You will begin the trial after qualifying for participation based on criteria including being at least 18 years old, having chronic hepatitis D infection (confirmed by a positive anti-HDV antibody test or HDV RNA at least 6 months before starting), having HDV RNA levels above 500 IU/mL, and elevated liver enzymes (ALT above normal limits).

You will need to be taking or willing to take one of these hepatitis B medications: tenofovir disoproxil fumarate (TDF), tenofovir alafenamide fumarate (TAF), or entecavir (ETV). You must continue taking this medication throughout the study.

You will be randomly assigned to receive either brelovitug (BJT-778) or bulevirtide (BLV). Both are solutions for injection used to treat chronic hepatitis D infection.

The study is open-label, which means both you and your healthcare providers will know which medication you are receiving.

You will receive your assigned medication (brelovitug or bulevirtide) via injection for 48 weeks.

Throughout this period, you will need to continue taking your hepatitis B medication (TDF, TAF, or ETV) as prescribed.

You will attend regular clinic visits for blood tests to monitor your HDV RNA levels (amount of hepatitis D virus in your blood) and ALT levels (a liver enzyme that indicates liver health).

At Week 24, you will undergo several assessments including:

Blood tests to check HDV RNA levels and liver function

A liver stiffness test (using FibroScan, a non-invasive procedure similar to an ultrasound that measures liver stiffness)

Calculation of APRI (AST-to-platelet ratio index, a blood test that helps assess liver fibrosis)

If you have cirrhosis, additional tests to calculate your CTP score and MELD score (measures of liver function and disease severity)

Quality of life questionnaires: CLDQ-HBV (Chronic Liver Disease Questionnaire) and FACIT-F (assessing fatigue levels)

At Week 48, you will have a comprehensive evaluation to assess if you’ve achieved the main goal of the treatment: undetectable HDV RNA (virus levels below detection) and normalized ALT (liver enzyme levels returned to normal range).

You will undergo the same tests performed at Week 24 (blood tests, liver stiffness measurement, APRI calculation, and quality of life questionnaires).

If you have cirrhosis, your CTP and MELD scores will be calculated again to track changes in liver function.

The study continues for another 48 weeks (96 weeks total).

If you were in the bulevirtide group (Arm 2), you may switch treatments at Week 48.

You will continue to receive treatment and attend regular clinic visits for monitoring.

At Weeks 72 and 96, you will undergo assessments similar to those at Week 48 to determine if treatment benefits are maintained.

The Week 96 visit will include the final comprehensive evaluation with all tests performed previously (blood tests, liver stiffness measurement, APRI calculation, and quality of life questionnaires).

If you have cirrhosis, your CTP and MELD scores will be calculated one final time.

Throughout the entire 96-week study period, you will be monitored for any treatment-emergent adverse events (side effects).

Your serum total bile acid levels will be measured to monitor for potential side effects.

An Independent Data Monitoring Committee will assess if there are any signs of clinical disease progression related to hepatitis D.