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Halt called on single-drug antimalarial prescriptions

January 20, 2006 By Jacqueline Ruttimann This article courtesy of Nature News.

Irresponsible treatments could render artemisinin ineffective.

The World Health Organization (WHO) is calling for pharmaceutical companies to stop marketing a key malarial drug as a single, as opposed to combination, treatment amidst fears that the malaria parasite will develop resistance to the drug.

On 19 January, WHO representatives in Washington DC announced that although most countries have adopted combination therapies as their first line of treatment, many have not yet pulled their practices into line with their policies. Out of 34 African countries committed to combination therapies, at least ten still allow the distribution of artemisinin, one of the most effective antimalarials, on its own.

Experts worry that this practice will encourage the parasite to become resistant to artemisinin, with disastrous consequences for malaria treatment. "If we lose artemisinin, we will no longer have an effective cure for malaria," says Arata Kochi, director of the WHO's malaria department.

If we lose artemisinin, we will no longer have an effective cure for malaria.
Arata Kochi
Director of the WHO's malaria department
If the bug is blitzed with a combination of drugs instead, the chances of it evolving resistance are minimized.

The day before the announcement, the WHO met with pharmaceutical companies to go over their new malaria treatment guidelines, and to ask them to stop marketing artemisinin as a single drug. Half of these companies already produce the combination therapy as well as the single-drug therapy, says Andrea Bosman, a medical officer with the Roll Back Malaria programme. He says the cost of such a shift "would be very minimal".

Artemisinin combination therapies currently are the single most effective treatment to cure malaria. These combination therapies have a 95% cure rate and work more quickly than artemisinin alone, but can be more expensive.

Past mistakes repeated?

The malaria parasite has a history of overcoming antimalarial drugs. The once-popular chloroquine, for example, is no longer effective in many parts of the world. Sulphadoxine-pyrimethamine lost about 90% of its effectiveness in Thailand within five years of being introduced in 1977. And the parasite became resistant to atovaquone within just one year of its introduction in 1997.

"We cannot afford to repeat mistakes from the past," says Kochi. "The only way to beat malaria is to be ahead of the parasite and counter drug resistance before it develops."

There are no signs of resistance to artemisinin so far, but with other drug options still many years down the pipeline, healthcare officials do not want to take the chance.

Single-drug bans

A dozen malaria-endemic countries have systems in place to restrict the marketing and availability of a single-drug form of artemisinin, says Bosman. Sudan, for instance, has a ban on the import of these monotherapies.

But Bosman says at least seven pharmaceutical companies with a strong presence in Africa are still marketing single-drug treatments.

Herwig Jansen, research and medical director of Dafra Pharma, told that they are aware of the problem and will try to comply with the guidelines. "It's not that easy," says Jansen. Jansen says that a large part of the market is still flooded with single-drug-based treatments in countries where it is being distributed. He warns that a sudden ban, rather than a phase out, may cause people to resort to cheaper forms of treatment that are less effective and already have resistance problems.

Malaria afflicts approximately 350 million to 500 million people worldwide, most of which are in Africa and Southeast Asia. One child dies every 30 seconds from this disease. Due to the large numbers of people affected, Bosman says, malaria is a billion-dollar market for pharmaceutical companies.


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