Long Term Follow-up Registry of Individuals Treated in A Gilead-Sponsored Trial in Individuals With Chronic Hepatitis B Infection

Study Overview
=================
Brief Summary
-----------------
This study will evaluate the long term effects of hepatitis B virus (HBV) treatment on the HBV serologic changes and HBV DNA levels through Week 144. This registry will enroll only individuals who were treated in a Gilead-sponsored trial for chronic hepatitis B (CHB).

Official Title
-----------------
A Long Term Follow-up Registry of Subjects Treated in A Gilead-Sponsored Trial in Subjects With Chronic Hepatitis B Infection

Conditions
-----------------
Chronic Hepatitis B

Intervention / Treatment
-----------------
* Drug: GS-4774
* Drug: GS-9620
* Drug: Tenofovir disoproxil fumarate (TDF)


Participation Criteria
=================
Eligibility Criteria
-----------------
Key Inclusion Criteria: Must have participated in a Gilead-sponsored chronic hepatitis B (CHB) study no more than 120 days prior to Baseline (Day 1), except for participants from previous Gilead-sponsored study number GS-US-174-0149, who will have up to one year from their last visit in that protocol. Must have the ability to understand and sign a written informed consent form, which must be obtained prior to initiation of study procedures Must be willing and able to comply with the visit schedule and study requirements Must have documented HBV DNA < 2,000 IU/mL at time of screening visit, which shall occur no later than 1 year post last study visit in GS-US-174-0149 Must have documented hepatitis B surface antigen (HBsAg) negative status anytime during participation in GS-US-174-0149 regardless of ongoing HBV treatment Key Exclusion Criteria: Patient participating or planning to participate in another clinical study with an investigational agent History of clinically-significant illness or any other major medical disorder that may interfere with follow-up, assessments or compliance with the protocol Believed by the Study Investigator to be inappropriate for study participation for any reason not otherwise listed Received TDF monotherapy either as part of GS-US-174-0149 Arm C (TDF monotherapy arm) or for TDF retreatment, and have taken any HBV antiviral therapy since completion of GS-US-174-0149 Note: Other protocol defined Inclusion/Exclusion criteria may apply.

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Arms and Interventions

| Intervention/Treatment |
| --- |
|Drug: GS-4774|Exposure of interest for participants who received GS-4774 (administered as a subcutaneous injection) in a previous Gilead study for chronic hepatitis B virus infection.|
|Drug: GS-9620|Exposure of interest for participants who received GS-9620 (tablets administered orally) in a previous Gilead study for chronic hepatitis B virus infection.|
|Drug: Tenofovir disoproxil fumarate (TDF)|Exposure of interest for participants who received TDF (tablets administered orally) in a previous Gilead study for chronic hepatitis B virus infection.|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Proportion of participants with serum hepatitis B surface antigen (HBsAg) decline ≥ 0.5 log10 IU/ml from baseline at Week 48 | This endpoint will be measured for participants who are HBsAg positive at baseline. | Week 48 | 
| Proportion of participants who remain HBsAg negative at Week 48 | This endpoint will be measured for participants who are HBsAg negative at baseline. | Week 48 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Proportion of participants with serum HBsAg decline ≥ 0.5 log10 IU/ml from baseline at Week 144 | This endpoint will be measured for participants who are HBsAg positive at baseline. | Week 144 | 
| Proportion of participants who achieve HBsAg loss at Weeks 48 and 144 | This endpoint will be measured for participants who are HBsAg positive at baseline. | Weeks 48, 144 | 
| Proportion of participants who remain HBsAg negative at Week 144 | This endpoint will be measured for participants who are HBsAg negative at baseline. | Week 144 | 
| Proportions of participants with hepatitis B envelope antigen (HBeAg) loss and seroconversion at Week 48 | This endpoint will be measured for participants who are HBeAg positive at baseline. | Week 48 | 
| Proportions of participants with HBeAg loss and seroconversion at Week 144 | This endpoint will be measured for participants who are HBeAg positive at baseline. | Week 144 | 
| Proportions of participants who remain HBeAg negative and hepatitis B envelope antibody (HBeAb) positive at Week 48 | This endpoint will be measured for HBeAg positive who achieved HBeAg seroconversion during the parental study. | Week 48 | 
| Proportions of participants who remain HBeAg negative and HBeAb positive at Week 144 | This endpoint will be measured for HBeAg positive who achieved HBeAg seroconversion during the parental study. | Week 144 | 
| Proportion of participants with HBV DNA < the lower limit of quantitation (LLOQ) at Weeks 48, 96 and 144 | This endpoint will be measured for participants who are on treatment with oral antiviral (OAV) anti-HBV. | Weeks 48, 96 and 144 | 
| Change from Baseline in HBV DNA at Weeks 48, 96, and 144 |  | Baseline; Week 48; Week 96; Week 144 |