A Study to Investigate Safety, Tolerability, and Pharmacokinetics of AZD3974 in Healthy Participants

This is a first in human, randomized, single-blind, placebo-controlled study. It consists of two parts. Part A (single ascending dose - SAD): This study part will enroll six cohorts (plus two optional additional cohorts) of healthy participants (Part A1), three cohorts (plus one optional additional cohort) of healthy Japanese participants (Part A2) and one cohort (plus one optional additional cohort) of healthy Chinese participants (Part A3). Cohort 3 of Part A1 will be extended to evaluate the effect of food intake on the PK of AZD3974. In Part A (all cohorts), participants will receive a single dose of AZD3974 or placebo. Part B (Multiple Ascending Dose - MAD): This study part will consist of four cohorts (plus two optional additional cohorts) of healthy participants (Part B1) and one cohort (plus one optional additional cohort) of healthy Japanese participants (Part B2). In all Part B cohorts, participants will receive multiple doses of AZD3974 or placebo. Both Part A and Part B will comprise of: * A Screening Period of maximum 28 days * A Dosing session during which participants will receive the study intervention at study specific time points. * Follow-up Period of 7 days post last-dose.