Cardiac myosin inhibitor (oral)

Camzyos (mavacamten)

An approved treatment for Hypertrophic Cardiomyopathy.

FDA Approved (2022)by Bristol Myers Squibb

Preclinical

Phase 1

Phase 2

Phase 3

Approved

2022

Drug facts

The same compound appears under different names depending on the context. Here is how to identify Mavacamten wherever you encounter it, plus the key facts at a glance.

Generic name: Mavacamten
Brand name: Camzyos
Development code: MYK-461
Drug class: Cardiac myosin inhibitor (oral)
Manufacturer: Bristol Myers Squibb
How it's taken: A capsule taken once a day with or without food, in strengths of 2.

The first cardiac myosin inhibitor, approved April 28, 2022 for adults with symptomatic NYHA class II to III obstructive hypertrophic cardiomyopathy. A supplemental application to extend it to adolescents aged 12 to 17 is under FDA priority review with a September 30, 2026 decision date.

Where Mavacamten fits

First-line drug therapy for obstructive HCM has been beta-blockers and non-dihydropyridine calcium channel blockers for decades, with disopyramide, septal myectomy surgery or alcohol septal ablation for those who do not respond. Mavacamten is the first drug that treats the mechanism, and the 2024 US HCM guideline lists cardiac myosin inhibitors as an option for symptomatic obstructive patients alongside those older choices. A second cardiac myosin inhibitor, aficamten (Myqorzo, Cytokinetics), was approved by the FDA on December 19, 2025 for adults with symptomatic obstructive HCM.

How Mavacamten works

In obstructive HCM the heart muscle is not weak; it is overactive. Too many myosin motor proteins engage with each beat, the thickened wall squeezes too hard, and the outflow channel from the main pumping chamber narrows during contraction. Mavacamten binds to cardiac myosin and reduces the fraction of those motors that can engage, so the muscle contracts less forcefully and the obstruction eases. Because it lowers contraction on purpose, the same mechanism can push pumping function too low, which is why the drug carries a boxed warning for heart failure, requires echocardiograms before and during treatment, and is dispensed only through a REMS program. The dose is adjusted against 2 echo measurements: the Valsalva LVOT gradient (how obstructed) and LVEF (how much reserve is left).

Mechanism: Selective, reversible, allosteric inhibitor of cardiac myosin that reduces the number of myosin heads able to enter force-producing states, easing the hypercontractility that drives outflow obstruction

Side effects and safety

What patients report

Boxed warning

Mavacamten reduces left ventricular ejection fraction and can cause heart failure; echocardiograms are required before and during treatment, it should not be started if LVEF is below 55%, and it must be interrupted if LVEF falls below 50% or heart failure symptoms appear.

Label warnings

Heart failure. risk is higher during a serious illness such as an infection or an arrhythmia like atrial fibrillation; new shortness of breath, chest pain, palpitations, fatigue or leg swelling should prompt an echo
Drug interactions. contraindicated with strong CYP2C19 inhibitors and with moderate to strong CYP2C19 or CYP3A4 inducers; over-the-counter omeprazole, esomeprazole and cimetidine are among the interacting drugs
Other heart drugs. avoid with disopyramide, ranolazine, or verapamil or diltiazem combined with a beta-blocker, which add to the reduction in contraction
REMS program. prescribers, pharmacies and patients must all be enrolled in the CAMZYOS REMS Program
Pregnancy. may cause fetal harm based on animal studies; pregnancy must be excluded before starting and effective contraception used during treatment and for 4 months after, and the drug can reduce the effectiveness of some hormonal contraceptives

Most common in trials

dizziness (27% vs 18% on placebo)fainting (syncope, 6% vs 2%)

What gets monitored

Echocardiogram for LVEF and Valsalva LVOT gradient before starting and at weeks 4, 8 and 12, then 4 weeks after any dose increase; once stable on a dose with a gradient under 30 mm Hg, every 6 months
Pregnancy test before starting for females of reproductive potential
Review of every new medication, including over-the-counter, for CYP2C19 and CYP3A4 interactions

Report a suspected reaction to Bristol Myers Squibb at 1-800-721-5072, or to the FDA at 1-800-FDA-1088.

In context

In the 251-patient EXPLORER-HCM trial the only reactions occurring in more than 5% of patients and more often than on placebo were dizziness (27% versus 18%) and syncope (6% versus 2%). The safety issue that shapes everything else is the drug's intended effect taken too far: 7 patients on mavacamten (6%) and 2 on placebo had LVEF drop below 50% during the trial, and in all 7 it recovered after the drug was paused. Syncope (0.8%) was the only reaction that led anyone to stop. In the adolescent SCOUT-HCM trial no patient's LVEF fell below 50%, and 2 patients in each arm had serious adverse events.

This is not a complete list of side effects. Talk to your doctor or pharmacist about what to expect and when to seek medical attention.

Taking Mavacamten

A capsule taken once a day with or without food, in strengths of 2.5, 5, 10 and 15 mg. Adults start at 5 mg (2.5 mg if on certain interacting drugs) and the dose is adjusted up or down at scheduled echo visits, to a maximum of 15 mg. The label's titration algorithm runs on 2 numbers from each echo: LVEF must stay at 50% or above, and the dose goes up only if the Valsalva gradient is still 30 mm Hg or higher. Patients can take it only from a REMS-certified pharmacy.

Availability and cost

No generic available

Only available as the brand-name product.

Why it costs what it costs

A branded small-molecule drug with no generic, taken indefinitely, and dispensed only through REMS-certified specialty pharmacies. Coverage typically runs through prior authorization, and BMS Access Support exists to work that process; the label's own requirements (symptomatic obstructive HCM, LVEF of at least 55%, REMS enrollment) are what a prior authorization documents.

Help paying for Camzyos

Pick your insurance to see which help fits. Drugmaker copay cards can't be used with Medicare, Medicaid or TRICARE; charity funds are the usual route there.

Your insurance

From the drugmaker

Camzyos (Mavacamten)

MyCAMZYOS Patient Support

Official program page Call 1-855-226-9967

Copay help
Eligible commercially insured patients may pay as little as $10 per month; maximum limits apply. Medicare, Medicaid, TRICARE, VA and other government plans excluded.
For: private insurance · source
Other support
Echo Co-Pay: eligible commercially insured patients may pay as little as $0 for required echocardiograms, up to $2,500 per year. For patients 18 and older with commercial insurance; not for government insurance or residents of MA, MN or RI. Covers the echo procedure only.
For: private insurance · source
Other support
One-time 35-day free trial for first-time patients, regardless of insurance type.
The official page does not say who qualifies. Ask the program. · source
Bridge or quick-start supply
Bridge Program for commercially insured patients; government-insured patients are not eligible.
For: private insurance · source
Insurance and case manager help
Patient Access Specialists help you understand prescription insurance coverage and out-of-pocket costs.
The official page does not say who qualifies. Ask the program. · source
Free medicine program
The Bristol Myers Squibb Patient Assistance Foundation (800-736-0003) may give CAMZYOS free to eligible US residents within its income limits who have no coverage for it, or who have Medicare and have spent at least 3% of household income on prescriptions this year. People who qualify for Medicare Extra Help are not eligible.
For: no insurance, Medicare · source

Good to know: Copay card needs patients 18 or older.

Checked on the drugmaker's official pages on September 28, 2026. Programs change; confirm with the program before you rely on it.

Charity funds for Hypertrophic Cardiomyopathy

From a charity · HealthWell Foundation
Cardiomyopathy (Medicare Access) fund
Open
Apply on the foundation’s page
Pays for: Copays, premiums or other treatment costs. Medicare patients only.
From a charity · TotalAssist (formerly PAN Foundation)
Hypertrophic Cardiomyopathy fund
Open
Apply on the foundation’s page
Pays for: Out-of-pocket costs for approved medications, up to $7,200 per year. Requires health insurance (any kind).
From a charity · Hypertrophic Cardiomyopathy Association
HCMA Lori Fund fund
Apply directly
Apply on the foundation’s page
Pays for: Transportation, meals and lodging to reach an HCMA Center of Excellence, up to $600 per year.
The foundation says: “Status not shown on page”

Status as each foundation showed it on September 28, 2026.

More ways to get help paying for treatment →

Access and eligibility

Manufacturer

Bristol Myers Squibb

Eligibility requirement

Approved for adults with symptomatic NYHA class II or III obstructive HCM. Not for non-obstructive HCM, and not recommended if LVEF is already below 55%. The label states that safety and effectiveness have not been established in children; the pending adolescent indication covers ages 12 to 17 with symptomatic obstructive HCM, the population SCOUT-HCM enrolled.

Source: Camzyos.com Savings & Support

Access program details are provided for informational purposes and may vary based on insurance coverage, geographic location, and individual circumstances. Confirm current eligibility directly with the manufacturer or your specialty pharmacy.

Clinical trial results

Adult approval rested on EXPLORER-HCM (NCT03470545), a 30-week randomized, double-blind, placebo-controlled trial of 251 adults with symptomatic NYHA class II to III obstructive HCM. 37% of patients on mavacamten met the composite primary endpoint of improved exercise capacity and symptoms versus 17% on placebo (p=0.0005). VALOR-HCM (112 patients already referred for septal reduction surgery) then showed that after 16 weeks only 18% on mavacamten still qualified for or chose surgery, versus 77% on placebo. For adolescents, SCOUT-HCM (NCT06253221) randomized 44 patients aged 12 to 17 (23 mavacamten, 21 placebo) at 47 sites in 9 countries. At week 28 the Valsalva LVOT gradient fell by a mean of 48.5 mm Hg on mavacamten versus 0.5 mm Hg on placebo, a difference of 48.0 mm Hg (95% CI 67.7 to 28.3; p<0.001), from baselines of about 80 mm Hg. Results were presented at ACC 2026 and published in The New England Journal of Medicine on March 29, 2026.

Development history

Mavacamten was discovered by MyoKardia, a South San Francisco company built around the idea of drugging the sarcomere directly rather than treating HCM's downstream symptoms. Bristol Myers Squibb completed its $13.1 billion purchase of MyoKardia on November 17, 2020, months after EXPLORER-HCM read out. The FDA approved Camzyos on April 28, 2022, the first drug ever approved that targets the underlying mechanism of obstructive HCM rather than its symptoms. By May 2026 BMS said it had been prescribed by more than 4,500 US clinicians to almost 25,000 patients and approved in more than 60 countries. The adolescent supplemental application was accepted for priority review on May 29, 2026 with a September 30, 2026 action date.

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Other Hypertrophic Cardiomyopathy treatments

Adolescents with obstructive HCM have had no approved drug; they are treated off-label with adult drugs or referred for surgery. The SCOUT-HCM trial is the first randomized, placebo-controlled trial of any HCM drug in this age group. Its 28-week active phase and up to 144-week open-label extension continue, with the study listed as active but no longer recruiting.

Common questions about Mavacamten

▸What is Mavacamten (Camzyos)?

▸How does Mavacamten work?

▸What are the side effects of Mavacamten?

▸How is Mavacamten taken?

▸Is Mavacamten FDA approved?

Yes, Mavacamten (Camzyos) is FDA approved (2022) for the treatment of Hypertrophic Cardiomyopathy.

▸Is Camzyos approved for teenagers?

Not yet. As of September 2026 the US label covers adults only, and it states that safety and effectiveness in children have not been established. Bristol Myers Squibb's application to add adolescents aged 12 to 17 with symptomatic obstructive HCM is under FDA priority review with a decision date of September 30, 2026.

▸What did the SCOUT-HCM trial show?

In 44 adolescents with symptomatic obstructive HCM, 28 weeks of mavacamten lowered the Valsalva LVOT gradient by a mean of 48.5 mm Hg versus 0.5 mm Hg on placebo, from a starting point of about 80 mm Hg in both groups. No patient's ejection fraction fell below 50%, and 2 patients in each arm had a serious adverse event.

▸Why does Camzyos need echocardiograms and a REMS program?

Because it works by reducing how hard the heart contracts, it can reduce contraction too far and cause heart failure. The label requires an echo before starting, at weeks 4, 8 and 12, 4 weeks after any dose increase, and every 6 months once stable, and dispenses the drug only through the CAMZYOS REMS Program so that every prescriber, pharmacy and patient is tracked.

▸Which common medicines interact with Camzyos?

Strong CYP2C19 inhibitors are contraindicated, as are moderate to strong inducers of CYP2C19 or CYP3A4. The label specifically warns about over-the-counter omeprazole, esomeprazole and cimetidine, and says to avoid disopyramide, ranolazine and the combination of verapamil or diltiazem with a beta-blocker. Every new medication, including supplements, should be checked with the prescriber.

▸How much does Camzyos lower the obstruction in adults?

In EXPLORER-HCM, 37% of adults on mavacamten met a combined endpoint of better exercise capacity and fewer symptoms versus 17% on placebo. In VALOR-HCM, 112 adults already referred for septal reduction surgery took the drug or placebo for 16 weeks; at the end, 18% of the mavacamten group still met guideline criteria for surgery or chose it, versus 77% on placebo.

Sources and references

Every factual claim on this page is drawn from the public sources listed below. Click any reference to open the original document.

Bristol Myers Squibb · 2025-04. CAMZYOS (mavacamten) capsules: US Prescribing Information, revised 4/2025. https://packageinserts.bms.com/pi/pi_camzyos.pdf
U.S. Food and Drug Administration · 2022-04-28. FDA approves new drug to improve heart function in adults with rare heart condition. https://www.fda.gov/drugs/news-events-human-drugs/fda-approves-new-drug-improve-heart-function-adults-rare-heart-condition
Bristol Myers Squibb via Business Wire · 2026-05-29. U.S. Food and Drug Administration Accepts for Priority Review Bristol Myers Squibb's Supplemental New Drug Application for Camzyos (mavacamten) to Treat Adolescents with Symptomatic Obstructive Hypertrophic Cardiomyopathy (oHCM). https://www.businesswire.com/news/home/20260529154810/en/
The New England Journal of Medicine · 2026-03-29. Mavacamten in Adolescents with Obstructive Hypertrophic Cardiomyopathy. https://pubmed.ncbi.nlm.nih.gov/41910394/
ClinicalTrials.gov. A Study of Mavacamten in Adolescents With Symptomatic Obstructive Hypertrophic Cardiomyopathy (SCOUT-HCM). https://clinicaltrials.gov/study/NCT06253221
ClinicalTrials.gov. Clinical Study to Evaluate Mavacamten (MYK-461) in Adults With Symptomatic Obstructive Hypertrophic Cardiomyopathy (EXPLORER-HCM). https://clinicaltrials.gov/study/NCT03470545
Bristol Myers Squibb. CAMZYOS REMS Program. https://www.camzyosrems.com/