A Study of ABI-H0731 + Nucleos(t)Ide as Finite Treatment for Chronic Hepatitis B Patients

This is an open-label extension protocol which will assess the safety of long-term (up to 18
months in total) combination therapy and its effect on serum biomarkers of sustained
virologic response (SVR) such as sustained clearance of serum HBV DNA, quantitative and
qualitative reduction in the viral antigens hepatitis B "e" antigen (HBeAg), and hepatitis B
surface antigen (HBsAg), as well as exploratory biomarkers such as reduction in circulating
HBV RNA.

Inclusion Criteria:

1. Willing and able to provide informed consent.

2. Previously enrolled on a study of ABI-H0731 and completed the treatment period, with
demonstrated compliance in the opinion of the investigator.

3. Female subjects must agree to use an effective birth control method for the duration
of the study and follow-up, or be surgically sterile for at least 6 months, or at
least 2 years postmenopausal with serum follicle-stimulating hormone (FSH) levels
consistent with a postmenopausal status. Effective birth control methods include male
or female condom (may not be used together due to increased risk of breakage),
vasectomy, intrauterine device (IUD), diaphragm, or cervical cap. Female subjects of
childbearing potential must have a negative serum pregnancy test.

4. All heterosexually active male subjects must agree to use an effective birth control
method for the duration of the study and follow-up. Effective birth control methods
include male or female condom (may not be used together due to increased risk of
breakage), vasectomy, hormone-based contraception (only female partner of a male
subject), IUD, diaphragm, or cervical cap.

5. Agreement to adhere to Lifestyle Considerations (including abstaining from alcohol
abuse [defined as alcohol consumption exceeding 2 standard drinks per day on average
(1 standard drink = 10 grams of alcohol)] and the use of illicit substances, herbal or
other substances, or unnecessary over-the-counter medications throughout study
duration.

6. In good general health except for chronic HBV infection.

7. Have the ability to take oral medication and be willing to adhere to the ABI-H0731-211
regimen in the opinion of the Investigator.

Exclusion Criteria:

1. Must not have had evidence of HBV resistance-associated variants (RAVs) or lack of
compliance on a previous study of ABI H0731.

2. Must not have had a treatment-emergent adverse event or laboratory abnormalities
deemed clinically significant and possibly or probably related to drug while on a
previous study of ABI-H0731, that in the opinion of the Investigator or the Sponsor
makes the subject unsuitable for this study.

3. Current clinically significant cardiac or pulmonary disease, chronic or recurrent
renal or urinary tract disease, liver disease other than HBV, endocrine disorder,
autoimmune disorder, diabetes mellitus requiring treatment with insulin or
hypoglycemic agents, neuromuscular, musculoskeletal, or mucocutaneous conditions
requiring frequent treatment, seizure disorders requiring treatment, or other medical
conditions requiring frequent medical management or pharmacologic or surgical
treatment that in the opinion of the Investigator or the Sponsor makes the subject
unsuitable for the study.

4. Females who are lactating or pregnant or wish to become pregnant within the duration
of the ABI-H0731-211 study.