Old drug shows new promise to treat leishmaniasis
University of Dundee scientists study fexinidazole
Scientists at the University of Dundee have shown the antiparasitic agent fexinidazole could potentially be used to treat visceral leishmaniasis, a disease that kills 50,000–60,000 people a year in Africa, Asia and Latin America.
Fexinidazole, originally developed by German pharmaceutical company Hoechst, has recently been tested in Phase I clinical trials for treating human African trypanosomiasis (HAT, also known as sleeping sickness). Because the parasites that cause HAT and leishmaniasis are closely related, the Dundee researchers, including scientists at the Wellcome Trust-funded Drug Discovery Unit at the university decided to see whether the drug could also work against leishmaniasis.
Their results, published in Science Translational Medicine, confirmed that treating mice with fexinidazole reduced the number of leishmaniasis parasites by more than 98%, which is comparable to current treatments for the disease.
The researchers say current treatments have various disadvantages, including cost and the rapid development of drug resistance. Some can only be given by injection, which is not practical in poor rural areas where people are at most risk of leishmaniasis, and the only drug that can be given orally cannot be used in women of childbearing age because of the risk of birth defects.
Professor Alan Fairlamb, lead author of the research and co-director of the Drug Discovery Unit, said: ‘The current treatments are far from ideal, and we need to find better, cheaper and more easily delivered drugs to tackle the disease. Our research suggests that fexinidazole has strong potential to do that.
‘The Drugs for Neglected Disease initiative (DNDi) [with Sanofi] has already established that fexinidazole is safe in early clinical trials for African sleeping sickness, so it is some way along the development path.’
The next steps for assessing fexinidazole as a treatment for leishmaniasis will be to test it in other animal models and to see how effectively it works against various strains of the parasite that infect people. If the results of those studies are favourable, development of the drug as a new oral treatment for leishmaniasis will be made faster and cheaper because of the ongoing HAT trials.