TNX-1800 (live modified horsepox virus vaccine) is being developed by Tonix Pharmaceuticals in a strategic collaboration with Southern Research to support the development of a vaccine to protect against the new coronavirus disease, COVID-19. TNX-1800 is based on Tonix’s proprietary horsepox vaccine platform. It is believed that horsepox has the potential to serve as a vector for vaccines to protect against other infectious agents. The new research collaboration will develop and test a potential horsepox vaccine that expresses protein from the virus that causes COVID-19 to protect against the disease.
TNX-801 is a live virus vaccine based on synthesized horsepox1,2. TNX-1800 is a modified horsepox virus that is designed to express a protein from the virus that causes COVID-19, which is known as SARS-CoV-2. Molecular analysis suggests that TNX-801 has relatively “complete” left and right inverted terminal repeats (ITRs) while different vaccinia isolates have a variety of deletions in the left and right ITRs. Therefore, TNX-801 has additional genes, relative to vaccinia vaccines, that may play roles in host immune interactions and one or more of such proteins may serve as antigens for protective immunity. Molecular analysis also shows that horsepox is closer than modern vaccines in DNA sequence to the vaccine discovered and disseminated by Dr. Edward Jenner2,3,4. No new gene elements were added to the natural isolate and the small plaque size in culture appears identical to the U.S. Centers for Disease Control publication of the natural isolate5. Relative to vaccinia, horsepox has substantially decreased virulence in mice1. TNX-801 vaccinated macaques showed no overt clinical signs after monkeypox challenge6.
*TNX-801 and TNX-1800 are in the pre-IND stage and have not been approved for any indication.