Alliance for Pandemic Preparedness

April 20, 2021

Safety and Immunogenicity of SARS-CoV-2 Recombinant Protein Vaccine Formulations in Healthy Adults: Interim Results of a Randomised, Placebo-Controlled, Phase 1–2, Dose-Ranging Study

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  • The SARS-CoV-2 recombinant protein vaccine candidate CoV2 preS dTM (Sanofi Pasteur) was safe and immunogenic in a randomized Phase I/II trial (n=439) but elicited lower immune responses than anticipated. Both a one and two dose regimen were tested but a single vaccine dose did not generate neutralizing antibody titers above placebo levels in any group. After two doses 22 days apart, geometric mean neutralizing titers (GMTs) were highest in the high-dose group with the GlaxoSmithKline adjuvant AS03 (GMT=75.1) and lowest in the low-dose group with the Sanofi Pasteur adjuvant AF03 (GMT=13.1) versus placebo (GMT=5). GMTs were lower among participants 50 years and older. These titers were lower than anticipated and investigations suggested the final drug product delivered in the vaccine doses was 4-to-6-fold lower than planned due to contamination with other proteins. No unusual side effects were reported, but the vaccine was associated with more typical vaccine side effects such as local pain at the injection site than was anticipated based upon previous experience with similar vaccines.  

Goepfert et al. (Apr 19, 2021). Safety and Immunogenicity of SARS-CoV-2 Recombinant Protein Vaccine Formulations in Healthy Adults: Interim Results of a Randomised, Placebo-Controlled, Phase 1–2, Dose-Ranging Study. The Lancet Infectious Diseases. https://doi.org/10.1016/S1473-3099(21)00147-X