A Study of Bimagrumab in Participants With HFpEF

This study will look at how bimagrumab affects adults who have a type of heart failure called HFpEF (heart failure with preserved ejection fraction), where the heart pumps normally but does not fill with blood as well as it should. Participation in the study will last about 76 weeks.

Inclusion Criteria: * Have New York Heart Association Class II to III heart failure * Have left ventricular ejection fraction (LVEF) ≥ 50% * KCCQ-CSS ≤ 80 * 6MWD must be all of the following: * ≥100 and ≤ 450 meters (m) based on average of 2 tests conducted at screening visit, AND * ≥ 100 and ≤ 450 m on 1 test at randomization visit, AND * \< 20% change from average qualifying 6MWD obtained at screening * Have documented evidence of at least one of the following: * Heart failure event * Elevated NT-proBNP (N-terminal pro B-type natriuretic peptide) * Left atrium enlargement * Elevated filling pressure * Stable dose of heart failure medications * Body mass index (BMI) ≥ 23 kilograms per meter squared (kg/m²) Exclusion Criteria: * Heart failure hospitalization \< 4 weeks before screening * Myocardial infarction, coronary artery bypass graft surgery, or other major cardiovascular surgery/intervention, stroke or transient ischemic attack in past 12 weeks prior to screening, or unstable angina pectoris in past 4 weeks prior to screening or during screening * Type 1 diabetes * Hemoglobin A1c (HbA1c) ≥ 9.5%