The context of the project

• The evaluation of a booster vaccine capable of improving the magnitude and durability of anti-SARS-CoV-2 responses is important.
• The clinical trial is evaluating the humoral immune response to a new CD40.RBDv vaccine candidate: an anti-CD40 IgG4 monoclonal antibody fused to the RBD (receptor binding domain) of the original SARS-CoV-2 Wuhan strain and to an RBDv sequence harbouring mutations common to several coronaviruses, including Omicron.
• It has been launched by the French start-up LinKinVax on the basis of the vaccine platform developed over more than a dozen years by the Vaccine Research Institute (VRI) and supported by the ANRS MIE.

Methodology of the study

Type of study

• Phase 1/2a multicentre, randomised, open-label trial comprising four two-arm vaccine cohorts

Study objectives

• Primary objective: To assess the safety and reactogenicity of the vaccine strategies during the first 3 months after each dose.
• Co-primary objective: To determine the humoral immune response (neutralising antibodies) induced by the vaccine strategies.
• Secondary objectives: Evaluation and analysis of tolerance and immune response until the end of the trial.

Primary endpoint

• Primary safety endpoint: Proportion of participants with no solicited grade 3 or 4 local/systemic biological or clinical AEs, or unsolicited AEs between Day 1 and Month 3 after each administration of the investigational medicinal product (IMP)/vaccine and considered possibly related to the administration of the IMP.
• Primary immunogenicity endpoint: Neutralising antibody titres (anti-RBD) to D614G and VOCs circulating at the time of the study, up to 1 month (M1) after each dose: geometric mean of antibody titres and seroconversion rate (at least 4-fold increase in antibody titres between inclusion and month 1).