May 29, 2009

expert reaction to Cambodian reports of malaria parasite resistance to drugs

Scientists in Cambodia have reported growing resistance to the artemesinin family of drugs, which currently the most effective treatments for malaria available.

Prof Andrew Read FRSE, Professor of Biology and Entomology at Pennsylvania State University, said:

“This is bad news, but completely expected. The history of malaria is one of continual failure in the face of evolution; nothing this time was going to change that. It will also be true for the next generation of drugs. Unless we come up with something very radically different, it’s always going to be a question of when, not if. So we need to plan for the inevitable, and keep funding the treadmill of drug development. But we should also think about whether there are smart ways to use new generation drugs to slow that treadmill down.”

Prof Brian Greenwood, Professor of Tropical Medicine at the London School of Hygiene and Tropical Medicine, said:

“The findings in Cambodia are a matter for concern. It was always expected that resistance to the artemisinin-based drugs would emerge at some stage but we had hoped that this would not be for some time yet. `The evidence is sound that the falciparum parasites in western Cambodia have become partially resistant to artemisinins but treatment still works if a full course of artemisinin combination therapy (ACT) is taken. Thus, there is currently no need for panic but it would be serious if these partially resistant parasites reached Africa where great gains in malaria control are currently being made using ACTs and insecticide-treated bed nets. Attempts to eliminate these partially resistant parasite are, therefore, justified, but this is going to be difficult to achieve.”

Prof David Molyneux, Liverpool School of Tropical Medicine and President of the Royal Society of Tropical Medicine and Hygiene, said:

“The reports of reduced susceptibility to artemisines in Cambodia are evidence of history repeating itself. At least there is now increased attention being paid to malaria as a massive health problem with greater investment in developing new drugs. The lessons that have not been learned, however, are the urgent need to control markets in fake antimalarials, the need to upscale vector control to reduce transmission and the fact that the malaria parasite is the most rapidly reproducing parasite. Resistance is to be expected – we should not be surprised that it occurs. The reports suggest that the expectation of malaria ‘eradication’, let alone regional elimination of transmission, is an overoptimistic goal when research and public health authorities are confronting a parasite and vector of such adaptability and diversity. Control is more realistic, preferably with more integrated and comprehensive approaches.”

Dr Jasmina Saric, Department of Biomolecular Medicine, Imperial College London, said:

“The standard artemisinin-based combination therapy (ACT) at the Cambodia-Thailand border consists of artesunate and mefloquine, and a reduced anti-malarial activity of the same combination has already been detected in 2007 in the south of Cambodia. There are various factors which can contribute to the development of a drug resistance and reach from already existing resistances in the partner-drug, e.g. mefloquine, to a sub-optimal public health structure – which leads to inappropriate use of the drug and a poor control of quality and drug-distribution.”