UC Berkeley researchers have engineered yeast to produce a precursor to artemisinin, the most effective antimalarial drug known -- an achievement that could drastically lower the cost of the drug.
Artemisinin is nearly 100% effective in curing malaria, but it must be laboriously extracted from the sweet wormwood plant, Artemisia annua, grown primarily in China. A three-day supply of the drug costs $2.40 -- a big hurdle in developing countries where malaria is endemic.
The researchers think the new approach could bring the cost down to 25 cents.
Malaria strikes an estimated 300 million to 500 million people each year, killing at least 1 million and perhaps as many as 2.7 million. It is second only to AIDS as a cause of death by infectious disease.
Bioengineer Jay D. Keasling of UC Berkeley and his colleagues have been attempting to produce the drug, funded by a $43-million grant from the Bill and Melinda Gates Foundation.
They announced in 2003 that they had succeeded in producing a precursor to artemisinin called amorphadiene. But several chemical steps were still needed to make the desired product.
Last summer, Dae-Kyun Ro in Keasling’s laboratory identified the gene for an enzyme that converts amorphadiene to artemisinic acid, a chemical much closer to artemisinin. The team reported this week in the journal Nature that they then engineered yeast to produce artemisinic acid.
“This is probably as close to artemisinin as we are going to get in microbes,” Keasling said. “The rest is going to be done by chemistry.”
He predicted it would take up to five years to produce commercial quantities of the drug.
The rights to the process were donated to Amyris Biotechnologies of Emeryville, Calif., which will sell the drug at cost to African nations. Testing will be funded and overseen by the Institute for OneWorld Health, a San Francisco nonprofit.