key: cord-0816984-8fxrqorg
authors: Guebre-Xabier, Mimi; Patel, Nita; Tian, Jing-Hui; Zhou, Bin; Maciejewski, Sonia; Lam, Kristal; Portnoff, Alyse D.; Massare, Michael J.; Frieman, Matthew B.; Piedra, Pedro A.; Ellingsworth, Larry; Glenn, Gregory; Smith, Gale
title: NVX-CoV2373 vaccine protects cynomolgus macaque upper and lower airways against SARS-CoV-2 challenge
date: 2020-08-19
journal: bioRxiv
DOI: 10.1101/2020.08.18.256578
sha: 2eca3a6220675fb7ef8908fc55214381f60f2a7c
doc_id: 816984
cord_uid: 8fxrqorg

There is an urgent need for a safe and protective vaccine to control the global spread of SARS-CoV-2 and prevent COVID-19. Here, we report the immunogenicity and protective efficacy of a SARS-CoV-2 subunit vaccine (NVX-CoV2373) produced from the full-length SARS-CoV-2 spike (S) glycoprotein stabilized in the prefusion conformation. Cynomolgus macaques (Macaca fascicularis) immunized with NVX-CoV2373 and the saponin-based Matrix-M adjuvant induced anti-S antibody that was neutralizing and blocked binding to the human angiotensin-converting enzyme 2 (hACE2) receptor. Following intranasal and intratracheal challenge with SARS-CoV-2, immunized macaques were protected against upper and lower infection and pulmonary disease. These results support ongoing phase 1/2 clinical studies of the safety and immunogenicity of NVX-CoV2327 vaccine (NCT04368988). Highlights Full-length SARS-CoV-2 prefusion spike with Matrix-M1™ (NVX-CoV2373) vaccine. Induced hACE2 receptor blocking and neutralizing antibodies in macaques. Vaccine protected against SARS-CoV-2 replication in the nose and lungs. Absence of pulmonary pathology in NVX-CoV2373 vaccinated macaques.

The in-life portion of the study was conducted at BIOQUAL, Inc (Rockville, MD 

Anti-SARS-CoV-2 spike (S) protein IgG ELISA titers were measured as described 99

[1]. Anti-S IgG EC 50 titers were calculated by 4-parameter fitting using SoftMax Pro 100 6.5.1 GxP software. Individual animal anti-S IgG EC 50 titers, group geometric mean 101 titers (GMT) were plotted using GraphPad Prism 7.05 software. 102

Antibodies that block binding of hACE2 receptor to the S-protein and neutralize in a 104 cytopathic effect assay (CPE) in Vero E6 cells were measured as described previously 105 as the serum titer that blocks 100% CPE [1]. Serum antibody titer at 50% binding 106 inhibition (IC 50 ) of hACE2 to SARS-CoV-2 S protein was determined in the SoftMax Pro 107 program. Individual animal hACE2 receptor inhibiting titers, mean titers, and SEM were 108 plotted using GraphPad Prism 7.05 software. Neutralizing antibody titers were Figure 1A) . In contrast, SARS-CoV-2 anti-S antibody in convalescent human sera was 157 6.9-to 14.2-fold less with at GMT EC 50 of 23,614 ( Figure 1B) . And, hACE2 receptor 158 inhibition titers of 649, 1,410, and 1,320 in 2.5, 5, and 25 µg NVX-CoV2373 dose groups 159 respectively were 5.2 -11.2-fold higher than in convalescent sera ( Figure 1C) . Finally, 160 SARS-CoV-2 GMT neutralization antibody titers of 17,920 -23,040 CPE 100 in 161 immunized macaques, were 7.9 -10.1-fold higher than in convalescent sera ( Figure  162   1D) . 163

To evaluate the potential efficacy of NVX-CoV2373 vaccine, macaques were 165 challenged with SARS-CoV-2 virus in upper and lower airways. Macaques in the 166 placebo group had 9,131 sgRNA copies/mL in the BAL at 2 days post challenge and 167 remained elevated at day 4 except for one animal. In contrast, immunized animals had 168 no detectable sgRNA in BAL fluid other than one animal in the low dose group at day 2 169 which cleared replicating virus RNA by day 4 (Figure 1E) . Half of the controls had ~4 170 log10 of virus sgRNA copies in nasal swabs and in contrast, no detectable sgRNA was 171 in the nose of NVX-CoV2373 vaccinated animals ( Figure 1F) . X  -C  o  V  2  3  7  3  N  H  P  v  s  C  o  n  v  a  l  e  s  c  e  n  t  A  n  t  i  -S  I  g  G  T  i  t  e  r   5  g  2  5  g  2 . 

Funding for certain studies was provided by the Coalition for Epidemic Preparedness 198

Author contributions

conceptualization of 201 experiments, generation of data and analysis, and interpretation of the results

drafting and making critical revisions with 204 the help of others

SARS-CoV-2 spike glycoprotein vaccine candidate NVX-CoV2373 214 elicits immunogenicity in baboons and protection in mice

First-in-Human Trial of a SARS CoV 2 Recombinant Spike Protein 218

Cryo-EM structure of the 2019-nCoV spike in the prefusion conformation

Virological assessment of hospitalized patients with COVID-2019

Infection with novel 227 coronavirus (SARS-CoV-2) causes pneumonia in Rhesus macaques

SARS-CoV-2 infection protects against rechallenge in rhesus macaques

Development of an inactivated 233 vaccine candidate for SARS-CoV-2

Neeltje van Doremalen

ChAdOx1 nCoV-19 237 vaccination prevents SARS-CoV-2 pneumonia in rhesus macaques

DNA 240 vaccine protection against SARS-CoV-2 in rhesus macaques

Evaluation of the mRNA-1273

Vaccine against SARS-CoV-2 in Nonhuman Primates

Comparative pathogenesis of COVID-19, MERS, and SARS in a nonhuman primate 248 model

Authors MGX, NP, JHT, BZ, SM, KL, ADP, MJM, GG, GS and LE are current or past 207 employees of Novavax, Inc., a for-profit organization, and these authors own stock or 208 hold stock options. These interests do not alter the authors adherence to policies on 209 sharing data and materials. MBF and PAP declare no competing interests.