Drug resistance is the main barrier to effective malaria treatment. Artemisinin (extract of sweet wormwood , commonly used in Chinese herbal medicine) and its derivatives, artemether and artesunate, are of potential importance as other malarial drugs have been associated with microbial resistance.
A meta-analysis by the International Artemisinin Study Group of 16 randomised trials (12 from sub-Saharan Africa, three from Thailand, one from Peru) shows that artesunate was highly effective in treating malaria when added to other antimalarial drugs. Around 6000 patients were participants in the studies. Artesunate decreased parasite failure by around 80% and doubled the rate of parasite clearance compared with patients given standard malaria treatment.
Patrick E Duffy and Theonest K Mutabingwa consider in an accompanying Commentary (p 3) the policy implications for the use of artemisinin combination treatment (ACT) in different countries. They comment: "Will ACT reduce malaria incidence and prevent the emergence and spread of drug-resistant parasites in Africa, as occurred in southeast Asia? Only additional research will answer these questions. However, because of differences in epidemiology and intensity of transmission, reducing malaria incidence in Africa will be challenging."
A study from Vietnam in this week's issue (p 18) also assesses combination treatment for malaria. Tran Tinh Hien and colleagues found that the new combination dihydroartemisinin-piperaquine, formulated in a single tablet, is highly efficacious in Vietnam, where multidrug-resistant parasites are common. Authors of the Commentary state: "Dihydroartemisinin-piperaquine has a cost advantage (US$1 for an adult treatment) that brings it within reach of many but not all consumers, and encourages funding agencies to sponsor programmes that deliver these needed medicines to poorer countries."
Professor Paul Garner, International Health Division, Liverpool School of Tropical Medicine, Pembroke Place, LIVERPOOL L3 5QA; T) 44-151-707-1702; F) 44-151-708-8733; E) email@example.com
(Vietnam study) Dr Jeremy Farrar, Hospital for Tropical Diseases, Oxford University Research Unit, 190 Ben Ham Tu Quan 5, Ho Chi Minh City, Vietnam; T) 84-8-836-2225; F) 84-8-923-8904; E) firstname.lastname@example.org
Dr Patrick E Duffy, Malaria Antigen Discovery Program, Seattle Biomedical Research Institute, 4 Nickerson Street, Suite 200, Seattle, WA 98109, USA; T) 206-284-8846 x311; F) 206-284-0313; E) email@example.com