1955. Immunogenicity And Safety of a Virus-Like Particle (VLP) Protein Subunit SARS-CoV-2 Vaccine in Adults: a Phase 1/2 Study

Abstract Background COVID-19 continues to cause substantial morbidity and mortality globally. It is likely that booster vaccinations will be needed in future years protect older adults those with chronic medical conditions. We present interim topline results of a phase 1/2 study IVX-411 [ACTRN12621000738820.; ACTRN12621000882820], an investigational VLP protein subunit SARS-CoV-2 vaccine, aged 18–69 (Figure 1). Methods In Part 1, 84 SARS-CoV-2-naïve were randomized receive two doses on Days 0 28 either (5, 25, or 125µg) ± adjuvant, placebo 2a). 2, subjects received single dose adjuvant 3–6 months after completion primary licensed vaccine regimen 2b). Solicited adverse events (AEs) collected for 7 days each dose, immunogenicity assessed 0, 28, 49 [(Part 1) (Part 2). Primary outcomes both parts solicited unsolicited AEs, neutralizing antibody titers, spike protein-specific IgG titers. Results Demographics similar the groups vs placebo. 1 local reactogenicity was mild-to-moderate, higher rates AEs increasing addition 3a). Rates systemic across 3b). No vaccine-related severe serious noted. immunogenic vaccination: subjects, limited effect seen, significantly titers receiving adjuvanted (p< 0.01; Figure 4a). The magnitude responses to, below, Human Convalescent Sera levels. previously vaccinated boosted baseline no conclusive 4b). Immunogenicity observed all variants concern (beta, delta, omicron) parts, up 7- fold rises from 5). Conclusion met safety objectives, acceptable tolerability profiles vaccination. A clear subjects. Disclosures All Authors: reported disclosures.