Immunogenicity and Efficacy of TNX-1800, A Live Virus Recombinant Poxvirus Vaccine Candidate, against SARS-CoV-2 Challenge in Nonhuman Primates

Mayanka Awasthi; Anthony Macaluso; Dawn Myscofski; Jon Prigge; Fusataka Koide; Ryan S Noyce; Siobhan Fogarty; Helen Stillwell; Scott J Goebel; Bruce Daugherty; Farooq Nasar; Sina Bavari; Seth Lederman

doi:10.3390/vaccines11111682

Immunogenicity and Efficacy of TNX-1800, A Live Virus Recombinant Poxvirus Vaccine Candidate, against SARS-CoV-2 Challenge in Nonhuman Primates

Vaccines (Basel). 2023 Nov 2;11(11):1682. doi: 10.3390/vaccines11111682.

Authors

Affiliations

¹ Tonix Pharmaceuticals, Frederick, MD 21701, USA.
² BioQual, Rockville, MD 20850, USA.
³ Southern Research, Birmingham, AL 35205, USA.
⁴ Department of Medical Microbiology & Immunology, Li Ka Shing Institute of Virology, University of Alberta, Edmonton, AB T6G 2R3, Canada.
⁵ Tonix Pharma Limited, A96 HW25 Dublin, Ireland.
⁶ Department of Microbiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA.
⁷ Tonix Pharmaceuticals, Chatham, NJ 07928, USA.
⁸ Tonix Pharmaceuticals, Dartmouth, MA 02748, USA.

Abstract

TNX-1800 is a synthetically derived live recombinant chimeric horsepox virus (rcHPXV) vaccine candidate expressing Wuhan SARS-CoV-2 spike (S) protein. The primary objective of this study was to evaluate the immunogenicity and efficacy of TNX-1800 in two nonhuman primate species challenged with USA-WA1/2020 SARS-CoV-2. TNX-1800 vaccination was well tolerated with no serious adverse events or significant changes in clinical parameters. A single dose of TNX-1800 generated humoral responses in African Green Monkeys and Cynomolgus Macaques, as measured by the total binding of anti-SARS-CoV-2 S IgG and neutralizing antibody titers against the USA-WA1/2020 strain. In addition, a single dose of TNX-1800 induced an interferon-gamma (IFN-γ)-mediated T-cell response in Cynomolgus Macaques. Following challenge with SARS-CoV-2, African Green and Cynomolgus Macaques exhibited rapid clearance of virus in the upper and lower respiratory tract. Future studies will assess the efficacy of TNX-1800 against newly emerging variants and demonstrate its safety in humans.

Keywords: SARS-CoV-2; TNX-1800; antibody titer; horsepox virus; immunogenicity; spike protein; vaccine; vaccine platform.

Grants and funding

This work was performed under a research agreement with Tonix Pharmaceuticals, Inc. The funder played a role in the formulation of the project, the decision to publish, and the preparation of the manuscript. This research was conducted as a collaboration between Tonix Pharmaceuticals, Inc., and the University of Alberta, with funds provided by Tonix Pharmaceuticals, Inc.