Award-winning malaria scientist warns of drug resistance

Carly Weeks | 25 Oct 2010
Globe and Mail
The most effective malaria treatment ever discovered was not developed by a team of scientists in a high-tech lab. It was created using a traditional Chinese herbal remedy that had been used to treat illness for hundreds of years.

The treatment is made using a compound, artemisinin, isolated from a herb used in traditional Chinese medicine. It is 95 per cent effective at curing malaria, according to the World Health Organization.

But Nicholas White, one of the scientists who pioneered the development of artemisinin-based malaria therapies, is warning that growing parasite resistance to the treatment, spurred in large part by the massive marketing of counterfeit versions, could have major consequences down the road - perhaps even making the drug ineffective.

Malaria is caused by a parasite, which is spread to humans by infected mosquitoes. It causes a variety of symptoms, including fever and chills, and can progress to more serious illness or death.

Dr. White, director of Mahidol Oxford Tropical Medicine Research at Mahidol University in Bangkok and one of the world's leading malaria experts, is being honoured in Toronto this week as winner of the 2010 Canada Gairdner Global Health Award, given to those who have made major scientific advances in the developing world.

Six other individuals, including one Canadian, will also receive awards for their contributions to medicine and science at an awards gala in Toronto on Thursday. The Canada Gairdner award, one of the world's most prestigious medical honours, has developed a reputation for early recognition of future Nobel prize winners.

Dr. White said he first came across the use of artemisinin to treat malaria in a small Chinese journal in 1981. The treatment had been used there for years,and appeared to be safe and effective, he said.

It was a major breakthrough, since drugs that were commonly prescribed to treat malaria at the time failed to work in many people, largely because of parasite resistance.

"[It was] almost too good to be true," Dr. White said in an interview.

But after years of trying to convince the international health bureaucracy of how important artemisinin-based therapies could be, Dr. White said he continued to face resistance from officials who felt the treatment hadn't been studied well enough.

"Although there was a lot of evidence the drug worked, no one was recommending them or using them," Dr. White said.

His team launched its own trials to try to prove how well the drug worked, and what a difference it could make in the fight against malaria, which kills at least a million people around the world every year.

Amir Attaran, who holds a Canada Research Chair in Law, Population Health and Global Development Policy at the University of Ottawa, was one of the advocates who pressed Dr. White's case for wide acceptance of artemisinin-based malaria therapies.

Eventually, after years of work and political fighting, the World Health Organization began recommending a few years ago that artemisinin drugs should be the first line of treatment for malaria, so long as it was used in combination with other anti-malarial drugs.

It's an important caveat. Evidence shows that resistance to artemisinin treatments, when they are given on their own, is rising because the drugs weaken the parasite but don't kill it. Combining treatment with other anti-malarial drugs cures about 95 per cent of cases and dramatically reduces the risk of drug resistance.

The WHO's recommendations might not mean much, however, unless something is done to curb the market for counterfeit artemisinin drugs. These often contain small amounts of artemisinin - not enough to treat the malaria, but enough for the bug to develop resistance. Furthermore, people who take counterfeit artemisinin don't take the recommended combination of other anti-malarial drugs, which also greatly increases the chance of drug resistance.

It's a major problem that could threaten the future effectiveness of artemisinin-based therapies, Dr. White said.

"We have no idea what the real true proportion of counterfeits are, but some people say up to half are fake."

Programs have been put in place to subsidize the cost of the drug and make them widely available for a lower cost, which should help eliminate the black market for counterfeit drugs, Dr. White said.

It is still an uphill battle, and one that needs much more support from wealthy, developed countries such as Canada, he added. But his achievements, set in motion by Chinese researchers who recognized the importance of an ancient herbal remedy, mean the eradication of malaria is once again a possibility.