Cure for chronic Hepatitis B closer, bringing relief for an estimated 257 million people who suffer from the viral infection
A cure for chronic Hepatitis B infection is now closer than ever before. Researchers at Helmholtz Zentrum München and the Technical University of Munich, in collaboration with researchers at the University Medical Center Hamburg-Eppendorf and the University Hospital Heidelberg, have, for the first time, succeeded in conquering a chronic infection with the hepatitis B virus in a mouse model. While so far it has not been possible to control the virus fully, the research team demonstrated that "T cell therapy" can provide a permanent cure.
"T cell therapy is a promising means to treat chronic hepatitis B virus (HBV) infection and HBV-associated hepatocellular carcinoma (liver cancer)," stated the paper published in the Journal of Clinical Investigation. Researchers will now do more investigation to understand the potential of T-cell therapy and subsequently conduct clinical trials along with their partners.
Hepatitis B, a major global health problem, is a viral infection that attacks the liver and can cause both acute and chronic disease. According to the World Health Organization (WHO), an estimated 257 million people are living with hepatitis B virus infection. In 2015, hepatitis B resulted in 887,000 deaths, mostly from complications, which included liver cirrhosis and liver cancer. While vaccination prevents new hepatitis B virus infections, for people who are chronic carriers of the virus, a cure has not yet been found. Available drugs only prevent the virus from continuing to replicate in liver cells, but they cannot eliminate it. This can lead to severe complications such as liver cancer or liver cirrhosis in the long-term.
"Currently, chronic hepatitis B cannot be cured. We have now been able to show that T cell therapy, exploiting new technologies, presents an encouraging solution for the treatment of chronic hepatitis B virus infection and liver cancer that is triggered by the virus. That is because these living drugs are the most potent therapy we have at our disposal at present," said Professor Ulrike Protzer in a news release. She is Director of the Institute of Virology at the Helmholtz Zentrum München and the Technical University of Munich, both members of the German Center for Infection Research (DZIF).
The investigations were conducted using a complex "humanized" mouse model, which can be reconstituted with human liver cells, thus enabling the investigation of hepatitis b virus and the preclinical evaluation of antiviral drug candidates. According to Dr. Karin Wisskirchen, first author of the study and scientist in the group of Ulrike Protzer, the new T cell therapy was specifically developed as an approach to fight hepatitis B virus infection and hepatitis B virus-associated liver cancer.
"It is known that in chronically infected patients, virus-specific T cells either cannot be detected or they demonstrate decreased activity. However, if patients can keep the virus under control by themselves, a strong T cell response becomes detectable. The obvious answer is, therefore, to use virus-specific T cells to make up for this deficit," Dr. Wisskirchen said in the release.
The researchers explained that they got the genetic information for hepatitis B virus-specific T cell receptors from patients with resolved infection. "In the laboratory, it can then be introduced into T cells from the blood of patients with chronic hepatitis B. This leads to the formation of new, active T cells, which fight the virus or virus-induced cancer cells. T cells created in this way were able to eliminate HBV-infected cells in the cell culture," said the findings.
The release explained the process further, stating that the immune cells were then tested in a humanized mouse model. "A single dose of the receptor-modified T cells was sufficient to control the virus in the liver. The T cells only attacked infected liver cells and spared healthy tissue. An experimental drug, which has been developed, was then administered to prevent the virus from infecting healthy liver cells again as soon as the T cells had stopped circulating. As a result, the infection was completely cured," it said.