Last checked at 
* Trials halted due to health condition of a participant
* Independent panel to review any link to vaccine prototype
* AstraZeneca has supply deals for 3 bln doses
(Adds details in British trial, expert comment, FT report)
By Ludwig Burger
LONDON, Sept 9 (Reuters) - AstraZeneca has suspended
global trials of its experimental coronavirus vaccine after an
unexplained illness in a participant in Britain, casting doubt
on prospects for an early rollout.
The vaccine to combat COVID-19, which Britain's AstraZeneca
is developing with the University of Oxford, has been described
by the World Health Organization as probably the world's leading
candidate and the furthest developed.
However, AstraZeneca said on Tuesday it had paused trials,
including late-stage ones, to allow an independent committee to
review safety data, and it was working to minimise any potential
impact on the timeline.
"It is obviously a challenge to this particular vaccine
trial," Britain's Health Secretary Matt Hancock told Sky News.
The pause follows reports that the United States was aiming
for fast-track approval before November's presidential election.
The stakes are high because AstraZeneca, Britain's largest
drugmaker by market value, has already agreed to supply close to
three billion doses to governments across the globe.
This is more than any other vaccine project. Asked whether
the pause would set back the development process, Hancock said:
"Not necessarily, it depends on what they find when they do the
investigation".
Most states will contribute financially to developing the
vaccine, even if the trial fails.
'ROUTINE ACTION'
Britain's medical regulator said it is urgently reviewing
information available to determine whether trials can restart as
quickly as possible.
A New York Times report citing a person familiar with the
situation said a participant based in Britain was found to have
transverse myelitis, an inflammatory syndrome that affects the
spinal cord and is often sparked by viral infections.
Whether this was directly linked to AstraZeneca's vaccine
remains unclear, it said. AstraZeneca declined to comment.
"People fall ill for a multitude of reasons, and the project
team will now be reviewing in depth what is the cause of this
person's illness and whether it is linked to having been given
the vaccine or not," said Doug Brown, Chief Executive of the
British Society for Immunology.
The Financial Times quoted people associated with the trial
as saying it could resume early next week, after the study’s
independent data monitoring board has investigated.
AstraZeneca officials were not immediately available to
comment on that report.
The suspension triggered a fall of as much as 3% in
AstraZeneca's shares, which have the second biggest weighting in
the FTSE 100 index, but were trading 0.5% up by 1540 GMT.
The British trial began in May with more than 12,000
participants, from 5 years old to over 70.
The U.S. trial, with a targeted 30,000 participants, was
launched last week for the vaccine AZD1222, which is also in
late-stage clinical trials in Brazil and South Africa.
Additional trials are planned in Japan and Russia, with a
targeted 50,000 participants globally.
South Korea said it would look into the suspension and
review its plan to participate in manufacturing the vaccine and
health ministry official Yoon Tae-ho added such suspensions of
clinical trials were not rare "as various factors interact".
This was echoed by Germany's Leukocare, which is working on
a vaccine similar to AstraZeneca's but is at an earlier stage.
"When you are inoculating 20,000 people, it is a foregone
conclusion that at some point you will have severe adverse
events. As soon as a link to the vaccine can clearly be ruled
out, the trial continues," CEO Michael Scholl said.
Immune-related conditions such as inflammations, however,
would be subject to particular scrutiny, he added.
MONKEY VIRUS
The Oxford vaccine is designed to instruct human cells to
make distinguishing parts of the coronavirus. That allows the
immune system to build an arsenal against future infections.
A harmless virus known as adenovirus is used to bring the
genetic instruction into the body, an approach which is also
being pursued by China's CanSino, Russia's Gamaleya institute or
Johnson & Johnson.
Backers of the Gamaleya candidate, the first Russian
COVID-19 vaccine, underscored the difference between their jab,
based on an adenovirus in humans, and the British contender with
an adenovirus found in monkeys.
"We have consistently drawn attention to human adenoviral
platform being much safer and much more studied than any other
new platform," the head of Russia's sovereign wealth fund Kirill
Dmitriev told Reuters.
In choosing a monkey virus, AstraZeneca, as well as
Leukocare, are trying to avoid the risk of the immune system
attacking the vector, due to a previous bout with an adenovirus.
The decision to put the trial on hold seemed to have had
little impact on clinical trials being conducted by other
vaccine makers.
Serum Institute of India said its trials of AstraZeneca's
vaccine were ongoing and had not faced any issues.
The U.S. National Institutes of Health, which is providing
funding for AstraZeneca's trial, declined to comment.
Moderna said in an emailed statement it was "not aware of
any impact" to its ongoing COVID-19 vaccine study.
Leading U.S. and European vaccine developers pledged on
Tuesday to uphold scientific safety and efficacy standards for
their experimental vaccines.
Nine companies, including AstraZeneca, Moderna and Pfizer,
issued an "historic pledge" after concerns that safety standards
might slip under political pressure to rush out a vaccine.
The other signatories were Johnson & Johnson, Merck & Co
, GlaxoSmithKline, Novavax Inc, Sanofi
and BioNTech.
(Reporting by Guy Fauconbridge, Estelle Shirbon, Kate Kelland
in London, Deena Beasley; Additional reporting by Peter
Henderson in San Francisco, Rocky Swift in Tokyo, Sangmi Cha in
Seoul and Miyoung Kim in Singapore; Editing by Alexander Smith
and Emelia Sithole-Matarise)
