Dose-finding Study to Evaluate the Safety, Tolerability, PK, and PD of CK-3773274 in Adults With HCM

Inclusion Criteria

Males and females between 18 and 85 years of age at screening.
Body weight is ≥45 kg at screening.

Diagnosed with HCM per the following criteria:

Has left ventricular (LV) hypertrophy with non-dilated LV chamber in the absence of other cardiac disease.
Has minimal wall thickness ≥15 mm (minimal wall thickness ≥13 mm is acceptable with a positive family history of HCM or with a known disease-causing gene mutation).
Adequate acoustic windows for echocardiography.

For Cohorts 1, 2 and 3 has LVOT-G during screening as follows:

Resting gradient ≥50 mmHg OR
Resting gradient ≥30 mmHg and <50 mmHg with post-Valsalva LVOT-G ≥50 mmHg
For Cohort 4 has resting and post-Valsalva LVOT-G < 30 mmHg at the time of screening
For Cohort 4 has elevated NT-proBNP > 300 pg/mL at the time of screening
LVEF ≥60% at screening.
New York Heart Association (NYHA) Class II or III at screening.
Patients on beta-blockers, verapamil, diltiazem, or ranolazine should have been on stable doses for >4 weeks prior to randomization and anticipate remaining on the same medication regimen during the study.
For Cohort 3: Patients must be taking disopyramide. Patients should have been on stable disopyramide doses for >4 weeks prior to screening and anticipate remaining on the same medication regimen during the study.

Exclusion Criteria

Aortic stenosis or fixed subaortic obstruction.
Known infiltrative or storage disorder causing cardiac hypertrophy that mimics oHCM (eg, Noonan syndrome, Fabry disease, amyloidosis).
History of LV systolic dysfunction (LVEF <45%) at any time during their clinical course.
Documented history of current obstructive coronary artery disease (>70% stenosis in one or more epicardial coronary arteries) or documented history of myocardial infarction.
Has been treated with septal reduction therapy (surgical myectomy or percutaneous alcohol septal ablation) or has plans for either treatment during the study period (Cohorts 1, 2, and 3 only). Patients having undergone septal reduction therapy > 12 months prior to screening who remain symptomatic from nHCM, and who meet all other criteria for inclusion, may be enrolled in Cohort 4.
For Cohorts 1, 2 and 4: Has been treated with disopyramide or antiarrhythmic drugs that have negative inotropic activity within 4 weeks prior to screening. (For Cohort 3, use of disopyramide is required).
Has any ECG abnormality considered by the investigator to pose a risk to patient safety (eg, second degree atrioventricular block type II).
Paroxysmal atrial fibrillation or flutter documented during the screening period.
Paroxysmal or permanent atrial fibrillation requiring rhythm restoring treatment (eg, direct-current cardioversion, ablation procedure, or antiarrhythmic therapy) ≤6 months prior to screening. (This exclusion does not apply if atrial fibrillation has been treated with anticoagulation and adequately rate-controlled for >6 months).
History of syncope or sustained ventricular tachyarrhythmia with exercise within 6 months prior to screening.
Has received prior treatment with CK-3773274 or mavacamten.
For Cohort 4: has any documented history of LVOT-G ≥ 30 mmHg at rest, with Valsalva, or with exercise (for subjects who have had prior septal reduction therapy, this exclusion criteria only applies to gradients detected following septal reduction therapy).