Immunogenicity and efficacy of mRNA COVID-19 vaccine MRT5500 in preclinical animal models

• Published in: npj vaccines Vol. 6; no. 1; p. 61
• Main Authors: Kalnin, Kirill V., Plitnik, Timothy, Kishko, Michael, Zhang, Jinrong, Zhang, Donghui, Beauvais, Adrien, Anosova, Natalie G., Tibbitts, Tim, DiNapoli, Josh, Ulinski, Gregory, Piepenhagen, Peter, Cummings, Sheila M., Bangari, Dinesh S., Ryan, Susan, Huang, Po-Wei D., Huleatt, James, Vincent, Deanne, Fries, Katherine, Karve, Shrirang, Goldman, Rebecca, Gopani, Hardip, Dias, Anusha, Tran, Khang, Zacharia, Minnie, Gu, Xiaobo, Boeglin, Lianne, Abysalh, Jonathan, Vargas, Jorel, Beaulieu, Angela, Shah, Monic, Jeannotte, Travis, Gillis, Kimberly, Chivukula, Sudha, Swearingen, Ron, Landolfi, Victoria, Fu, Tong-Ming, DeRosa, Frank, Casimiro, Danilo
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 19-04-2021; Nature Publishing Group; Nature Portfolio
• Subjects: 631/250; 631/326; 631/61; 692/420; 692/699; Animal models; Biomedical and Life Sciences; Biomedicine; Coronaviruses; COVID-19; COVID-19 vaccines; Immunogenicity; Infectious Diseases; Laboratory animals; Medical Microbiology; Neutralization; Pandemics; Public Health; Respiratory diseases; Ribonucleic acid; RNA; Severe acute respiratory syndrome coronavirus 2; Vaccine; Vaccines; Virology
• ISSN: 2059-0105; 2059-0105
• DOI: 10.1038/s41541-021-00324-5

Emergency use authorization of COVID vaccines has brought hope to mitigate pandemic of coronavirus disease 2019 (COVID-19). However, there remains a need for additional effective vaccines to meet the global demand and address the potential new viral variants. mRNA technologies offer an expeditious path alternative to traditional vaccine approaches. Here we describe the efforts to utilize an mRNA platform for rational design and evaluations of mRNA vaccine candidates based on the spike (S) glycoprotein of SARS-CoV-2. Several mRNA constructs of S-protein, including wild type, a pre-fusion stabilized mutant (2P), a furin cleavage-site mutant (GSAS) and a double mutant form (2P/GSAS), as well as others, were tested in animal models for their capacity to elicit neutralizing antibodies (nAbs). The lead 2P/GSAS candidate was further assessed in dose-ranging studies in mice and
Cynomolgus
macaques, and for efficacy in a Syrian golden hamster model. The selected 2P/GSAS vaccine formulation, designated MRT5500, elicited potent nAbs as measured in neutralization assays in all three preclinical models and more importantly, protected against SARS-CoV-2-induced weight loss and lung pathology in hamsters. In addition, MRT5500 elicited T
H
1-biased responses in both mouse and non-human primate (NHP), thus alleviating a hypothetical concern of potential vaccine-associated enhanced respiratory diseases known associated with T
H
2-biased responses. These data position MRT5500 as a viable vaccine candidate for entering clinical development.