SciDev.Net

Treating malaria with a range of therapies, rather than one standard drug, could cut deaths and postpone drug resistance, say researchers.

The research was published in Proceedings of the National Academy of Sciences this week (16 September).

Researchers used a computer model to simulate how using multiple first-line therapies (MFT) alongside each other would work within large populations and shows significant advantages over using single therapies.

Maciej Boni, lead author of the paper and a researcher at Princeton University, United States, says with multiple therapies it is difficult for the malaria parasite to evolve resistance as it is transmitted from person to person because it encounters a different drug every time.

Developing world governments currently use drug cycling — giving populations single drugs over limited periods of time — to treat malaria, which often fails because the parasite becomes resistant to the drug. 

Boni says when single-line therapies fail, it can take years to switch over to the new drug and people continue using drugs that are ineffective. 

"Some first line therapies you may only be able to use for five years, others for 20 years, and if you're unlucky you may only use it for a short period of time and you wind up getting rid of it too soon and have no alternative for your patients," says Boni.

Using an MFT strategy could result in a 2.5 to three-fold increase in the amount of time a single drug could be used, Boni added, reducing costly surveillance methods for drug resistance.

Boni says there are two main approaches for governments and clinics using MFT. One is to have clinics give different drugs to different people — an approach which could pose ethical problems.

"If you don't have three perfectly equal drugs how do you medically justify to a patient that you're giving [them] the second best or the third best drug? I think that's a big problem."

Another approach is subsidising new drugs, such as artemisinin-based combination therapies (ACTs), to make all antimalarials the same price and allow patients to choose their drug.

A pilot project subsidising ACTs in two districts of Tanzania, funded by the Clinton Foundation, has made them more widely available, displacing other less effective therapies. 

Megumi Gordon, a manager with the Clinton Foundation's Malaria Control Team, says, "I think that MFT does offer a very promising way to delay resistance to ACTs," said Gordon. "The drawback to it is the challenges in implementing and making sure it is executed well."

Link to full paper in Proceedings of the National Academy of Sciences