A Study to Investigate the Safety, Tolerability, and Pharmacokinetics of KYN-5356 in Healthy Subjects Aged 18 to 55 Years

Exclusion Criteria

• •Subject has positive serology for HBsAg, HCV, or HIV, or history of hepatitis from any cause with the exception of hepatitis A that was resolved at least 3 months prior to first dosing of the Investigational Medicinal Product.
• •Subject has any illness judged by the Principal Investigator as clinically significant, in the 3 months prior to first dosing of the Investigational Medicinal Product.
• •Subject has a suicidality score of "yes" on item 4 or item 5 of the suicidal ideation section of the C-SSRS, if this ideation occurred in the past 6 months, or "yes" on any item of the suicidal behavior section, except for the "Non-Suicidal Self-Injurious Behavior" (item also included in the suicidal behavior section), if this behavior occurred in the past 2 years.
• •Subject has a history or current sign or symptom of psychiatric or neurologic disease.
• •Subject has a history of head trauma in the past year and/or current seizures.
• •Subject is a smoker (use of tobacco products in the previous 3 months from Screening) or uses nicotine or nicotine-containing products and has a positive urine cotinine test at Screening or Admission.
• •Subject has a history of alcohol and/or illicit drug abuse within 2 years of entry or has a positive screening test for alcohol and/or drugs of abuse at Screening or Admission.
• •Subject consumes caffeine containing beverages exceeding 500 mg caffeine per day (5 cups of coffee) during the off-site days during the study.
• •Subject has regular excessive consumption of alcohol within 6 months prior to Screening (7 drinks/week for females, 14 drinks/week for males where 1 drink = 150 mL of wine or 360 mL of beer or 45 mL of hard liquor).
• •Subject has a history or current sign or symptom of a cardiovascular, renal, or metabolic bone disease or disease of bone remodeling, or any history of endocrine disease, including an abnormal laboratory result for pre-specified clinical laboratory safety parameters related to these conditions.
• •Subject has a history or presence of clinically significant abnormalities detected on 12-lead ECG of either rhythm or conduction. A first-degree atrioventricular block will not be considered as a significant abnormality. Subject has QTcF \> 450 ms (mean values per parameter will be considered) detected on the 12-lead ECG at Screening or Admission.
• •Presence or sequelae of gastrointestinal, liver, kidney (creatinine clearance \<85 mL/min, using the Cockcroft-Gault formula), or other conditions known to interfere with the absorption, distribution, metabolism, or excretion of drugs at Screening or Admission.
• •Subject has a history of malignancy within the past 5 years prior to Screening with the exception of excised and curatively treated non-metastatic cell carcinoma of the skin which is considered cured with minimal risk of recurrence.
• •Subject tests positive for SARS-CoV-2 at Admission.
• •Subject uses any prescription drugs, herbal supplements, within 4 weeks prior to initial dosing, and/or over-the-counter medication, dietary supplements (vitamins included) within 2 weeks prior to initial dosing, other than what is allowed per protocol.
• •Subject received vaccination 1 month before admission or plans to receive vaccination during the study.
• •Use of other investigational drugs/devices within 5 half-lives of the drug from enrollment (time of the subject signing the informed consent form), or within 30 days, whichever is longer.
• •Donation or loss of 400 mL or more of blood within 8 weeks prior to initial dosing.
• •Plasma donation (\> 200 mL) within 7 days prior to first dosing.
• •Resting vital signs at Screening (blood pressure \> 140/90 mmHg, heart rate \> 90 beats per minute, respiratory rate \> 20 breaths per minute, and clinically significant elevated body temperature), or any clinically significant abnormalities in vital signs requiring intervention in the opinion of the Investigator. Up to 2 repeat measurements are permitted to confirm eligibility.