A Phase I Study to Evaluate Safety and Pharmacokinetics of Escalating Single Doses and Multiple Doses of SP-8356

Inclusion Criteria:

1. Healthy males
2. Aged 18 to 55 years, inclusive, at the time of signing informed consent
3. Body mass index (BMI) of 18.0 to 32.0 kg/m2 as measured at screening
4. Must be willing and able to communicate and participate in the whole study
5. Must provide written informed consent
6. Must agree to adhere to the contraception requirements

Exclusion Criteria:

1. Females
2. Subjects who have received any IMP in a clinical research study within the 90 days prior to the planned first dosing date
3. Subjects who are, or are immediate family members of a study site or sponsor employee
4. Evidence of recent or current SARS-CoV-2 infection. A minimum period of 3 months from resolution of COVID-19 symptoms to dosing must have passed
5. Subjects who have previously been administered IMP in this study.
6. Subjects who have taken part in Part 1 are not permitted to take part in Part 2
7. History of any drug or alcohol abuse in the past 2 years
8. Regular alcohol consumption in males > 21 units per week (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)
9. A confirmed positive alcohol breath test at screening or admission
10. 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
11. Current users of e-cigarettes and nicotine replacement products and those who have used these products within the last 12 months
12. Subjects who do not have suitable veins for multiple venepunctures/cannulation as assessed by the investigator or delegate at screening
13. Clinically significant abnormal biochemistry, haematology, or urinalysis as judged by the investigator. Subjects with Gilbert's Syndrome are not allowed
14. Subjects that have either a known of family history of QT prolongation or chronic QT prolongation syndrome (i.e. QTc > 450 msec) in repeated ECG
15. Subjects with any clinically significant medical disorders increasing tendency to bleed easily, or having history of recent trauma or surgery, or having history of gout or renal stones
16. Subjects with a clinically significant history of skin disorder such as photosensitivity, eczema or psoriasis.
17. Subjects with a clinically significant history of eye disorders that may affect the interpretation of the ophthalmology assessments as per the judgement of the investigator (only for subjects where ophthalmology assessments will be performed).
18. Confirmed positive drugs of abuse test result
19. Positive hepatitis B surface antigen (HBsAg), hepatitis C virus antibody (HCV Ab) or human immunodeficiency virus (HIV) antibody results
20. Evidence of renal impairment at screening, as indicated by an estimated glomerular filtration rate (eGFR) of <80 mL/min/1.73 m2 using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation
21. History of clinically significant cardiovascular, renal, hepatic, chronic respiratory or gastrointestinal disease, neurological or psychiatric disorder, as judged by the investigator
22. Subjects with a history of cholecystectomy or gall stones (Part 1 Cohort 3 only)
23. Serious adverse reaction or serious hypersensitivity to any drug or the formulation excipients
24. Presence or history of clinically significant allergy requiring treatment, as judged by the investigator. Hay fever is allowed unless it is active
25. Donation or loss of greater than 400 mL of blood within the previous 3 months
26. Has a history of photosensitivity or photoallergy
27. 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 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
28. Is taking medication known to cause phototoxic reactions (e.g., tetracyclines, thiazides, nonsteroidal anti-inflammatory drugs) within 4 weeks of enrolling into the study
29. Failure to satisfy the investigator of fitness to participate for any other reason