Safety and immunogenicity of a variant-adapted SARS-CoV-2 recombinant protein vaccine with AS03 adjuvant as a booster in adults primed with authorized vaccines
Authors: de Bruyn Guy , Wang Joyce , Purvis Annie , Ruiz Martin Sanchez , Adhikarla Haritha , Alvi Saad , Bonaparte Matthew I , Brune Daniel , Bueso Agustin , Canter Richard M , Ceregido Maria Angeles , Deshmukh Sachin , Diemert David , Finn Adam , Forrat Remi , Fu Bo , Gallais Julie , Griffin Paul , Grillet Marie-Helene , Haney Owen , Henderson Jeffrey A , Koutsoukos Marguerite , Launay Odile , Torres Federico Martinon , Masotti Roger , Michael Nelson L , Park Juliana , Rivera M Doris M , Romanyak Natalya , Rook Chris , Schuerman Lode , Sher Lawrence D , Tavares-Da-Silva Fernanda , Whittington Ashley , Chicz Roman M , Gurunathan Sanjay , Savarino Stephen , Sridhar Saranya 
Published: December 2022

Background

Booster vaccines providing protection against emergent SARS-CoV-2 variants are needed. In an international phase 3 study, we evaluated booster vaccines containing prototype (D614) and/or Beta (B.1.351) variant recombinant spike proteins and AS03 adjuvant (CoV2 preS dTM-AS03).

Methods

Adults, primed 4–10 months earlier with mRNA (BNT162b2, mRNA-1273]), adenovirus-vectored (Ad26.CoV2.S, ChAdOx1nCoV-19) or adjuvanted protein (CoV2 preS dTM-AS03 [D614]) vaccines and stratified by age (18-55 and ≥56 years), were boosted with monovalent (MV) D614 (5μg, n=1285), MV (B.1351) (5μg, n=707) or bivalent (BiV) (2.5μg D614 plus 2.5μg B.1.351, n=625) CoV2 preS dTM-AS03. SARS-CoV-2-naïve adults (controls, n=479) received a primary series (two injections, 21 days apart) of CoV2 preS dTM-AS03 containing 10μg D614. Antibodies to D614G, B.1.351 and Omicron BA.2 and BA.1 variants were evaluated using validated pseudovirus (lentivirus) neutralization (PsVN) assay. D614G or B.1.351 PsVN titers 14 days (D15) post-booster were compared with pre-booster (D1) titers in BNT162b2-primed participants (18-55 years old) and controls (D36), for each booster formulation (co-primary objectives). Safety was evaluated throughout the trial. Results of a planned interim analysis are presented.

Results

Among BNT162b2-primed adults (18-55 years old), PsVN titers against D614G or B.1.351 were significantly higher post-booster than anti-D614G titers post-primary vaccination in controls, for all booster formulations, with an anti-D614G GMT ratio (98.3% CI) of 2.16 (1.69; 2.75) for MV(D614), an anti-B.1.351 ratio of 1.96 (1.54; 2.50) for MV (B.1.351) and anti-D614G and anti-B.1.351 ratios of 2.34 (1.84; 2.96) and 1.39 (1.09; 1.77), respectively, for BiV. All booster formulations elicited cross-neutralizing antibodies against Omicron BA.2 across vaccine priming subgroups and against Omicron BA.1 (evaluated in BNT162b2-primed participants). Similar patterns in antibody responses were observed for participants aged ≥56 years. No safety concerns were identified.

Conclusion

CoV2 preS dTM-AS03 boosters demonstrated acceptable safety and elicited robust neutralizing antibodies against multiple variants, regardless of priming vaccine.

ClinicalTrials.gov

NCT04762680

Funding

Sanofi and federal funds from the Biomedical Advanced Research and Development Authority (BARDA), part of the office of the Administration for Strategic Preparedness and Response at the U.S. Department of Health and Human Services under Contract # HHSO100201600005I, and in collaboration with the U.S. Department of Defense Joint Program Executive Office for Chemical, Biological, Radiological and Nuclear Defense under Contract # W15QKN-16-9-1002.