2888. Safety and Immunogenicity of an Adjuvanted Chikungunya Virus (CHIKV) Virus-like Particle (VLP) Based Vaccine in Two Pivotal Phase 3 Trials, ≥12 Years of Age
Bibliographic record
Abstract
Abstract Background CHIKV remains a significant public health concern globally. We report the results of two phase 3 trials evaluating an aluminum hydroxide adjuvanted CHIKV VLP vaccine. Methods Two multicenter, randomized, double-blind, placebo-controlled, parallel-group trials were conducted: an adult/adolescent trial (NCT05072080) in ages 12-64 years and an older adult trial in ages ≥ 65 years (NCT05349617). Participants received CHIKV VLP vaccine or placebo as a single intramuscular dose. Immunogenicity objectives assessed anti-CHIKV NT80 serum neutralizing antibody (SNA) titers at selected timepoints. Seroresponse rate (SRR) was the percentage of participants who achieved NT80 SNA titer ≥ 100 (FDA/EMA agreed threshold). Safety outcomes were evaluated through monitoring adverse events (AEs) through Day 183. Study overview. Results Adult/adolescent trial: 3254 participants (2790 CHIKV VLP vaccine, 464 placebo) were enrolled. Primary endpoints were met with a Day 22 SRR of 98% (2503/2559) for vaccine and 1% for placebo (5/424; p< 0.0001), as well as lot consistency, and superiority to placebo in geometric mean titer (GMT). A rapid antibody response was observed in the CHIKV VLP vaccine group with Day 8 SRR=47% (1169/2510) and Day 15 SRR=97% (2355/2434); responses were durable through Day 183 with SRR=86% (1967/2301). Older adult trial: 413 participants (206 CHIKV VLP vaccine, 207 placebo) were enrolled. Primary endpoints were met with a Day 22 SRR of 87% (167/191) for vaccine and 1% for placebo (2/183; p< 0.0001), as well as by GMT. At Day 15 a rapid antibody response was observed in the CHIKV VLP vaccine group with SRR=82% (150/182). CHIKV VLP vaccine demonstrated a favorable safety profile, and most AEs were mild to moderate in severity. The most common AEs were myalgia, fatigue, and headache. Conclusion CHIKV VLP vaccine is the only VLP-based vaccine in clinical development for active immunization against CHIKV disease. Results demonstrate that CHIKV VLP vaccine induces a rapid and robust immune response in most people by Day 15 and through Day 183. These findings support the potential of this VLP-based vaccine to help protect individuals 12 years and older from CHIKV. Disclosures Jason S. Richardson, PhD, Bavarian Nordic Canada Inc: Stocks/Bonds Debbie Anderson, MS, Bavarian Nordic: Employee|Emergent BioSolutions: Stocks/Bonds Sufia Muhammad, MD, Bavarian Nordic: Employee|Emergent BioSolutions: Stocks/Bonds Lauren Tindale, PhD, Bavarian Nordic: Employee Tobi Loreth, n/a, Emergent BioSolutions: Stocks/Bonds Sarah Royalty Tredo, MBA, Emergent Biosolutions: Employee|Emergent Biosolutions: Stocks/Bonds Victoria Jenkins, PhD, Bavarian Nordic: Employee Patrick Ajiboye, MD, Bavarian Nordic: Employee|Emergent BioSolutions: Stocks/Bonds Lisa Bedell, Director Biostatistic, Bavarian-Nordic: Advisor/Consultant|Emergent BioSolutions: Employee|Emergent BioSolutions: Stocks/Bonds
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".