A Study of the Efficacy and Safety of Danicamtiv in Participants With Symptomatic Genetic and Familial Dilated Cardiomyopathy

Inclusion criteria

• Has a diagnosis of DCM due to probable disease-causing variants of MYH7, TTN, or other identified genetic DCM variants, or with familial DCM
• Has New York Heart Association (NYHA) Class II-IV at Screening with stable symptoms for ≥1 month.
• Has at least mild left ventricular enlargement (LVE) and has adequate acoustic windows to enable accurate TTEs according to the Echocardiography Core Laboratory.
• Has a LVEF of ≤45%.
• Is on stable doses of maximally tolerated standard-of-care heart failure (HF) therapies reflecting current guidelines for at least 4 weeks prior to the first visit.
• Has DCM not attributed to substance abuse, amyloidosis, sarcoidosis, or any other secondary form of cardiomyopathy per the Investigator.
• Can perform an upright cardiopulmonary exercise training (CPET) with a peak oxygen uptake (pV̇O2) of 80% or less of predicted for a healthy individual and respiratory exchange ratio (RER) of ≥1.05 Key

Exclusion criteria

• Has heart failure with reduced ejection (HFrEF) caused primarily by ischemic heart disease, chronic valvulopathy, or another condition, as determined by the Investigator.
• Recent (\<90 days) clinically significant cardiac events, including acute coronary syndrome, hemodynamically significant epicardial coronary disease (per Investigator), coronary revascularization (percutaneous coronary intervention \[PCI\] or coronary artery bypass graft \[CABG\]), or hospitalization for heart failure/intravenous (IV) diuretic use.
• Presence of disqualifying cardiac rhythms that might interfere with reliable echocardiographic measurements of left ventricle (LV) function, as determined by the Investigator including: (a) inadequately rate-controlled atrial fibrillation, (b) ectopic beats (atrial, junctional or ventricular) of sufficient frequency (e.g. \> 10% of total beats) that the participant's cardiac rhythm is irregular potentially interfering with reliable echocardiographic measurements of LV function.
• Unstable or untreated severe ventricular arrythmia (eg, ventricular tachycardia or ventricular fibrillation).
• History of malignancy of any type within 5 years prior to Screening
• Severe renal insufficiency (defined at the time of Screening as current estimated glomerular filtration rate \[eGFR\] \<15 mL/min/1.73m2 by simplified Modification of Diet in Renal Disease equation \[sMDRD\]).
• History or evidence of any other clinically significant disorder, condition, or disease that, in the opinion of the Investigator or Sponsor, would pose a risk to participant safety or interfere with the study evaluation
• History of heart transplantation or anticipated heart transplantation in the next 6 months.
• Ongoing or anticipated advanced cardiac interventions, including chronic IV inotropic therapy, planned cardiac resynchronization therapy (CRT) or major surgery, or current/anticipated ventricular assist device placement within 6 months
• Clinically significant laboratory abnormalities at Screening