From Vietnam to Burma, the leading drug against malaria is losing potency, according to a new study in the New England Journal of Medicine.
On the plus side, the same issue of the journal reports that a new antimalarial drug looks promising in an early test.
Artemisinin-based drugs have helped make dramatic gains against malaria worldwide.
“If we lose this class of drugs, it’s really going to be a global health catastrophe,” said Dr. Chris Plowe at the University of Maryland School of Medicine. “There’s nothing on the shelf that’s ready to replace those.”
Resistance on the move
Plowe and colleagues studied resistance rates in seven Asian and three African countries. The worst problems were along the Thailand-Cambodia border, where the first artemisinin drug failures were reported. But they found significant resistance from southern Vietnam to central Burma.
The fact that it’s on the move in Southeast Asia “speaks to the possibility that from there it can jump into Africa, which is the big concern, ultimately,” said Columbia University microbiologist David Fidock, who was not involved in the research.
That’s what happened with resistance to previous malaria drugs, and it cost countless lives.
In fact, Plowe said that part of the world has proved to be a drug-resistant malaria hotspot.
“It’s happened again and again, with at least four different antimalarial drugs, where resistant parasites popped up along the border between Thailand and Cambodia,” he said.
It’s not clear why. It could be the quality of the drugs available, or how they are taken. Plowe doubts that, though, considering that both are issues elsewhere, too.
Or it may be something to do the genetics of the parasite. Researchers are looking into that, too.
The good news is Plowe’s group did not find artemisinin resistance in Africa. And the drugs still work, although they take longer.
But he adds, “We don’t have very much time with the artemisinins based on the rate at which resistance appears to be emerging and spreading.”
In another study in the same issue of The New England Journal of Medicine, the pharmaceutical company Novartis reports its new drug spiroindolone quickly rid 21 patients of malaria parasites.
It is on track to be the first to take over when the artemisinin drugs fail.
“It’s very early days,” Plowe cautions. “This is a very small study. But the initial news is pretty good.”
Fidock notes, however, that the drug’s target is known to mutate quickly.
“It’s already to some degree susceptible to resistance,” he said.
Spiroindolone would be combined with at least one other drug to slow down resistance.
And other drugs are in the pipeline, racing to be ready for the day when artemisinin fails.