NCT05997264

Anthrax AV7909 Boost Evaluation Study

A Randomized, Double-blinded, Multicenter Study in Healthy Adults to Evaluate Safety and Immunogenicity of AV7909 Administered at Two Dose Levels on Two Vaccination Schedules, Including a Primary Series and Booster Doses

• Status: Active Not Recruiting
• Phase: Phase 2
• Study type: Interventional
• Enrollment: 220 (actual)
• Sponsor: Biomedical Advanced Research and Development Authority · Federal
• Sex: All
• Age: 18 Years – 65 Years
• Healthy volunteers: Accepted

Summary

This randomized, phase 2, double-blinded, multicenter study is designed to assess the safety and immune response kinetics of CYFENDUS™ (henceforth AV7909) administered on 2 primary series vaccination schedules followed by 6- and 12-month boosters.

Detailed description

This trial is a randomized, double-blinded, multicenter study designed to evaluate safety and immune response kinetics of full and half doses of AV7909 administered on 2 primary series vaccination schedules followed by 6- and 12-month boosters. Healthy adult male and female subjects aged 18 through 65 years, inclusive, will be screened for baseline health status to ensure trial eligibility. Subjects meeting all the inclusion and none of the exclusion criteria will be randomized to receive either half or full doses of AV7909 on 1 of 2 vaccination schedules. Randomization will be stratified by sex. Subjects will be randomized 1:1:1:1 within stratum across 4 treatment groups (approximately 55 subjects per group). Subjects will receive a total of 5 intramuscular (IM) injections. Primary series investigational product (IP) doses will be administered on Days 1, 15, and 29, and booster IP doses will be administered on Days 181 and 366. On each IP administration day, each subject will receive an IM injection of full-dose AV7909 (0.5 mL), half-dose AV7909 (0.25 mL), or placebo (0.5 mL or 0.25 mL sodium chloride for injection), based on their assigned treatment group. Update: The 2 treatment groups (Study Groups 1 and 2) in which subjects are to receive full doses of AV7909 were closed to enrollment on 13 May 2024 to preserve resources for the groups that BARDA considers the highest priority and reflects no concerns due to a safety signal or request of the Data Safety Monitoring Board (DSMB). Subjects randomized prior to this date will continue in the study in their assigned treatment group as described in the protocol. Subjects randomized on or after 13 May 2024 will be randomized 1:1 within stratum across the 2 remaining treatment groups (Study Groups 3 and 4), and on each IP administration day will receive an IM injection of half-dose AV7909 (0.25 mL) or placebo (0.25 mL sodium chloride for injection), based on their assigned treatment group. There are no other changes to the study protocol. Safety assessments will be based on solicited adverse events (AEs; local and systemic reactogenicity symptoms) with onset within 7 days after each IP administration; unsolicited treatment-emergent adverse events (TEAEs) with onset within 30 days after each IP administration; and treatment-emergent serious adverse events (SAEs), potentially immune-mediated medical conditions (PIMMCs), and medically attended adverse events (MAAEs) occurring during study participation (ie, up to 1 year after the last IP administration). For this study, a PIMMC is considered to be unexpected and will be treated as a serious and unexpected suspected adverse reaction (SUSAR) per 21 CFR 312.32. Immunogenicity assessments will include geometric mean titer (GMT), seroprotection rate, and seroconversion rate by toxin-neutralizing antibody (TNA) 50% neutralization factor (NF50) and enzyme-linked immunosorbent assay (ELISA) anti-protective antigen (PA) Immunoglobulin G (IgG).

Conditions

• Anthrax

Interventions

Type	Name	Description
BIOLOGICAL	AV7909 Full Dose (0.5 mL)	AV7909 Anthrax Vaccine is being developed by Emergent Product Development Gaithersburg Inc. (Emergent) for post-exposure prophylaxis (PEP) of disease in persons 18 through 65 years of age following suspected or confirmed B. anthracis exposure when administered in conjunction with the recommended antibacterial regimen. AV7909 is a combination product containing BioThrax and CPG 7909, a synthetic immunostimulatory oligodeoxynucleotide that has been shown to be a potent vaccine adjuvant. CPG 7909 is a Toll-like receptor 9 agonist designed to induce both an enhanced antigen-specific antibody response and a natural killer T-cell immune response when used in combination with prophylactic (preventative) or therapeutic vaccines.
BIOLOGICAL	AV7909 Half Dose (0.25 mL)	AV7909 Anthrax Vaccine is being developed by Emergent Product Development Gaithersburg Inc. (Emergent) for PEP of disease in persons 18 through 65 years of age following suspected or confirmed B. anthracis exposure when administered in conjunction with the recommended antibacterial regimen. AV7909 is a combination product containing BioThrax and CPG 7909, a synthetic immunostimulatory oligodeoxynucleotide that has been shown to be a potent vaccine adjuvant. CPG 7909 is a Toll-like receptor 9 agonist designed to induce both an enhanced antigen-specific antibody response and a natural killer T-cell immune response when used in combination with prophylactic (preventative) or therapeutic vaccines.
BIOLOGICAL	Placebo: Sodium Chloride Injection, USP 0.9% (0.5 mL)	Sodium chloride 9 mg water for injection Quantum satis (q.s.). It contains no bacteriostat, antimicrobial agent, or added buffer. The solution may contain hydrochloric acid and/or sodium hydroxide for pH adjustment (pH 4.5-7.0).
BIOLOGICAL	Placebo: Sodium Chloride Injection, USP 0.9% (0.25 mL)	Sodium chloride 9 mg water for injection Quantum satis (q.s.). It contains no bacteriostat, antimicrobial agent, or added buffer. The solution may contain hydrochloric acid and/or sodium hydroxide for pH adjustment (pH 4.5-7.0).

Timeline

• Start date: 2023-12-05
• Primary completion: 2025-08-28
• Completion: 2026-08-01
• First posted: 2023-08-18
• Last updated: 2026-02-24

Locations

7 sites across 1 country: United States

Regulatory

• FDA-regulated drug study