Ebola Vaccines Show Promise in New Study
October 11 2017 - 5:30PM
Dow Jones News
By Thomas M. Burton
The first placebo-controlled study of two vaccines against the
Ebola virus found they both successfully created a powerful
antibody response for a year, suggesting they both could be tools
to save lives in a future epidemic of the deadly disease.
The research, by doctors from the U.S. and Liberian governments
and elsewhere, was published Wednesday in the New England Journal
of Medicine. The study looked at 1,500 patients in Liberia, and
took place amid and after the outbreak of Ebola in Liberia from
2014 into 2015.
Five hundred participants received a vaccine developed by Merck
& Co., 500 got one from GlaxoSmithKline PLC, which was based on
work by the National Institutes of Health, and 500 received a
placebo.
With the Merck vaccine, at one month, 83.7% of patients had
developed antibodies to Ebola virus, versus 70.8% with the Glaxo
vaccine and a negligible number, 2.8%, in the placebo group. The
relationship of antibody responses was similar after 12 months,
with 79.5%, 63.5% and 6.8% of patients, respectively, showing
antibody response.
There is a "reasonable chance that either of these vaccines
would play a role in preventing infection," said H. Clifford Lane,
deputy director for clinical research at the National Institute for
Allergy and Infectious Diseases and a principal investigator in
this study. NIAID is part of the National Institutes of Health. The
Liberian Ministry of Health and other researchers also conducted
the study.
The West African Ebola outbreak -- the worst in recorded history
-- caused an estimated 11,000 deaths amid 25,582 cases in the three
nations of Guinea, Liberia and Sierra Leone. The hemorrhagic fever,
which can be fatal in half or more cases, spread from West Africa
to a handful of cases in Europe and the U.S., including among
health care workers. The disease appears and disappears
unpredictably in the African forests, and is widely believed to be
spread by bats.
In Dr. Lane's view, given previously existing positive evidence
from a Guinea study of the Merck vaccine, if doctors in a future
epidemic had to choose, it would probably be the one from
Merck.
That Merck vaccine was shown to be "highly efficacious" during
the Ebola epidemic in Guinea by World Health Organization doctors
writing in The Lancet in December. But the methodology of that
study -- including the lack of a placebo group -- raised questions
among some scientists about how conclusive those findings were.
A detailed report by the prestigious National Academy of
Medicine in April questioned the methodology of the Merck vaccine
study in Guinea. It concluded the Merck vaccine "most likely
provides some protection" to recipients but that the protection
"could in reality be quite low."
One of the authors of that Academy of Medicine report, vaccine
specialist and pediatrics professor Kathryn M. Edwards of
Vanderbilt University, said the new evidence shows "the safety of
the two vaccines is comparable." But she said any comparison of the
two vaccines based on the antibody evidence "is a bit undecided"
because it is unknown precisely what antibody levels are needed to
protect patients.
Merck said the "safety and immunogenicity results observed" in
this most recent research "are consistent with what we observed in
other studies." GSK said it is too early to know whether the
immunity differences between the two vaccines "indicate a
clinically meaningful difference." The NIH/GSK vaccine was the
focus of a page-one Wall Street Journal article about it and the
NIH scientist, Nancy J. Sullivan, who developed it.
The two different studies arose through a kind of scientific
war. Several British and other European medical groups, including
some who funded the Guinea study of the Merck vaccine, had argued
that giving any patients a placebo wasn't ethical in the middle of
a raging epidemic. But U.S. government doctors, including leaders
of the NIH, said a placebo group was necessary to ensure patients
truly got benefit, and weren't harmed, from either a vaccine or a
drug.
This current study, in Liberia, was designed to avoid those
pitfalls through its classic placebo-controlled design. But it ran
into another obstacle: Ebola cases in Liberia began to dwindle
early in 2015, and the outbreak there was declared over on May 9 of
that year. By the time this work was fully under way, it was too
late to see if vaccines actually prevented Ebola sickness and
death.
It still was possible, however, to measure patients'
immune-systems' response, measured by how many produced significant
antibodies to the Ebola virus. Also, vaccine safety could be
assessed, and both vaccines appeared safe.
NIH scientists now are evaluating antibody levels out to two
years.
The level of serious adverse events was higher in the placebo
group than either vaccine group, and "most of the serious adverse
events were attributed to malaria," the researchers wrote.
Write to Thomas M. Burton at tom.burton@wsj.com
(END) Dow Jones Newswires
October 11, 2017 17:15 ET (21:15 GMT)
Copyright (c) 2017 Dow Jones & Company, Inc.
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