's wort;
• an antibiotic eg.clarithromycin, rifabutin, rifampin, rifapentine, telithromycin;
• antifungal medicine eg. itraconazole, ketoconazole;
• antiviral medicine for HIV or hepatitis C eg. boceprevir, cobicistat, dasabuvir, elvitegravir, indinavir, lopinavir/ritonavir, nelfinavir, ombitasvir, paritaprevir saquinavir, telaprevir, tipranavir;
• cancer medicine eg. apalutamide, enzalutamide, mitotane;
• seizure medicine eg. carbamazepine, oxcarbazepine, phenytoin, primidone;
• steroid medicine eg. dexamethasone, prednisone;

Tell your doctor if you have ever had:

• an irregular heartbeat;
• heart failure; or
• if you have an infection.

Pregnancy

Mavacamten may harm an unborn baby. You may need a pregnancy test to make sure you are not pregnant for using this medicine. Use effective birth control while using this medicine and for at least 4 months after your last dose. Tell your doctor if you become pregnant.

Hormonal contraceptives containing a combination of ethinyl estradiol and norethindrone may be used with this medicine, but it can make other birth control pills less effective. Ask your doctor about all birth control options, such as an injection, implant, skin patch, vaginal ring, condom, diaphragm, cervical cap, or contraceptive sponge.

Breastfeeding

Ask a doctor if it is safe to breastfeed while using this medicine.

How should I take mavacamten?

Take mavacamten once a day.

Swallow the capsule whole. Do not break, open, or chew the capsule.

You will start with an initial dose, and over weeks, your Doctor will increase your dose depending on how you respond to the medicine.

Your healthcare provider may change your dose, temporarily stop, or permanently stop your treatment if you have certain side effects.

Take mavacamten capsules exactly as your healthcare provider tells you to take them.

Do not change your dose without talking to your healthcare provider first.

What happens if I miss a dose?

If you miss a dose, take it as soon as possible and take your next dose at your regularly scheduled time the next day. Do not take 2 doses on the same day to make up for a missed dose.

What happens if I overdose?

If you take too much or overdose, call your healthcare provider or go to the nearest hospital emergency room right away.

Dosing information

Usual Adult Dosage for Hypertrophic Cardiomyopathy

Starting mavacamten dose: 5 mg orally once a day

Allowable subsequent doses with titration: 2.5, 5, 10, or 15 mg orally once a day

Comments

• Patients may develop heart failure while taking this drug; regular left ventricular ejection fraction (LVEF) and Valsalva left ventricular outflow tract (LVOT) gradient assessment is needed for careful titration to achieve an appropriate target Valsalva LVOT gradient while maintaining LVEF at least 50% and avoiding heart failure symptoms.
• When initiating or titrating this drug, LVEF should be considered first, then the Valsalva LVOT gradient and patient clinical status should be considered to guide appropriate dosing; the algorithms for INITIATION and MAINTENANCE should be followed for appropriate dosing and monitoring schedules.
• If LVEF is less than 50% during therapy, this drug should be interrupted; the algorithm for INTERRUPTION should be followed for guidance on interrupting, restarting, or discontinuing this drug. If interrupted at 2.5 mg, the patient should either restart at 2.5 mg or permanently discontinue this drug.

Available Strengths

Camzyos brand is available as 2.5 mg, 5mg, 10mg, and 15mg capsules.

What other drugs will affect mavacamten?

Tell your doctor about all your other medicines, especially:

• moderate to strong CYP2C19 inhibitors or strong CYP3A4 inhibitors
• moderate to strong CYP2C19 inducers or moderate to strong CYP3A4 inducers
• heart medications such as disopyramide, ranolazine, or verapamil that are taken with a beta blocker, or diltiazem with a beta blocker as these medications and combinations increase the risk of left ventricular systolic dysfunction and heart failure symptoms
• other medicines to treat obstructive hypertrophic cardiomyopathy; or
• omeprazole, esomeprazole, or cimetidine.

Mavacamten is an inducer of CYP3A4, CYP2C9, and CYP2C19. Using mavacamten with CYP3A4, CYP2C9, or CYP2C19 substrates may reduce the plasma concentration of these drugs. Ask your healthcare provider if you are taking one of these medications.

Progestin and ethinyl estradiol are CYP3A4 substrates. Using mavacamten with these medicines may decrease blood levels of certain progestins which may lead to contraceptive failure. Combined hormonal contraceptives (CHCs) containing a combination of ethinyl estradiol and norethindrone may be used, but if other CHCs are used, patients should add nonhormonal contraception (such as condoms) during concomitant use and for 4 months after the last dose of mavacamten.

This list is not complete. Other drugs may affect Camzyos, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.

Click on the link below to check for interactions with mavacamten.

Camzyos Package Insert

Review the Camzyos Package Insert for more detailed information about this medicine. Discuss any medical questions you have with your doctor or other health care provider. This is not all the information you need to know about this medicine for safe and effective use, and it does not take the place of talking to your doctor about your treatment.

Storage

Store at room temperature between 68°F to 77°F (20°C to 25°C).

Ingredients

Camzyos Active ingredient: mavacamten

Camzyos Inactive ingredients: croscarmellose sodium, hypromellose, magnesium stearate (non-bovine), mannitol, and silicon dioxide. The capsule contains black iron oxide, gelatin, red iron oxide, titanium dioxide, and yellow iron oxide.

Company

Camzyos company Bristol-Myers Squibb Company, Princeton, NJ 08543 USA

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Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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