Molecules spun off from a cancer drug may have a second job in fighting malaria. Researchers at the University of São Paulo’s School of Pharmaceutical Sciences tested 14 compounds derived from an anticancer drug against the malaria parasite growing in laboratory cultures.
Published in ACS Omega, the results showed activity at more than one point in the parasite’s life cycle.
That double hit is what makes the work interesting. Instead of targeting only the stage that causes illness, the compounds also acted against forms involved in passing the parasite to mosquitoes. In theory, that could open the door to a treatment that tackles infection while also helping limit transmission.
FAPESP, the São Paulo Research Foundation that funded the work, describes repurposing drugs developed for other diseases as a potentially faster and cheaper route to new therapies.
But a large gap remains between an encouraging dish experiment and a useful medicine. For now, the biggest question is what happens when these molecules leave the lab.
One Parasite, Two Weak Spots
The parasite changes form as it goes, and these compounds worked on two of those forms.
The parasite is Plasmodium falciparum, and its changing life cycle gives researchers more than one place to attack it. During the asexual stage, it multiplies inside blood cells and causes the fever associated with malaria. Gametocytes, meanwhile, infect mosquitoes and keep the parasite moving from one host to another.
In laboratory cultures, the compounds eliminated parasites during the asexual stage. They also showed activity against gametocytes.
That second finding from the study is what makes the transmission angle possible. A drug that affects both stages could potentially do more than treat an infection. Still, gametocyte activity in a dish does not prove that a medicine will stop transmission in the real world. That question will require testing beyond cultured parasites.
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Why Scientists Keep Hunting For New Malaria Drugs
Drug resistance keeps the search going, and this study put a resistant parasite in the dish.
The World Health Organization estimates that about 600,000 people died of malaria in 2024. Célia Regina da Silva Garcia, a professor at the school and co-author of the study, estimates that P. falciparum causes 90% of those deaths.
Meanwhile, resistance continues to complicate treatment. Malaria medicines such as chloroquine and artemisinin are facing growing resistance, giving researchers another reason to look for new options.
The study’s abstract reports that the derivatives worked at nanomolar concentrations against both standard and chloroquine-resistant strains of P. falciparum. Nanomolar refers to laboratory potency, meaning the compounds were active at very small concentrations. It does not tell researchers what a safe dose would be in humans, or whether the compounds could produce a cure.
The resistance result specifically involves chloroquine. How these molecules perform against artemisinin-resistant parasites remains unanswered, as does which of the 14 compounds performed best.
Researchers Are Tinkering With The Chemistry
The aim is a molecule that hits the parasite harder than it hits human cells.
The compounds are 6-anilinopurine derivatives, meaning they are chemical relatives of an anticancer drug rather than the drug itself. Researchers compared how small structural differences affected each compound’s activity, then used those findings to design additional molecules.
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Garcia says the newer designs are becoming more potent and more selective against the parasite.
The team’s working theory centers on histone deacetylases, a family of enzymes that may provide a useful malaria target. The paper’s title identifies one in particular, PfHDAC1. The experiments strengthened the case for that target without settling it.
Selectivity matters because killing a parasite is only part of the challenge. Some compounds showed reduced efficacy in tests with human cells while maintaining their effects on the parasite. Researchers viewed that pattern as a possible sign of improved selectivity and a lower risk of serious side effects.
The Idea Has Been Tried In Reverse, Too
Cancer research has borrowed from malaria’s medicine cabinet before.
The exchange between malaria and cancer research has gone the other way, too.
In 2016, researchers investigated atovaquone, an existing malaria medicine, as a way to make cancer cells more susceptible to radiotherapy. Tumor cells starved of oxygen are harder to treat with radiation, and experiments in mice found that atovaquone raised oxygen levels inside tumors.
A clinical trial had begun to see whether those findings could translate to patients. Atovaquone is also one half of Malarone, the atovaquone-proguanil combination used to prevent and treat malaria.
That effort also highlighted a different challenge: money. Off-patent medicines can be inexpensive, but without patent protection and a clear financial return, drugmakers may be reluctant to fund the costly late-stage research needed to turn an old medicine into a treatment for a new disease.
A Different Malaria Drug Is Much Further Along
One new malaria treatment has already gone through a large trial in people.
While the cancer-derived compounds remain at the laboratory stage, another malaria treatment has already reached much further.
In November 2025, results were released from a phase III trial of GanLum, a combination of ganaplacide and lumefantrine. The study involved 1,688 adults and children across 12 African countries and reported a cure rate of 97.4%, compared with 94% for the existing artemether-lumefantrine treatment.
Among parasites carrying a mutation linked to artemisinin resistance, clearance took about 47 hours with GanLum versus about 71 hours with the standard treatment.
Those numbers should not be read as a comparison with the University of São Paulo compounds. The studies use different designs and endpoints, and the cancer-derived molecules have not yet reached human trials.
At the time, Novartis said it was submitting GanLum for regulatory approval, potentially making it the first new class of malaria drug approved in more than 25 years.
Which health story have you watched move from an early lab result to an approved treatment?
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