NCT07095231

Safety, Reactogenicity, and Immunogenicity Trial of STX-S SARS-CoV-2 Vaccine in Adults

A Phase 1 Dose Escalation Study to Assess the Safety, Reactogenicity, and Immunogenicity of STX-S for Prevention of SARS-CoV-2 Infection as a Booster Dose

• Status: Active Not Recruiting
• Phase: Phase 1
• Study type: Interventional
• Enrollment: 60 (actual)
• Sponsor: National Institute of Allergy and Infectious Diseases (NIAID) · NIH
• Sex: All
• Age: 18 Years – 64 Years
• Healthy volunteers: Accepted

Summary

This phase 1 clinical trial will evaluate the safety, reactogenicity, and immunogenicity of STX-S in adults who have previously received a primary series and at least one booster with an authorized or licensed SARS-CoV-2 parenteral vaccine. The study is designed as a non-randomized, open-label, dose-escalation clinical trial evaluating three dose levels of STX-S. A sample size of 60 participants (20 participants per dose cohort) is anticipated. The primary objective is to evaluate the safety and reactogenicity of a single intramuscular injection of three different dose levels (25 ng, 50 ng, and 125 ng) of STX-S in previously vaccinated healthy adults

Detailed description

This phase 1 clinical trial will evaluate the safety, reactogenicity, and immunogenicity of STX-S in adults who have previously received a primary series and at least one booster with an authorized or licensed SARS-CoV-2 parenteral vaccine. The study is designed as a non-randomized, open-label, dose-escalation clinical trial evaluating three dose levels of STX-S. A sample size of 60 participants (20 participants per dose cohort) is anticipated. The primary objective is to evaluate the safety and reactogenicity of a single intramuscular injection of three different dose levels (25 ng, 50 ng, and 125 ng) of STX-S in previously vaccinated healthy adults. The secondary objectives are to evaluate the systemic anti-Spike humoral immune responses of a single Intramuscular (IM) injection of STX-S and to evaluate nasal mucosal Immunoglobulin A (IgA) and Immunoglobulin G (IgG) responses after study product administration.

Conditions

• COVID-19

Interventions

Type	Name	Description
BIOLOGICAL	STX-S	A proprietary vaccine developed internally by Capricor utilizing exosomes that were engineered to express spike proteins on the surface

Timeline

• Start date: 2025-08-11
• Primary completion: 2026-06-15
• Completion: 2026-06-15
• First posted: 2025-07-31
• Last updated: 2026-04-14

Locations

3 sites across 1 country: United States

Regulatory

• FDA-regulated drug study