A Study to Assess the Effect AZD4831 in Japanese and Chinese Healthy Volunteers

Inclusion Criteria: * Provision of signed and dated, written informed consent prior to any study specific procedures. * Healthy male Japanese and Chinese subjects aged 18 - 50 years (inclusive at Screening) with suitable veins for cannulation or repeated venipuncture. A Japanese subject is defined as having both parents and 4 grandparents who are ethnically Japanese. This includes second and third generation Japanese whose parents or grandparents are living in a country other than Japan. A Chinese subject is defined as having both parents and 4 grandparents who are ethnically Chinese. This includes second and third generation Chinese whose parents or grandparents are living in a country other than China. * Have a body mass index (BMI) between 18 and 30 kg/m2 inclusive and weigh at least 50 kg and no more than 100 kg inclusive. * Provision of signed, written and dated informed consent for optional genetic/biomarker research. If a subject decline to participate in the genetic component of the study, there will be no penalty or loss of benefit to the subject. The subject will not be excluded from other aspects of the study described in this protocol. Exclusion Criteria: * History of any clinically important disease or disorder which, in the opinion of the Investigator, may either put the subject at risk because of participation in the study, or influence the results or the subject's ability to participate in the study. * History or presence of gastrointestinal, hepatic or renal disease or any other condition known to interfere with absorption, distribution, metabolism or excretion of drugs. * Presence of infection(s) (particularly fungal infection), as judged by the Investigator. * History of, or current thyroid disease. * Any ongoing skin disorder, history of or ongoing clinically significant allergy/hypersensitivity. * Any clinically important illness, medical/surgical procedure or trauma within 4 weeks of the first administration of investigational medicinal product (IMP). * Any clinically significant abnormalities in clinical chemistry, hematology, or urinalysis results, as judged by the Investigator at Screening and/or Day -1. 1. Alanine transaminase (ALT) not within normal range 2. Aspartate aminotransferase (AST) not within normal range 3. Creatinine not within normal range 4. White blood cell (WBC) count not within normal range 5. Hemoglobin not within normal range; 6. Estimated Glomerular Filtration Rate (eGFR) not within normal range. * Any positive result at Screening for serum hepatitis B surface antigen, hepatitis C antibody and human immunodeficiency virus (HIV) type 1 and 2. * Abnormal vital signs, after 10 minutes supine rest, at Screening and/or Day -1, defined as any of the following: 1. SBP \< 90 mmHg or ≥ 140 mmHg. 2. DBP \< 50 mmHg or ≥ 90 mmHg. 3. Pulse \< 45 or \> 85 bpm. * Any clinically significant abnormalities in rhythm, conduction or morphology of the resting electrocardiogram (ECG) and/or any clinically significant abnormalities in the 12-lead ECG, as judged by the Investigator that may interfere with the interpretation of QTc interval changes, including abnormal ST-T-wave morphology, particularly in the protocol defined primary lead or left ventricular hypertrophy at Screening and/or Day -1. * Prolonged QTcF \> 450 ms or shortened QTcF \< 340 ms or family history of long QT syndrome at Screening and/or Day -1. * PR(PQ) interval shortening \< 120 ms (PR \> 110 ms but \< 120 ms is acceptable if there is no evidence of ventricular pre-excitation) at Screening and/or Day -1. * PR(PQ) interval prolongation (\> 240 ms) intermittent second (Wenckebach block while asleep is not exclusive) or third-degree atrioventricular (AV)-block, or AV dissociation at Screening and/or Day -1. * Persistent or intermittent complete bundle branch block, incomplete bundle branch block, or interventricular conduction delay with QRS \> 110 ms. Subjects with QRS \> 110 ms but \< 115 ms are acceptable if there is no evidence of, for example, ventricular hypertrophy or pre-excitation at Screening and/or Day -1. * Electrocardiogram findings suggesting a metabolic or other non-cardiac condition that may confound interpretation of serial changes (such as hypokalemia) at Screening and/or Day -1. * Known or suspected history of drug abuse as judged by the Investigator. * Current smokers or those who have smoked or used nicotine products (including e-cigarettes) within 3 months of Screening. * History of alcohol abuse or excessive intake of alcohol as judged by the Investigator. * Positive screen for drugs of abuse, cotinine (nicotine) or alcohol at Screening and/or Day -1. * History of severe allergy/hypersensitivity or ongoing clinically important allergy/hypersensitivity, as judged by the Investigator or history of hypersensitivity to drugs with myeloperoxidase (MPO) inhibitors and anti-thyroid drugs with similar theorem motifs as AZD4831. * Excessive intake of caffeine-containing drinks or food (e.g., coffee, tea, chocolate,) as judged by the Investigator. * Use of drugs with enzyme inducing properties such as St John's Wort within 3 weeks prior to the first administration of IMP. * Use of any prescribed or nonprescribed medication including antacids, analgesics (other than paracetamol/acetaminophen), herbal remedies, mega-dose vitamins (intake of 20 to 600 times the recommended daily dose) and minerals during the 2 weeks prior to the first administration of IMP or longer if the medication has a long half-life. * Plasma donation within 1 month of Screening or any blood donation/blood loss \> 500 mL during the 3 months before Screening. * Has received another new chemical entity (defined as a compound which has not been approved for marketing) within 1 month of first administration of IMP in this study (period of exclusion begins 1 month after the final dose of the previous chemical entity or last visit in the previous study, whichever is longest), 1. if the previous chemical entity has a half-life that would not indicate complete clearance at the time of screening to this study, 2. if the previous chemical entity has significant drug-drug interactions or enzyme inductions that could potentially have an impact on the PK of this study's IMP, even if the previous chemical entity is cleared at the time of screening to this study, 3. and if the subject has not completed all follow-up activity in the previous study, including last study visit, unresolved AEs, and abnormal laboratory values. * Vulnerable subjects, e.g., kept in detention, protected adults under guardianship, trusteeship, or committed to an institution by governmental or juridical order. * Involvement of any Astra Zeneca, Parexel or study site employee or their close relatives. * Judgement by the Investigator that the subject should not participate in the study if they have any ongoing or recent (i.e., during the Screening Period) minor medical complaints that may interfere with the interpretation of study data or are considered unlikely to comply with study procedures, restrictions and requirements. * Subjects who are vegans or have medical dietary restrictions, or any other dietary restrictions. * Subjects who cannot communicate reliably with the Investigator. * Previous bone marrow transplant. * Non leukocyte depleted whole blood transfusion within 120 days of the date of the genetic sample collection.