Therapeutic vaccine for chronic hepatitis B enters first clinical trial in patients
After more than ten years of research, “TherVacB” reaches the clinic: In June 2025, the first patient was treated with the vaccine (symbolic image).
TherVacB, a novel therapeutic vaccine for chronic hepatitis B developed under the leadership of Helmholtz Munich in collaboration with the German Center for Infection Research (DZIF), has entered its first clinical trial in patients. Following a successful phase Ia trial in healthy volunteers, where the vaccine demonstrated a favorable safety profile and triggered the desired immune responses, the study has now progressed to a multi-center phase Ib/IIa trial. The first patient was enrolled in June 2025.
TherVacB: Over a decade of research reaches the clinic
"After 13 years of research, seeing TherVacB enter patient trials is exciting as it is a critical step towards providing a potential cure for chronic hepatitis B," says Prof. Ulrike Protzer, the vaccine's inventor and Director of the Institute of Virology at Helmholtz Munich and Chair for Virology at the Technical University of Munich. "This vaccine aims to activate the natural immune response in a way that could finally enable the body to eliminate the virus," adds Protzer, who also coordinates the research area "Hepatitis" in the DZIF.
TherVacB uses an innovative heterologous prime-boost strategy: it first introduces proteins that prime the immune system, followed by a modified viral vector (MVA) to boost the cellular immune response. This approach is designed to stimulate both antibody and T-cell responses targeted at the hepatitis B virus. The vaccine is also tailored to cover over 95 percent of global HBV strains, making it potentially effective for the more than 250 million chronically infected humans worldwide.
Sponsored by LMU University Hospital Munich and led by sponsor representative Prof. Michael Hoelscher, Director of the Institute of Infectious Diseases and Tropical Medicine and Speaker of the DZIF Partner Site Munich, the current trial is being conducted at clinical sites in Germany, Italy, Spain, England, and Tanzania. It aims to evaluate the safety, tolerability, and immune activity of the vaccine in patients with chronic hepatitis B whose infections are currently managed with antiviral medication. 81 patients will participate in two phases. In the first part (phase Ib), participants receive increasing doses of the vaccine components to determine the safest and most effective dose. In the second part (phase IIa), the best dose identified will be tested in a larger group of patients to confirm its safety and determine how well it stimulates the immune system to control the virus. The aim is to determine the optimal dose that is both safe and effective in helping the body fight hepatitis B.
A new chapter in hepatitis B treatment
If successful, TherVacB could represent a breakthrough in the treatment of chronic hepatitis B. The ability to stimulate a functional immune response in already-infected patients could lay the groundwork for a true cure—something no existing therapy offers.
"The outcomes of this trial may not only shape future phases of clinical development but also redefine the global strategy for managing hepatitis B—especially in regions with high disease burden and limited access to existing treatments," says Michael Hoelscher.
About chronic hepatitis B
Chronic hepatitis B is a serious and widespread infectious disease, affecting 254 million people worldwide. It significantly increases the risk of liver damage, cirrhosis, and liver cancer. Although preventive vaccines and antiviral treatments exist, no curative therapy has been developed to date. Current treatments suppress the virus but require lifelong use and are not universally available. According to the World Health Organization (WHO), hepatitis B causes 1.1 million deaths per year, highlighting the urgent need for curative strategies.
Further information
- Find detailed information about the phase Ia/IIb clinical trial in patients:
https://clinicaltrials.gov - For more information on the therapeutic vaccine TherVacB, visit:
https://www.thervacb.eu/
Funding information
Funding for the study is provided by the European Union through the Horizon 2020 research program.
