A Phase 2 Extension Study Evaluating the Immunogenicity, Safety, and Tolerability of 3 or 4 Doses of a Clostridioides difficile Vaccine in Healthy US Adults Aged 65 to 85 Years.
J Infect Dis
; 229(2): 367-375, 2024 Feb 14.
Article
em En
| MEDLINE
| ID: mdl-37531657
ABSTRACT
BACKGROUND:
This phase 2 extension explored the long-term antibody persistence of an investigational Clostridioides difficile vaccine and the safety, tolerability, and immunogenicity of dose 4 approximately 12 months post-dose 3.METHODS:
One year post-dose 3, healthy US 65- to 85-year-olds (N = 300) were randomized to dose 4 of vaccine at previously received antigen levels (100 or 200 µg) or placebo. Assessments included safety and percentages of participants achieving neutralizing antibody titers above prespecified thresholds (≥219 and ≥2586 neutralization units/mL for toxins A and B, respectively).RESULTS:
In participants previously given three 200-µg doses and placebo in the extension, toxin A and B neutralizing antibodies were above prevaccination levels 48 months post-dose 3 (36 months after placebo); 24.0% and 26.0% had toxin A and B antibodies at or above prespecified thresholds, respectively. Neutralizing antibodies increased post-dose 4 (12 months post-dose 3) and persisted to 36 months post-dose 4. Thirty days post-dose 4, all participants had toxin A and 86.5% to 100% had toxin B titers at or above prespecified thresholds. Local reactions were more frequent in vaccine recipients. Systemic and adverse event frequencies were similar across groups.CONCLUSIONS:
C difficile vaccine immune responses persisted 48 months post-dose 3. Dose 4 was immunogenic and well tolerated, supporting continued development. Clinical Trials Registration. ClinicalTrials.gov NCT02561195.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Clostridioides difficile
Tipo de estudo:
Clinical_trials
Limite:
Adult
/
Humans
Idioma:
En
Revista:
J Infect Dis
Ano de publicação:
2024
Tipo de documento:
Article