Key Inclusion Criteria:

• Must be aged ≥ 18 years.
• Must have a clinical diagnosis of AIH and signs of active disease or disease flare despite standard-of-care therapy for ≥ 3 months, including:
  • Screening ALT values that are 1.25 to 10 times the upper limit of the normal range (ULN);
  • Liver biopsy results with Ishak score (modified HAI) ≥ 5/18 indicating active AIH, from a biopsy performed at Screening, or within 6 months prior to Screening;
  • Mild or no hepatic impairment (Child Pugh category A);
  • Must be willing to use and taper glucocorticoid therapy.

Key Exclusion Criteria:

• Have a concomitant diagnosis of primary biliary sclerosis, primary sclerosing cholangitis, IgG 4 related cholangitis, drug related AIH (at Screening) or a history of drug-related AIH.
• Are receiving oral or injectable immunomodulating treatment for any other autoimmune disease prior to enrollment in the study. Patients who have been using such treatments must follow the specified washout periods.
• Have an active infection (e.g., acute hepatitis E, cytomegalovirus, or Epstein-Barr virus) requiring systemic therapy with antibiotic, antiviral, or antifungal treatment, or has had any febrile illness within 7 days prior to Day -1.
• Have a history of thyroiditis, celiac disease, or other autoimmune disorder known to be associated with transaminitis.
• Have liver cirrhosis with significant impairment of liver function (Child Pugh category B or C) or have decompensated cirrhosis.
• Patients with histology confirmed coincident non-alcoholic steatohepatitis.

Note: Other protocol defined Inclusion/Exclusion Criteria may apply.

Eligibility last updated 12/28/22. Questions regarding updates should be directed to the study team contact.