ASTRAZENECA and OXFORD COVID-19 (SARS-Cov-2) - 2020

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AstraZeneca, Oxford University and AZD122
(ChAd0X1) Adenovirus Ad26 vector-based vaccine
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Study Single-shot Ad26 vaccine protects against
SARS-CoV-2 in rhesus macaques Published online
30 July 2020 - Nature
The optimal Ad26 vector-based vaccine for
SARS-CoV-2, termed Ad26.COV2.S, is currently
being evaluated in clinical trials.
Fifty-two rhesus macaques were immunized with
Ad26 vectors encoding S variants or sham control,
without adjuvant at week 0. and were challenged
with SARS-CoV-2 by the intranasal and
intratracheal routes (of those, S.dTM.PP (N6),
S.PP (N6), which have Furin cleavage site
mutations
Median Nab (Neutralising antibodies) titers in
the Ad26-S.PP vaccinated macaques were 4-fold
higher than median Nab titers in previously
reported cohorts of 9 convalescent macaques 9
and 27 convalescent humans following recovery
from SARS-CoV-2 infection 10
The Ad26-S.PP vaccine also induced detectable
S-specific IgG and IgA responses in
bronchoalveolar lavage (BAL)
Analysis of a cohort of 10 similarly immunized
animals demonstrated that a single immunization
of 1011 vp Ad26-S.PP elicited consistent IFN-?
ELISPOT responses but minimal to no IL-4 ELISPOT
responses, suggesting induction of Th1-biased
responses.
At week 6, all animals were challenged with
1.0x105 TCID50 (Tissue Culture Infectious Dose)
SARS-CoV-2 (which was derived from USA-WA1/2020
(NR-52281 BEI Resources 9) by the intranasal
(IN) and intratracheal (IT) routes. Ad26 vectors
were constructed with seven variants of the
SARS-CoV-2 spike (S) protein sequence
(Wuhan/WIV04/2019 Genbank MN996528.1).
The S.PP immunogen contains the wild-type leader
sequence, the full-length membrane-bound S,
mutation of the furin cleavage site, and two
proline stabilizing mutations 15.
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Whereas inactivated virus vaccines and nucleic
acid vaccines typically require two or more
immunizations, certain adenovirus vectors can
induce robust and durable NAb responses after a
single immunization 2224. However, we would
expect that a two-dose vaccine with Ad26-S.PP
would be more immunogenic... both single-dose and
two-dose regimens of the Ad26-S.PP vaccine should
be evaluated in clinical trials
These data suggest that serum NAb titers may be a
potential biomarker for vaccine protection,
although this will need to be confirmed in
additional SARS-CoV-2 vaccine efficacy studies in
both nonhuman primates and humans.
The role of T cell responses in vaccine
protection remains to be determined.
Our studies also were not specifically designed
to assess safety or the possibility of
vaccine-associated enhanced respiratory disease
or antibody-dependent enhancement (ADE) of
infection 29
However, it is worth noting that the Ad26-S.PP
vaccine elicited Th1-biased rather than
Th2-biased T cell responses, and animals with
sub-protective NAb titers did not demonstrate
enhanced viral replication or clinical disease
It is likely that protection in both the upper
and lower respiratory tracts will be required to
prevent transmission and disease in humans. The
identification of a Nab correlate of protection
should prove useful in the clinical development
of SARS-CoV-2 vaccines. The optimal Ad26-S.PP
vaccine from this study, termed Ad26.COV2.S, is
currently being evaluated in clinical trials.
Western blot - 24 well plates were seeded with
MRC-5 cells (1.25x105 cells/well), and after
overnight growth they were transduced with Ad26
vectors encoding SARS-CoV-2 Spike transgenes.
CR3046 is a human monoclonal antibody directed
against SARS-CoV Spike and binds to the Spike S2
domain and also cross-reacts with SARS-CoV-2
Spike S2 (unpublished data).
Plaque-forming unit (PFU) assay For plaque
assays, confluent monolayers of Vero E6 cells
were prepared in 6-well plates.
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Pseudovirus neutralization assay - The SARS-CoV-2
pseudoviruses expressing a luciferase reporter
gene were generated in an approach similar to as
described previously 9,10,16. Briefly, the
packaging construct psPAX2 (AIDS Resource and
Reagent Program), luciferase reporter plasmid
pLenti-CMV Puro-Luc (Addgene), and spike protein
expressing pcDNA3.1-SARS-CoV-2 S?CT were
co-transfected into HEK293T cells with calcium
phosphate. The supernatants containing the
pseudotype viruses were collected 48 h
post-transfection
To determine the neutralization activity of the
antisera from vaccinated animals, HEK293T-hACE2
cells were seeded in 96-well tissue culture
plates at a density of 1.75 x 104 cells/well
overnight.
Live virus neutralization assay - A full-length
SARS-CoV-2 virus based on the Seattle Washington
isolate was designed to express nanoluciferase
(nLuc) and GFP and was recovered via reverse
genetics and described previously 17,18.
luciferase activity was measured via Nano-Glo
Luciferase Assay System (Promega)
IFN-? enzyme-linked immunospot (ELISPOT) assay
ELISPOT plates were coated with mouse anti-human
IFN-? monoclonal antibody from BD Pharmingen at a
concentration of 5 µg/well overnight at 4 C.
The plates were washed with coulter buffer and
incubated for 2 h with Rabbit polyclonal
anti-human IFN-? Biotin from U-Cytech (1 µg/mL).
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COVID-19 (SARS-Cov-2) FRONT RUNNERS
University of Oxford, AstraZeneca and partners
AZD1222 (formerly ChadOx1 nCoV-19)
Phase III D8110C00001 trial (NCT04516746)
Adenovirus Type 26 (Ad26)
1AstraZeneca acknowledged September 8 that it
paused (but has not disclosed specifics on the
adverse reaction and when it took place) the
up-to-30,000 patient Phase III trial of AZD1222
to investigate a potentially unexplained
illness involving a participant from the U.K.
 UK health secretary Matt Hancock said 30
million doses already contracted with AstraZeneca
On September 7, Australias federal government
has reached agreement with Melbourne-based CSL to
manufacture a total 84.8 million doses of AZD1222
and V451, a vaccine developed by CSL with the
University of Queensland
Albany Molecular Research, Inc. (AMRI) to provide
sterile fill/finish of AZD1222 through 2021 at
AMRIs drug product manufacturing facility in
Albuquerque, NM, under a supply agreement
announced September 3 by AMRI
September 1, AstraZeneca agreed to pay Oxford
Biomedica a 15 million (20.1 million) upfront
capacity reservation fee under an 18-month supply
agreement announced by Oxford Biomedica (Oxbox
commercial manufacturing center in Oxford, U.K),
part of a three-year Master Supply and
Development Agreement with AstraZeneca for
large-scale commercial manufacture of AZD1222.
Oxford Biomedicas partnership established in
June with the UKs Vaccine Manufacturing
Innovation Centre (VMIC). AZD1222 has been
developed by the Universitys Jenner Institute.
U.K. Health Secretary Matt Hancock pledged 20
million (25 million) in government funding to
support development of the vaccine.
1 https//www.genengnews.com/covid-19-candidates/u
niversity-of-oxford-and-partners/
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Unlike CanSino, Moderna and Pfizer, AstraZeneca
and Oxford University only tested one high-dosage
formulation of the vaccine, providing less data
on the optimal relation of antibody response
induction to acceptable side effects, Philipp
Rosenbaum, PhD, Senior Infectious Diseases
Analyst and Breen, PhD, Director of Infectious
Diseases at GlobalData, stated.
In the context of a pandemic wave where a single
higher, but more reactogenic, dose might be more
likely to rapidly induce protective immunity, the
use of prophylactic paracetamol appears to
increase tolerability and would reduce confusion
with COVID-19 symptoms that might be caused by
short-lived vaccine-related symptoms without
compromising immunogenicity, the researchers
explained
1 Another 22.5 million is to fund Phase II
testing of a coronavirus vaccine in development
by Imperial College London, which is projected to
start human testing in June. The Imperial College
London funding will also be used to help prepare
for Phase III studies. We will throw everything
weve got at developing a vaccine, Hancock
added. The U.K. is at the forefront of the
global effort and for all of the efforts around
the world, two of the leading vaccine
developments are taking place here at home, at
Oxford and Imperial.
The start of human testing in the U.K. coincides
with Germanys regulator, the Paul-Ehrlich-Institu
t, giving German biotech BioNTech and partner
Pfizer the green light (under global
Lightspeed COVID-19 vaccine development
program) to start the first coronavirus vaccine
clinical trial in the country. The Phase I/II
study will evaluate the BNT162 vaccine program in
200 healthy volunteers aged 1855 years. Each
candidate represents a different mRNA format and
target antigen. Two of the four vaccine
candidates are nucleoside modified mRNA (modRNA)
vaccines, a third is a uridine containing mRNA
(uRNA), and the fourth vaccine candidate utilizes
self-amplifying mRNA (saRNA). Each mRNA format is
combined with a lipid nanoparticle (LNP)
formulation.
1 https//www.genengnews.com/news/uk-starts-oxford
-coronavirus-vaccine-trial-as-germany-green-lights
-clinical-trial-for-biontech-and-pfizer/
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The team started work on designing a coronavirus
vaccine on January 10, 2020. Their vaccine
candidate is based on a non-replicating
chimpanzee adenovirus vector, ChAdOx1, which was
originally developed at the Jenner Institute.
Engineered to encode the SARS-CoV-2 spike
protein, the ChAdOx1 nCoV-19 construct is
designed to trigger production of the viral
protein which then primes the immune system to
recognize SARS-CoV-2 infection. The Phase I
ChAdOx1 nCoV-19 trial will be carried out through
a collaboration between the Oxford Vaccine
Groups clinical teams and the Universitys
Jenner Institute, and include 510 volunteers aged
1855 years.
Imperial College Londons self-amplifying RNA
vaccine, developed by a team led by Robin
Shattock, PhD, at the department of infectious
diseases, is designed to trigger muscle cells to
produce the SARS-Co-2 spike protein that will
stimulate the immune system to generate
neutralizing antibodies against the virus. Tests
in animals have been underway since February, and
clinical trials could start in the summer, the
team projects.
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Study Safety and immunogenicity of the ChAdOx1
nCoV-19 vaccine against SARS-CoV-2 a
preliminary report of a phase I/II, single-blind,
randomised controlled trial 1090 Healthy adults
aged 1855 years - Published Online July 20, 2020
(ClinicalTrials.gov Identifier NCT04324606)
Funding UK Research and Innovation, Coalition for
Epidemic Preparedness Innovations, National
Institute for Health Research (NIHR), NIHR Oxford
Biomedical Research Centre, Thames Valley and
South Midlands NIHR Clinical Research Network,
and the German Center for Infection Research
(DZIF), Partner site Giesen-Marburg-Langen
Methods We did a phase 1/2, single-blind,
randomised controlled trial in five trial sites
in the UK of a chimpanzee adenovirus-vectored
vaccine (ChAdOx1 nCoV-19 (n543)) expressing the
SARS-CoV-2 spike protein as a single
intramuscular injection compared with a
meningococcal conjugate vaccine (MenACWY) as
control. 2 of 5 sites (Oxford and Southampton) a
protocol amendment (amendment date May 6, 2020)
allowed prophylactic paracetamol to be
administered before vaccination. Safety was
assessed over 28 days after vaccination. Here, we
report the preliminary findings on safety,
reactogenicity, and cellular and humoral immune
responses. The study is on-going, and was
registered at ISRCTN, 15281137, and
ClinicalTrials.gov, NCT04324606
Local and systemic reactions were more common in
the ChAdOx1 nCoV-19 group and many were reduced
by use of prophylactic paracetamol (1 g of
paracetamol every 6 h for 24 h to reduce
vaccine-associated reactions)., including pain
(injection site pain, tenderness, warmth,
redness, swelling, induration, and itch), feeling
feverish, chills, muscle ache, headache, fatigue,
nausea and malaise
In the ChAdOx1 nCoV-19 group, spike-specific
T-cell responses peaked on day 14
Added value of this study ChAdOx1 nCoV-19 has
previously been reported to be immunogenic and
protective against pneumonia in a rhesus macaque
challenge model. We report the results of the
first clinical study of ChAdOx1 nCoV-19
(AZD1222). The vaccine was safe and tolerated,
with reduced reactogenicity when paracetamol was
used prophylactically for the first 24 h after
vaccination.
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There are currently more than 137 candidates
undergoing pre-clinical development and 23 in
early clinical development, according to WHO 2.
Implications of all the available evidence A
vaccine against SARS-CoV-2 could be used to
prevent infection, disease, and death in the
global population, with high-risk populations
such as hospital workers and older adults (eg,
65 years of age) prioritised to receive
vaccination.
Adenoviral vectors have previously been combined
with DNA and poxviral vectors to attempt to
improve immunogenicity, with adenovirus or
modified vaccinia virus Ankara prime-boost
regimens showing enhancement of both cellular and
humoral immunity.
We have previously shown (Clinical trial
identifier NCT04170829 ) that a single dose of
ChAdOx1 MERS, a chimpanzee adenovirus vectored
vaccine that encodes the spike protein of Middle
East respiratory syndrome coronavirus (MERS-CoV),
protected non-human primates against
MERS-CoV-induced disease 7 and data from a
phase 1 clinical trial showed that ChAdOx1 MERS
was safe and well tolerated at all three doses
tested. In addition, the highest dose elicited
both humoral and cellular responses against
MERS-CoV in all vaccines within 1 month of
vaccination.
The ChAdOx1 nCoV-19 vaccine (AZD1222) consists of
the replication-deficient simian adenovirus
vector ChAdOx1, containing the full-length
structural surface glycoprotein (spike protein)
of SARS-CoV-2, with a tissue plasminogen
activator leader sequence. ChAdOx1 nCoV-19
expresses a codon-optimised coding sequence for
the spike protein (GenBank accession number
MN908947).
We did a phase 1/2 single-blind, randomised
controlled trial of ChAdOx1 nCoV-19 compared with
a licensed meningococcal group A, C, W-135, and Y
conjugate vaccine (MenACWY Menevo, Nimenrix,
Pfizer, UK), as control vaccine, in healthy
adults in the UK.(See next study)
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Safety and immunogenicity of the ChAdOx1 nCoV-19
vaccine against SARS-CoV-2 a preliminary report
of a phase 1/2, single-blind, randomised
controlled trial
Figure 1 Solicited local (A) and systemic (B)
adverse reactions in first 7 days after
vaccination as recorded in participant symptom
electronic diaries. Fatigue and headache were the
most commonly reported systemic reactions.
Fatigue was reported in the ChAdOx1 nCoV-19 group
by 340 (70) participants without paracetamol
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In the ChAdOx1 nCoV-19 group, antibodies against
SARS-CoV-2 spike protein peaked by day 28 and
remained elevated to day 56
Discussion Our preliminary findings show that
the candidate ChAdOx1 nCoV-19 vaccine given as a
single dose was safe and tolerated, despite a
higher reactogenicity profile than the control
vaccine, MenACWY.
Before vaccination, only one (1) of 98
participants who were tested had high titre
(gt200) neutralising antibodies against ChAdOx1.
Antibodies were detectable at a lower level in a
further 18 (1) participants, High levels of
neutralising antibody at baseline seen in a small
number of participants probably indicates prior
asymptomatic infection,
Importantly, there are accumulating data to
suggest T-cell responses play an important role
in COVID-19 mitigation individuals who were
exposed but asymptomatic developed a robust
memory T-cell response without symptomatic
disease in the absence of a measurable humoral
response.2022
However, a boost in cellular responses was not
observed following the second ChAdOx1 nCoV-19
dose. This is consistent with previous findings
on viral vectored vaccines given as part of a
homologous prime-boost regimen.12
Additionally, the study findings are not easily
generalisable, as this is a first-in-human study
of fairly young and healthy volunteers, the
majority of whom were white. Further studies are
required to assess the vaccine in various
population groups including older age groups,
those with comorbidities, and in ethnically and
geographically diverse populations.
In conclusion, ChAdOx1 nCoV-19 was safe,
tolerated, and immunogenic, while reactogenicity
was reduced with paracetamol.
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Declaration of interests SCG is co-founder and
board member of Vaccitech (collaborators in the
early development of this vaccine candidate) and
named as an inventor on a patent covering use of
ChAdOx1-vectored vaccines and a patent
application covering this SARS-CoV-2 vaccine. TL
is named as an inventor on a patent application
covering this SARS-CoV-2 vaccine and consultant
to Vaccitech. PMF is a consultant to Vaccitech.
AJP is Chair of the UK Department of Health and
Social Cares Joint Committee on Vaccination
Immunisation (JCVI), but does not participate in
policy advice on coronavirus vaccines, and is a
member of the WHO Strategic Advisory Group of
Experts (SAGE).
SUMMATION/NOTES OF INTEREST
Other vaccine studies (now recruiting) involving
ChAdOx1 85A Aerosol Versus Intramuscular
Vaccination in Healthy Adults (TB039) -
Mycobacterium Tuberculosis, Protection Against
Tuberculosis Estimated completion December 31,
2020 There is no mention of IL-2 and regulatory
T-Cells promotion (Tregs) in this study, and
humoral stimulation (adaptive) is not as
important as innate cell-mediated immune
responses. Just observing TH1 outcomes does not
necessitate a positive stimulation without other
compounds like IL-2 induced Tregs. More
inflammatory TH2 responses would be expected
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More to follow.