A CHEAP and effective treatment for malaria could be available within a decade after scientists genetically engineered a form of yeast to make the key ingredient of the drug best able to fight the disease.

The advance by a research team in the United States should reduce greatly the cost of manufacturing artemisinin, the most effective therapy for the world’s second-most deadly infectious disease.

Artemisinin combination therapies (ACTs), in which the drug is given in combination with older anti-malarial treatments, are recommended by the World Health Organisation as the best way of fighting malaria. But the cost places them beyond the means of many of the developing countries where malaria is most prevalent.

At present, artemisinin can be made only by using an acid extracted from the sweet wormwood plant, Artemisia annua, which is grown in China. The raw material is expensive, raising the cost of a dose of ACT to about £1.35 per person. By producing artemisinic acid, the key precursor of artemisinin, artifically from genetically modified yeast or bacteria, the researchers hope that they will eventually be able to reduce the cost to as little as 14p per dose, making it more widely available in poor countries.

Malaria kills more people than any infection other than HIV/Aids, with an annual death toll estimated at between 1 million and 2.7 million. It infects between 300 million and 500 million a year, chiefly in Africa.

The new strain of yeast has been engineered by a team led by Jay Keasling, Professor of Bioengineering at the University of California, Berkeley, which discovered two years ago that it was possible to modify microbes to make artemisinic acid.

The yeast, details of which are published today in the journal Nature, is an efficient producer of the acid and should allow scientists to sidestep expensive laboratory processes needed at present to synthesise artemisinin.

Although the scientists do not believe that it will be possible to make artemisinin itself in microbes, they say that making the precursor is almost as good. All the artimisinin drugs on the market are made from the precursor acid.

“This is probably as close to artemisinin as we are going to get in microbes,” Professor Keasing said. “The rest is going to be done by chemistry. This was our highest hurdle, what kept me up at night. Now that we’ve got all the parts, I feel it’s just a matter of time before we have a microbe ready for scale-up to production.”

It will probably take five to ten years to develop the yeast as a large-scale producer of artemisinic acid. The work, which also involves Amyris Biotechnologies, a California-based company, is supported by a $43 million (£25 million) grant from the Bill and Melinda Gates Foundation.

Victoria Hale, chief executive of the Institute of OneWorld Health, a non-profit pharmaceutical company that will start testing the new product, said: “The team at UC Berkeley has done a great job. We still have a long way to go, but this puts us one step closer to a low-cost treatment for malaria.”

Other groups of scientists are working on an entirely synthetic drug called OZ227, which is based on artemisinin’s action and could also be mass-produced at low cost.

KILLER DISEASE

Famous sufferers: Alexander the Great, Genghis Khan, Oliver Cromwell, Edward IV, Caravaggio and David Livingstone are thought to have died of malaria. Figures who contracted it and recovered include Lord Nelson, Sir Arthur Conan Doyle, Mahatma Gandhi, Ernest Hemingway and John F. Kennedy

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