Poor quality malaria drugs endanger millions of lives

Poor quality artemisinin combination therapies (ACTs) may contribute to the emergence of drug resistance, thus risking the millions of lives that depend on the continued availability and efficacy of these drugs.

“Poor quality ACTs, along with poor prescribing practices and adherence, provide fertile grounds for the spread of artemisinin resistant parasites,” explains Dr Paul Newton, co-author of a recent report on suspect antimalarial samples collected from 11 African countries between 2002 and 2010. 

Poor quality medicines are of two main types: falsified and substandard. Falsified medicines (also known as counterfeit or fake) are intended to deceive health workers and patients, and usually contain either none of the active ingredient or the wrong active ingredients. Substandard medicines are the result of mistakes in pharmaceutical production or poor shipping and warehousing practices: they usually contain insufficient quantities of the active ingredient.

Dr Newton and his colleagues documented falsified antimalarials in eight of the African countries. Some of the falsified medicines contained substances with potentially serious side effects, both for individual patients – sometimes life-threatening – and for public health.  For example, falsified DHA-piperaquine containing sildenafil (Viagra) was found. Sildenafil may have serious adverse effects in very sick patients, who would not normally take this medicine, and in those taking anti-retrovirals for HIV. Others, such as falsified ‘halofantrine’, contained sub-therapeutic levels of artemisinin derivatives, which are very unlikely to cure malaria but greatly increase the risk of the emergence of resistance. Worryingly, they may also contain just enough of the artemisinin derivatives to pass quality screening tests, mistakenly allowing them to enter supply chains undetected.

The report illustrates the global challenges in controlling the manufacture and distribution of antimalarial medicines. No evidence was found to suggest that the falsified drugs had been manufactured in Africa, although illicit packaging material production facilities have been seized in Nigeria. Pollen analyses implied that the poor quality drugs may have been made in eastern Asia, where poor quality drugs already pose a significant public health threat. 

“Although our study does not allow us to estimate the frequency of poor quality antimalarials in Africa, the fact that they exist at all is a matter for grave concern,” comments Dr Newton.

A critical challenge facing the international community is the lack of information on the scale of the problem. As suggested by the variety of falsified medicines uncovered by Dr Newton and his colleagues, even defining falsified drugs can be a difficult.  Last December, Dr Newton headed a call by leading scientists to put public health considerations ahead of intellectual property in efforts to define poor quality medicines and improve the quality of medicines in developing countries. In a PLoS Medicine essay examining the issues, the authors proposed that the World Health Organization is supported and encouraged to take more urgent action in reaching agreement on, and finding solutions to, issues related to substandard and falsified medicines, and to play a more prominent role in improving the world’s medicine quality and supply.

Dr Newton emphasizes, “We need comprehensive information to understand poor quality antimalarials and where they are entering the supply chain.”

WWARN is uniquely positioned to support international efforts through knowledge sharing activities. WWARN aims to work with key stakeholders to collate information that will improve our understanding of the prevalence and distribution of poor quality antimalarial drugs; facilitate standardisation of terminology; improve sampling and analytical methodology; and, to advocate for more investment in this vital aspect of public health. 

As Dr Newton recently told the BBC, “The enormous investment in the development, evaluation and deployment of antimalarials is wasted if the medicines that patients actually take are, due to criminality or carelessness, of poor quality and do not cure.” 

“Our duty is to act fast to stop patients, usually the world’s poorest, dying needlessly of a disease that can be cured with timely good quality medicines,” concludes Dr Newton.