AFRO-NETS> NYTimes.com Article: Genetic Map Speeds Hunt for New Malaria

[Leela McCullough <leela@usa.healthnet.org>]

NYTimes.com Article: Genetic Map Speeds Hunt for New Malaria
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Date: Wed, 2 Oct 2002 17:05:50 -0400 (EDT)
Copied as Fair Use

Genetic Map Speeds Hunt for New Malaria Drugs
October 2, 2002
By REUTERS

LONDON (Reuters) - As part of a campaign against malaria, scientists 
have decoded the genetic codes of the malaria parasite and the mos-
quito that spreads it. Cracking the genetic code of the malaria para-
site will speed the hunt for new drugs to tackle the killer disease, 
which is growing resistant to conventional medicines. Professor Brian 
Greenwood, head of the 80-strong malaria center at London School of 
Hygiene and Tropical Medicine, sees the breakthrough announced 
Wednesday as a major advance. "It will accelerate the rate at which 
we get new tools for malaria control," he told Reuters. In addition 
to new drugs, understanding the genetic make-up of both the mosquito 
and its Plasmodium falciparum parasite could help in the development 
of new insect repellents and traps to prevent mosquito bites. The 
need for new medicines has never been more urgent.

Malaria kills more than one million people each year -- 90 percent of 
them in sub-Saharan Africa, where infections are running at record 
levels.

And traditional tablets are losing their potency. "It's very impor-
tant to find new drug targets. The present cheap drugs that we've got 
are useless in Southeast Asia and the parasite is becoming increas-
ingly resistant in Africa," Greenwood said. For decades, the mainstay 
treatment for malaria has been chloroquine, a medicine costing about 
six cents for a course, which has saved millions of lives. But now 
parasites are becoming resistant to chloroquine and, more recently, 
to sulphadoxine-pyrimethamine, or Fansidar, another cheap drug chosen 
when chloroquine fails.

Other, newer drugs have been developed, including artemisinin-based 
combination therapies, derived partly from a Chinese herb -- but the 
number of options in the medicine cabinet is running low. NEW TARGETS 
With the entire inventory of genes in P.falciparum at their finger-
tips, scientists are seeking new ways to hit the parasite. "Any an-
timicrobial drug has to knock out a biochemical pathway in a pathogen 
but not affect the human host. The way to identify those drugs is to 
look for pathways which are unique to the pathogen," said Dr. Neil 
Hall of Britain's Sanger Institute. The team of 150 researchers in 
the United States and Britain that sequenced all the genes in the 
threadlike organism have, in fact, already pinpointed six potential 
new drug targets. Screening and developing active pharmaceuticals 
against those targets will take time -- and money. Big pharmaceutical 
firms have little commercial incentive to do this work, since malaria 
is not a major problem in the West, but a number of public-private 
initiatives are tapping into companies' know-how to find cheap alter-
native treatments. Britain's GlaxoSmithKline Plc is one group working 
with the World Health Organization and various charities to try and 
roll back malaria, via new drugs and vaccines. Dr Joe Cohen of GSK's 
biologicals division in Belgium believes the latest genome work will 
be a boon to drug researchers who can use robots to screen rapidly 
for new compounds that block against specific genes and proteins. 
Making an effective vaccine, though, will take longer.

"It is positive for vaccine development in the long term, but I would 
see most of the benefits in the short to medium term in helping iden-
tify new targets for drug development," he said. 

VACCINE BY 2010? 
Creating a malaria vaccine is proving more difficult than scientists 
had expected because the parasite has many mutations. That makes it a 
moving target and, while some 30 different approaches are being as-
sessed, there are no guarantees they will work or be effective in 
different countries. Dr. Filip Dubovsky, chief scientific officer 
with the Malaria Vaccine Initiative in Washington, said developing 
and testing new vaccines would be a long, drawn-out process. "Devel-
opment is the stumbling block. Even after you have the sequence and 
the protein, it still requires a huge amount of work to translate 
that into a product in a vial that you can test on people," he said. 
The most advanced vaccine candidate, being developed by GSK in asso-
ciation with non-profit making groups, is currently in clinical tri-
als in Mozambique. "I think by the end of this decade we could launch 
that, if everything goes well," Dubovsky said. 
http://www.nytimes.com/2002/10/02/health/02RTRS-


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Dr. Leela McCullough
Director of Information Services
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