| NEW YORK
NEW YORK Aug 29 The experimental Ebola drug
ZMapp cured all 18 of the lab monkeys infected with the deadly
virus, including those suffering the fever and hemorrhaging
characteristic of the disease and just hours from death,
scientists reported on Friday.
Even monkeys not treated until five days after infection
survived. No other experimental Ebola therapy has ever shown
success in primates when given that long after infection; the
five days is analogous to nine to 11 days after infection in
Although two American aid workers who contracted Ebola in
Liberia were cured after receiving ZMapp, their physicians do
not know if the drug helped. A Liberian doctor with the disease
died this week despite being given the drug, as did a Spanish
ZMapp, produced by San Diego-based Mapp Biopharmaceutical,
has never been scientifically tested in people, and the current
study was the first in primates. The success is therefore a
"monumental achievement," virologist Thomas Geisbert of the
University of Texas Medical Branch wrote in a commentary on the
paper, published online in Nature.
There are no approved Ebola vaccines or treatments, but
human safety trials will begin next week on a vaccine from
GlaxoSmithKline Plc and this autumn on one from NewLink
The Ebola outbreak in West Africa has killed 1,552 people
out of 3,069 confirmed cases, the World Health Organization
said, and is on pace to infect 20,000. Neither governments nor
private medical groups have been able to contain the outbreak,
which WHO said will almost certainly continue into 2015.
ZMapp is a mix of three antibodies that bind to proteins on
Ebola viruses and trigger the immune system to destroy them.
Mapp had previously developed two different cocktails of
antibodies, but they protected only 43 percent of monkeys when
given as late as five days after infection.
For the current study, scientists led by Gary Kobinger of
the Public Health Agency of Canada set out to identify the
optimal mix of antibodies from the earlier cocktails. His team
tested the antibodies in guinea pigs one at a time and in
various combinations, identifying the two best performers last
The two graduated to tests in 12 rhesus monkeys. This spring
the winner of that face-off, ZMapp, was given to another 18
infected monkeys - three doses at three-day intervals starting
three, four or five days after infection.
All three untreated monkeys, in contrast, died of Ebola by
day eight. With ZMapp, even advanced symptoms such as rashes,
liver dysfunction and hemorrhaging disappeared, a result
Kobinger called "beyond my own expectations."
"This is an extremely encouraging result," said David Evans,
professor of virology at England's University of Warwick, who
was not involved in the study.
The success suggests that ZMapp "offers the best option" for
treating Ebola, Kobinger's team wrote, and should be tested for
safety in people to enable its compassionate use "as soon as
The Ebola strain in the study is the Kikwit variant, not the
Guinea strain responsible for the current outbreak. ZMapp
inhibited replication of the Guinea strain in lab dishes,
however, suggesting it might be broadly effective.
Mapp has no more doses of ZMapp, which is produced in the
leaves of tobacco plants at Kentucky BioProcessing, a unit of
Reynolds American Inc. Greenhouses there began making
more ZMapp "a couple of weeks ago, but the process takes time,"
said Reynolds spokeswoman Maura Payne.
It aims to produce enough for tests necessary to seek
regulatory approval of ZMapp, she said, "and we plan to begin
that testing protocol by year-end."
(Editing by Matthew Lewis)