The purpose of this study is to assess the effects on the single-dose drug levels of mavacamten in healthy participants.

Inclusion Criteria:

• Body mass index between 18 and 32 kilograms/meter squared (kg/m^2) inclusive, at the screening visit.
• Healthy, as determined by physical examination, vital signs, electrocardiograms (ECGs), and clinical laboratory assessments (including hematology, chemistry, and urinalysis) within the normal range at the screening visit and/or on Day -1.
• Cytochrome P450 (CYP) 2C19 normal, rapid, or ultrarapid metabolizer, as determined by genotyping during screening.

Exclusion Criteria:

• Any significant acute or chronic medical illness.
• Current or history of clinically significant cardiac condition, including but not limited to arrhythmia, left ventricular systolic dysfunction, coronary heart disease; current, history, or family history of hypertrophic cardiomyopathy; or evidence of prior myocardial infarction based on ECGs.
• CYP2C19 poor (*2/*2, *3/*3, or *2/*3) or intermediate (*1/*2, *1/*3, *2/*17) metabolizer, as determined by genotyping during screening.
• Use of CYP2C19 and CYP3A4 inducers or inhibitors within 28 days of study intervention administration.

Note: Other protocol-defined inclusion/exclusion criteria apply.