The study is designed to determine the absorption, distribution, metabolism and elimination (ADME) of BIA 28-6156 in humans, further explore the PK of BIA 28-6156, evaluate the extent of distribution of total radioactivity into blood cells, provide additional safety and tolerability information and collect samples for metabolite profiling and structural identification.

This is an open-label, single-dose, single period study in healthy male subjects. It is planned to enroll 6 subjects. All subjects will receive a single oral dose Carbon-14 BIA 28-6156. Blood samples will be collected at regular intervals for PK analysis, mass balance and metabolite profiling and identification from pre-dose up to 240 h post-dose. Urine and faecal samples will be collected at regular intervals for mass balance and metabolite profiling and identification from pre-dose until the mass balance criteria have been met.

Inclusion Criteria:

• Healthy males aged 30 to 65 years inclusive
• Body mass index (BMI) of 18.0 to 35.0 kg/m2
• Must be willing and able to communicate and participate in the whole study
• Must have regular bowel movements
• Must provide written informed consent
• Must agree to adhere to contraception requirements

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 from results of diagnostic tests or from symptoms reported at screening or admission
• History of any drug or alcohol abuse in the past 2 years
• Regular alcohol consumption
• A confirmed positive alcohol breath test at screening or admission
• Current smokers and those who have smoked within the last 12 months.
• 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.
• Subjects who do not have suitable veins for multiple venepunctures/cannulation
• Clinically significant abnormal clinical chemistry, haematology or urinalysis. Subjects with Gilbert's Syndrome are allowed.
• 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, neurological or psychiatric disorder
• Serious adverse reaction or serious hypersensitivity to any drug or the formulation excipients
• Presence or history of clinically significant allergy requiring treatment. 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 before IMP administration.
• Failure to satisfy the investigator of fitness to participate for any other reason