Patients infected with malaria and dengue virus are treated in an isolation ward at a hospital in Pakistan. The drugs, known as artemisinins, have proven extremely effective in helping malaria patients recover, but there are concerns that the malaria parasite is developing resistance. A new drug called GanLum appears to offer a promising alternative.
Zubair Abbasi/AFP via Getty Images
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Zubair Abbasi/AFP via Getty Images
At the turn of the millennium, a new class of drugs derived from ancient Chinese herbal medicines revolutionized the treatment of malaria. Artemisinins, as they are called, are based on sweet wormwood extracts. They come at a time when drugs used since the 1970s are becoming useless for many as the parasite that causes malaria develops resistance.
“The deaths that we saw in the late 1990s, early 2000s—about 2 million a year—were a direct result of drug failure,” says George JagoExecutive Vice President of Access and Product Management at Medicines for Malaria Venture. “Nobody ever wants to be behind the eight ball again.”
Since then, artemisinins have saved millions of lives and are now the mainstay of malaria treatment worldwide. But there is warning signs that these drugs follow in the footsteps of their predecessors. To prevent history from repeating itself, new drugs that target the malaria parasite differently are needed, Jagoe says.
“I would call it preparedness: having a fire extinguisher in the back that you're prepared to use, but maybe don't necessarily use, otherwise the house will catch fire and you'll have nothing left,” Jagoe says.
More than two decades later, researchers are on the verge of creating such a fire extinguisher.
A new drug called GanLum was more than 97% effective in treating malaria in clinical trials conducted in 12 African countries, researchers from the American Society of Tropical Medicine and Hygiene in Toronto reported Wednesday. This is as good, if not better, than the current standard of care. If approved by regulators, it could become a powerful new tool against a disease that kills around half a million people every year.
“This is a big deal,” says Kasturi Haldara biologist at the University of Notre Dame who has studied malaria for decades and was not involved in this study. “It’s also quite timely.”
This is due to artemisinin resistance. First discovered in Southeast Asia in the late 2000s, it has recently spread to the continent most affected by malaria. “Partial artemisinin resistance is spreading quite aggressively in many parts of Africa,” says David Fidockmicrobiologist at Columbia University who was not involved in the study. “We are sounding the alarm that we need new drugs if resistance leads to treatment failure. [GanLum] will help stop this significantly.”
GanLum stands for Ganaplacid/lumefantrine, a combination of two drugs, one new and one old (most antimalarial drugs are combinations of drugs that target parasites at different stages of infection). The new drug, Ganaplacid, was discovered by Novartis scientists after screening more than 2.3 million molecules. for antimalarial properties. It appears to work by interfering with the ability of malaria parasites to live inside human red blood cells.
In the laboratory, the researchers showed that it could kill all known forms of the parasite, including those with mutations associated with artemisinin resistance. It also attacks the stage of the parasite responsible for transmitting the infection. “Having a cure is very desirable,” says Haldar, as it can not only treat the patient but also prevent the spread.
In clinical trials, the drug also showed good results.
The research team enrolled more than 16,000 adults and children over 2 years of age with malaria in a dozen countries in Africa. Half of the patients took GanLum for three days, and half received the current standard of care, artemisinin-based treatment. The team found that both drugs were about equally effective, with GanLum slightly ahead. Both drugs had similar rates of side effects, including nausea and diarrhea. But the GanLum group vomited more often.
The drug still needs to overcome additional regulatory hurdles before it reaches patients. The team estimates it will take about a year and a half. Even if it is approved and implemented, GanLum will likely not be able to completely replace artemisinin-based treatments any time soon, as artemisinin-based treatments still work in many areas. “But for now it looks good enough to be used where there is a lack of response to the current situation. [artemisinin-based] drugs,” says Haldar.
Ultimately, this could extend the life of both drugs and help countries avoid the surge in deaths that occurs when resistance overwhelms existing tools.
