Halle (Saale), 26 June 2023. Icon Genetics GmbH, a wholly owned subsidiary of Denka Co. Ltd, Tokyo, Japan, has published a second milestone paper in the renowned journal “Frontiers in Immunology” detailing on the remarkable immune responses elicited by its norovirus vaccine candidate during the successfully completed Phase I clinical study.
Noroviruses are responsible for approximately 20% of all cases of acute gastroenteritis worldwide and are recognized as an important public health issue. Therefore, an effective vaccine is needed to reduce the global burden of gastrointestinal diseases elicited by it. Despite decades of intensive research in the field, no licensed vaccine for preventing norovirus disease and ameliorating detrimental health, societal, and economic effects in all age groups is available today.
The reported trial was a single-center, randomized, double-blind, controlled study that has been approved by the Belgian Health Authorities (Federal Agency for Medicine and Health Products-FAMHP) and run in the Center for Vaccinology (CEVAC) at the Ghent University Hospital (Ghent, Belgium). To assess the potential vaccine, the clinical trial was conducted on 60 adults. The study vaccine was a combination of two different types of norovirus antigens and adds no substances (adjuvants) to increase or modulate the immune response. The results for how well vaccination was tolerated and initial assessment of immune responses were published in October 2022 in “Frontiers in Immunology”. In the current publication, we focused on additional and more detailed analysis of immune responses elicited by the norovirus vaccine candidate. Results showed that the vaccine candidate elicits significant immune responses, with no need for an adjuvant. The vaccine elicited the production of IgA antibodies, which are important for mucosal immunity and protection from viral infection in the gut were also norovirus infection takes place. Furthermore, the immune response was not only detectable for norovirus antigens present in the vaccine but also for a variety of antigens not included, a very important finding given the complex norovirus epidemiology involving many different norovirus types. Finally, a significant cell-mediated immune response elicited by the vaccine candidate could be confirmed which is described as relevant for protection from other diseases elicited by viruses. The provided data show that Icon Genetics’ norovirus vaccine is a very promising product candidate for preventing norovirus gastroenteritis. Immune responses analyzed are on par or even exceeding results described for products in clinical development by competitors. In conclusion, further studies of Icon Genetics’ norovirus vaccine candidate are fully supported by the obtained results and need to evaluate efficacy, optimal formulation, and antigen composition.
For its candidate norovirus vaccine Icon Genetics produces norovirus-like particles (VLPs), that mimic the structure of the virus but are not infective, in high yield using the company’s magnICON® technology. The proprietary magnICON® technology utilizes tobacco plants for the rapid, scalable, and environment-friendly production of diverse recombinant proteins to serve the diagnostics and biopharmaceuticals markets. Unlike with older GMO technologies, Icon Genetics’ production host plants are not genetically modified in a stable manner but are rather temporarily instructed to produce a protein of interest by treatment with a bacterial vector carrying the genetic blueprint for the product. The target proteins are produced indoors and are subsequently extracted in pure form from the plants’ leaves. The norovirus vaccine candidate for the current clinical study was produced at Icon Genetics’ pilot-scale facility in Halle/Saale, Germany.