The goal of this clinical trial is to assess how the body processes, breaks down and removes a new test medicine (vapendavir) from the body in healthy male participants.The main question it aims to answer is how the body handles the test medicine. In order to do that, the test medicine will be radiolabeled to track the test medicine in the body.

Healthy male participants who meet entry criteria will be admitted to the clinic for a duration of approximately 9 days (Day -1 to Day 8). Participants will be admitted in the evening on the day before dosing (Day -1). Participants will take a single oral dose of radiolabeled vapendavir on Day 1 and have samples collected and safety tests completed during various times throughout their stay in the the clinic. The safety tests will provide additional information on the safety and tolerability of the test medicine.

Inclusion Criteria:

• Must provide written informed consent
• Must be willing and able to communicate and participate in the whole study
• Participants must demonstrate their ability to swallow 8 capsules
• Aged 30 to 65 years inclusive at the time of signing informed consent
• Must agree to adhere to the study contraception requirements
• Healthy male participants according to the assessment of the investigator, as based on a complete medical history including a physical examination, vital signs, 12- lead ECG, and laboratory safety tests without any clinically significant abnormalities
• Body mass index (BMI) of 18.0 to 35.0 kg/m2 as measured at screening
• Must have regular bowel movements (i.e. average stool production of ≥1 and ≤3 stools per day)

Exclusion Criteria:

• Serious adverse reaction or serious hypersensitivity to any drug or formulation excipients
• Presence or history of clinically significant allergy requiring treatment, as judged by the investigator
• History of clinically significant cardiovascular, renal, hepatic, dermatological, chronic respiratory or gastrointestinal disease, neurological or psychiatric disorder, as judged by the investigator
• Acute diarrhea or constipation in the 7 days before the predicted Day 1
• Participants who do not have suitable veins for multiple venepunctures/cannulation as assessed by the investigator or delegate at screening
• Clinically significant abnormal laboratory values at screening as judged by the investigator
• Positive hepatitis B surface antigen (HBsAg), hepatitis C virus antibody (HCV Ab) or human immunodeficiency virus (HIV) 1 and 2 antibody results
• Evidence of renal impairment at screening
• Participants who have received any IMP in a clinical research study within the 90 days prior to Day 1, or less than 5 elimination half-lives prior to Day 1, whichever is longer
• Radiation exposure, including that from the present study, excluding background radiation but including diagnostic x-rays and other medical exposures, exceeding 5 mSv in the last 12 months or 10 mSv in the last 5 years. No occupationally exposed worker, as defined in the Ionising Radiation Regulations 2017, shall participate in the study
• Donation of blood or plasma within the previous 3 months or loss of greater than 400 mL of blood
• Participants who are taking, or have taken, any prescribed or over-the-counter drug or herbal remedies (other than up to 3 g of paracetamol per day) in the 14 days before dosing
• History of any drug or alcohol abuse in the past 2 years
• Regular alcohol consumption >21 units per week (1 unit = 1⁄2 pint beer, or a 25 mL shot of 40% spirit, 1.5 to 2 = 125 mL glass of wine, depending on type)
• A confirmed positive alcohol breath test
• Current smokers and those who have smoked within the last 12 months
• Current users of e-cigarettes or nicotine replacement products and those who have used these products within the last 12 months
• A confirmed breath carbon monoxide reading of greater than 10 ppm
• Confirmed positive drugs of abuse test result
• Male participants with pregnant or lactating partners
• Participants who are, or are immediate family members of, a study site or sponsor or employee
• Failure to satisfy the investigator of fitness to participate for any other reason

Healthy male subjects