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A study comparing brelovitug to bulevirtide for treating chronic hepatitis delta infection in patients currently receiving bulevirtide

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What is this trial about?

A plain-language summary of the goals, design and what participants do

This study is looking at Chronic Hepatitis D Infection, which is a liver disease caused by the hepatitis D virus. People with this condition have long-term inflammation of the liver that can lead to serious liver problems over time. The study will test two different medications given as injections under the skin. The first medication is BJT-778, which is the main treatment being tested in this study. The second medication is bulevirtide, which participants are already receiving before joining the study. The purpose of the study is to see how well switching from bulevirtide to treatment with BJT-778 works for chronic hepatitis D infection after 24 weeks.

Participants entering this study must already be taking bulevirtide for at least 6 months for their chronic hepatitis D infection. They will also need to be taking one of the following medications for hepatitis B and continue taking it throughout the study: TDF, TAF, or ETV. During the study, participants will switch from their current bulevirtide treatment to receiving BJT-778 injections under the skin. The study will measure how many participants have the hepatitis D virus become undetectable in their blood after switching to the new treatment.

The study will also look at safety by tracking any unwanted effects that occur during treatment, how many participants stop treatment because of unwanted effects, and changes in bile salts in the blood. Other measurements will include how many participants have their virus levels drop significantly or become undetectable at different time points, whether liver enzyme levels called ALT return to normal, and whether the virus remains undetectable after treatment ends. The treatment period can last up to 96 weeks, with additional follow-up visits after treatment is completed.

The research process

The trial runs in 10 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Baseline and treatment start

    At the beginning of the study, your current treatment with bulevirtide will be switched to a new medication called brelovitug.

    You will continue taking your existing hepatitis B medication (tenofovir disoproxil fumarate, tenofovir alafenamide, or entecavir) at the same dose throughout the entire study. This medication must remain unchanged during your participation.

    Your blood will be tested to measure the amount of hepatitis delta virus (a virus affecting the liver) and alanine aminotransferase (a substance in the blood that indicates liver health). These measurements will serve as your starting point for comparison.

  2. Step 2

    Treatment period up to week 24

    You will receive brelovitug treatment. The medication is given as an injection under the skin.

    During this period, regular visits will be scheduled to monitor your response to the treatment.

    Blood samples will be collected to measure the level of hepatitis delta virus in your blood and to check your liver function through alanine aminotransferase levels.

    Your doctor will also monitor the levels of bile salts in your blood, which are substances produced by the liver.

    Any side effects or health changes you experience will be recorded and assessed.

  3. Step 3

    Week 24 assessment

    At week 24, a comprehensive evaluation will be performed to determine how well the treatment is working.

    Blood tests will measure whether the hepatitis delta virus in your blood has decreased significantly or has become undetectable.

    Your liver function will be assessed by measuring alanine aminotransferase levels to determine if they have returned to normal ranges.

    The safety of the treatment will be evaluated by reviewing any side effects you have experienced and changes in bile salt levels.

  4. Step 4

    Continued treatment from week 24 to week 48

    You will continue receiving brelovitug injections under the skin.

    Regular monitoring visits will continue with blood tests to track hepatitis delta virus levels and liver function.

    Any side effects will continue to be monitored and recorded.

  5. Step 5

    Week 48 assessment

    At week 48, another detailed evaluation will be conducted.

    Blood tests will check if the hepatitis delta virus remains undetectable or has decreased significantly from the starting point.

    Your liver health will be assessed through alanine aminotransferase measurements.

    The overall safety and tolerability of the treatment will be reviewed.

  6. Step 6

    Continued treatment from week 48 to week 72

    Treatment with brelovitug injections will continue.

    Regular monitoring of virus levels and liver function will be performed through blood tests.

    Side effects and overall health status will be continuously monitored.

  7. Step 7

    Week 72 assessment

    At week 72, blood tests will be performed to measure hepatitis delta virus levels and determine if the virus remains undetectable.

    Liver function will be evaluated through alanine aminotransferase testing.

    Safety monitoring will continue with assessment of any side effects.

  8. Step 8

    Final treatment period from week 72 to week 96

    You will continue receiving brelovitug injections under the skin until week 96.

    Regular blood tests will continue to monitor virus levels and liver function.

    All side effects and health changes will be documented.

  9. Step 9

    Week 96 final treatment assessment

    At week 96, the final assessment during the treatment period will be performed.

    Blood tests will measure hepatitis delta virus levels to determine if the virus is undetectable or has decreased significantly.

    Your liver function will be evaluated through alanine aminotransferase measurements.

    A comprehensive safety review will be conducted.

  10. Step 10

    Follow-up period after treatment ends

    After completing the treatment at week 96, you will enter a follow-up period where you will no longer receive brelovitug injections.

    You will be monitored for an additional 48 weeks to assess whether the treatment effects are maintained after stopping the medication.

    Blood tests will be performed at week 24 and week 48 of the follow-up period to check if the hepatitis delta virus remains undetectable.

    These follow-up visits will help determine the long-term effectiveness of the treatment.

Who can join the trial?

6 criteria

  • You must be willing and able to provide written informed consent, which means you agree to participate in the study after understanding all the details.
  • You must be at least 18 years of age or older at the time of the initial screening visit.
  • You must be male or female.
  • You must be taking or willing to take medications called TDF, TAF, or ETV at the start of the study. These are medicines used to treat hepatitis B virus. You must be willing to continue taking the same dose of these medicines throughout the entire study.
  • You must currently be taking a medicine called bulevirtide for your condition for at least 6 months before the screening visit.
  • Your blood test must show that you have HDV RNA levels of 100 or more international units per milliliter at screening. HDV RNA is a measurement of the hepatitis D virus in your blood.

Who cannot join the trial?

4 criteria

  • The specific reasons why patients cannot participate in this study have not been provided in the available trial information
  • Generally, clinical trials may exclude patients based on certain medical conditions, other medications they are taking, or specific test results, but these details are not listed in the current documentation
  • Patients who do not have Chronic Hepatitis D Infection, which is a long-term inflammation of the liver caused by the hepatitis D virus, would not be eligible for this study
  • The trial is designed for adults, so children and adolescents outside the specified age range would not be able to participate
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Investigated drugs

  • Brelovitug

    is an investigational medication being studied for the treatment of chronic hepatitis delta infection. In this trial, participants who are currently taking bulevirtide will switch to brelovitug to see if it helps control their hepatitis delta infection.

  • Bulevirtide

    is a medication used to treat chronic hepatitis delta infection. Participants in this trial are already taking this medication before switching to the investigational treatment being studied.

What is already known about the treatment

  • Brelovitug

    Brelovitug is an investigational medication currently being studied in clinical trials for the treatment of chronic hepatitis D infection, a serious liver disease caused by the hepatitis D virus. It is being tested as an alternative treatment option for patients who are already receiving bulevirtide, another medication for this condition. While the exact mechanism of action and form of administration are still being evaluated in ongoing research, brelovitug represents a potential new therapeutic approach for managing this challenging viral infection. The medication is classified as an antiviral agent and is being assessed for its ability to reduce viral levels and improve liver health in affected patients.

  • Bulevirtide

    Bulevirtide is an approved antiviral medication used for the treatment of chronic hepatitis D infection in adults with compensated liver disease. It is administered as a subcutaneous injection, meaning it is given as a shot under the skin, typically once daily. The medication works by blocking a specific protein called NTCP on liver cells, which prevents the hepatitis D virus from entering and infecting these cells. Bulevirtide belongs to the pharmacological class of viral entry inhibitors and has been shown to help reduce viral levels in the blood and improve liver inflammation in patients with this serious condition.

Investigated diseases

Chronic Hepatitis D – Chronic Hepatitis D is a long-term liver infection caused by the hepatitis D virus, which can only occur in people who are already infected with hepatitis B virus. The virus attacks liver cells and causes ongoing inflammation of the liver tissue. Over time, this continuous inflammation can lead to progressive damage to the liver. The infection persists in the body for months or years, making it a chronic condition. As the disease progresses, the liver may develop scarring and its function may gradually decline. The hepatitis D virus requires the presence of hepatitis B virus to replicate and spread within the body.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IVTrial ID2025-522015-42-00Protocol codeBJT-778-303Estimated enrolment125 patientsSponsorMirum Pharmaceuticals Inc.

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