This is a multi-center single and multiple ascending dose study (SAD and MAD).~Part A (SAD) will include 7 cohorts (8 healthy volunteers in each cohort) and will randomize to AZD3427 or placebo, in a 6:2 ratio. One cohort will entirely include participants of Japanese descent.~Part B (MAD) will include 6 cohorts (8 heart failure patients in each cohort) and will randomize to AZD3427 or placebo in a 6:2 ratio. Of these, 3 cohorts will contain participants with heart failure with reduced ejection fraction [HFrEF] and the other 3 cohorts will comprise of participants with heart failure with HF with ejection fraction (EF) ≥ 41%. There will be a maximum screening period of 27 days. Participants in part A and B will undergo study drug administration on Day 1. In addition, participants in part B will return for 4 additional doses on Days 8, 15, 22, and 29. Participants will be followed for at least 50 days after the last dose of study drug.
This first-time-in-human (FTIH) study will be conducted to evaluate the safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD), and immunogenicity of single doses of AZD3427 in healthy volunteers and multiple doses of AZD3427 in patients with heart failure (HF).