Ataciguat for Slowing the Progression of Moderate Calcific Aortic Valve Stenosis: A Randomized, Placebo Controlled Study

Key Inclusion Criteria: 1. Adult male or female at least 50 years of age 2. Has moderate CAVS as defined by: 1. An AVA of ≥1.0 cm2 to ≤1.50 cm2 2. An AVC score between ≥600 to 1200 Agatston units (AU) for women and between ≥600 to 2000 AU for men 3. Has a left ventricular ejection fraction (EF) of ≥45% at the time of Screening as determined by the echocardiography Imaging Core Laboratory 4. For participants on beta blockade, the dose must be stable for at least 90 days prior to the Screening Visit with no anticipated changes during the study Key Exclusion Criteria: 1. For participants in the CPET sub-study in Part A and all participants in Part B: Has any medical or physical condition that, in the Investigator's opinion, could lead to an inability to complete Protocol-required CPET procedures (eg, pulmonary disease, joint, leg, hip, back conditions that limit physical activity, or other absolute contraindications for CPET) 2. Anticipated or planned prior aortic valve replacement, repair, surgery, or intervention in the next 6 months 3. Has moderate, moderate-to-severe, or severe (Grade 2 or higher) mitral stenosis, mitral regurgitation, and/or aortic regurgitation 4. Has suspected or known congenital aortic valve disease including bicuspid aortic valve 5. New York Heart Association (NYHA) Class III or Class IV 6. Has a primary etiology for heart failure other than aortic valve disease 7. Has coronary artery disease or anticipating coronary stenting surgery 8. Abnormal electrocardiogram (ECG) results or long-standing persistent or permanent atrial fibrillation