This study has an adaptive design, in which dose escalation in Part A will inform dose expansion in Part B. Part A is a single-ascending dose, placebo-controlled study planned to consist of 5 cohorts evaluating 5 doses of APD418. Part B is a parallel-treatment group study planned to evaluate 2 doses of APD418 and placebo. Participants in Part A cannot participate in Part B.
The purpose of this study is to evaluate the safety, pharmacokinetics, and effect on cardiac function of intravenous APD418 in adult participants with heart failure with reduced ejection fraction (HFrEF).