Safety, Tolerability, Pharmacokinetics and Pharmacodynamics of EYP001a in Healthy Volunteers and Nonalcoholic Steatohepatitis Patients

Inclusion Criteria: 1. Have given voluntary written informed consent; 2. Male/female participants aged 18 years to 75 years with a Body Mass Index (BMI) ≥ 25 kg/m² and ≤ 45 kg/m² at screening. 3. A female participant is eligible to participate in this study if: 1. She is of non-childbearing potential (defined as females with a documented tubal ligation, bilateral oophorectomy or hysterectomy) or postmenopausal (defined as 12 months of spontaneous amenorrhea and follicle stimulating hormone level within the laboratory's reference range for postmenopausal females). A post-menopausal female receiving hormone replacement therapy (HRT) other than hormone replacement patches who is willing to discontinue hormone therapy 28 days before study drug dosing and agrees to remain off hormone replacement therapy for the duration of the study may be eligible for study participation. A post-menopausal female using Hormone Replacement patches who is willing to discontinue the patch 48 hours before Check in on Day -1 and until the completion of her End of Study visit is eligible for study participation. 2. She is of childbearing potential and is non-pregnant or non-lactating and willing to use adequate contraception from screening until 3 months after the End of Study visit. Adequate contraception is defined as a progesterone only intra uterine device combined with at least 1 of the following forms of contraception: a diaphragm or cervical cap, or a condom. Also, total abstinence in accordance with the lifestyle of the participant is acceptable. 3. She is of childbearing potential and is non-pregnant or non-lactating and taking the combined oral contraceptive pill and willing to discontinue the combined oral contraceptive pill 7 days prior to check in on Day -1 and until the completion of her End of Study visit and use adequate contraception from the day of cessation. Adequate contraception is defined as a diaphragm or cervical cap together with a condom. Also, total abstinence in accordance with the lifestyle of the participant is acceptable. 4. Have Alanine Aminotransferase (ALT) \>1.5 upper limit of normal (ULN) during screening period. 5. Fibroscan® Vibration-Controlled Transient Elastography (VTCE) liver stiffness (liver stiffness measure (LSM) for \>8.5 kPa) and steatosis (Controlled Attenuation Parameter (CAP) ≥250 decibels per meter (dB/m)). 6. Normal liver function at screening for alkaline phosphatase (ALP), Total Bilirubin (TBL), conjugated Bilirubin, platelets, International normalized ratio (INR). Nota Bene: Criteria 4 and 5 do not apply to healthy volunteers. Exclusion Criteria: 1. Employee of a contract research organization (CRO) participating in this study or the Sponsor. 2. Patients with known non-NASH chronic liver disease (alcohol, autoimmune, Human Immunodeficiency Virus (HIV), hepatitis B virus (HBV), active hepatitis C virus (HCV)). 3. Female with childbearing potential if no dual safe anti-contraception method can be provided. 4. Renal impairment (participants with an estimated glomerular filtration rate (eGFR) computed from the Modification of Diet in Renal Disease (MDRD) formula of \< 60ml/min/1.73m² are excluded). Note: participants with mild renal impairment (eGFR \>60 ml/min and ≤90 ml/min) are eligible. 5. Has clinically relevant immunosuppression from, but not limited to immunodeficiency conditions such as common variable hypogammaglobulinemia. 6. Has any known pre-existing medical or psychiatric condition that could interfere with the participant's ability to provide informed consent or participate in study conduct, or that may confound study findings. 7. Has a history of clinically significant gastrointestinal (GI) disease, especially peptic ulcerations, GI bleeding, ulcerative colitis, Crohn's disease or Inflammatory Bowel Syndrome, renal, hepatic, neurologic, hematologic, endocrine, oncologic, pulmonary, immunologic, or cardiovascular disease or any other condition which, in the opinion of the investigator, would jeopardize the safety of the participant or impact the validity of the study results. 8. Has participated in any drug study within 60 days prior to the first drug administration in the current study. 9. Has had major surgery within 30 days prior to the first drug administration. 10. Concomitant use of not listed drugs after discussion with Sponsor not admitted. 11. Has a history of relevant drug and/or food allergies