90% of Adults with Chronic Hepatitis Delta Who Cleared Virus on Bulevirtide Stayed Clear Nearly 2 Years After Stopping Treatment
Gilead Sciences, Inc. (Nasdaq: GILD) today announced final results from the Phase 3 MYR301 study showing that nearly 90% of adults with chronic hepatitis delta virus (HDV) who achieved undetectable HDV RNA after 96 weeks of treatment with bulevirtide remained virus-free for almost two years after stopping therapy.
Specifically, 36% (23 of 64) of adults treated with either 2 mg or 10 mg bulevirtide maintained virologic suppression for nearly two years post-treatment after reaching undetectable HDV RNA levels at the end of therapy (EOT). Notably, among participants who stayed undetectable for one year after stopping treatment, none experienced relapse in the second year. The data showed that longer periods of on-treatment viral suppression predicted a stronger post-treatment response — 90% (9 of 10) of those undetectable for ≥96 weeks at EOT remained undetectable off-treatment.
These results, presented at the 2025 European Association for the Study of the Liver (EASL) Congress, highlight the potential long-term value of bulevirtide monotherapy for some adults living with chronic HDV, even after they stop treatment.
“HDV is the most severe type of viral hepatitis, with faster progression to liver cancer and liver-related death,” said Professor Heiner Wedemeyer, Head of Gastroenterology, Hepatology, Infectious Diseases, and Endocrinology at Hannover Medical School. “Past data showed bulevirtide as a safe and effective option, with guidelines recommending continued treatment while patients benefit. Today’s results show the potential for some patients to maintain virologic suppression and liver health markers even after stopping therapy.”
The findings (LBO-004) build on earlier MYR301 data presented at The Liver Meeting® 2024 (AASLD), where some patients showed undetectable HDV RNA 48 weeks after stopping bulevirtide. The new data reveal that patients with longer periods of viral suppression during treatment were more likely to maintain undetectability after discontinuation.
Post-treatment liver-related serious adverse events (SAEs) were reported in 14% (20 of 142) of participants, but 85% (17 of 20) resolved, mostly in those who restarted bulevirtide.
“At Gilead, we are dedicated to advancing research on bulevirtide — exploring its potential as monotherapy, in combinations, and at different doses — to improve outcomes for people with chronic HDV,” said Anu Osinusi, Vice President of Clinical Research for Hepatitis, Respiratory, and Emerging Viruses at Gilead. “While earlier MYR301 data showed the value of long-term treatment, this new analysis gives us important insight into the durability of response even after treatment ends.”
HDV affects about 4.5% of people with chronic hepatitis B (HBV), with an estimated 12 million people worldwide living with the infection. Bulevirtide 2 mg is currently the only approved treatment for adults with chronic HDV and compensated liver disease in the European Economic Area (EEA), the UK, Switzerland, and Australia. Neither bulevirtide 2 mg nor the investigational 10 mg dose is approved in the U.S. or other regions.
Marketing Authorization
In July 2023, the European Commission (EC) granted full Marketing Authorization (MA) for Hepcludex® (bulevirtide) 2 mg for the treatment of adults with chronic HDV and compensated liver disease. Bulevirtide was initially granted a conditional MA from the EC in July 2020 to provide people living with HDV urgent access to treatment. Bulevirtide’s conditional MA license in the UK was converted to a full MA in August 2023, and a full MA was granted in Switzerland in February 2024. In regions where bulevirtide is not approved, including the U.S., bulevirtide 2 mg is an investigational product. In these regions, health authorities have not established the safety and efficacy of bulevirtide. Bulevirtide 10 mg is an investigational product and is not approved anywhere globally.
About MYR301
MYR301 is a Phase 3 clinical trial evaluating the long-term efficacy and safety of bulevirtide in 150 people living with chronic HDV randomly allocated to treatment with bulevirtide 2 mg once daily (n=49), 10 mg once daily (n=50) or no antiviral treatment (delayed treatment, n=51). Primary efficacy and safety data was assessed at Week 48. After Week 48, participants in the delayed treatment group of the study were switched to bulevirtide 10 mg once daily for an additional 96 weeks. The total duration of treatment across all groups in the study is 144 weeks. The primary endpoint, combined response, is defined as an undetectable HDV RNA or ≥2log10 IU/ml decline from baseline and ALT normalization at Week 48. Secondary endpoints at Week 48 include undetectable HDV RNA (key secondary endpoint), ALT normalization, and a change from baseline in liver stiffness measured by transient elastography.
About Gilead Sciences in Liver Disease
For decades, Gilead has pioneered the way forward to improve the lives of people living with liver disease around the world. The company has helped to transform hepatitis C from a chronic condition into a curable condition. For individuals living with hepatitis B or hepatitis delta (HDV), Gilead’s focus on advancing medicines drives hope that today’s research will turn into tomorrow’s cures. Beyond viral hepatitis, Gilead is working to deliver advanced treatments for people living with primary biliary cholangitis. The commitment of Gilead does not stop there. Through ground-breaking science and collaborative partnerships, the company strives to create healthier futures for everyone living with liver disease. Gilead remains devoted to a future without liver disease.
About Gilead Sciences
Gilead Sciences, Inc. is a biopharmaceutical company that has pursued and achieved breakthroughs in medicine for more than three decades, with the goal of creating a healthier world for all people. The company is committed to advancing innovative medicines to prevent and treat life-threatening diseases, including HIV, viral hepatitis, COVID-19, cancer and inflammation. Gilead operates in more than 35 countries worldwide, with headquarters in Foster City, California.
