Vaxart, Inc. (Nasdaq: VXRT) today announced top-line data from the
Phase 2 challenge study of its oral tablet monovalent norovirus
vaccine candidate (NCT05212168).
The Phase 2 challenge study enrolled 165 healthy
adults, who were randomized 1:1 to receive Vaxart’s monovalent oral
tablet vaccine targeting the norovirus GI.1 genotype or placebo.
Four weeks after vaccination, subjects were challenged with GI.1
norovirus. The study achieved its primary endpoints of a
statistically significant 29% reduction in the rate of norovirus
infection between the vaccinated and placebo arms through Day 8
post challenge, a strong induction of norovirus-specific
immunoglobulin A (IgA) and immunoglobulin G (IgG) antibodies, and
other immune response endpoints. Vaccination also led to a
reduction in norovirus AGE in the vaccine arm compared to placebo,
but this was not statistically significant. In a prespecified
analysis, the study also showed an 85% decrease in viral shedding
in the vaccine arm compared with placebo.
“Challenge studies use higher quantities of
virus than an individual may encounter during a naturally occurring
infection, yet our vaccine candidate demonstrated a significant
effect on infection and viral shedding, even though it did not
achieve a statistically significant reduction in norovirus AGE,”
said Dr. James F. Cummings, Vaxart’s Chief Medical Officer. “The
magnitude of the reduction in shedding could have an impact on
transmission and may have important public health benefits, as
norovirus spreads rapidly among people gathering in large numbers,
including settings such as daycare centers, nursing homes, and
workplaces, and may reduce the potential spread of the infection to
families at home.”
Key Study Findings:
- Primary Endpoints:
- 29% reduction in the rate of
infection in the vaccinated cohort compared with placebo (82% vs.
58%) (p=0.003)
- 21% reduction in the rate of
norovirus AGE in the vaccinated cohort compared with placebo (45%
vs. 57%) that was not statistically significant (p=0.149)
- Significant increase in the
induction of norovirus-specific IgA antibody-secreting cells (ASC)
in the vaccinated cohort, with a 79% response rate in the
vaccinated cohort, compared with 2.5% in the placebo cohort
(p<0.001) on Day 8 post-vaccination; mean response was 375 ASC
per million cells for the vaccinated cohort, compared with 26 ASC
per million cells for placebo
- Significant increase in the
induction of HBGA blocking anti-bodies in the vaccinated cohort
(GMFR 3.23) compared with the placebo cohort (GMFR 1.0) on Day 29
post-vaccination (p<0.001)
- Significant increases in
norovirus-specific serum IgA (GMFR 7.14) and IgG (GMFR 4.64) in the
vaccinated cohort compared with placebo from baseline to Day 29
post-vaccination (p<0.001)
- No vaccine-related SAEs or
dose-limiting toxicities were reported, consistent with the safety
profile observed in all of Vaxart’s norovirus trials
- Pre-specified
Analysis:
- 85% decrease in viral shedding in
the vaccinated cohort compared with placebo
- No statistically significant
difference in disease severity in the vaccinated cohort compared
with placebo
“The results of this study highlight the
potentially distinctive profile of mucosal vaccination and the
potential that our oral pill vaccines may have in protecting
against infection and blocking transmission – potential benefits
that have also been seen with our influenza vaccine. We are excited
to further our understanding of these data and determine the
optimal path forward for our norovirus program,” added Dr.
Cummings.
Norovirus is the leading cause of acute viral
gastroenteritis in all age groups in the U.S. However, there are no
approved vaccines for noroviruses. In the U.S. alone, the annual
disease burden from norovirus is $10.6 billion, as on average
norovirus causes 19 to 21 million cases of AGE, infects 15% of all
children under the age of 5, and leads to 465,000 emergency
department visits, 109,000 hospitalizations and 900 deaths.
Next StepsVaxart believes the
reduction in the rate of infection and increases in multiple
immunologic endpoints in this challenge study support the potential
for its norovirus vaccine program to provide significant public
health benefit. The Company also believes that the numeric
reduction in rate of AGE, while not statistically significant, is
encouraging, especially given the high dose of challenge virus used
in the study, compared with what would occur in a natural
infection.
Vaxart is currently conducting additional
analyses of the data from this challenge study and its prior
norovirus trials with the objectives of defining the timing of a
larger phase 2b study, and identifying ways to reduce the size and
duration of a subsequent Phase 3 registration study.
Conference CallThe Vaxart
senior management team will host a conference call to discuss the
data, beginning at 5:00 p.m. ET today.
The conference call can be accessed using the
following information:
Webcast: Click hereDate: Wednesday, September 6,
2023 – 5:00 p.m. ETDomestic: 877-407-6184International:
201-389-0877Conference ID: 13740946
A replay of the webcast will be available for 30
days on Vaxart’s website at www.vaxart.com following the conclusion
of the event.
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 pills that
can be stored and shipped without refrigeration and eliminate the
risk of needle-stick injury. Vaxart believes that its proprietary
pill 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
pill vaccines designed to protect against norovirus, coronavirus,
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 and
the timing of such results, 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 the timing of
receiving and reporting such 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 HerrVaxart, Inc.mherr@vaxart.com(203)
517-8957 Investor
Relations: Andrew Blazier FINN
Partners IR@vaxart.com(646) 871-8486
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