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 Artemisinin combination therapies
The need for combination therapies Artemisinin and its derivatives should be taken in conjunction with a partner drug as an Artemisinin Combination Therapy (ACT). There are two reasons for this. Firstly, artemisinin drugs do not last long in the human body. Because of this, partnering them with another drug that persists for longer improves treatment efficacy and reduces the duration of the treatment course that is required. Secondly, combining two drugs with different modes of action impedes the development of parasite resistance to either constituent: artemisinins are a vital part of our defences against malaria and so it is essential that their effectiveness is protected with combination therapies. The first ACT to become available internationally was Coartem™, a combination of artemether and lumefantrine, produced by Novartis. Its introduction to the KwaZulu Natal province of South Africa in 2000 contributed to a dramatic reduction in malaria transmission in conjunction with other measures such as insecticidal spraying and treated bed nets. A full treatment is a three-day course and the number of tablets per dose depends on body weight. It is taken orally with fluids (preferably drinks containing fat, such as milk). Other new ACTs are on the market or in development. Demand for artemisinin and ACTs The WHO has identified ACTs as the most effective treatments currently available for malaria. As a result, many malaria endemic countries have adopted them as their drugs of choice. From 2001-2006 demand for artemisinin rocketed from a few hundred thousand courses to around 80 million. In 2008 the Global Malaria Action Plan was published. This plan involved a major scaling up in the use of ACT malaria treatments. By 2010 annual demand had further risen to an estimated 229 million treatments. This level of usage requires around 115 tonnes of artemisinin. Novartis makes Coartem™ available at-cost for use by public health systems in developing countries, under an agreement with the WHO. Sanofi-Aventis also provides ASAQ on a no-profit basis. Despite these undertakings, ACTs are still more expensive than the medicines they are replacing. Treatment costs 37 - 87 cents with Coartem™ (depending on the age of the patient). This compares with a typical price of 10 -15 cents for treatment with chloroquine. Furthermore, a large proportion of anti-malarial drugs used in Africa are purchased through the private sector, where ACT prices are much higher. In Africa, private sector prices of as much as $12 for an adult ACT treatment were observed in 2007. The price of ACTs is an obstacle to their effective deployment. The situation should be helped by a global subsidy for ACTs, the Affordable Medicines Facility for Malaria (AMFm), which is due to be available globally by 2010. Lower ACT prices are essential to making these drugs accessible in countries where the annual health budget may be less than $4 per capita. The high production costs of artemisinin contribute to problems with expense and availability. Artemisinin production is expensive because of the low yield from Artemisia plants. High food prices make Artemisia an uneconomic choice for farmers. Planting areas are down and there is a fear of shortages. In the past, such shortages have led to price hikes. Poor quality and counterfeit drugs Effective malaria treatment is also threatened by poor quality drugs with incorrect composition or ingredients. his may be due to negligence, error, insufficient resources or counterfeiting. The number and sophistication of fake drugs on the market is increasing and the relatively high market value of ACTs makes them a prime target for counterfeiters. In some areas of Africa, up to 80 percent of the artemisinin drugs sold on the private market have been found to be counterfeited . The WHO estimates that poor quality or incorrectly used malaria drugs are responsible for 200,000 deaths every year.
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