NCT07019883

A Study to Evaluate the Safety and Immunogenicity of Two Doses of a Novel H5 Central Antigen mRNA-LNP in Healthy Adults

A Phase 1 Study to Evaluate the Safety and Immunogenicity of Two Doses of a Novel H5 Antigenically Central (AC)-Anhui mRNA-LNP Vaccine in Healthy Adults

• Status: Active Not Recruiting
• Phase: Phase 1
• Study type: Interventional
• Enrollment: 80 (actual)
• Sponsor: National Institute of Allergy and Infectious Diseases (NIAID) · NIH
• Sex: All
• Age: 18 Years – 49 Years
• Healthy volunteers: Accepted

Summary

This is a phase 1, multicenter, randomized, double-blind trial of two influenza A/H5 mRNA-based vaccines on healthy adult participants, 18-49 years of age. Stage 1 will serve as the open-label, dose finding stage. The first 10 participants will receive 12.5 mcg of H5 AC-Anhui RNA vaccine (Group 1), and the second 10 participants will receive 25 mcg of H5 AC-Anhui RNA vaccine (Group 2). After Protocol Safety Review Team (PSRT) review of reactogenicity and safety data through Day 8 for both Groups 1 and 2, another 10 participants may be enrolled to receive 50 mcg of H5 AC-Anhui RNA vaccine (Group 3). Safety data from 7 days after dose 2 for Groups 1 and 2 participants will be reviewed by the PSRT prior to clearing Group 3 participants for the second dose of vaccine. Individual participants will be followed for approximately 6 months following the second dose of vaccine. The primary objective is to assess the safety of two doses of H5 AC-Anhui RNA vaccine or H5-Astrakhan RNA vaccine administered intramuscularly in healthy adults (18-49 years). Once the Day 36 data from Group 3 are reviewed by the PSRT, a dose will be chosen (12.5 mcg, 25 mcg, or 50 mcg) for advancement to Stage 2 where 50 participants will be randomized 1:1 to receive either H5 AC-Anhui RNA (Group 4) or H5 Astrakhan RNA (Group 5) in a double-blinded manner.

Detailed description

This is a multicenter, randomized, double-blind trial of two influenza A/H5 mRNA-based vaccines. The trial population consists of healthy adult participants, 18-49 years of age. Stage 1 will serve as the open-label, dose finding stage. The first 10 participants will receive 12.5 mcg of H5 AC-Anhui RNA vaccine (Group 1), and the second 10 participants will receive 25 mcg of H5 AC-Anhui RNA vaccine (Group 2). These groups will be enrolled sequentially without pause unless study halting rules are triggered. After Protocol Safety Review Team (PSRT) review of reactogenicity and safety data through Day 8 for both Groups 1 and 2, another 10 participants may be enrolled to receive 50 mcg of H5 AC-Anhui RNA vaccine (Group 3). Safety data from Day 36 (7 days after dose 2) for Groups 1 and 2 participants will be reviewed by the PSRT prior to clearing Group 3 participants for the second dose of vaccine. Once the Day 36 data from Group 3 are reviewed by the PSRT, a dose will be chosen (12.5 mcg, 25 mcg, or 50 mcg) for advancement to Stage 2 where 50 participants will be randomized 1:1 to receive either H5 AC-Anhui RNA (Group 4) or H5 Astrakhan RNA (Group 5) in a double-blinded manner. Participants will be randomized on the day of enrollment. Screening and enrollment can occur on the same day. Individual participants will be followed for approximately 6 months following the second dose of vaccine. The primary objective is to assess the safety of two doses of H5 AC-Anhui RNA vaccine or H5-Astrakhan RNA vaccine administered intramuscularly in healthy adults (18-49 years). The secondary objective is to assess the serum antibody responses to H5 AC-Anhui RNA vaccine or H5-Astrakhan RNA vaccine.

Conditions

• Avian Influenza

Interventions

Type	Name	Description
BIOLOGICAL	H5 AC-Anhui RNA Vaccine	A nucleoside-modified mRNA vaccine encoding a stabilized, antigenically central hemagglutinin (HA) from influenza A(H5), based on A/Anhui/1/2005 (clade 2.3.4) with substitutions 222QL, 224GS, 156TA, and 134TA. The 2119-nt mRNA is encapsulated in lipid nanoparticles (LNPs) for intramuscular delivery.
BIOLOGICAL	H5 Astrakhan RNA Vaccine	The vaccine product consists of a monovalent nucleoside-modified mRNA that encodes a traditionally selected avian influenza HA. The H5 Astrakhan RNA encodes the HA from the clade 2.3.4.4b A/Astrakhan/3212/2020 virus.
OTHER	Sodium Chloride, 0.9%	0.9% Sodium Chloride Injection

Timeline

• Start date: 2025-06-12
• Primary completion: 2026-05-15
• Completion: 2026-05-15
• First posted: 2025-06-13
• Last updated: 2026-01-30

Locations

3 sites across 1 country: United States

Regulatory

• FDA-regulated drug study