EXG-5003

EXG-5003 is a temperature-sensitive, intradermally administered, controllable self-replicating RNA (c-srRNA) vaccine that encodes the receptor binding domain (RBD) of the SARS-CoV-2 spike protein. Developed by Elixirgen Therapeutics, it is designed to induce strong T cell-mediated immunity against COVID-19. Unlike conventional mRNA vaccines, EXG-5003 does not use lipid nanoparticles for delivery and is active at skin temperature (~33°C), but inactive at core body temperature (~37°C), potentially improving safety and reducing off-target effects. Clinical trials have shown that EXG-5003 elicits antigen-specific cellular immunity with a favorable safety profile and may prime long-term cellular responses to subsequent approved mRNA vaccines[1][4][5].