Mpox Vaccination in Preclinical Study Demonstrates Immunity

Today, Chatham, NJ-based Tonix Pharmaceuticals announced results from its preclinical work on its investigational mpox vaccine, TNX-801, which showed protection with sterilizing immunity in animal studies.

The study’s results were published in the journal Viruses.

"It is often forgotten that vaccines don’t always produce sterilizing immunity and so it’s very exciting to be able to report that a horsepox-based vaccine works so well in such a challenging infection model,” study investigator and publication author David Evans, PhD, FCAHS, professor and former vice-dean (Research) Faculty of Medicine and Dentistry at the University of Alberta author of the publication, said in a statement.

The publication’s authors describe data from animals in which 8 out of 8 vaccinated with TNX-801 were fully protected with sterilizing immunity from a challenge with intra-tracheal mpox (central African, or Congo Basin, clade).

“The vaccine was well tolerated and protected animals from the development of lesions and severe disease,” the study authors wrote.

To learn more about the company’s vaccine platform and some history of vaccination, check out this Contagion interview with Tonix CEO Seth Lederman, MD.

According to the investigators, these data show that the immunity generated by TNX‐801 was able to provide protection against a lethal challenge with mpox virus and is the first study to demonstrate the efficacy of TNX‐801 vaccination against mpox virus challenge in a non‐human primate model.

Synthetic horsepox virus is the basis for the company’s TNX-801 vaccine in development to protect against mpox and smallpox and for the company’s Recombinant Pox Virus (RPV) platform to protect against other pathogens, including COVID-19.

Mpox and smallpox are diseases in humans caused by the Mpox and smallpox (or variola) viruses, respectively. Mpox and variola are closely related orthopox viruses. Vaccination against smallpox with live virus vaccines based on horsepox or vaccinia protects against monkeypox.

The company is predicting it will go into phase 1 clinical trial for TNX-801 in the latter part of this year.