By Jenny Strasburg and Joseph Walker
LONDON -- Peer-reviewed data from late-stage human trials of a
Covid-19 vaccine developed by the University of Oxford and
AstraZeneca PLC reaffirmed the shot's strong safety results and
provided some additional evidence that halving the first of two
doses of the shot boosts its effectiveness.
AstraZeneca and Oxford said the data gave them confidence to ask
the U.K. and other countries for emergency-use authorization of the
vaccine, but said regulators will have to decide which dosing
regimen to approve. Last month, AstraZeneca and Oxford said trial
data showed the vaccine was between 62% and 90% effective, but that
the higher results were observed in a small subset of the wider
trial.
This subset received a half-sized initial dose followed by a
full second dose. The group was also all under 55 years old,
raising questions about whether the lower dosing would also be
effective in older subjects.
AstraZeneca and Oxford on Tuesday declined to say whether they
would ask regulators to approve the lower-dose regimen, leaving
unclear whether an initial vaccine approval and rollout would be
limited to the less-effective regimen. The 62% effectiveness shown
in the majority of the trial participants is still better than what
health experts deem necessary to protect people against severe
Covid-19.
The publication of the data in the Lancet -- the first full
peer-reviewed results from any of the late-stage human trials
disclosed so far by the West's three leading vaccine makers --
comes on the day that a vaccine developed by Pfizer Inc. and
Germany's BioNTech SE was being administered for the first time
outside trials, in the U.K. The country authorized the vaccine for
emergency use last week.
It also coincided with a preliminary assessment by the U.S. Food
and Drug Administration on Tuesday showing the agency was satisfied
with the Pfizer shot's effectiveness and safety, paving the way for
a potential emergency-use authorization in the U.S. in coming
days.
The FDA is also reviewing Moderna Inc.'s vaccine, with a verdict
expected shortly.
While those two vaccines have raced ahead of AstraZeneca's in
the U.S. regulatory process, much of the rest of the world is
betting on latter. Oxford and AstraZeneca have promised to provide
many more doses across a wider geographic footprint then either
Pfizer or Moderna.
The partners also promised to provide the shot at cost, making
it the vaccine of choice for much of the developing world.
Results from an ongoing U.S. study will likely be needed before
a potential approval in the U.S., said Menelas Pangalos,
AstraZeneca's head of biopharmaceutical research, citing
conversations with regulators at the FDA.
The U.K. government already has asked its medicines regulator to
review AstraZeneca's shot for emergency-use authorization. The
published results push the vaccine closer to a potential rollout in
Britain, while late-stage trials of the shot continue in the
U.S.
"We hope to see regulatory approval in the coming weeks," Sarah
Gilbert, an Oxford vaccinology professor and a lead scientist on
the vaccine, said on a call with reporters.
The researchers continue to collect data from the studies and
expect to have more answers in the future about differences in the
effectiveness of the two regimens and between age groups, said
Prof. Gilbert.
AstraZeneca has described the half-dose results as the product
of a lucky error in calibrating dosage in the early stages of human
trials, but that it is still trying to understand the surprising
result. An Oxford scientist said Tuesday that the half-dose was
unplanned but that the study design was amended to include the
half-dose group in its analysis. Both said the half-dose regimen
will be tested further.
The Lancet study authors said further analysis in recent weeks
has been promising: They said they found that the change in dosage
-- not age or another factor -- appears to cause the 90%
effectiveness. That determination came after a deeper analysis of
the data to isolate the effects of the half-dose from other
differences between trial volunteers. The Lancet authors said more
study was needed to make a determination. A standard schedule of
two full doses was shown to be 62% effective, the same as the
vaccine partners said two weeks ago.
The effectiveness results are based on late-stage trials
involving more than 11,600 people in the U.K. and Brazil. Tuesday's
data contained more information than previous results about the
safety of the vaccine, including data from trials involving more
than 23,700 participants in the U.K., Brazil and South Africa.
Of those, three participants experienced serious adverse events,
including one person who received the vaccine and 14 days later
developed what was reported to be a case of transverse myelitis, a
neurological disorder. Independent investigators monitoring the
study said it possibly was related to the vaccine but couldn't
determine that for certain. Regulators allowed trials to resume
following the independent evaluations.
The 62% effectiveness clears the 50% hurdle set earlier this
year for emergency authorization of Covid-19 vaccines by regulators
including the FDA. That hurdle is in addition to requirements for
safety and manufacturing quality.
The peer-reviewed data showed the vaccine provides protection
against severe Covid-19 disease, a promising result that could help
ease the burden on hospitals. The Oxford-AstraZeneca vaccine
appears to protect against transmission of the disease by people
not showing symptoms, though scientists said they need more data to
confirm the findings.
Scientists involved in the vaccine, including AstraZeneca
executives, said that even at its lowest effectiveness, the vaccine
can be a crucial tool in fighting the pandemic, along with other
shots and treatments.
"Personally I think we need to be completely agnostic about
which vaccine is being used, because we need multiple vaccines as
soon as possible," Prof. Andrew Pollard of Oxford, a lead scientist
on the vaccine study, said. "Otherwise we'll still be in this
position in six months' time."
But some other researchers said they would like to see more data
to know how effective the vaccine is in older adults and in
nonwhite groups disproportionately affected by the disease. The
trials started off in younger, lower-risk groups. Also, some
researchers have concerns that the vaccine's baseline 62%
effectiveness -- while helpful in keeping people out of the
hospital -- could be insufficient to stop the virus from
spreading.
The Oxford-AstraZeneca vaccine's 62% effectiveness reading fell
short of results from Moderna, at 94.5%, and Pfizer, at 95%.
Write to Jenny Strasburg at jenny.strasburg@wsj.com and Joseph
Walker at joseph.walker@wsj.com
(END) Dow Jones Newswires
December 08, 2020 13:12 ET (18:12 GMT)
Copyright (c) 2020 Dow Jones & Company, Inc.
AstraZeneca (NASDAQ:AZN)
Historical Stock Chart
Von Jun 2024 bis Jul 2024
AstraZeneca (NASDAQ:AZN)
Historical Stock Chart
Von Jul 2023 bis Jul 2024