Study of ADI-PEG 20 Versus Placebo in Subjects With NASH

Inclusion Criteria:

1. Males and non-lactating, pregnancy test negative females between 18 - 80 years ofage with biopsy proven F1 - F3 NASH. Limit F1 fibrosis to ≤ 20% of total subjectpopulation.

2. Willingness to use appropriate contraceptive measures though out study treatment andfor 90 days thereafter (see Appendix A).

3. Body mass index (BMI) > 25 kg/m2

4. Must have confirmation of ≥ 10% liver fat content on MRI-PDFF at screening.

5. Biopsy-proven NASH. Must have had a liver biopsy within 4 weeks of randomizationwith fibrosis stage 1 to 3 and a non-alcoholic fatty liver disease (NAFLD) activityscore (NAS) of ≥ 4 with at least a score of 1 in each of the following NAScomponents:

6. Steatosis (scored 0 to 3),

7. Ballooning degeneration (scored 0 to 2), and

8. Lobular inflammation (scored 0 to 3).

9. Must have no evidence of worsening of ALT and AST (within 50%) measurements at thescreening (-4 weeks) and pre-baseline (-2 weeks) visits.

10. Screening laboratory parameters, as determined by the central laboratory:

11. Estimated glomerular filtration rate (eGFR) ≥ 60 mL/min, as calculated by theCockcroft- Gault equation;

12. HbA1c ≤ 9.5% (or serum fructosamine ≤ 381 µmol if HbA1c is unable to beresulted);

13. Hemoglobin ≥ 11 g/dL;

14. INR ≤ 1.3, unless due to therapeutic anticoagulation;

15. Direct bilirubin ≤ 0.5 mg/dL;

16. Total bilirubin ≤ 1.3 x upper limit of normal (ULN), unless due to an alternateetiology such as Gilbert's syndrome or hemolytic anemia;

17. Creatinine kinase < 3 x ULN;

18. Platelet count ≥ 150,000/µL;

19. Serum triglyceride level ≤ 500 mg/dL;

20. ALT < 5 x ULN;

21. AST < 5 x ULN;

22. ALP < 2 x ULN.

23. FibroScan® measurement > 7.0 kPa

24. Subjects on non-insulin dependent diabetic, weight loss, or lipid-modifyingmedication(s) must be on stable dose(s) for at least 3 months prior to thediagnostic liver biopsy through randomization.

Exclusion Criteria:

1. Weight gain or loss > 5% in the 3 months prior to randomization or > 10% in the 6months prior to screening.

2. Type 1 and insulin-dependent Type 2 diabetes.

3. Presence of cirrhosis on liver biopsy (stage 4 fibrosis).

4. Poorly controlled hypertension (blood pressure [BP] > 160/100 mmHg).

5. Prior history of decompensated liver disease including ascites, hepaticencephalopathy (HE), or variceal bleeding.

6. Chronic hepatitis B virus (HBV) infection (hepatitis B surface antigen [HBsAg]positive).

7. Chronic hepatitis C virus (HCV) infection (HCV antibody [Ab] and HCV ribonucleicacid [RNA] positive). Subjects cured of HCV infection less than 2 years prior (basedon date of RNA polymerase chain reaction [PCR] negative confirmation followingconclusion of treatment) to the screening visit are not eligible.

8. Prior or planned (during the study period) bariatric surgery (e.g., gastroplasty,roux-en-Y gastric bypass), surgery reversal or removal of intragastric balloon > 2years prior to enrollment would be eligible.

9. Other causes of liver disease based on medical history and/or centralized review ofliver histology, including but not limited to: alcoholic liver disease, autoimmunedisorders (e.g., primary biliary cholangitis [PBC], primary sclerosing cholangitis [PSC], autoimmune hepatitis), drug-induced hepatotoxicity, Wilson disease,clinically significant iron overload, or alpha-1-antitrypsin deficiency requiringtreatment.

10. History of liver transplantation.

11. Current or prior history of hepatocellular carcinoma (HCC).

12. Alcohol intake above an average limit of 2 drinks per day for women and 3 drinks perday for men.

13. Human immunodeficiency virus (HIV) infection.

14. Unstable cardiovascular disease in the 6 months prior to screening.

15. Life expectancy less than 2 years.

16. Use of any investigational medication within 30 days or within 5 half-lives of theinvestigational medication, whichever is longer, prior to screening and throughoutthe study is prohibited.

17. Subjects with a history of (12 months prior to screening) or current use ofprescription drugs associated with liver steatosis (e.g. methotrexate, amiodarone,high-dose estrogen, tamoxifen, systemic steroids, anabolic steroids, valproic acid)should be excluded.