科学与发展网络(SciDev.Net)

Artemisinin annua

USDA/Scott Bauer

[HYDERABAD] Scientists report that a low-cost antimalarial drug could hit the market in the next two years.

Jay Keasling, professor at the Department of Chemical Engineering and Bioengineering at the US-based University of California, Berkeley, reported at the 13^th Human Genome Meeting in Hyderabad, India, last week (26 September) that drug firm Sanofi is making cheaper antimalarials using a technology based on genetically-engineered yeast cells.

The cells are engineered to contain the gene for artemisinin, an antimalarial compound from the herb Artemisia annua.

The technology was developed in 2005 by the Berkeley team, headed by Keasling, and the California-based firm Joint Bioenergy Institute. The team has licensed the technology to Sanofi for commercial drug production.

Keasling points out, "Currently, it costs US$1–2.5 per treatment (dose) with artemisinin per person. This is too expensive in many developing countries."

The WHO recommends the faster-acting, more effective artemisinin-based drugs for malaria, in view of the widespread resistance to quinine.

Other problems with using the natural plant product include uncertainties in the quality and quantity of the extract, and fluctuations in market price of artemisinin.

"Our goal is to make the yeast-derived version as cheap as possible," Keasling says. It takes a year-and-a-half for the Artemisia plant to start producing artemisinin, but only a week for yeast cells to produce the substance in a fermenter.

Keasling estimates the new drug should hit the market by late 2010. He did not disclose exactly how much cheaper it would be compared to natural artemisinin, but says it is expected to cost less than the current price.

In another development, scientists from the US-based University of Illinois have developed a technique that can make bacteria produce large amounts of an antimalarial compound they call 'FR900098'. It belongs to a group of substances called phosphonates that are made naturally by bacteria.

A team led by William Metcalf, professor of microbiology at the university, isolated and sequenced the bacterial genes responsible for making phosphonates.

Reporting the details in the 25 August issue of Chemistry and Biology, the scientists say the bacteria can now be genetically manipulated to produce large amounts of the substances.