Malaria, which affects almost quarter of a billion people worldwide, claims more than 850,000 lives each year, particularly children in the poorer nations of Africa and Asia.
Preventative measures such as the use of insecticide-treated bed nets has helped cut infection rates dramatically in some of the worst-hit countries and treatments based on a class of drugs called artemisinin have sharply reduced mortality.
However, according to the World Health Organisation (WHO), rise of new, drug-resistant strains of the disease could wipe out that progress unless alternative compounds are found. An international team of researchers led by R. Kiplin Guy of St. Jude Children’s Research Hospital in Memphis, Tennessee combed through more than 300,000 candidate chemicals.
The study identified around 1,100 agents out of more than 300,000 candidates that inhibited growth of the deadly P. falciparum parasite that causes the disease by at least 80%. The study further said that an even more select subset of 172 compounds all had chemical structures unlike those in existing antimalarial drugs.
The fact that these novel agents acted on different targets in the mosquito-borne parasite could prove crucial in beating back the emerging threat of drug-resistant variants. As a proof of principle, the researchers showed that one of the compounds was effective in treating malaria in a mouse, albeit at a very high concentration.
In a second study, Jose Garcia-Bustos of GlaxoSmithKline and colleagues screened around two million agents in the pharmaceutical giant’s in-house chemical library. Setting a similar threshold for blocking the parasite’s growth, the researchers uncovered 13,500 promising active compounds. Out of those, 8,000 were equally effective against multi-drug resistant P. falciparum parasites.
More than 11,000 of the “hits” were proprietary compounds owned by the drug company, which has taken the unusual step of transferring them to the public domain, where they are available researchers anywhere in the world. “These reports offer tremendous opportunities to develop the next generation of antimalarial drugs,” commented David Fidock, a researcher at the Columbia University Medical Center in New York.