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* Therapy cut deaths by one-fifth in the seronegative
* Can be used in combination with other treatments
* Finding bodes well for other antibody treatments
(Adds quote, comments on cost effectiveness)
By Alistair Smout
LONDON, June 16 (Reuters) - A COVID-19 antibody cocktail
developed by Regeneron Pharmaceuticals Inc and Roche
reduced deaths in hospitalised patients whose own immune
systems had failed to produce a response, a large British study
found on Wednesday.
The therapy, REGEN-COV, has been granted emergency use
authorisation for people with mild-to-moderate COVID-19 in the
United States, but results from the RECOVERY trial provide the
clearest evidence of its effectiveness among hospitalised
patients.
It found that the antibody therapy reduced by a fifth the
28-day mortality of people admitted to hospital with COVID-19
whose immune system had not mounted an antibody response, known
as seronegative.
The result translates into six fewer deaths for every 100
seronegative patients treated with the therapy, researchers
said.
There was no discernible effect of the treatment on those
who had generated natural antibody responses.
"People have been very, very sceptical, that any treatment
against this particular virus would work by the time people get
in hospital," Martin Landray, the joint chief investigator on
the trial, told reporters.
"If you haven't raised antibodies of your own, you really
would benefit from getting some," he said.
The treatment also shortened the hospital stay of those who
were seronegative and reduced their chances of needing a
mechanical ventilator, Landray said.
Regeneron had previously said its treatment had shown enough
promise in hospitalised patients to warrant continuing its
trial. This data provides the first large-scale confirmation of
that assertion.
There were 9,785 patients hospitalised with COVID-19 who
were randomly allocated to receive usual care plus the antibody
combination therapy or just usual care, of which 30% were
seronegative.
The RECOVERY trial also showed the steroid dexamethasone and
Roche's arthritis drug Actemra (tocilizumab) cut deaths
in hospitalised patients.
While those treatments focus on inflammation caused by
reaction to the coronavirus, Regeneron's therapy, which belongs
to a class of biotech drugs called monoclonal antibodies, mimic
natural antibodies the body produces to fight off the infection.
"This is the first time we've got one that's actually
targeting the virus itself," Landray said, adding that it could
be used along with the other treatments.
"It's not that you do one thing or another thing. These
benefits are additive in these patients," he said.
POSSIBILITY FOR OTHERS
Other companies have been developing similar treatments.
U.S. emergency use authorization has been granted to
antibody treatments developed by Eli Lilly and Co as
well as by Vir Biotechnology Inc with GlaxoSmithKline
Plc. Both are approved for use in mild-to-moderate
cases.
On Tuesday, AstraZeneca said its antibody therapy
had shown no evidence of protecting people from developing the
disease following exposure, although other trials of its
cocktail as a prevention or a treatment are ongoing.
Landray said the RECOVERY results should give developers of
other monoclonal antibody therapies optimism that they can also
be used in some hospitalised patients.
"This opens up the possibility for many, many others," he
said.
"People see a few negative trials and they say 'well that'll
never work' and they opt out and go off and do something else.
(But) this is very, very clear, the picture that we've got from
this trial."
Regeneron has enlisted Swiss pharmaceutical Roche to help
manufacture the drug.
Some cautioned that the full cost-benefit of the drug would
not be clear until more details of the study were available.
"The absolute magnitude of benefit in mortality is not
large, and it means that a large (possibly 20) number of people
have to be treated with the extremely expensive drug for a
single death to be prevented," said Stephen Evans, Professor of
Pharmacoepidemiology, London School of Hygiene & Tropical
Medicine.
"If (patients) can be readily identified and treated it will
have some benefit in practice, but its benefits should not be
overstated."
(Reporting by Alistair Smout
Editing by Bill Berkrot and Elaine Hardcastle)
