The primary objective is to determine the single-dose pharmacokinetics (PK) of T-817 and T-817M5 (metabolite of T-817) in subjects with mild, moderate or severe hepatic impairment compared to matched healthy control subjects.

The secondary objective is to determine the safety and tolerability of single-dose T -817MA (Maleate salt of T-817) in subjects with mild, moderate or severe hepatic impairment.

Inclusion Criteria:

For subjects with mild, moderate or severe hepatic impairment

1. Adult male or female, 18 - 75 years of age
2. Must weigh at least 50 kg and have a body mass index (BMI) ≥ 18.5 and ≤ 40.0 kg/m2
3. Have mild, moderate or severe defined by Child-Pugh classification hepatic impairment

For Matched Healthy Control Subjects Healthy adult male or female subjects will be matched 1:1 to a specific subject in the mild, moderate, or severe hepatic impairment cohort based upon age, weight, gender, and smoking status

Exclusion Criteria:

1. Subject is mentally or legally incapacitated or has significant emotional problems at the time of the screening visit or expected during the conduct of the study.
2. History or presence of clinically significant medical or psychiatric condition or disease in the opinion of the PI.
3. History or presence of hypersensitivity or idiosyncratic reaction to the study drug, related compounds, or inactive ingredients.
4. Female subjects who are pregnant or lactating.