Swiss TPH researchers have tested the veterinary drug oxfendazole in people infected with whipworm for the first time. In a trial on Pemba Island, Tanzania, a three-day course cured 76% of participants. Single doses did no better than the standard treatments. The findings are published today in eClinicalMedicine. The trial was part of eWHORM, a platform for developing more effective treatments for neglected worm infections.
On Pemba Island, Swiss TPH and partners are testing oxfendazole, a veterinary deworming drug, against whipworm. Whipworm is among the hardest-to-treat soil-transmitted worm infections.
Soil-transmitted worm infections affect an estimated 1.5 billion people worldwide. Most of them live in tropical and subtropical regions of sub-Saharan Africa, South America and Asia, where sanitation is poor and access to clean water is limited. They can cause diarrhoea and abdominal pain, and in children they can lead to malnutrition and impaired growth and development.
Whipworm (Trichuris trichiura and Trichuris incognita) is among the hardest of these infections to treat. The widely used drugs albendazole and mebendazole cure fewer than half of all people with a single dose, and few new treatments are in development. Oxfendazole has long been used to treat worms in livestock and pets. Repurposing animal medicines is an important strategy for new human treatments, because it builds on existing safety data and speeds up development. Together with partners, Swiss TPH is also developing emodepside, another veterinary drug that has shown very high cure rates in people with parasitic worm infections.
Study results show good tolerability and efficacy with multiple doses
The early-stage (phase 2a) randomized trial of oxfendazole included 127 adults and was double-blind and placebo-controlled. Swiss TPH conducted the study with the Public Health Laboratory Ivo de Carneri on Pemba Island, in collaboration with other partners from the eWHORM consortium. Participants received either 800 mg of oxfendazole on three consecutive days, a single dose of 400 mg or 800 mg oxfendazole, or placebo. The three-day course cured 76% of participants, compared with 20% in the placebo group. Oxfendazole was well tolerated, with mostly mild side effects.
“The results show that oxfendazole is effective when given over several days,” said Annina Schnoz, first author of the study and PhD student at Swiss TPH, who led the trial on Pemba Island.
Single doses cured 31–35% of participants, about as many as reported for albendazole and mebendazole. Control programmes currently rely on mass drug administration: a single dose is given regularly to whole at-risk communities, without individual testing, to reduce worm burden and prevent illness. “A single dose offers no advantage over the current drugs, so it is unlikely to improve mass treatment programmes,” said Schnoz. “A multi-day course, however, could suit targeted treatment, where people are tested first and then treated,” said Schnoz.
Even single doses reduced egg counts in stool by about 90%. This suggests that oxfendazole may stop worms from producing eggs rather than killing them directly, which needs further investigation.
Potential for broader use against parasitic worms
All participants who received oxfendazole and were also infected with roundworm or hookworm were cleared of these infections, although numbers were small and further studies are needed to confirm this. “In many communities, people are infected with several types of worms at once,” said Jennifer Keiser, Head of Helminth Research and Medicines at Swiss TPH and senior author of the publication. “What makes oxfendazole so interesting is its broad activity against several parasitic worms like the soil-transmitted helminths or filarial worms. A multi-day regimen could treat co-endemic infections at the same time and make disease control and elimination programmes more efficient.”
About eWHORM
eWHORM brings together African and European research institutes, universities and not-for-profit organisations to test oxfendazole against several neglected worm diseases in different African countries. Higher doses and longer treatment schedules are now being tested for onchocerciasis (river blindness), loiasis and mansonellosis. The consortium aims to contribute to a profound change in how helminth diseases are treated and eliminated.
The study was funded by the Swiss State Secretariat for Education, Research and Innovation (SERI). The eWHORM project is supported by the Global Health EDCTP3 Joint Undertaking and its members.
Contact for media requests: communications@swisstph.ch
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