“We have developed a therapeutic vaccine that may offer the prospect of a cure for the first time using two consecutively administered vaccines,” explains Ulrike Protzer, Professor of Virology at the TUM and Research Group Leader at the Helmholtz Zentrum in Munich.
Anyone not yet infected with the Hepatitis B virus can receive the vaccine. It cannot, however, be used to treat individuals who already have a chronic infection; the available drugs may stem the proliferation of viruses in the body but cannot cure the disease. Patients with chronic Hepatitis B therefore have a higher risk of suffering from liver cirrhosis or liver cancer.
Dual impact against Hepatitis B
Two different components are combined in the new therapeutic vaccine. Proteins of the Hepatitis B virus are administered directly in an initial vaccine (prime) to trigger the formation of suitable antibodies and to prepare immune cells, so-called T cells, for their deployment. The antibodies neutralize the virus and prevent it from spreading further. The T cells are important immune cells in the human body that can destroy cells infected with viruses.
This immune response is then boosted with a second vaccine. To this effect, the researchers use a harmless smallpox vaccination virus that carries parts of the genotype of the Hepatitis B virus within it. This viral vector is trimmed to activate T cells and aims to increase the number of specific T cells combatting the Hepatitis B virus and to make them target the infected cells.
This ‘prime boost vaccine’ proved extremely successful in studies using animal models. “Both effective antibodies, which reduced the quantity and spread of the virus in the blood, and T cells, which killed the infected liver cells, were formed,” explains Protzer.
Preparation under way for first clinical study
The researchers are now using the successfully secured funding to prepare the first clinical study on humans. This involves both the specialist production of the vaccine components as well as the toxicological and pharmacodynamics studies beforehand. The clinical study is being carried out by Prof. Dr. Marylyn Addo at the University Hospital of Hamburg-Eppendorf (UKE).
Project selected from 83 applications
The proof of concept is a key stage in securing authorization for drugs and vaccines. To facilitate this step, which often presents researchers with an insurmountable obstacle, the Fraunhofer-Gesellschaft and the Helmholtz Society together with the Deutsche Hochschulmedizin launched the PoC initiative. From 83 applications, the project was one of four selected to receive funding.
The project is being carried out in cooperation with the Fraunhofer Institute for Cell Therapy and Immunology in Leipzig and the University Hospitals “Rechts der Isar” in Munich and Hamburg-Eppendorf. The German Center for Infection Research (DZIF) is also providing funding of 1.3 million euros for the project.
Prof. Ulrike Protzer
Institute of Virology
Technical University of Munich
Tel: +49 89-4140 6821