A single ascending oral dose(s) study to evaluate the safety, tolerability, pharmacokinetics, and pharmacodynamics of YCT-529 in healthy male subjects.

This is a Phase 1a, double-blind, placebo controlled, first in human study to evaluate the safety, tolerability, PK, and PD of YCT-529 in 2 cohorts of 8 subjects. Cohorts 1 and 2 will be dosed in the fasted state in Periods 1 and 2. Each cohort will receive two doses of study drug separated by a washout period. One cohort will then return for a third dose of study drug under fed conditions in Period 3 to study the effect of food on YCT-529.

Inclusion Criteria:

1. Male subject in good health as confirmed by physical examination, medical history, and clinical laboratory tests of blood and urine at the time of Screening.
2. Subject must provide written informed consent.
3. Subject must be willing and able to communicate and participate in the whole study.
4. Subject is 25 to 60 years of age (inclusive).
5. Subject has been vasectomized for at least 6 months prior to enrolment
6. Subject has body mass index (BMI) 18.0 to 32.0 kg/m2.
7. Subject has no history of hormonal therapy uses in the 90 days prior to the first screening visit.
8. Subject agrees to use a condom during the study until the final return visit to ensure the safety of the study participants and their sexual partner(s)
9. Subjects will refrain from donating blood or plasma during the study.
10. Subjects will not use cannabis or any recreational drugs for at least 120 days before completing Screening and during the study.
11. In the opinion of the investigator, subject is able to adhere to the study requirements, restrictions, schedule of assessments, and requirements related to sperm sample collection and maintenance of the sexual activity diary.

Exclusion Criteria:

1. Men participating in another clinical study involving an investigational drug within the last 90 days prior to the first dosing or less than 5 elimination half-lives prior to first dosing, whichever is longer.

2. Clinically significant abnormal physical and/or laboratory findings at Screening

3. Abnormal serum chemistry values at screening or admission, that indicate liver or kidney dysfunction or that may be considered clinically significant, such as bilirubin of >20 micro mol/L and ALT, AST, GGT and ALP above the upper limit of normal.

4. Evidence of renal impairment at screening, as indicated by an estimated eGFR of <80 mL/min/1.73 m2 using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI; 2009) equation.

5. Use of androgens within 90 days before first screening visit.

6. Ongoing use of body building nutritional supplements.

7. Systolic blood pressure (BP) >140 mmHg (<45 years) or >160 mmHg (≥45 years) and diastolic BP >90 mmHg at screening or predose.

8. Clinically significant abnormal electrocardiogram (ECG) or a duration of corrected QT interval in ECG (QTc) interval of >450 msec at screening or predose.

9. Known history of androgen deficiency due to hypothalamic-pituitary or testicular disease or multiple endocrine deficiencies.

10. Known history of significant cardiovascular, renal, hepatic (cholecystectomy is not permitted), or prostatic disease or significant psychiatric illness. Gilbert's syndrome is allowed (subject will be excluded if total bilirubin is ≥1.5 x ULN if known Gilbert's syndrome). If subject has elevations only in total bilirubin that are >ULN and <1.5xULN, fractionate bilirubin to identify possible undiagnosed Gilbert's syndrome (i.e., direct bilirubin <35% of the total bilirubin).

11. Current or clinically relevant history of any psychiatric disorder or clinical assessment of significant suicidal risk or risk of self-injury as per the Investigator's judgement. This will be re-assessed at admission to Period 2 and Period 3 if applicable.

12. Serious adverse reaction or serious hypersensitivity to any drug or formulation excipients.

13. Presence or history of clinically significant allergy requiring treatment, as judged by the investigator. Hay fever is allowed unless it is active.

14. Positive hepatitis B surface antigen (HBsAg), hepatitis C virus antibody (HCV Ab) or human immunodeficiency virus (HIV) 1 and 2 antibody results at screening visit.

15. Known or suspected alcoholism or drug abuse within the last 2 years that may affect metabolism/transformation of steroid hormones or study treatment compliance.

16. Subjects who do not have suitable veins for multiple venepunctures/cannulation as assessed by the investigator or delegate at screening.

17. Regular alcohol consumption in males >14 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).

18. Current smokers and those who have smoked within the last 6 months. A confirmed breath carbon monoxide reading of greater than 10 ppm at screening or admission.

19. Confirmed positive drugs of abuse test result.

20. Subjects who are taking, or have taken, any prescribed or over-the-counter drug or vitamins/herbal remedies/supplements (other than up to 4 g of paracetamol per day in the 14 days before IMP administration). COVID-19 vaccines are accepted concomitant medications. Exceptions may apply, as determined by the investigator, if each of the following criteria are met: medication with a short half-life if the washout is such that no PD activity is expected by the time of dosing with IMP; and if the use of medication does not jeopardize the safety of the trial subject; and if the use of medication is not considered to interfere with the objectives of the study.

21. Male subjects with pregnant or lactating partners.

22. Subjects who are taking, or have taken, any prescribed or over-the-counter drug or vitamins/herbal remedies/supplements (other than up to 4 g of paracetamol per day in the 14 days before IMP administration). COVID-19 vaccines are accepted concomitant medications. Exceptions may apply, as determined by the investigator, if each of the following criteria are met: medication with a short half-life if the washout is such that no PD activity is expected by the time of dosing with IMP; and if the use of medication does not jeopardize the safety of the trial subject; and if the use of medication is not considered to interfere with the objectives of the study.

23. Any site staff member with delegated study responsibilities or a family member of a site staff member with delegated study responsibilities.

24. Any other medical condition that, in the opinion of the investigator, could alter the subject's well-being, the study conduct, or the interpretability of the results.

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Sex assigned at birth is required to be "male"

Double blind, placebo controlled