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Nov 26 (Reuters) - AstraZeneca is likely to run an
additional global trial to assess the efficacy of its COVID-19
vaccine using a lower dosage, its chief executive was quoted as
saying on Thursday amid questions over the results from its
late-stage study.
Instead of adding the trial to an ongoing U.S. process,
AstraZeneca might launch a fresh study to evaluate a lower
dosage of its vaccine that performed better than a full dosage,
Pascal Soriot was quoted as saying in a Bloomberg News report.
"Now that we've found what looks like a better efficacy we
have to validate this, so we need to do an additional study," he
said.
Soriot said it would probably be another "international
study, but this one could be faster because we know the efficacy
is high so we need a smaller number of patients."
The news comes as AstraZeneca faces questions about its
success rate that some experts say could hinder its chances of
getting speedy U.S. and EU regulatory approval.
Several scientists have raised doubts about the robustness
of results released on Monday showing the experimental vaccine
was 90% effective in a sub-group of trial participants who, by
error initially, received a half dose followed by a full dose.
Soriot said he did not expect the additional trial to delay
UK and European regulatory approvals.
Asked about the Bloomberg report, an AstraZeneca spokesman
said there was "strong merit in continuing to further
investigate the half-dose/ full dose regimen."
"We are further evaluating the data and will work with
regulators on the best approach for further evaluation," he
said.
"This would add to data from existing trials which are
currently being prepared for regulatory submission."
AstraZeneca told Reuters earlier on Thursday that
administering of the half dose had been reviewed and approved by
independent data safety monitors and the UK regulator, adding
that the regulator publicly confirmed there was "no concern".
Clearance from the U.S. Food and Drug Administration (FDA)
may take longer though because the agency is unlikely to approve
the vaccine based on studies carried out elsewhere, especially
given the questions over the results, Soriot said.
Authorisation in some countries is still expected before the
end of the year, he added.
AstraZeneca research chief Mene Pangalos told Reuters on
Monday that researchers had stumbled upon the half-dose regime
by accident, saying a sub-group of the trial was given a smaller
initial dose by mistake.
Earlier he had said that the firm would start discussions
with the FDA to change the design of its experimental COVID-19
vaccine trial to add the more-effective dosage regime.
Running an additional trial might not be too much of a
complication for the British drugmaker in the race to develop a
successful vaccine to help tame the pandemic, which has killed
more than a million people and roiled the global economy.
Helen Fletcher, professor of immunology at the London School
of Hygiene & Tropical Medicine, said that another trial would
not necessarily delay getting a green light as efficacy in the
higher dose regime still met the World Health Organization's
target, and it was not unusual to run new studies on approved
vaccines.
"It’s entirely possible AZ and Oxford could license the high
dose and then quickly seek an amendment to use the low dose when
they have sufficient data," she said.
The vaccine is one of three that could get approved before
the end the year. Earlier this month, Pfizer and Moderna
reported that their vaccines were about 95% effective
in preventing illness, setting the bar sky-high.
Even so, the AstraZeneca shot developed with Oxford
University is cheaper to make, easier to distribute and faster
to scale up than its rivals.
A peer-reviewed analysis of the trial data will be published
in a medical journal in the coming weeks.
The UK's Medicines and Healthcare products Regulatory Agency
(MHRA) is continuing its rolling review of the vaccine, the
regulator's Chief Executive June Raine said in an email on
Thursday.
"Any vaccine must undergo robust clinical trials in line
with international standards, with oversight provided by the
Medicines and Healthcare products Regulatory Agency (MHRA), and
no vaccine would be authorised for supply in the UK unless the
expected standards of safety, quality and efficacy are met," she
said.
The European Medicines Agency did not immediately respond to
requests for comment on the potential for another study.
(Reporting by Sabahatjahan Contractor in Bengaluru and Alistair
Smout in London
Writing by Josephine Mason; Editing by Alexander Smith, Pravin
Char, Elaine Hardcastle and Tom Brown)
