A CHINESE herbal medicine could avert a health disaster in sub-Saharan
Africa, as quinine-resistant malaria threatens the continent. Two new
studies have found that the medicine, known as artemether, can treat the
disease. But millions may still die because they cannot afford to pay for
it.
Malaria can be treated with a range of drugs if it is caught early.
Later on,
when the malaria parasite becomes established in the bloodstream, infected red
blood cells can block blood vessels in the brain, leading to coma and
death.
For years, the only really effective treatment for cerebral malaria was
quinine, which is derived from the bark of the chinchona tree. But in the past
few years, forms of the malaria parasite that are not affected by quinine have
emerged in Southeast Asia. Artemether came along just in time. 鈥淚n Cambodia we
were in danger of soon approaching the point of having no drugs to treat
cerebral malaria with,鈥� says Brian Greenwood of the London School of
Hygiene and
Tropical Medicine.
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The fear now is that quinine resistance will spread to Africa, where 90 per
cent of the world鈥檚 cases of cerebral malaria occur. Already, 2.7 million
Africans die each year from malaria, and that figure could rise to almost 7
million if quinine resistance spreads from Southeast Asia. 鈥淚t鈥檚 a terrifying
thought,鈥� says Greenwood. In general, new forms of drug resistance take about
five years to reach Africa from Asia.
The two studies suggest that artemether, which is derived from the shrub
wormwood, could save Africa from a malaria catastrophe. A team led by
Greenwood,
who until last year was director of the Medical Research Council鈥檚 laboratories
in Gambia, examined 586 children with cerebral malaria. In a group treated with
artemether, 79.5 per cent survived, compared with 78.5 per cent treated with
quinine. Left untreated, cerebral malaria is almost always fatal.
In the second study, the team led by Nick White, director of the Wellcome
Trust in Vietnam, found that artemether was as effective as quinine against
cerebral malaria among adults in Asia. And while quinine can cause a dangerous
drop in blood glucose, artemether cleared the parasite from the blood more
quickly and with fewer side effects. The only disadvantage was that patients
treated with artemether took slightly longer to recover from coma. Both teams
report their findings in the 11 July issue of The New England Journal of
Medicine.
Already, the researchers predict that thousands of lives could be saved each
year in Southeast Asia by replacing quinine with artemether. 鈥淭his is the first
time it鈥檚 been shown that this drug is effective against severe cerebral
malaria. It鈥檚 very good news,鈥� says Greenwood.
鈥淭his family of drugs represents a major advance in the treatment of
malaria,鈥� says White. 鈥淲ith declining pharmaceuticals company interest in
developing drugs to treat tropical disease, we鈥檙e very fortunate nature had
given us such an effective drug.鈥�
The plan is to hold artemether in reserve in Africa until quinine resistance
emerges. But harsh economics could prevent people benefiting from the drug.
鈥淧eople can just about afford it in the Far East,鈥� says Piero Olliaro of the
Tropical Diseases Research Programme (TDR) in Geneva. 鈥淏ut in Africa the price
could be a real problem.鈥�
Olliaro says that drugs firms have been slow to develop artemether, because
they cannot apply for patents on a drug that is already used in traditional
Chinese medicine and has been described in the scientific literature. This
means
that no company can have the monopoly that would guarantee them a healthy
profit.
The French company Rh么ne-Poulenc Rorer currently manufactures the drug
from shrub wormwood extracts. The overall cost of artemether treatment is
comparable with quinine, which requires monitoring of blood sugar levels to
check for side effects. But the drug itself costs twice as much. This is a
problem, says Olliaro, because drugs must be paid for by patients or their
families in many African countries.
A course of artemether, consisting of six 80-milligram doses that must be
injected into the muscles, will cost about 拢9. This price is already
subsidised under a deal between Rh么ne-Poulenc Rorer and the TDR.
Jean-Pierre Helenport, artemether project manager for Rh么ne-Poulenc
Rorer,
says that the cost has been cut as much as possible. If the drug was on sale in
France, he adds, a course would cost about 拢18.
The best hope may be the development of drugs related to artemether that are
cheaper. Another shrub wormwood extract called arteether is currently being
developed by the TDR and a Dutch company called Artecef. 鈥淲e are hoping
that the
drug might be registered in 1998 and the cost will be low,鈥� says Olliaro.