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Scientists have
developed a compound that both cured and prevented malaria in animals. They say
the experimental drug even is effective against resistant strains of the
mosquito-borne parasite. If the experimental treatment pans out in humans, it
could be a huge breakthrough in the treatment and prevention of malaria, a
disease that strikes an estimated 200 million people each year.
The parasitic
illness is responsible for about 425,000 deaths annually, most of them children
in sub-Saharan Africa. Scientists found the compound, called MMV048, blocks the
parasite across its multiple life stages, interrupting the infection cycle and
potentially curing the disease in humans.
'Exciting
profile’
Kelly Chibale is
a professor of organic chemistry at the University of Cape Town in South Africa
and director of the Cape Town Drug Discovery and Development Center. He is
senior author of a study describing the work in the journal Science
Translational Medicine.
In animal
trials, Chibale said MMV048 cured 100 percent of mice that were infected with
malaria.
It was shown to
wipe out an infection in three days, said Chibale, adding, “Overall, it
presents an exciting profile in terms of the potential to contribute to malaria
eradication.”
And, MMV048
completely protected monkeys that received a dose of the compound. Researchers
were unable to infect them, according to Chibale, who said he hopes the
experimental drug has the same effect in humans.
“It’s present in
the body in the blood already," he explained, "so even when you get
bitten by a mosquito, the parasites that initially end up in the blood they
will find the drug already waiting for them and they’ll be killed off before
they increase in population.” In the
animal studies, Chibale said the compound lasted for at least eight days in the
bloodstream, acting as a shield against infection.
Not a vaccine
Chibale is quick
to caution that the compound is not a vaccine, which stimulates the immune
system to afford long-lasting protection against a pathogen. Development of a
vaccine against malaria has been a difficult and frustrating process. Instead,
Chilabe said, MMV048 targets a protein that the parasite needs to protect
itself from the immune system.
The parasites
are destroyed in the liver, said Chilabe, the first place they travel after
someone is bitten by an infected mosquito. The parasites are thus prevented
from migrating into the bloodstream where they infiltrate red cells by the
thousands, maturing into a form that can be transmitted back to mosquitoes.
Chibale said
MMV048 appears to be effective against parasites that have become resistant to
existing drugs. But he said the drug, in all likelihood, would have to be used
as part of drug cocktail with existing anti-malarials to prevent the
development of drug resistance. Early clinical trials show that the compound is
safe in healthy humans.
The next stage
of clinical trials – to begin testing MMV048’s effectiveness in humans infected
with malaria – is likely to begin later this year. Human trials will determine
the drug’s proper dose and how often it needs to be given to protect against
malaria.