Study of Bulevirtide in Participants Who Have Normal or Impaired Liver Function

Key Inclusion Criteria:

All individuals:

• Body mass index (BMI) of 18 ≤ BMI ≤ 40 kg/m^2 at screening.

• Have a calculated creatinine clearance (CLcr) of at least 60 mL/min (using theCockcroft-Gault method) based on serum creatinine and actual body weight as measuredat screening.

• Individuals assigned male at birth and individuals assigned female at birth and ofchildbearing potential who engage in heterosexual intercourse must agree to useprotocol-specified method(s) of contraception as described in the protocol.

• Individuals have not donated blood within 56 days of study entry or plasma within 7days of study entry and must refrain from blood donation from clinic admission,throughout the study period, and continuing for at least 30 days following the lastdose of study drug.

• 12-lead electrocardiogram (ECG) evaluations at screening must be without clinicallysignificant abnormalities as assessed by the investigator.

• Aside from hepatic impairment among the individuals with hepatic impairment, theindividual must, in the opinion of the investigator, be sufficiently healthy forstudy participation based upon medical history, physical examination, vital signs,and screening laboratory evaluations.

• Must be willing and able to comply with all study requirements.

Individuals With Hepatic Impairment:

• Have a diagnosis of chronic (> 6 months), stable hepatic impairment (moderate orsevere based upon the Child-Pugh-Turcotte (CPT) classification system for moderateor severe hepatic impairment [CPT Class B or C, respectively]) with no clinicallysignificant change in hepatic status (as determined by the investigator) within the 2 months (60 days) prior to screening.

• Individuals with moderate or severe hepatic impairment must have a score of 7to 9 or 10 to 15 on the CPT classification system at screening. If anindividual's score changes during the study, the score at screening will beused for classification.

• Must meet all of the following laboratory parameters at screening:

• alanine aminotransferase (ALT) ≤ 10 × upper limit of normal (ULN)

• aspartate aminotransferase (AST) ≤ 10 × ULN

• platelets ≥ 25,000/mm^3

• hemoglobin ≥ 9 g/dL

• Individuals with hepatic impairment who have not been on a stable dose ofconcomitant medications for at least 4 weeks prior to screening (or 5 half-lives,whichever is longer) and/or for whom dose changes are likely to occur during thestudy should have their medications reviewed and approved by the sponsor.

Matched Control Individuals With Normal Hepatic Function:

• Have alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkalinephosphatase, international normalized ratio, and total bilirubin at or below theULN; and albumin above the lower limit of normal at screening and at admission.

• Must be matched for age (± 10 years), sex (assigned at birth), and BMI (± 20%, 19 ≤BMI ≤ 40 kg/m^2) with a individual in the hepatic impairment group.

Key Exclusion Criteria:

All Individuals:

• Positive serum pregnancy test at screening and at admission.

• Breastfeeding individual.

• Have received any study drug within 30 days prior to study dosing.

• Have current alcohol or substance abuse judged by the investigator to potentiallyinterfere with individual compliance or individual safety, or a positive drug oralcohol test at screening or admission.

• Have poor venous access that limits phlebotomy.

• Have been treated with systemic steroids, immunosuppressant therapies, orchemotherapeutic agents within 3 months prior to screening or is expected to receivethese agents during the study.

• Have a history of any of the following:

• Significant serious skin disease, such as but not limited to rash, foodallergy, eczema, psoriasis, or urticaria.

• Significant drug sensitivity or drug allergy (such as anaphylaxis orhepatoxicity).

• Known hypersensitivity to the study drugs, their metabolites, or to formulationexcipients.

• Significant cardiac disease (including history of myocardial infarction basedon ECG and/or clinical history, any history of ventricular tachycardia,congestive heart failure, or dilated cardiomyopathy with left ventricularejection fraction ≤ 40%); or a family history of long QT syndrome, orunexplained death in an otherwise healthy individual between the ages of 1 and 30 years.

• Syncope, palpitations, or unexplained dizziness.

• Implanted defibrillator or pacemaker.

• Have any serious or active medical or psychiatric illness (including depression).

• Requirement for ongoing therapy with or prior use of any prohibited medicationslisted in the protocol.

Individuals With Hepatic Impairment:

• Have a positive test result for human immunodeficiency virus (HIV) antibody,hepatitis B surface antigen (HBsAg), or hepatitis C virus (HCV) antibody withdetectable HCV ribonucleic acid (RNA) at screening.

• Suspicion of hepatocellular carcinoma (ie, if alpha-fetoprotein > 20 ng/mL atscreening).

• Anticipated changes in concomitant medications or dosage used to treat symptoms ofhepatic impairment or associated comorbid conditions that could lead to clinicallysignificant changes in medical conditions during the study.

• Use of known hepatotoxic medications, clinical organic anion transportingpolypeptide (OATP)1B1/3 inhibitors, or sodium-taurocholate cotransportingpolypeptide (NTCP) inhibitors (half-maximal inhibitory concentration (IC50) orkinetic inhibition constant [Ki] < 20 μM).

• Positive test for drugs of abuse, including alcohol at screening or admission, withthe exception of opioids and tetrahydrocannabinol (marijuana) under prescription andverified by the investigator as for pain management.

Matched Control Individuals With Normal Hepatic Function:

• Have a positive test result for HIV antibody, HBsAg, or HCV antibody.

• Have a history of liver disease including Gilbert's disease.

• Have taken any prescription medications or over-the-counter medications, includingherbal products, within 28 days prior to start of study drug dosing, with theexception of vitamins and/or acetaminophen and/or ibuprofen and/or hormonalcontraceptive medications.

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