Outwitting the counterfeiters: falsified drugs and the fight against malaria

Not many research scientists find themselves working with Interpol to track down the manufacturers of illegal drugs on the border between China and Burma. But that was one of the outcomes of a project led by Dr Paul Newton, who directs the Lao Oxford Mahosot Wellcome Trust Research Unit (LOMWRU) in Vientiane, Laos. In the style of a TV detective drama, forensic evidence suggested a location, the Chinese police pounced, perpetrators were arrested, and an important supply route for drugs was broken.

These drugs were not heroin or cocaine, but fake versions of the most effective treatment for malaria (the artemisinins). Research coordinated from the Mahidol Oxford Research Unit (MORU) in Bangkok in the past two decades proved that artesunate, a plant-based drug developed in China, considerably reduces deaths from severe malaria in both adults and children. Giving artesunate in combination with another antimalarial as artemisinin combination therapy (ACT) helps to guard against the emergence of resistant strains of parasite.

The success of ACTs has led to the wide distribution of counterfeits, which if unchecked could destroy their impact and leave malaria-endemic countries with no effective response to the disease. 'Fake drugs have a history going back to the Ancient Greeks', says Dr Newton, 'but in the past 50 years their study has been neglected.'

'Falsified artesunate is very widespread, but how common it is we just don't know,' he adds. His own early studies were, he volunteers, based on 'convenience sampling': going to local pharmacies, buying a few packets and testing them. Although these studies found falsified drugs in circulation across Africa and Asia, they were not designed to estimate the frequency of the problem.

The fakes often contained not just chalk or some inert substance, but a whole range of other chemicals, sometimes including a reduced dose of artesunate. Spotting them takes specialist knowledge – tiny errors in the printing of the packaging may give them away, or a variety of chemical techniques can be used to analyse the content of the pills. But the major problem, says Dr Newton, is not a matter of technology.

'A lot of countries – 30 per cent in Africa – do not even have a national regulatory agency for drugs', he says. 'International agencies have focused their attention on access to medicines, and medicine quality has been neglected.' Dr Newton's experience suggests that surveillance involving close cooperation between researchers, forensic specialists, medicines regulatory agencies and police is necessary to keep track of the problem, but he acknowledges that it is 'time-consuming and expensive'.

Neglecting drug quality could prove much more costly in the long run, however: fake artesunate has already caused deaths from untreated malaria, loss of confidence in a valuable drug, and loss of income for legitimate manufacturers. The first signs of resistance to ACTs have already emerged in Cambodia and Thailand: if falsified drugs contribute to this worrying development, says Dr Newton, the consequences for public health could be disastrous.