A Safety, Reactogenicity and Immunogenicity Trial of RVX-sCPD9 Booster Intranasal COVID-19 Vaccine

This Phase 1 clinical trial will evaluate the safety, reactogenicity, and immunogenicity of RVX-sCPD9 administered as an intranasal (IN) booster in previously vaccinated healthy adults. The study is designed as a non-randomized, open-label, dose-escalation trial assessing four dose levels of RVX-sCPD9 (10\^2, 10\^3, 10\^4, and 5 × 10\^4 FFU) delivered intranasally. A total of 80 participants will be enrolled, with 20 participants in each cohort. Eligibility will be determined at screening and confirmed again on Day 1 prior to study product administration. Participants will be healthy adults aged 18 to 64 years, regardless of prior SARS-CoV-2 infection status, who have completed a primary COVID-19 vaccination series and received at least one booster dose, with the most recent vaccination administered at least 16 weeks prior to study vaccination. Each participant will receive a single dose of RVX-sCPD9 administered intranasally using a nasal atomization device, delivering 0.25 mL per nostril. Three sentinel participants under 50 years of age will be enrolled initially, followed by enrollment of the remaining participants. The total study duration is approximately 1.5 years, with each participant involved for up to 7 months. The primary objective is to evaluate the safety and reactogenicity of a single intranasal administration of 4 ascending dose levels of RVX-sCPD9 in previously vaccinated healthy adults. Secondary objectives include include evaluating systemic anti-Spike humoral immune responses and evaluating nasal mucosal Immunoglobulin A (IgA) and Immunoglobulin G (IgG) responses after intranasal administration of RVX-sCPD9.