UPDATE 3-AstraZeneca's antibody therapy prevents COVID-19, study shows

* Astra in frame to launch new prevention tool on top of
vaccines

* Antibody combo 77% effective in preventing COVID-19

* New hope for immunocompromised with low vaccine protection

* AstraZeneca pursuing initial approval well before year-end

*
(Adds expert comment, background on mode of action)

By Ludwig Burger

Aug 20 (Reuters) - Trial data from AstraZeneca on
Friday raised the prospect of a new treatment to prevent
COVID-19 beyond vaccines, giving hope in particular for people
who respond poorly to immunisation shots.

The British drugmaker said its new antibody therapy reduced
the risk of people developing any COVID-19 symptoms by 77% in a
late-stage trial.

While vaccines rely on an intact immune system to develop an
arsenal of targeted antibodies and infection-fighting cells,
AstraZeneca's AZD7442 therapy consists of lab-made antibodies
that are designed to linger in the body for months to stifle the
coronavirus in case of an infection.

The company said that 75% of the participants in the trial
for the therapy - which comprises two types of antibodies
discovered by Vanderbilt University Medical Center in the United
States - had chronic conditions including some with a lower
immune response to vaccinations.

Similar therapies made with a drug class called monoclonal
antibodies are being developed by Regeneron, Eli Lilly
and GlaxoSmithKline with partner Vir,
competing for a role in COVID treatment and prevention.

But AstraZeneca is first to publish positive prevention
trial data in the field and is now targeting conditional
approval in major markets well before the end of the year,
aiming to produce roughly 1 to 2 million doses by then.

Penny Ward, Visiting Professor in Pharmaceutical Medicine at
Kings College in London, said the news bode well for people who
have responded poorly to vaccination or who must take
immune-suppressants for post-transplant, autoimmune disease and
other conditions.

"It could potentially be game changing for these
individuals, who are currently being advised to continue to
shield despite being fully vaccinated," she said.

The good news on the therapy was tempered, however, by a
separate AstraZeneca statement https://www.astrazeneca.com/media-centre/press-releases/2021/update-on-ultomiris-phase-iii-als-trial.html
on Friday.

It said a trial of a treatment for the rare neurological
disorder amyotrophic lateral sclerosis (ALS), developed by
AstraZeneca's newly acquired Alexion, had been stopped early due
to a lack of efficacy.

AstraZeneca shares were up just 0.1% at 1400 GMT.

AstraZeneca executive Mene Pangalos said the therapy trial
results were taken three months after the antibodies were
injected and investigators would follow up as far out as 15
months in the hope the company can tout the shot as a year-long
shield.

"We’re really trying to help patients that need an added
level of protection on top of a vaccine," said Pangalos.

He signalled that the prospects of a new COVID-19 product in
AstraZeneca's medicine cabinet could also enhance the strategic
value of its existing vaccine Vaxzevria, which it developed in
collaboration with Britain's Oxford University.

"No other company has delivered two molecules against
SARS-CoV2. This definitely helps us in positioning us in terms
of COVID," Pangalos told Reuters. SARS-CoV2 is the scientific
term for the coronavirus that causes COVID-19.

Another leading AstraZeneca executive, Ruud Dobber, had said
last month that different strategic options were being explored
for AstraZeneca's vaccine operations, which have faced a string
of challenges.

APPROVAL TARGETS

The Anglo-Swedish drugmaker has suffered production problems
during the rollout of Vaxzevria while very rare cases of blood
clotting have weighed heavily on demand for the shot in Europe.
The vaccine has also yet to win clearance in the United States.

Concerns over the new Delta variant of COVID-19 and waning
vaccine efficacy have prompted several high-income countries to
offer a third vaccine shot on top of the usual two-shot regimen
to the immunocompromised and other groups at risk.

The immunocompromised, such as those with organ transplants
or in cancer care, make up about 2% of the population and would
be the main target group for the new therapy. Naval forces on
missions could also benefit, among others, Pangalos said.

Even though only 12% to 13% of the trial volunteers were
vaccinated when the therapy trial data was generated,
AstraZeneca will seek to position the shot as a top-up to
previous inoculations.

One or two manufacturing sites at as-yet undisclosed
locations would serve world demand, said Pangalos, adding that
AstraZeneca stood ready to boost production if countries or
international organisations placed bulk orders.

(Additional Reporting by Muvija M in Bengaluru; Editing by
Sriraj Kalluvila, Jason Neely, David Clarke and Susan Fenton)