Inclusion Criteria:
* Weight of at least 50 kg with body mass index (BMI) between 18 and 32 kg/m2
* Is in good health, determined by no clinically significant findings from medical history, physical examination, 12-lead ECG, vital signs measurements, and clinical laboratory evaluations
* All females have a negative pregnancy test and are not planning to get pregnant for the duration of the trial
* Female of non-childbearing potential by reason of surgery or at least 1 year post menopause
* Additional inclusion criteria apply and will be assessed by the study team
Exclusion Criteria:
* Any clinically significant abnormalities, medical, or psychiatric conditions identified by a detailed medical history, or physical examination
* Any surgical or medical condition which might significantly alter the absorption, distribution, metabolism, or excretion of drugs. Examples of such conditions include (but are not limited to):
1. History of inflammatory bowel syndrome, gastritis, gastrointestinal or rectal bleeding
2. History of major gastrointestinal tract surgery (ie, gastrectomy, bowel resection, cholecystectomy etc.)
3. History or evidence of pancreatic injury or pancreatitis
* History or presence of impaired renal function supported by estimated glomerular filtration rate \[eGFR\]\<60 mL/min/1.73m2 or clinically significant abnormal urinary constituents (eg, protein)
* History of cancer except for nonmelanoma skin cancer resected \>2 years ago and that has been definitively treated and considered cured.
* History of any lifetime suicide attempt or active suicidal ideation with intent as indicated by a "Yes" response to either Question 4 or 5 on the C-SSRS "Baseline/ Screening" version
* History of left bundle branch block, arrhythmias, Brugada syndrome, congenital heart disease, familial short QT syndrome, or family (first degree relative) history of sudden death, ventricular or clinically significant arrhythmias, including idiopathic ventricular fibrillation.
* Abnormal standard 12-lead ECG after at least 5 minutes resting in the supine position
* Abnormal vital signs after at least 5 minutes resting in the supine position:
* Has any of the following: a serum total bilirubin value \>1.1× the upper limit of normal (ULN), a serum alanine aminotransferase (ALT) value \>1.5×ULN, or aspartate aminotransferase (AST) value \>1.5×ULN
* Serology test positive for human immunodeficiency virus (HIV), or hepatitis B or C
* Known allergy or hypersensitivity to any component of the formulation of PRAX 628 or history of severe allergy or anaphylaxis to a drug, food, or other exposure
* Use of any experimental or investigational drug or device within 30 days prior to the first dose of study drug or 5 times the terminal half-life of the drug, whichever is longer
* Use of systemic prescription medications; or over-the-counter medication, including multivitamins; and dietary and herbal supplements within 2 weeks or 5 times the terminal half-life of the medication prior to the first dose of study drug (whichever is longer) and for the duration of the trial
* Donation of blood within 1 month prior to Screening, plasma within 1 week prior to Screening, or platelets within 6 weeks prior to Screening
* Any vaccination within 28 days of the first dose of study drug
* Additional exclusion criteria apply and will be assessed by the study team
