Vaccines (Nov 2023)

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
https://doi.org/10.3390/vaccines11111682
Journal volume & issue
Vol. 11, no. 11
p. 1682

Abstract

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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.

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