3 Malaria news items
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'Resistance is Emerging' to Antimalarial Drug of Choice
SciDev.Net (London)
December 2, 2005
Posted to the web December 2, 2005
By Wagdy Sawahel
Malaria parasites found in West Africa are showing signs of re-
sistance to what is thought to be the most powerful antimalarial
drug, say researchers.
Artemisinin was introduced in several African countries after
the parasite developed resistance to chloroquine, previously one
of the most common drugs.
Yet, in The Lancet this week (3 December), a team of researchers
from Cambodia, France and Senegal show that some resistance to
the drug is emerging in French Guiana and Senegal.
Ronan Jambou, who led the project at the Pasteur Institute in
Dakar, Senegal, says that "for the moment we can expect no im-
pact on the treatment of malaria in Africa" because artemisinin
is administered not in isolation but only in combination with
other antimalarial drugs.
Researchers believe the parasite is less likely to develop re-
sistance to a combination of drugs than to a single drug used in
isolation.
He adds, however, that the parasite's resistance to artemisinin
should be carefully monitored to avoid a repetition of what hap-
pened with chloroquine.
"Forty years separated the first description of chloroquine re-
sistance from its withdrawal. We think that we have time [to
avoid widespread resistance] if we use these compounds care-
fully," Jambou told SciDev.Net.
The team took blood samples from 530 malaria patients in Cambo-
dia, French Guiana and Senegal, and tested the parasites to see
if they were resistant to artemisinin.
No resistant parasites were found in the Cambodian samples, but
samples from French Guiana and Senegal showed signs of resis-
tance.
The report suggests that the uncontrolled use of artemisinins
might have created conditions favourable for the rise of resis-
tant malaria -- especially in French Guiana, where the local
parasite population has undergone considerable genetic mutation
over time.
They also predict that under the carefully controlled regime of
artemisinin use prevalent in Cambodia, resistance might be de-
layed or possibly even prevented.
In response to the widespread emergence of malaria parasite
strains that are resistant to several drugs, the World Health
Organization (WHO) has recommended the use of artemisinin-based
combination drug therapy as first-line treatment.
Artemisinin, which is extracted from a Chinese herb known as
sweet wormwood, is the most potent and fastest-acting antimalar-
ial. So far, there has been no evidence of resistance to it in
human malaria parasites.
Jambou told SciDev.Net that lowered sensitivity to artemisinin
in the parasite was associated with mutations -- changes in DNA
-- in a gene called serca, which is known to be sensitive to
this class of compound.
To prevent any widespread incidence of artemisinin-resistant ma-
laria, Jambou says that monitoring and further research are im-
portant.
"We need to survey any appearance of new mutations, especially
in Africa, where all the control programmes are currently moving
their drug policy to ACTs," he says. "We also need to research
other genes potentially involved in artemisinin resistance by in
vitro studies."
Jambou adds that the drug should only be administered in ap-
proved artemisinin-based combination therapies (ACTs), and never
alone.
He says it is possible that the Cambodian samples showed no sign
of resistance because at the time they were taken, in 2001, ar-
temisinin was only used in combination therapies there. Accord-
ing to the Cambodian health ministry, however, there is now an
illegal market for artemisinin in the country.
"Jambou and colleague's paper is a wake-up call," write US re-
searchers Patrick Duffy and Carol Sibley in a comment published
with the report.
"We ignore this warning at the risk of a rapid demise of ACTs
that are currently just being tested and deployed," they add.
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More Evidence of Malaria Vaccine Breakthrough
Agencia de Informacao de Mocambique (Maputo)
December 12, 2005
Posted to the web December 12, 2005
London
The London-based medical journal "The Lancet" has published fur-
ther evidence that a malaria vaccine being tested on over two
thousand children in Maputo province provides partial protection
for at least 18 months.
The team working at the Health Research Centre in Manhica, about
80 kilometres north of the Mozambican capital, have found that
the vaccine reduces the risk of clinical malaria by 35 per cent,
and nearly halves the risk of severe malaria over a period of a
year and a half.
Malaria, along with tuberculosis and HIV/AIDS, are key diseases
that need to be tackled in Africa if chronic poverty and sick-
ness are to be overcome. It has been estimated that the economic
cost of malaria in Africa is 12 billion US dollars annually.
Worldwide, malaria kills over a million people each year.
The latest issue of "The Lancet" contains hope that a vaccine
can be developed and brought onto the market. It states that
"with sustained funding and improved international partnerships,
the first two decades of this century are likely to witness vac-
cines being part of the armoury against malaria in use through-
out the endemic areas of Africa".
The vaccine under trial, RTS,S/AS02A, has been developed by the
pharmaceutical giant GlaxoSmithKline (GSK), in collaboration
with the Walter Reed Army Institute of Research. Fears had been
raised after a study in the Gambia had found that the effects of
RTS,S/AS02A were short lived when tested on adults.
To ensure that the trial was carried out ethically, both in
terms of getting unbiased results and crucially making sure that
the children involved in the trial were treated according to the
highest international standards, the methodology was approved by
the National Mozambican Ethics Review Committee, and the Hospi-
tal Clinic of Barcelona Ethics Review Committee.
As part of its findings, the team working on the vaccine in Mo-
zambique found that the vaccine was safe and well-tolerated.
Research is continuing into how to further improve the effec-
tiveness of the vaccine.
"The Lancet" concludes that RTS,S/AS02A is "a promising vaccine
candidate and strongly suggests that malaria vaccines have an
important role as future public-health instruments".
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Malaria 'Wonder' Drug to Cost Less
The Nation (Nairobi)
December 15, 2005
Posted to the web December 15, 2005
By Gatonye Gathura And Reuters
Nairobi
The cost of the latest and most effective malaria pills could
drop from the current average of Sh500 per dose to less than
Sh100 by next year- but in a strange turn of events new studies
claim resistance is already building against these drugs.
Seen as the last line of defence against malaria, the artemesi-
nin-based combination therapies or ACTs cost between Sh450 and
Sh700 in Kenya and only available in the private sector. Poor
Kenyans who cannot afford this are still using the much less ef-
fective SP drugs costing about Sh80 per dose.
Although the country officially shifted to the new line of
treatment two years ago the pills are yet to appear in public
hospitals following complex government procurement structures.
Consequently, the availability of the drugs at less than Sh100
per dose could make the difference between live and death for
thousands of Kenyans.
According the Drugs for Neglected Diseases Initiative, a not-for
profit group, two pharmaceutical companies have agreed to pro-
duce cheap and easy-to-take combination doses of these malaria
pills.
France's Sanofi-Aventis and Brazil's Far-Manguinhos will make
the drugs without patenting them, and will work to get the cost
down to less than $1 (about Sh75) a dose, the group said.
"The reason that countries are using lousy drugs to treat ma-
laria is that they can't afford better drugs," said Nick White
of Britain's Oxford University and the nonprofit Wellcome Trust,
who worked on the initiative.
"Malaria actually could be fixed. We don't need a miracle drug.
We don't need a miracle vaccine. We have the tools now," White
added. "We actually could save millions of lives."
But this optimism could be shattered by a new study indicating
that this class of malaria drugs is already losing its potency.
In a paper published in The Lancent last week, scientists from
the Pasteur Institute Network had found resistance to artemisi-
nin in blood samples from patients in Senegal and in French
Guiana. In both countries, they said, the drugs were not being
used with proper controls.
The scientists, Ronan Jambou, Eric Legrand and colleagues, also
tested blood from patients in Cambodia, where the drugs are con-
trolled, and did not find resistance in those samples.
In French Guiana the scientists uncovered resistance in Cacao, a
small town where artemisinin derivatives were being illegally
imported from south-east Asia. Resistance was also found in the
gold mining region along the Maroni river, where people were
treating themselves with illegally imported artemisinin drugs.
In Senegal the artemisinin drugs were being given alone, and not
in combination with other anti-malarials, as is normally recom-
mended.
Last month, malaria experts reported that counterfeiters in
South East Asia were producing dilute fake versions of the drugs
- raising the risk of resistance.
A British Broadcasting Corporation report said the fake versions
being produced by counterfeiters do not contain enough of the
active ingredient to kill the malaria parasite, falciparum. So
exposure to it gives the malaria the chance to develop resis-
tance.
Although it is not known how wide-spread the fake drugs are, Af-
rica a net exporter of malaria medicines, will be the most af-
fected with its weak regulatory and monitoring systems.
Dr Bernard Pecoul, executive director of the Drugs for Neglected
Diseases Initiative, said the group was now talking to the US
Agency for International Development, the World Bank and the
Global Fund for Aids, Tuberculosis and Malaria to see if they
would help pay for and distribute the pills.
Gilles Roche of Sanofi said the company was looking at ways to
grow the artemisia plant in Africa. "The problem is the Chinese
-they keep the price up. They have a monopoly," Roche said in an
interview.
"We have to break the monopoly."
That will help get the price down to a dollar a dose, he said.
--
Leela McCullough, Ed.D.
Director of Information Services
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