Fake antimalarial drugs analysis highlights threat to global health

A unique collaboration between scientists, public health workers and police has led to the arrest by the Chinese authorities of alleged traders of fake anti-malarial drugs in southern China and the seizure of a large quantity of drugs. The work, involving teams from across the globe, has highlighted both the growing threat posed by fake pharmaceuticals and the complexities of tracking down those responsible for the trade.

Dubbed Operation Jupiter, the investigation was coordinated by the International Criminal Police Organisation (INTERPOL), the World Health Organization’s Western Pacific Regional Office, and the Wellcome Trust-University of Oxford SE Asian Tropical Medicine Research Programme, in close cooperation with Chinese authorities. Scientists from 5 other laboratories analysed the composition of the fake drugs and their packaging. The results of this collaboration are published in the open access journal PLoS Medicine.

Fake anti-malarial drugs are an increasingly serious problem, particularly in South-East Asia and Africa. In countries with a large burden of malaria, such as Myanmar (Burma), the Lao PDR, Cambodia and Viet Nam, as many as half of all artesunate tablets – one of the most effective anti-malarial drugs – is counterfeit.

Most of the fakes examined as part of Operation Jupiter contained no artesunate, and some contained a wide range of potentially toxic wrong active ingredients. Also of grave concern was the fact that counterfeiters sometimes included dangerously small amounts of artesunate in the tablets. This may be done to foil screening tests of drug quality, but these doses are too low to be efficacious, yet high enough to contribute to malaria parasites becoming resistant to this class of drugs.

"Artesunate, as part of artemisinin-based combination therapy, is vital for malaria treatment and is one of the most effective weapons we have against this terrible scourge," says Dr Paul Newton of the Wellcome Trust-University of Oxford SE Asian Tropical Medicine Research Programme. "Those who make fake anti-malarials have killed with impunity, directly through the criminal production of a medicine lacking active ingredients and by encouraging drug resistance to spread. If malaria becomes resistant to artesunate, the effect on public health in the tropics will be catastrophic."

In addition to analysing the chemistry of the samples, researchers used a technique known as forensic palynology to study pollen contamination within the fake tablets with the aim of tracking down the likely location of manufacture. The pollen evidence suggested that at least some of the counterfeit artesunate came from southern China, and this was supported by examination of the mineral calcite, found in some of the samples.

Armed with these findings by INTERPOL, Chinese authorities arrested a suspect in China’s Yunnan Province in 2006. He is alleged to have traded 240,000 blisterpacks of counterfeit artesunate, enough to "treat" almost a quarter of a million adults with a medicine with no activity against a potentially fatal disease. Whilst the Chinese authorities were able to seize 24,000 of these packs, the remainder are alleged to have been sold at crossings on the border of Yunnan and Myanmar (Burma), accounting for almost a half of all blisterpacks of artesunate sold to the region.

The work of the Jupiter group highlights the need for more to be done internationally to support countries with a high prevalence of counterfeit anti-malarials in their attempts to combat this severe but under-recognised public health problem.

"Criminal investigations and legal action are important in disrupting and inhibiting the trade in fake medicines, but to be effective these will require financial support and resources," says Dr Newton. "Forensic tools may make it easier to identify the fake drugs and allow over-stretched police forces to focus on objective leads, greatly increasing the risks to counterfeiters of being caught. However, there are very few laboratories with the resources to perform detailed forensic chemistry or pollen analysis of fakes, particularly in the countries where they are most needed."

(Source: PLoS Medicine: Craig Brierley: Wellcome Trust: February 2008)