Researchers in the United States and the Netherlands conducted a preclinical study to support the initiation of Phase 3 trials to test the double-dose regimen of Janssen Ad26.COV2.S vaccine candidates in adults and the elderly.
The team has already tested the vaccine as a single-dose regimen in a phase 3 trial called ENSEMBLE, following the effect of promoting the immune response in adults and the elderly in the Phase 1 / 2a trial.
However, further administration may improve the magnitude and endurance of these immune responses, said Janssen Vaccines and Prevention BV in Leiden, Biomedical Primate Research Center in Rijswijk, Harvard Medical Center in Leiden University, and Harvard in Boston. The University Medical School team said.
Researchers now show that a second dose of the vaccine given eight weeks after the first dose significantly increased immunogenicity in both adult and aged rhesus monkeys compared to a single immunization. Shown.
“These data support the start of a double-dose Ad26.COV2.S regimen in Phase 3 clinical trials in adults and the elderly,” the team wrote.
The study also showed that the single-dose regimen produced a neutralizing antibody response that lasted at least 14 weeks, thereby supporting the team’s decision to evaluate the single-dose regimen in the current Phase 3 ENSEMBLE trial. It was.
The preprinted version of the paper bioRxiv * Servers and articles have been peer reviewed.
Competition Challenges for Developing Safe and Effective Vaccines
Since the COVID-19 pandemic began in Wuhan, China at the end of last year (2019), researchers have been safe and effective against the causative agent, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We have been working on the development of vaccines.
“Ideally, especially in pandemic situations, vaccines provide both early-onset protection and lasting protection,” Roland Zahn and colleagues write.
People of all ages are at risk of contracting SARS-CoV-2, but the risk of developing severe COVID-19 increases with age, ensuring that the vaccine provides lasting immunity to the elderly. Emphasizes the importance of.
However, among older people, the immune response to the vaccine tends to be reduced, both in size and duration, and the effectiveness of the vaccine may be reduced, the researchers say.
About Ad26.COV2.S vaccine candidates
The Ad26.COV2.S vaccine candidate encodes a viral surface structure called the SARS-CoV-2 spike protein that SARS-CoV-2 uses to bind and infect host cells.
The vaccine elicited a rapid and potent immune response after a single dose to both adults and the elderly who participated in Phase 1 / 2a clinical trials.
Based on this data, the prophylactic effect of this single-dose regimen is currently being tested in the Phase 3 ENSEMBLE trial.
However, “although the benefits of single-dose vaccines, especially for use during pandemics, are clear, multiple doses may improve the magnitude and endurance of the immune response,” Zahn et al.
Researchers are currently planning to initiate a phase II trial, ENSEMBLE 2, to evaluate the efficacy and endurance of a two-dose Ad26.COV2.S regimen in adults and the elderly. I am.
What was included in the current study?
In the current study, the team evaluated the immunogenicity of single- and double-dose Ad26.COV2.S regimens in adult and aged rhesus monkeys.
60 macaques (57 females, 3 males) were 3.3-5.0 years old (adult group) and 20 animals (all females) were 13.75-21.9 years old (old group).
SARS-CoV-2 spike-specific antibody reactions were tested every two weeks for 14 weeks after initial vaccination using enzyme-linked immunosorbent assay (ELISA) and pseudovirus neutralization assay (psVNA).
How was your research result?
In both adult and aged macaques, SARS-CoV-2 spike-specific binding and neutralizing antibody responses were detected only 2 weeks after the first vaccination and were significantly increased by 4 weeks after immunization.
The kinetics and magnitude of the response appeared to be similar between adult and aged macaques across all evaluated dosing regimens.
For single-dose regimens, the neutralizing antibody response was maintained for at least 14 weeks after immunization, showing early signs of persistent immunity induced by Ad26.COV2.S.
In addition, a second dose of the vaccine given 8 weeks after the first immunity significantly increased spike-specific binding and neutralizing antibody responses in both adult and aged macaques compared to a single dose regimen. I was allowed to.
Findings support both current and planned trials
The findings suggest that double-dose Ad26.COV2.S vaccine therapy may also elicit a stronger and more durable immune response in humans compared to single-dose regimens. I am.
“Overall, these data assess a single dose of Ad26.COV2.S in the Phase 3 ENSEMBLE trial and initiate a second Phase 3 study ENSEMBLE2 to assess the protective effect of the double dose of Ad26. The team concludes with the COV 2.S regimen, which confirms our decision.
bioRxiv Publish preliminary scientific reports that should not be considered definitive as they are not peer-reviewed, guide clinical / health-related behaviors, and should not be treated as established information.
New discoveries support current and planned clinical trials of the Janssen SARS-CoV-2 vaccine
Source link New discoveries support current and planned clinical trials of the Janssen SARS-CoV-2 vaccine