This is a randomised, single-blind, placebo-controlled Phase I study to investigate the safety, tolerability and pharmacokinetics after administration of single doses of AZD2820 to healthy male subjects.

Inclusion Criteria:

• Provision of signed and dated, written informed consent prior to any study specific procedures.
• Healthy male subjects aged ≥20 - ≤45 years with suitable veins for cannulation or repeated venepuncture.
• Male subjects should be willing to use barrier contraception ie, condoms, from the day of dosing until 3 months after dosing with the investigational product.
• Have a body mass index (BMI) between≥ 18 and ≤30 kg/m2 and weigh at least 50 kg and no more than 100 kg.
• Provision of signed, written and dated informed consent for genetic research. If a subject declines 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 Clinical Study Protocol, so long as they consent.

Exclusion Criteria:

• History of any clinically significant 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
• A history of erectile dysfunction or anatomic abnormality of the penis (eg, cavernosal fibrosis, Peyronie's disease, or plaques) which interferes with normal erectile function
• Predisposition or history of priapism (eg, sickle cell anemia or trait).
• Any clinically significant illness, medical/surgical procedure or trauma within 4 weeks of the first administration of investigational product