SOLSTICE: Combination Therapy for the Treatment of Chronic Hepatitis D Infection.

Inclusion Criteria:

• Male or female ages 18 to < 70 years at screening

• Chronic HDV infection for >/= 6 months

• On NRTI therapy for at least 12 weeks prior to day 1

• ALT>ULN and < 5x ULN

• Anti-HBs >10 mIU/mL at screening if only adding a select set of EC

• Non-cirrhotic and CPT-A cirrhotic

Exclusion Criteria:

• Any clinically significant chronic or acute medical or psychiatric condition thatmakes the participant unsuitable for participation.

• History of significant liver disease from non-HBV or non-HDV etiology

• History of allergic reactions, hypersensitivity, or intolerance to study drug, itsmetabolites, or excipients.

• History of anaphylaxis

• History of immune complex disease

• History of autoimmune disorder

• History or evidence of alcohol or drug abuse

• Prior or concomitant therapy with an immunomodulatory agent, IFN-alpha, cytotoxic orchemotherapeutic agent, or chronic corticosteroids.