The study will evaluate the safety, tolerability, and the pharmacokinetics (PK) of AZD7503 following multiple subcutaneous doses in healthy Japanese participants.

This is a Phase I, randomised, single-blind, placebo-controlled study. The healthy Japanese participants will receive randomly (3:1) either AZD7503 or placebo subcutaneously.

The study will comprise of:

• A screening period of 28 days.
• Randomization on Day 1.
• A 9-week Treatment Period. Dose 1 will be administered on Day 1. Dose 2 will be administered at the study site on Day 29. Dose 3 will be administered on Day 57.
• A follow-up period of 10 week after last dose of study intervention.
• The total duration of the study will be 23 weeks

Inclusion Criteria:

• For Japanese participants: A Japanese participant is defined as having both parents and 4 Japanese grandparents as confirmed by the interview. This includes second and third generation Japanese whose parents or grandparents are living in a country other than Japan. Participants must have suitable veins for cannulation.
• Females must be of non-childbearing potential.
• Males and females must adhere to the contraception methods.
• Have a Body mass index between 18 and 30 kg/m2 inclusive.

Exclusion Criteria:

• History of any clinically significant disease or disorder in the investigator's opinion.
• History or presence of gastrointestinal, hepatic or renal disease, or any other condition known to interfere with absorption, distribution, metabolism, or excretion of drugs.
• Any clinically important illness, medical/surgical procedure or trauma.
• Any abnormal laboratory values, clinical chemistry, hematology or urinalysis results, vital signs, Electrocardiography.
• Any clinically significant cardiovascular event.
• Participants with known autoimmune disease or on-treatment with immune-modulatory drugs.
• Any positive result at the Screening Visit for serum Hepatitis B surface antigen, hepatitis C antibody and Human Immunodeficiency virus.
• Confirmed COVID-19 infection during screening as per local guidelines.
• History of severe allergy/hypersensitivity or ongoing clinically important allergy/hypersensitivity.
• Use of any prescribed or nonprescribed medication.
• History of major bleed or high-risk of bleeding diathesis.
• Any clinically important illness, medical/surgical procedure or trauma within 4 weeks of the first administration of study intervention.
• Participants who have previously received AZD7503 or any investigational drug targeting HSD17B13.
• Vulnerable participants.

The study is single blind where the study site staff including the investigator will remain blinded during the clinical conduct of a given cohort.