Dr. Kent Brantly was given the
medication, ZMapp, shortly after telling his doctors he thought he would die,
according to a source familiar with his case. Within an hour, doctors say his
symptoms -- labored breathing and a widespread rash -- dramatically improved.
Nancy Writebol, another missionary working with Samaritan's Purse, received two
doses of the medication and has also shown significant improvement, sources
say.
As there is no proven treatment and no
vaccine for Ebola, this experimental drug is raising lots of questions.
How the
experimental Ebola serum works
1. Who makes the
drug?
The drug was developed by the biotech
firm Mapp Biopharmaceutical Inc.,
which is based in San Diego. The company was founded in 2003 "to develop
novel pharmaceuticals for the prevention and treatment of infectious diseases,
focusing on unmet needs in global health and biodefense," according to its website.
Mapp Biopharmaceutical has been working
with the National Institutes of Health and the Defense Threat Reduction Agency,
an arm of the military responsible for countering weapons of mass destruction,
to develop an Ebola treatment for several years.
2. Are there
other experimental Ebola drugs out there?
"A whole menu of antibodies have
been identified as potentially therapeutic, and researchers are eager to figure
out which combinations are most effective and why," a news release about
the grant said.
Tekmira, a Vancouver-based company that
has a $140 million contract with the U.S. Department of Defense to develop an Ebola drug, began
Phase 1 trials with its drug in January. But the FDA recently halted the trial,
asking for more information.
At least one potential Ebola vaccine
has been tested in healthy human volunteers, according to Thomas Geisbert, a
leading researcher at the University of Texas Medical Branch. And last week,
the NIH announced a safety trial of another Ebola vaccine will start as early as September.
3. How does
ZMapp work?
Antibodies are proteins used by the
immune system to mark and destroy foreign, or harmful, cells. A monoclonal
antibody is similar, except it's engineered in a lab so it will attach to
specific parts of a dangerous cell, according to the Mayo Clinic, mimicking your immune system's natural response. Monoclonal
antibodies are used to treat many different types of conditions.
West African
Ebola epidemic
Second Ebola
patient heading to U.S.
Can camera
help detect Ebola?
Sources told CNN the medicine given to
Brantly and Writebol abroad was a three-mouse monoclonal antibody, meaning that
mice were exposed to fragments of the Ebola virus and then the antibodies
generated within the mice's blood were harvested to create the medicine.
However, the drug can also be produced
with proteins made from tobacco plants. ZMapp manufacturer Kentucky
BioProcessing in Owensboro has been working with Samaritan's Purse and Emory
University Hospital to provide limited quantities of the drug to Emory,
according to company spokesman David Howard.
4. Why did
American missionary workers get the drug?
The World Health Organization says it
was not involved in the decision to treat Brantly and Writebol. Both patients
had to give consent to receive the drug, knowing it had never been tested in
humans before.
The process by which the medication was
made available to the American patients may have fallen under the U.S. Food and
Drug Administration's "compassionate use" regulation, which allows
access to investigational drugs outside clinical trials.
5. Did doctors
know it would work?
No. The drug had shown promise in
primates, but even in those experiments, just eight monkeys received the
treatment. In any case, the human immune system can react differently than
primates', which is why drugs are required to undergo human clinical trials
before being approved by government agencies for widespread use.
The two Americans' cases will be
studied further to determine how the drug worked with their immune systems.
6. Will the drug
be made available to other Ebola patients?
It's unclear. Rolling out an untested
drug during a massive outbreak would be very difficult, Doctors Without Borders
said in a statement. Experimental drugs typically not mass-produced, and
tracking the success of such a drug if used would require extra medical staff
where resources are already scarce.
"Having worked with administering
antibodies for people for a really long time, that would be distinctly
unusual," he told CNN. "As we all know in medicine ... you have to
withhold judgment."
7. Does the
company have more vials of the drug?
The company has very few doses ready
for patient use, Fauci told CNN.
"(Kentucky BioProcessing) is
working closely with Mapp, various government agencies, and other parties to
increase production of ZMapp, but this process will take several months,"
Howard said.
8. Who paid for
the drug and how much did it cost?
We don't know. Samaritan's Purse
covered the cost of Brantly and Writebol's evacuations but did not pay for the
drug, according to a spokesman.
When a patient gets an experimental
drug, the drug company can donate the product under compassionate use. Mapp
Biopharmaceutical Inc. might have done that in this case.
Health insurance companies typically do
not pick up the tab for treatments that have not been approved by the FDA. But
they usually would cover the cost of any doctor fees associated with giving the
drug and any costs associated with monitoring how the drug is working.
9. Would this
drug stop the Ebola epidemic?
If it were widely available, it
certainly couldn't hurt. An effective Ebola drug could help doctors treat the
deadly virus, which is killing about 60% of the people infected in West Africa.
But a vaccine would be a much more effective tool in stopping this, and future,
epidemics.
Vaccines are given to healthy people to
prevent them from ever becoming infected. One challenge with Ebola, experts
say, is that companies don't believe they could make much money from developing a vaccine, so few companies show interest.
