Science Translational Medicine has published the results of a Duke
University-led preclinical hamster transmission study that found
that Vaxart’s (NASDAQ: VXRT) S-only oral COVID-19 vaccine candidate
inhibited the transmission of SARS-CoV-2. The report also described
updated results from Vaxart’s Phase I clinical trial that suggest
Vaxart’s other vaccine candidate, the one targeting both the S and
N proteins, could be effective against a range of diverse
coronaviruses.
The study compared various measures of immunity and viral
shedding in hamster cohorts immunized with Vaxart’s S-only vaccine
candidate (administered orally and intranasally), an intramuscular
protein vaccine control and placebo. The vaccinated hamsters were
then infected with high doses of SARS-CoV-2 to create vaccine
breakthrough and exposed to naïve animals during the breakthrough
period. The study authors concluded that Vaxart’s S-only construct
“reduced disease and decreased airborne transmission in a hamster
model.”
The publication also reported results from the Phase I clinical
study of Vaxart’s S+N vaccine candidate showing that it stimulated
SARS-CoV-2-specific IgA antibodies in saliva and nasal samples from
human subjects and was cross-reactive to many different
coronaviruses that are more divergent than circulating variants of
SARS-CoV-2.
“The publication of these results in a highly
respected, peer-reviewed journal such as Science Translational
Medicine underscores the potential value of Vaxart’s oral COVID-19
vaccine platform in solving multiple aspects of the COVID-19
pandemic,” said Dr. Sean Tucker, Vaxart’s Chief Scientific Officer
and senior author on the publication.
The S-only data from the hamster transmission
preclinical study was initially reported last October in the
non-peer reviewed journal bioRxiv. Vaxart first reported the
potential cross-reactive properties of its S+N vaccine candidate in
May 2021. The new Science Translational Medicine publication
includes additional detail regarding IgA antibody responses in
human subjects.
Vaxart has moved to Phase II clinical trials
with the S-only vaccine candidate and expects to report those
results later this year. Vaxart has also completed and published
preliminary Phase I results from its S+N vaccine candidate. As
previously stated, the company plans to compare the S-only and S+N
vaccine candidates and to decide which approach offers the best way
forward for its COVID-19 vaccine development program, particularly
in the face of emerging variant strains.
Hamster StudyThe results from
the preclinical study conducted by Duke University, Lovelace
Biomedical and Vaxart demonstrated that Vaxart’s S-only vaccine
candidate stimulates mucosal IgA and serum IgG antibodies and can
reduce both SARS-CoV-2 infection and airborne transmission.
Decreased transmission is important for protecting unvaccinated
individuals, including the nearly 34% of Americans who are not
fully vaccinated.1
“The recent COVID-19 variant outbreaks have
shown us that vaccinated individuals who become infected with
SARS-CoV-2 can spread the virus to unvaccinated members of their
family and community, significantly contributing to public health
risk,” said Dr. Stephanie Langel, Scientist and Medical Instructor
at Duke University and first author on the publication. “A vaccine
that protects against infection and reduces transmission would
provide significant personal and public health benefits. Moreover,
an oral vaccine has the potential to address vaccine hesitancy
among individuals who are averse to injection, which could help
increase overall vaccination rates.
Phase I StudyIn the Phase I
study, subjects with at least a two-fold increase in virus-specific
IgA also showed an increase in IgA antibodies that cross-reacted
with a variety of other coronaviruses. This broad cross-reactivity
has the potential to provide enhanced protection against COVID-19
variants compared with injected vaccines that largely stimulate IgG
responses in serum. Data from the Phase I study also demonstrated
that Vaxart’s S+N vaccine candidate stimulates robust T cell
responses, particularly CD8+ T cells.
The Phase I clinical study was designed to
evaluate the safety and immunogenicity of Vaxart’s S+N oral
COVID-19 vaccine candidate in 35 subjects. Participants received a
single high dose (n=15), a single low dose (n=15) or two low doses
(n=5) of the vaccine. IgA levels in saliva and nasal samples were
assessed 29 days post-vaccination. More than half (54%) of subjects
had at least a two-fold increase in IgA antibodies in either their
saliva or nasal samples. Responses were similar for both S and N
protein as well as for the receptor-binding domain. Subjects with
at least a two-fold increase in virus-specific IgA in saliva or
nasal samples also showed an increase in cross-reactive IgA that
bound to spike proteins from the four endemic strains of
coronavirus as well as Middle East respiratory syndrome coronavirus
(MERS-CoV) and SARS-CoV-1. The observed responses did not differ
among the various doses.
Reference1 U.S. Centers for
Disease Control and Prevention. COVID-19 Vaccination in the United
States. Available at:
https://covid.cdc.gov/covid-data-tracker/#vaccinations_vacc-total-admin-rate-total
About Vaxart Vaxart is a
clinical-stage biotechnology company developing a range of oral
recombinant vaccines based on its proprietary delivery
platform. Vaxart vaccines are designed to be administered
using tablets that can be stored and shipped without refrigeration
and eliminate the risk of needle-stick
injury. Vaxart believes that its proprietary tablet
vaccine delivery platform is suitable to deliver recombinant
vaccines, positioning the company to develop oral versions of
currently marketed vaccines and to design recombinant vaccines for
new indications. Vaxart’s development programs currently include
tablet vaccines designed to protect against coronavirus, norovirus,
seasonal influenza, and respiratory syncytial virus (RSV), as well
as a therapeutic vaccine for human papillomavirus (HPV), Vaxart’s
first immune-oncology indication. Vaxart has filed broad
domestic and international patent applications covering its
proprietary technology and creations for oral vaccination using
adenovirus and TLR3 agonists.
Note Regarding Forward-Looking
Statements This press release contains
forward-looking statements that involve substantial risks and
uncertainties. All statements, other than statements of historical
facts, included in this press release
regarding Vaxart's strategy, prospects, plans and
objectives, results from preclinical and clinical trials,
commercialization agreements and licenses, and beliefs and
expectations of management are forward-looking statements. These
forward-looking statements may be accompanied by such words as
"should," "believe," "could," "potential," "will," "expected,"
“anticipate,” "plan," and other words and terms of similar meaning.
Examples of such statements include, but are not limited to,
statements relating to Vaxart's ability to develop and
commercialize its product candidates, including its vaccine booster
products; Vaxart's expectations regarding clinical
results and trial data; and Vaxart's expectations with respect
to the effectiveness of its product
candidates. Vaxart may not actually achieve the plans,
carry out the intentions, or meet the expectations or projections
disclosed in the forward-looking statements, and you should not
place undue reliance on these forward-looking statements. Actual
results or events could differ materially from the plans,
intentions, expectations, and projections disclosed in the
forward-looking statements. Various important factors could cause
actual results or events to differ materially from the
forward-looking statements that Vaxart makes, including
uncertainties inherent in research and development, including the
ability to meet anticipated clinical endpoints, commencement,
and/or completion dates for clinical trials, regulatory submission
dates, regulatory approval dates, and/or launch dates, as well as
the possibility of unfavorable new clinical data and further
analyses of existing clinical data; the risk that clinical trial
data are subject to differing interpretations and assessments by
regulatory authorities; whether regulatory authorities will be
satisfied with the design of and results from the clinical studies;
decisions by regulatory authorities impacting labeling,
manufacturing processes, and safety that could affect the
availability or commercial potential of any product candidate,
including the possibility that Vaxart's product
candidates may not be approved by the FDA or non-U.S. regulatory
authorities; that, even if approved by the FDA or
non-U.S. regulatory authorities, Vaxart's product
candidates may not achieve broad market acceptance; that
a Vaxart collaborator may not attain development and
commercial milestones; that Vaxart or its partners may
experience manufacturing issues and delays due to events within, or
outside of, Vaxart's or its partners' control;
difficulties in production, particularly in scaling up initial
production, including difficulties with production costs and
yields, quality control, including stability of the product
candidate and quality assurance testing, shortages of qualified
personnel or key raw materials, and compliance with strictly
enforced federal, state, and foreign regulations;
that Vaxart may not be able to obtain, maintain, and
enforce necessary patent and other intellectual property
protection; that Vaxart's capital resources may be
inadequate; Vaxart's ability to resolve pending legal
matters; Vaxart's ability to obtain sufficient capital to
fund its operations on terms acceptable to Vaxart, if at all;
the impact of government healthcare proposals and policies;
competitive factors; and other risks described in the "Risk
Factors" sections of Vaxart's Quarterly and Annual
Reports filed with the SEC. Vaxart does not assume
any obligation to update any forward-looking statements, except as
required by
law. Contacts Vaxart Media
Relations Mark Herr Vaxart,
Inc. mherr@vaxart.com(203)
517-8957
Investor Relations Andrew
BlazierFINN Partners IR@Vaxart.com(646)
871-8486
Vaxart (NASDAQ:VXRT)
Historical Stock Chart
From Mar 2024 to Apr 2024
Vaxart (NASDAQ:VXRT)
Historical Stock Chart
From Apr 2023 to Apr 2024