New Momentum in Hepatitis D Research and Treatment, With Tatyana Kushner, MD

Despite growing awareness of hepatitis D virus (HDV) infection, experts say the true burden of the disease remains difficult to define, with limited testing, gaps in provider awareness, and historically restricted access to diagnostics all contributing to persistent uncertainty about epidemiology.

In an interview with HCPLive, Tatyana Kushner, MD, an associate professor of medicine in the division of gastroenterology and hepatology at Weill Cornell Medicine, noted that routine testing for HDV was not widely recommended until relatively recently, leaving significant blind spots in prevalence estimates. Much of what clinicians know today is based on patients who were tested, diagnosed, and subsequently documented through diagnostic codes or laboratory confirmation. Patients who were never tested, however, remain invisible in these data.

“Up until relatively recently, there was no recommended routine testing for delta hepatitis, and there was somewhat limited access to appropriate testing,” she said. “On top of that, there is still a lack of knowledge about delta hepatitis, so providers don't know who to test, when to test, and about delta hepatitis in general.”

As a result, Kushner noted that prevalence estimates did not include a large portion of patients because they were not being tested or diagnosed. As this has improved over time and experts get a better understanding of HDV epidemiology, geographic gaps in prevalence have become increasingly evident.

Certain regions of the world, including parts of Eastern Europe, Central Asia, and Africa, have a substantially greater prevalence of HDV. In the United States, many patients diagnosed with the infection originate from these endemic regions. However, clinicians are increasingly identifying cases among US-born individuals, raising new questions about transmission patterns and risk factors that are not yet fully understood.

Kushner emphasizes that expanding education and improving access to testing will be critical to refining prevalence estimates. As awareness grows among clinicians and screening becomes more common, researchers may begin to develop a clearer understanding of HDV’s true national and global burden.

At the same time, the treatment landscape for HDV is beginning to evolve after decades of limited therapeutic options. In the absence of US Food and Drug Administration-approved treatments, current guidance from the American Association for the Study of Liver Diseases recommends off-label use of pegylated interferon for patients with active infection who do not have contraindications. However, this therapy presents challenges due to significant side effects and relatively modest efficacy.

“We don't have excellent treatment options available at the moment in the US,” Kushner said. “However, it is a very exciting time, because there are several new treatments on the horizon.”

In Europe, the entry inhibitor bulevirtide is already approved for HDV treatment, supported by both clinical trial and real-world evidence demonstrating meaningful antiviral activity. The therapy requires daily injections, which Kushner says may limit uptake among some patients but has nonetheless represented an important advance.

She pointed to additional therapies that are also progressing through clinical development, specifically highlighting brelovitug, a monoclonal antibody being developed by Mirum Pharmaceuticals that is currently being evaluated in phase 3 trials across multiple countries, including the United States.

“Just 10 years ago, we had nothing available, so I think the field is seeing an exciting development where we hopefully will have options for our patients who really need it,” Kushner said.

Editors’ Note: Kushner reports relevant disclosures with Gilead, Abbvie, GSK, Ipsen, Mirum, and Madrigal.

References

1. Ghany MG, Pan CQ, Lok AS, et al. AASLD ISDA Practice Guideline on treatment of chronic hepatitis B. Hepatology. Published online November 4, 2025. doi:10.1097/HEP.0000000000001549

2. MYR Pharmaceuticals. MYR Pharmaceuticals receives Conditional Marketing Authorization by the European Commission for HEPCLUDEX®. August 4, 2020. Accessed March 12, 2026. https://www.prnewswire.com/news-releases/myr-pharmaceuticals-receives-conditional-marketing-authorization-by-the-european-commission-for-hepcludex-301105418.html

3. Mirum Pharmaceuticals. Mirum Pharmaceuticals Completes AZURE-1 Enrollment and AZURE-4 Screening in Phase 3 Program of brelovitug in Chronic Hepatitis Delta Virus. March 5, 2026. Accessed March 12, 2026. https://ir.mirumpharma.com/news/news-details/2026/Mirum-Pharmaceuticals-Provides-AZURE-Clinical-Program-Update-for-brelovitug-in-Chronic-Hepatitis-Delta-Virus/default.aspx