A Study to Evaluate the Safety, Tolerability, Pharmacokinetics, Pharmacodynamics, Bioavailability, and Food-effects of EA1080 in Healthy Caucasian and Japanese Male Participants

The drug being tested in this study is called EA1080. EA1080 is being tested to find a safe and well-tolerated dose in healthy Caucasian and Japanese male participants. The study consists of 2 parts as mentioned below:

Part A: This part of the study is fully adaptive and will be performed in three sub-parts as follows:

• Single ascending dose (SAD)
• Food Effect (FE) and optional bioavailability
• Multiple ascending dose (MAD)

Part B: This part of study is comprised of four sub-parts to assess Formulation E and Formulation F as follows:

• SAD
• An additional FE period in SAD cohorts (SAD-FE)
• Food Effect and bioavailability (FE/BA)
• MAD

Inclusion criteria

Participants must meet all of the following criteria to be eligible for enrolment in this study:

• Participants in Caucasian cohorts must be healthy males, aged greater than or equal (>=) 18 to less than or equal to (<=) 45 years at the date of signing informed consent
• Participants in Japanese cohorts must be healthy males, aged >=20 to <=45 years at the date of signing informed consent
• Participants must have a body mass index (BMI) between 18.5-25.0 kilogram per square meter (kg/m^2) inclusive at screening, Day -3, Day -2 or Day -1.

Exclusion criteria

Participants will be excluded from enrolment in this study if they meet any of the following criteria:

• Positive test for Hepatitis B surface antigen (HBsAg), Hepatitis C antibody (HCV Ab), or human immunodeficiency virus antibody (HIV Ab) at screening
• Consumption of herbal remedies or dietary supplements containing St. John's Wort 30 days before the first day of dosing
• Has donated or lost 400 milliliter (mL) blood or more within the last 16 weeks preceding the first day of dosing
• An inability to follow a standardised diet and meal schedule or inability to fast, as required during the study
• Prior screen failure (where the cause of the screen failure is not deemed to be temporary), randomisation, participation, or enrolment in this study. Participants who initially failed due to temporary non-medically significant issues are eligible for re-screening once the cause has resolved
• Participants with veins on either arm that are unsuitable for intravenous puncture or cannulation (example, veins that are difficult to locate, or a tendency to rupture during puncture)
• Participants with any medical condition which may cause raised intracranial pressure, participants with new or changing headaches, and participants with history of head or spinal trauma
• An absolute lymphocyte count below 0.9*10^9 per liter (/L) at screening or on Day -1
• Participants in receipt of any vaccination for Corona virus disease (COVID-19) within 14 days prior to the first dose administration.
• History of COVID-19 polymerase chain reaction (PCR) positivity within 3 months of Day 1, suspected COVID-19 based on clinical presentation within 3 months of Day 1, or presence of clinically relevant long term sequelae of COVID-19.
• Unwillingness to receive COVID-19 testing per local or site COVID-19 guidance.