A Study to Investigate Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of AZD4954 in Healthy Adult Participants With or Without Elevated Lipoprotein (a) (Lp[a]) Levels, and Participants With Dyslipidemia

This is a first time in human, placebo-controlled, single and multiple ascending dose (SAD and MAD) study in healthy male and female participants (Part A) or healthy participants with elevated Lp(a) levels (≥ 30 mg/dL, \[62 nmol/L\]) and participants with dyslipidemia with elevated Lp(a) levels (≥ 70 mg/dL, \[150 nmol/L\]) and low-density lipoprotein cholesterol (LDL-C) ≥ 70 mg/dL and \< 190 mg/dL (Part B). The study consists of 2 parts: Part A (SAD) and Part B (MAD). Part A of the study will consist of Part A1 and Part A2, comprising: * A Screening Period of maximum 28 days. * Admission to study site (Day -1). * A Treatment Period (Day 1 to Day 15 at the study site) with a single dose of AZD4954 or placebo on Day 1. * A Follow-up Visit within 26 to 30 days after the study intervention dose for all cohorts (Day 29 ±2 days). Part B has 3 types of MAD cohorts - global cohorts with healthy participants, global cohort with participants with dyslipidemia, and a Japanese cohort. The global MAD cohorts (healthy participants) and Japanese MAD cohort will comprise: * A Screening Period of maximum 28 days. * Admission to study site (Day -1). * A Treatment Period during which participants will receive either AZD4954 or placebo once daily for 21 days (Day 1 to 21). * A Follow-up Visit within 26 to 30 days after the last study intervention dose (Day 49 ±2 days). The global MAD cohort (participants with dyslipidemia) will comprise: * A Screening Period of maximum 28 days. * Residential study site visits from Day -1 to Day 2 and Day 21 to Day 22. * Non-residential study site visits on Day 8 and Day 15. * A Treatment Period during which participants will receive either AZD4954 or placebo once daily for 21 days (Day 1 to 21). * A Follow-up Visit within 26 to 30 days after the last study intervention dose (Day 49 ± 2 days).