The primary objective of this study is to evaluate the effect of itraconazole, a strong inhibitor)of cytochrome P4503A , and phenytoin a strong inducer of cytochrome P450 3A, CYP3A4, CYP1A2 and CYP2C19 on the pharmacokinetics of ASC41, a THR beta agonist tables in healthy subjects. The PK, Safety and Tolerability of ASC 41 in Subjects with NAFLD will also be evaluated. Approximately 24 subjects including 16 healthy volunteers (HVs) and 8 subjects with NAFLD will be enrolled. This study consists of 3 cohorts.

This multiarm study in HVs and subjects with NAFLD is designed to further characterize the PK, safety and tolerability of ASC41. Part I of the study will assess the effect of itraconazole and phenytoin on the single-dose PK of ASC41 in HVs. Part II of the study will evaluate the PK, safety and tolerability of a single dose of ASC41 in subjects with NAFLD. The pharmacokinetics of ASC41 and its metabolite ASC41-A will be assessed in both parts I and II. The secondary objective of the study is to characterize the safety and tolerability of oral ASC41 in subjects in the U.S. with NAFLD and in HVs. Approximately 24 male and female participants will be enrolled. This study consists of 3 cohorts.

Key Inclusion Criteria:

• Part I Healthy subjects between 18 to 55 years of age

• Part II

  1. Subjects with NAFLD
  2. Subjects between 18 to 65 years of age

Key Exclusion criteria:

• Part I

  1. A history of thyroid disease
  2. A history of, or current liver disease, or liver injuries
  3. Platelet count <150,000/mcL
  4. INR> 1.2
  5. History of, or current electrocardiogram (ECG) abnormalities, arrhythmias or heart valve diseases judged to be clinically significant by the investigator

• Part II

  1. A history of thyroid disease
  2. Current or history of cirrhosis or decompensated liver disease
  3. AST or ALT > 5X ULN
  4. DBIL > ULN
  5. Acute or chronic liver disease other than NAFLD
  6. A history of bariatric surgery
  7. HbA1c >9.5% at screening
  8. Testosterone or estrogen replacement therapy
  9. Inducers or inhibitors of CYP3A4, including herbal therapies such as St John's Wort (CYP3A4 Inducer)