{"id":210,"date":"2011-11-08T17:21:49","date_gmt":"2011-11-08T17:21:49","guid":{"rendered":"https:\/\/blogs.nature.com\/spoonful\/2011\/11\/antimalarial-armament-remains-strong-despite-lingering-concerns-over-drug-resistance.html"},"modified":"2011-11-08T17:21:49","modified_gmt":"2011-11-08T17:21:49","slug":"antimalarial_armament_remains","status":"publish","type":"post","link":"https:\/\/blogs.nature.com\/spoonful\/2011\/11\/antimalarial_armament_remains.html","title":{"rendered":"Antimalarial armament remains strong, despite lingering concerns over drug resistance"},"content":{"rendered":"

\"naturemed20111108.jpg\"Earlier this month, Indian regulatory authorities granted conditional approval<\/a> to the country\u2019s first homegrown drug, a malaria-fighting pill that combines a new synthetic form of artemisinin with an older antimalarial compound called piperaquine. If the decision is ratified by the country\u2019s Central Drugs Standard Control Organization, the new drug \u2014 developed from start to finish by the New Delhi-based pharmaceutical company Ranbaxy Laboratories \u2014 will add to doctors\u2019 armament of artemisinin-based combination therapies (ACTs), the World Health Organization\u2019s medicine of choice<\/a> for tackling the parasite. Yet with so many options, the question is: which ACT<\/span> is actually best at treating the infectious disease?<\/p>\n

A study comparing four ACTs should go a long way to answering that question. In a randomized clinical trial involving more than 4,100 newly infected children at 12 sites across seven sub-Saharan African countries, three widely-used artemisinin variants proved equally effective at ridding youngsters of the malaria parasite. All three ACTs cleared the infection in more than 95% of trial participants up to 63 days post-treatment. But a fourth combo drug \u2014 a newer antimalarial that combines chlorproguanil, dapsone and artesunate \u2014 proved only around 85% effective, and was removed from the study after its maker, London-based GlaxoSmithKline, pulled it from the market in 2008 because of adverse effects. The results were published today<\/a> in PLoS Medicine<\/em>.<\/p>\n

\u201cThis should reassure people that these are good drugs that are highly effective and well tolerated and that we should get them to people that need them,\u201d says Nicholas White<\/a>, a malaria epidemiologist at the University of Oxford in the UK, who was not involved in the study.<\/p>\n


\nThe three favorable ACTs are, naturally, combinations of synthetic forms of artemisinin, the active ingredient found<\/a> in the Chinese medicinal herb Artemisia annua<\/em>, with other anti-malaria drugs that are included in the mix to reduce the chance of malaria parasites developing resistance<\/a> to the stronghold artemisinin. The most widespread and oldest ACT \u2014 called AL for artemether-lumefantrine \u2014 was first used in clinical trials in 1998. Although it is still quite effective throughout the world, its twice-daily dosing creates compliance issues. The combination of artesunate and amodiaquine, or ASAQ, only requires once-daily dosing and has been quickly adopted since its release in 2007. The new kid on the block is a once-daily combination of dihydroartemisinin and piperaquine, or DHAPQ, which was approved in the EU<\/a> under the brand name Eurartesim earlier this year.<\/p>\n

Although all three were equally robust at eliminating malaria from the bloodstream after a single infection, two of the medicines \u2014 DHAPQ and ASAQ \u2014 provided better protection against secondary infections than AL, the new study found.<\/p>\n

The authors suspect that these two ACTs may persist in the blood longer, acting as a prophylactic against new infectious mosquito bites. But the longer action of these drug combinations comes with a price: it may allow new parasites to adapt and become resistant to the drugs, an effect that has plagued malaria treatment worldwide. The anti-malarial chloroquine, once used extensively, is no longer effective in some parts of the world because of parasite resistance, and mosquitoes are developing resistance to pyrethroids<\/a>, the insecticides used on bednets. In Southeast Asia, ACTs are less successful at treating malaria<\/a>, raising concerns about resistance to the first-line arteminisin-based medicines in that region \u2014 and the possible spread of those parasites to Africa.<\/p>\n

The high and comparable efficacy of ACTs in Africa, as demonstrated in this study, suggests that such resistant parasites have not yet reached the region, says White, who won last year’s Gairdner Prize<\/a> for his work on developing arteminisin as an anti-malaria drug. \u201cA great worry is that if those parasites would get to Africa, these results would no longer be excellent,\u201d he says. \u201cWe have to be vigilant about keeping resistance from getting to Africa.\u201d<\/p>\n

Image<\/a>: bottle of cloroquine, which has been replaced by ACTs as the recommended anti-malaria medication due to parasite resistance. Photo by Mat Honan on flickr under Creative Commons<\/a> licensing<\/em><\/p>\n","protected":false},"excerpt":{"rendered":"

Earlier this month, Indian regulatory authorities granted conditional approval to the country\u2019s first homegrown drug, a malaria-fighting pill that combines a new synthetic form of artemisinin with an older antimalarial compound called piperaquine. If the decision is ratified by the country\u2019s Central Drugs Standard Control Organization, the new drug \u2014 developed from start to finish by the New Delhi-based pharmaceutical company Ranbaxy Laboratories \u2014 will add to doctors\u2019 armament of artemisinin-based combination therapies (ACTs), the World Health Organization\u2019s medicine of choice for tackling the parasite. Yet with so many options, the question is: which ACT is actually best at treating the infectious disease?  Read more<\/a> Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":128,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7,20],"tags":[],"class_list":["post-210","post","type-post","status-publish","format-standard","hentry","category-drugs-drugs-and-more-drugs","category-malaria"],"_links":{"self":[{"href":"https:\/\/blogs.nature.com\/spoonful\/wp-json\/wp\/v2\/posts\/210","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.nature.com\/spoonful\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.nature.com\/spoonful\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.nature.com\/spoonful\/wp-json\/wp\/v2\/users\/128"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.nature.com\/spoonful\/wp-json\/wp\/v2\/comments?post=210"}],"version-history":[{"count":0,"href":"https:\/\/blogs.nature.com\/spoonful\/wp-json\/wp\/v2\/posts\/210\/revisions"}],"wp:attachment":[{"href":"https:\/\/blogs.nature.com\/spoonful\/wp-json\/wp\/v2\/media?parent=210"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.nature.com\/spoonful\/wp-json\/wp\/v2\/categories?post=210"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.nature.com\/spoonful\/wp-json\/wp\/v2\/tags?post=210"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}