General Information

Camzyos (mavacamten) is a cardiac myosin inhibitor.

Camzyos is specifically 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 is supplied as capsules for oral administration. Capsules are supplied in 2.5 mg, 5 mg, 10 mg, and 15 mg strengths. Dosage must be individualized based on clinical status and echocardiographic assessment of patient response. Refer to the Full Prescribing Information for instructions.

Mechanism of Action

Mavacamten is an allosteric and reversible inhibitor selective for cardiac myosin. Mavacamten modulates the number of myosin heads that can enter “on actin” (power-generating) states, thus reducing the probability of force-producing (systolic) and residual (diastolic) cross-bridge formation. Excess myosin actin cross-bridge formation and dysregulation of the super-relaxed state are mechanistic hallmarks of HCM. Mavacamten shifts the overall myosin population towards an energy-sparing, recruitable, super-relaxed state. In HCM patients, myosin inhibition with mavacamten reduces dynamic LVOT obstruction and improves cardiac filling pressures.

Side Effects

Adverse effects associated with the use of Camzyos may include, but are not limited to, the following:

• dizziness
• syncope

The Camzyos drug label comes with a Boxed Warning for the risk of heart failure. Camzyos reduces left ventricular ejection fraction (LVEF) and can cause heart failure due to systolic dysfunction. Because of the risk of heart failure due to systolic dysfunction, Camzyos is available only through a restricted program under a Risk Evaluation and Mitigation Strategy (REMS).

Clinical Trial Results

FDA approval was based on data from the Phase 3 EXPLORER-HCM trial. The double-blind, randomized, placebo-controlled, parallel group trial enrolled a total of 251 adult patients with symptomatic (NYHA class II or III), obstructive hypertrophic cardiomyopathy. At Week 30, 37% (n=45/123) of patients taking Camzyos achieved the composite primary endpoint, defined as the proportion of patients who achieved either improvement of mixed venous oxygen tension plus no worsening in NYHA class, versus 17% (n=22/128) treated with placebo, a difference was 19%. Additionally at Week 30, patients receiving Camzyos had greater improvement compared to placebo group across all secondary endpoints.