Phylex BioSciences Publishes Positive Results of Protection Study Against SARS-CoV-2 Delta Variant with its Second Generation mRNA Vaccine

March 23, 2022

DEL MAR, California – March 23, 2022 – Two years into the COVID-19 pandemic there is still a need for vaccines to effectively control the spread of novel SARS-CoV-2 variants and associated cases of severe disease. The current vaccines offer limited protection over time against the omicron variant that is now dominating worldwide and likely less protection against future variants of concern. This week scientists of the Centers for Disease Control and Prevention (CDC) reported the first evidence of a delta- omicron hybrid variant in the US.

Phylex BioSciences has published the preprint of a research article ( on the results of immunogenicity and protection studies of its novel mRNA vaccine. The studies were conducted in collaboration with the Pasteur Institute in Paris, France and the Institute of Virology and Immunology, University of Bern, Switzerland and conclude that the vaccine elicits robust neutralizing antibody response with neutralizing titers an order of magnitude above currently approved mRNA vaccines. The vaccine also provides protective immunity against the delta variant in a widely used transgenic mouse model. The mRNA vaccine encodes for a nanoparticle displaying 60 copies of the antigen based upon the receptor binding domain of the delta variant.

In virus neutralization assays neutralization titers of Phylex vaccine-elicited sera against the SARS-CoV-2 delta variant were up to 32-fold as compared with current mRNA vaccine-elicited sera. In another experiment the same Phylex vaccine achieved protection against lung infection and associated COVID-19 disease in the transgenic mouse model with data also indicating long-term protection from cell-mediated immunity.

The same technology is being applied in an ongoing study against the omicron variant with the same collaborations. This booster candidate will offer two fundamental advantages as compared with the current mRNA vaccines: first, improved immune response against the delta and omicron variants and second, elimination of antibodies enhancing infection.

“In the US, with a majority of the population vaccinated with at least 2 doses, daily reported new cases of infection reached a staggering peak of 301,000 cases for the delta variant in September 2021 and 1,178,000 cases for the omicron variant in January 2022. With the CDC reporting this week the first delta-omicron hybrid in the US there is clearly urgent need for a new vaccine technology to combat future variants”, said Pascal Brandys, co-founder and CEO of Phylex BioSciences, which is currently developing a second-generation mRNA SARS-CoV-2 vaccine. “In this study we confirm that our mRNA vaccine encoding for a highly immunogenic nanoparticle provides a flexible platform for rapid development of a new vaccine and will be of great value in combatting current and future SARS-CoV-2 variants of concern”.

About Phylex BioSciences

Founded at the beginning of the SARS-CoV-2 pandemic by genomics pioneer Pascal Brandys and coronavirus specialist Jens Herold, Phylex BioSciences is the first company to pursue the development of a booster mRNA vaccine against both SARS-CoV-2 delta and omicron variants.

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