Evaluation of Mavacamten-Based Practice in Chinese Adults With Obstructive Hypertrophic Cardiomyopathy

• Mavacamten (Drug): As per product label

Primary outcomes

• Number of participants in each study cohort [Baseline and months 1, 2, 3, 6, 9, 12 and 15]
• Absolute change (mmHg) from baseline in resting peak left ventricular outflow tract (LVOT) gradient assessed by transthoracic echocardiography [Baseline and at months 1, 2, 3, 6, 9, 12 and 15]
• Absolute change (mmHg) from baseline in post-Valsalva peak left ventricular outflow tract (LVOT) gradient assessed by transthoracic echocardiography [Baseline and at months 1, 2, 3, 6, 9, 12 and 15]

Secondary outcomes

• Number of participants with at least 1-class improvement from baseline in New York Heart Association (NYHA) functional class [Baseline and at months 1, 2, 3, 6, 9, 12 and 15]
• New York Heart Association (NYHA) functional class classification as assessed by the treating physician [Baseline and at months 1, 2, 3, 6, 9, 12 and 15]
• Change from baseline in left atrial dimension (LAD) or left atrial volume index (LAVI) assessed by transthoracic echocardiography [Baseline and at months 1, 2, 3, 6, 9, 12 and 15]
• Change from baseline in interventricular septal thickness (IVST) assessed by transthoracic echocardiography [Baseline and at months 1, 2, 3, 6, 9, 12 and 15]
• Change from baseline in E/e' ratio assessed by transthoracic echocardiography [Baseline and months 1, 2, 3, 6, 9, 12 and 15]
• Prescribed mavacamten dose (mg) [Day 1 and months 1, 2, 3, 6, 9, 12 and 15]
• Prescribed mavacamten maintenance dose (mg) during follow-up [Up to 15 months]
• Number of participants reaching mavacamten maintenance dose [Up to 15 months]
• Number of participants whose prescribed mavacamten dose changed during the observation period [Day 1 and and up to 15 months]
• Time (days) from Index Date to achieving mavacamten maintenance dose [Day 1 and up to 15 months]
• Number of participants that discontinued mavacamten treatment [Up to 15 months]
• Time (days) from Index Date to mavacamten discontinuation [Day 1 and up to 15 months]
• Duration of mavacamten treatment during follow-up [Day 1 and up to 15 months]
• Prior hypertrophic cardiomyopathy (oHCM) medication drug class [Baseline and up to 15 months]: Drug class of background oHCM medications, including beta-blockers and calcium channel blockers
• Prior hypertrophic cardiomyopathy (oHCM) medication dose [Baseline and up to 15 months]: Dose of background oHCM medications, including beta-blockers and calcium channel blockers

Sex: All, ages: 18 Years to any

Inclusion Criteria:

Participants must meet all of the following criteria to be included:

1. Diagnosis: Have a documented diagnosis of obstructive hypertrophic cardiomyopathy (oHCM), identified by the corresponding International Classification of Diseases (ICD)-10 codes in the medical record system.
2. Medication Exposure: Have a first-ever recorded prescription for Mavacamten within the Patient Identification Period (24 October 2024 to 31 March 2026). This date is defined as the Index Date.
3. Age: Be ≥ 18 years of age at the Index Date.
4. Treatment Continuity: Have at least two valid clinical records of any type (e.g., outpatient visit, inpatient encounter, prescription refill, laboratory test, or echocardiogram) after the Index Date.

Exclusion Criteria:

Participants meeting any of the following criteria will be excluded:

(1) Prior Use of Study Drug: Have any documented history of Mavacamten use (based on medical history records, prescription records, or clinical notes) at any time prior to the Index Date.

• Bristol-Myers Squibb, Study director, Bristol-Myers Squibb