The objective of this study is to assess the mass balance and routes of excretion of total radioactivity after a single oral dose of 1600 mg [14C]-NV-5138.

Inclusion Criteria:

• Healthy males aged 40 to 65 years inclusive at the time of signing informed consent.
• Body mass index of 18.0 to 32.0 kg/m2 as measured at screening

Exclusion Criteria:

• Subjects who have received any IMP in a clinical research study within the 90 days prior to Day 1
• Subjects who are, or are immediate family members of, a study site or sponsor employee
• Evidence of current SARS-CoV-2 infection
• History of any drug or alcohol abuse in the past 2 years
• Regular alcohol consumption of >21 units per week and (1 unit = ½ pint beer, or a 25 mL shot of 40% spirit, 1.5 to 2 units = 125 mL glass of wine, depending on type)
• A confirmed positive alcohol breath test at screening or admission
• Current smokers and those who have smoked within the last 12 months. A confirmed breath carbon monoxide reading of greater than 10 ppm at screening or admission
• Current users of e-cigarettes and nicotine replacement products and those who have used these products within the last 12 months
• Subjects with pregnant or lactating partners
• 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 shall participate in the study
• Subjects who have participated in an ADME study involving carbon-14 within 12 months of screening.
• Clinically significant abnormal clinical chemistry, haematology or urinalysis as judged by the investigator. Subjects with Gilbert's Syndrome are not allowed
• Clinically significant abnormalities on vital signs or ECGs as judged by the investigator at screening or pre-dose
• Confirmed positive drugs of abuse test result
• Positive hepatitis B surface antigen (HBsAg), hepatitis C virus antibody (HCV Ab) or human immunodeficiency virus (HIV) antibody results
• Evidence of renal impairment at screening, as indicated by an estimated creatinine clearance (CLcr) of <80 mL/min using the Cockcroft-Gault equation
• History of clinically significant cardiovascular, renal, hepatic, dermatological, chronic respiratory or gastrointestinal disease or neurological disorder, as judged by the investigator
• Any history of major depression disorder (MDD) requiring treatment or counselling or any other clinically significant psychiatric history, as judged by the investigator
• Serious adverse reaction or serious hypersensitivity to any drug or the formulation excipients
• Presence or history of clinically significant allergy requiring treatment, as judged by the investigator. Hay fever is allowed unless it is active
• Donation of blood or plasma within the previous 3 months or loss of greater than 400 mL of blood
• Subjects who are taking, or have taken, any prescribed or over-the-counter drug or herbal remedies (other than up to 4 g of paracetamol per day) in the 14 days or 5 half-lives, whichever is longer, before IMP administration. COVID-19 vaccines are accepted concomitant medications. Exceptions may apply on a case by case basis, if considered not to interfere with the objectives of the study, as determined by the investigator.
• Subject answers "yes" to "Suicidal Ideation" Items 1 or 2 on the C-SSRS at screening
• Failure to satisfy the investigator of fitness to participate for any other reason.