Preclinical evaluation of a SARS-CoV-2 mRNA vaccine PTX-COVID19-B

Jun Liu, Patrick Budylowski, Reuben Samson, Bryan D. Griffin, Giorgi Babuadze, Bhavisha Rathod, Karen Colwill, Jumai A. Abioye, Jordan A. Schwartz, Ryan Law, Lily Yip, Sang Kyun Ahn, Serena Chau, Maedeh Naghibosadat, Yuko Arita, Queenie Hu, Feng Yun Yue, Arinjay Banerjee, W. Rod Hardy, Karen MossmanSamira Mubareka, Robert A. Kozak, Michael S. Pollanen, Natalia Martin Orozco, Anne Claude Gingras, Eric G. Marcusson, Mario A. Ostrowski

Research output: Contribution to journalArticlepeer-review

25 Scopus citations


Safe and effective vaccines are needed to end the COVID-19 pandemic. Here, we report the preclinical development of a lipid nanoparticle-formulated SARS-CoV-2 mRNA vaccine, PTX-COVID19-B. PTX-COVID19-B was chosen among three candidates after the initial mouse vaccination results showed that it elicited the strongest neutralizing antibody response against SARS-CoV-2. Further tests in mice and hamsters indicated that PTX-COVID19-B induced robust humoral and cellular immune responses and completely protected the vaccinated animals from SARS-CoV-2 infection in the lung. Studies in hamsters also showed that PTX-COVID19-B protected the upper respiratory tract from SARS-CoV-2 infection. Mouse immune sera elicited by PTX-COVID19-B vaccination were able to neutralize SARS-CoV-2 variants of concern, including the Alpha, Beta, Gamma, and Delta lineages. No adverse effects were induced by PTX-COVID19-B in either mice or hamsters. Based on these results, PTX-COVID19-B was authorized by Health Canada to enter clinical trials in December 2020 with a phase 2 clinical trial ongoing.

Original languageEnglish (US)
Article numbereabj9815
JournalScience Advances
Issue number3
StatePublished - Jan 2022
Externally publishedYes

ASJC Scopus subject areas

  • General


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