Table 1. Patient Baseline Characteristics.
| Characteristic | Patients, No. (%) | |
|---|---|---|
| Mavacamten group (n = 54) | Placebo group (n = 27) | |
| Age, mean (SD), y | 52.4 (12.1) | 51.0 (11.8) |
| Sex | ||
| Male | 41 (75.9) | 17 (63.0) |
| Female | 13 (24.1) | 10 (37.0) |
| Vital signs | ||
| BMI, mean (SD) | 25.2 (3.5) | 26.1 (3.6) |
| Heart rate, mean (SD), beats/min | 65.2 (11.4) | 64.4 (7.5) |
| Systolic blood pressure, mean (SD), mm Hg | 117.1 (13.1) | 112.6 (14.6) |
| Diastolic blood pressure, mean (SD), mm Hg | 74.4 (9.8) | 70.9 (9.7) |
| NYHA functional class | ||
| II | 44 (81.5) | 18 (66.7) |
| III | 10 (18.5) | 9 (33.3) |
| CYP2C19 phenotypea | ||
| Normal | 23 (42.6) | 9 (33.3) |
| Intermediate | 24 (44.4) | 17 (63.0) |
| Poor | 7 (13.0) | 1 (3.7) |
| Background therapy for HCM | ||
| β-Blocker | 48 (88.9) | 24 (88.9) |
| Calcium channel blocker | 4 (7.4) | 2 (7.4) |
| Others | 2 (3.7) | 1 (3.7) |
| Key echocardiographic parameters | ||
| Resting LVOT peak gradient, mean (SD), mm Hg | 74.6 (35.1) | 73.4 (32.2) |
| Valsalva LVOT peak gradient, mean (SD), mm Hg | 106.8 (43.2) | 99.8 (41.1) |
| LVEF, mean (SD), % | 77.8 (6.9) | 77.0 (6.7) |
| Maximum LV wall thickness, mean (SD), mm | 22.9 (4.9) | 24.3 (6.4) |
| Left atrial volume index, mean (SD), mL/m2 | 43.3 (12.1) | 47.5 (14.7) |
| CMR imaging parametersb | ||
| LV mass index, mean (SD), g/m2 | 98.6 (45.0) | 108.5 (54.8) |
| KCCQ-CSS, mean (SD), points | 82.4 (16.9) | 84.4 (17.0) |
| Cardiac biomarkers | ||
| NT-proBNP, geometric mean (CV%), ng/L | 810.5 (138.3) | 1250.3 (159.9) |
| hs-cTnI, geometric mean (CV%), ng/L | 33.5 (325.0) | 38.7 (443.1) |
Abbreviations: BMI, body mass index (calculated as weight in kilograms divided by height in meters squared); CMR, cardiac magnetic resonance; CV, coefficient of variation; HCM, hypertrophic cardiomyopathy; hs-cTnI, high-sensitivity cardiac troponin I; KCCQ-CSS, Kansas City Cardiomyopathy Questionnaire Clinical Summary Score; LV, left ventricular; LVEF, left ventricular ejection fraction; LVOT, left ventricular outflow tract; NT-proBNP, N-terminal pro B-type natriuretic peptide; NYHA, New York Heart Association.
Normal phenotype included CYP2C19 genotype *1/*1; intermediate phenotype included CYP2C19 genotypes *1/*2, *1/*3, and *2/*17; poor phenotype included CYP2C19 genotypes *2/*2 and *2/*3; rapid phenotype included CYP2C19 genotype *1/*17; ultra-rapid phenotype included CYP2C19 genotype *17/*17. There were no rapid or ultrarapid metabolizers in either group.
Based on subset of 58 patients (39 in mavacamten group and 19 in placebo group) eligible for CMR imaging.