Triple Drug Combination Shows High Activity Against Parasitic Worm Infections

Current strategy not sufficient to control parasitic worm infections

The current strategy of the World Health Organization (WHO) against soil-transmitted Helminthiasis - so called preventive chemotherapy - entails the administration of single dose albendazole and mebendazole to at-risk populations without prior diagnosis. Low efficacy of mebendazole against hookworm infections now threatens the success of these programmes. In addition, both mebendazole and albendazole show low efficacy against human whipworm (Trichuris trichiura).

"The potential development of resistance against current drugs further threatens current treatment strategies," said Jennifer Keiser, Head of Helminth Drug Development at Swiss TPH. "New drugs or the combination of two or more drugs are therefore urgently needed."

"A game changer for future elimination strategies"

To that end, Swiss TPH in collaboration with the Lao Tropical and Public Health Institute and the Department of Pharmaceutical Sciences at the University of Basel, conducted a clinical trial testing different drug combinations. A triple drug therapy including albendazole, pyrantel pamoate and oxantel pamoate overall showed highest efficacy against all soil-transmitted helminths. "This triple therapy could therefore be a game changer in future global elimination strategies for soil-transmitted helminth infections," said Wendelin Moser, scientist at Swiss TPH and first author of the study.

The researchers were also able to show that high efficacy against all three soil-transmitted helminths could be reached with the co-administration of albendazole plus oxantel pamoate and of pyrantel pamoate plus oxantel pamoate. Both co-administrations could be used to increase the efficacy over single drugs.

"Pyrantel pamoate which is already on the market but not used in preventive chemotherapy programmes in combination with other drugs might be a useful alternative to prevent benzimidazole resistance," said Wendelin Moser. "We therefore advise WHO to adapt their strategies accordingly and include the use of co-administrations in an alternating manner in preventive chemotherapy programmes."

A centre of expertise in parasitic worm infections

Swiss TPH is active in a broad range of activities related to research and control of parasitic worm infections. The work comprises basic research, drug discovery and clinical trials, evaluation and development of new diagnostic tools, modelling and mapping of risk areas and burden of disease, support of countries in building their control and elimination programmes as well as teaching and training both in Switzerland and in endemic areas. Swiss TPH hosts a WHO Collaborating Centre for Epidemiology and Control of Helminth Infections.