Immunogenicity and safety of a quadrivalent plant-derived virus like particle influenza vaccine candidate-Two randomized Phase II clinical trials in 18 to 49 and ?50 years old adults.
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ABSTRACT: BACKGROUND:New influenza vaccines eliciting more effective protection are needed, particularly for the elderly who paid a large and disproportional toll of hospitalization and dead during seasonal influenza epidemics. Low (?15 ?g/strain) doses of a new plant-derived virus-like-particle (VLP) vaccine candidate have been shown to induce humoral and cellular responses against both homologous and heterologous strains in healthy adults 18-64 years of age. The two clinical trials reported here addressed the safety and immunogenicity of higher doses (?15 ?g/strain) of quadrivalent VLP candidate vaccine on 18-49 years old and ?50 years old subjects. We also investigated the impact of alum on the immunogenicity induced by lower doses of the vaccine candidate. METHOD:In the first Phase II trial reported here (NCT02233816), 18-49 year old subjects received 15, 30 or 60 ?g/strain of a hemagglutinin-bearing quadrivalent virus-like particle (QVLP) vaccine or placebo. In the second trial (NCT02236052), ?50 years old subjects received QVLP as above or placebo with additional groups receiving 7.5 or 15 ?g/strain with alum. Along with safety recording, the humoral and cell-mediated immune responses were analyzed. RESULTS:Local and systemic side-effects were similar to those reported previously. The QVLP vaccine induced significant homologous and heterologous antibody responses at the two higher doses, the addition of alum having little-to-no effect. Serologic outcomes tended to be lower in ?50 years old subjects previously vaccinated. The candidate vaccine also consistently elicited both homologous and heterologous antigen-specific CD4+ T cells characterized by their production of interferon-gamma (IFN-?), interleukine-2 (IL-2) and/or tumor-necrosis factor alpha (TNF-?) upon ex vivo antigenic restimulation. CONCLUSION:Overall, the 30 ?g dose produced the most consistent humoral and cellular responses in both 18-49 and ?50 years old subjects, strongly supporting the clinical development of this candidate vaccine. That particular dose was chosen to test in the ongoing Phase III clinical trial.
SUBMITTER: Pillet S
PROVIDER: S-EPMC6550445 | biostudies-literature | 2019
REPOSITORIES: biostudies-literature
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