Vaxart Announces Positive Top-line Phase II Clinical Study Data Demonstrating Safety and Immunogenicity of Its Wuhan S-Only COVID-19 Pill Vaccine Candidate
September 01 2022 - 6:30AM
Vaxart, Inc. (NASDAQ: VXRT) today reported positive top-line data
from the first part of a planned two-part Phase II study of its
Wuhan S-only oral pill COVID-19 vaccine candidate, VXA-CoV2-1.1-S.
The data demonstrate that the trial met its primary safety and
secondary immunogenicity endpoints and will inform ongoing
development of new Omicron-based vaccine constructs.
Serum neutralizing antibodies rose after oral
vaccination, and the increases were particularly notable in
subjects who had previously received an mRNA vaccine. Additionally,
all subjects who had a mucosal immune response to the Wuhan-based
vaccine had mucosal immune responses that cross-reacted with the
Omicron variants, including BA 4/5, as well as other coronaviruses.
Vaxart is the first company to advance an oral pill COVID-19
vaccine to Phase II clinical development.
“These Phase II data represent a very important
milestone in the development of the world’s first COVID-19 pill
vaccine,” said Dr. James F. Cummings, Vaxart’s Chief Medical
Officer. “These data also demonstrate that a pill vaccine can
induce strong serum antibody responses as well as mucosal and T
cell responses. Unfortunately, for the past two years the emergence
of new variants has outpaced the ability to update the currently
approved injectable vaccines. We believe that activating multiple
mechanisms of the immune system that can address emerging variants
may help the global community get ahead of the immunologic curve of
protection. It could transform how we fight this and future
pandemics.”
"The results reported today clearly indicate
that the S-only construct improved antibody responses compared with
the data we previously generated for the S+N construct
(VXA-CoV2-1), and also boosted immune responses in subjects who
previously received an mRNA vaccine. These are the critical data we
sought when this trial was initiated in October 2021,” said Dr.
Sean Tucker, Vaxart's Founder and Chief Scientific Officer.
“Additionally, the observed increase in mucosal IgA is very
encouraging, and we believe that the positive findings for multiple
immunologic responses may ultimately translate to enhanced
protection against infection with, and/or transmission of,
SARS-CoV-2.”
Study Key Findings
- The VXA-CoV2-1.1-S vaccine
construct was safe and well-tolerated. No vaccine-related solicited
grade 3 adverse events (AEs) and no vaccine-related serious adverse
events (SAEs) were reported.
- Vaccination with VXA-CoV2-1.1-S
increased levels of SARS-CoV-2-specific serum IgG and IgA
antibodies at Days 29 and 57.
- The geometric mean titer (GMT)
increase of SARS-CoV-2-specific serum neutralizing antibodies from
Day 1 to Day 57 ranged by cohort between 1.2- and 2-fold, with
higher increases for higher doses.
- Among 18-55 year-old subjects
previously vaccinated with mRNA vaccines, the geometric mean titer
(GMT) of SARS-CoV-2-specific serum neutralizing antibodies
increased 1.6-fold, from 481 AU/ml at Day 1 to 778 AU/ml at Day 57.
The subjects who had lower starting titers showed greater increases
after oral boosting.
- Approximately 50% of all subjects,
as well as 50% of subjects that previously received an mRNA
vaccine, had at least a 1.5-fold increase in mucosal IgA
antibodies.
- All subjects who had a mucosal
response to Wuhan S from VXA-CoV2-1.1-S (a Wuhan-based vaccine)
also had mucosal immune responses that cross-reacted with the
Omicron variants, including BA 4/5, as well as other coronaviruses.
This includes subjects that had previously received an mRNA-based
vaccine.
- SARS-CoV-2-specific T cell
responses were observed in the majority of subjects after the
second dose of VXA-CoV2-1.1-S.
“These very exciting data support the great
potential of our platform,” said Andrei Floroiu, Vaxart’s Chief
Executive Officer. “We are now a step closer to the day when we
could get vaccinated against COVID-19 with an oral pill vaccine
that offers broad protection against current and future variants by
harnessing multiple immune system mechanisms. I believe this is
what transformative innovation looks like. We will continue
working toward the promise of vaccinating more people around the
world, faster, with more protective vaccines, with just a pill and
a glass of water."
Clinical Trial Next StepsAs
previously announced, Vaxart is evaluating new Omicron-based
constructs as Omicron-only monovalent vaccine candidates and as
bivalent candidates in combination with the Company’s Wuhan
constructs. Vaxart will also compare the clinical results of its
S-only and S+N constructs to determine the best path forward in
developing a vaccine that can hinder viral infection and
transmission for current and emerging variants. These constructs
are expected to be evaluated in preclinical models this year and to
advance to clinical trials in the first half of 2023. The Company
expects to move forward with the best possible vaccine constructs
for its planned COVID-19 Omicron challenge in the second half of
2023 with hVIVO, as well as larger trials in the U.S. and
internationally.
Clinical Study DesignPart 1 of
the open-label, Phase II study enrolled 66 healthy adult
volunteers, including subjects who had or had not received prior
mRNA COVID-19 vaccination, ages 18-55 years and 56-75 years.
Subjects were randomized into six cohorts stratified by age,
vaccination history and dose. Subjects received either a high or a
low dose of VXA-CoV2-1.1-S on Day 1 and Day 29, and immune
responses were assessed prior to vaccine administration on Day 1,
Day 29 and on Day 57.
Conference Call
InformationThe Vaxart senior management team
will host a conference call today, beginning at 8:30 a.m.
ET.
The conference call can be accessed using the
following information:Webcast: Click hereDate: Thursday,
September 1, 2022 – 8:30 a.m. ETDomestic:
877-407-0832International: 201-689-8433Conference ID: 13732510
Investors may submit written questions in
advance of the conference call to ir@vaxart.com. A replay of
the webcast will be available on the Company’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 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
StatementsThis 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.
Please also refer to the 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: |
Investor
Relations: |
Mark Herr |
Andrew Blazier |
Vaxart, Inc. |
Finn Partners |
mherr@vaxart.com |
IR@Vaxart.com |
(203) 517-8957 |
(646) 871-8486 |
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