Less effective antimalarial therapies can help fight malaria better

November 12, 2015

Oxford University scientists have found that the more effective way to beat malaria is to use less effective drugs some of the time.

The current drug of choice for malaria - artemisinin - is extremely effective at saving lives from the disease, but artemisinin-resistant malaria parasites are spreading as the drug is used more and more. A computer simulation study now suggests that treating malaria in a population by simultaneously using a non-artemisinin therapy amongst more effective artemisinin-based combinations is the best way to combat the disease, while still reducing the spread of drug-resistant malaria. Writing in the Lancet Global Health, scientists at the Nuffield Department of Clinical Medicine at Oxford University found that this combination worked best even when the non-artemisinin drug was only effective 85% of the time in treating malaria.

Currently, to stop the spread of artemisinin-resistant parasites, the World Health Organization (WHO) encourages the use of the drug in combination with other anti-malarials; the malaria parasite would have to become simultaneously resistant to both the drugs in order to survive this two-hit artemisinin combination therapy.

However, malaria parasites in South-East Asia have begun to acquire characteristics to help evade even this double hit, and these resistant strains are likely to spread over the next decade as the use of artemisinin combination therapies becomes more widespread.

Health policy makers are therefore in bind, having to decide whether to safeguard artemisinin effectiveness (by avoiding its overuse), or to encourage the use of artemisinin wherever possible to save people's lives.

Professor Maciej Boni and his colleagues ran computer simulations to find out if there was an optimal strategy that could stop the spread of drug-resistant malaria parasites across populations, while still effectively treating malaria in individual patients. They found that simultaneously dosing a population with several artemisinin-combination therapies - say, by prescribing artemisinin in combination with different partner drugs on different days of the week - was more effective than either cycling between different artemisinin combination therapies, or by sticking to one specific combination until the combination started failing.

The simulation also found that if this simultaneous dosing also included a combination without artemisinin, malaria parasites that were resistant to artemisinin were slower to emerge, and slower to spread. Including this potentially less effective treatment option didn't necessarily mean that many more people would not recover from malaria: in the worst case scenario of the non-artemisinin treatment being only 75% as effective as artemisinin combination therapy, fewer than 7% of malaria patients would still have post-treatment malaria parasites in their blood as a result of not being prescribed an artemisinin drug.

Professor Boni said, 'For this subgroup of patients, second-line treatment with an artemisinin combination therapy would be recommended. The ethical implications of such a treatment policy will need to weighed against the benefit of delaying and slowing down the spread of artemisinin resistance.

'But the nightmare we all want to avoid is the establishment of artemisinin resistance in Africa, where hundreds of millions of individuals rely on artemisinin-based therapies as their first-line antimalarial treatment. By deploying different antimalarial therapies simultaneously - including non-artemisinin-based therapies - national malaria control programs in Africa should be able to slow down the spread of artemisinin-resistant parasites when they are imported into the continent.'
-end-


University of Oxford

Related Malaria Articles from Brightsurf:

Clocking in with malaria parasites
Discovery of a malaria parasite's internal clock could lead to new treatment strategies.

Breakthrough in malaria research
An international scientific consortium led by the cell biologists Volker Heussler from the University of Bern and Oliver Billker from the UmeƄ University in Sweden has for the first time systematically investigated the genome of the malaria parasite Plasmodium throughout its life cycle in a large-scale experiment.

Scientists close in on malaria vaccine
Scientists have taken another big step forward towards developing a vaccine that's effective against the most severe forms of malaria.

New tool in fight against malaria
Modifying a class of molecules originally developed to treat the skin disease psoriasis could lead to a new malaria drug that is effective against malaria parasites resistant to currently available drugs.

Malaria expert warns of need for malaria drug to treat severe cases in US
The US each year sees more than 1,500 cases of malaria, and currently there is limited access to an intravenously administered (IV) drug needed for the more serious cases.

Monkey malaria breakthrough offers cure for relapsing malaria
A breakthrough in monkey malaria research by two University of Otago scientists could help scientists diagnose and treat a relapsing form of human malaria.

Getting to zero malaria cases in zanzibar
New research led by the Johns Hopkins Center for Communication Programs, Ifakara Health Institute and the Zanzibar Malaria Elimination Program suggests that a better understanding of human behavior at night -- when malaria mosquitoes are biting -- could be key to preventing lingering cases.

Widely used malaria treatment to prevent malaria in pregnant women
A global team of researchers, led by a research team at the Liverpool School of Tropical Medicine (LSTM), are calling for a review of drug-based strategies used to prevent malaria infections in pregnant women, in areas where there is widespread resistance to existing antimalarial medicines.

Protection against Malaria: A matter of balance
A balanced production of pro and anti-inflammatory cytokines at two years of age protects against clinical malaria in early childhood, according to a study led by ISGlobal, an institution supported by ''la Caixa'' Foundation.

The math of malaria
A new mathematical model for malaria shows how competition between parasite strains within a human host reduces the odds of drug resistance developing in a high-transmission setting.

Read More: Malaria News and Malaria Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.