Are new anthelmintics needed to eliminate human helminthiases?

Anthelmintic mass drug administration (MDA) has limited pathology and transmission of filariases, schistosomiasis and gastrointestinal nematodiases in many areas of the world. This record has led to the adoption of ambitious goals for eliminating these infections on a global scale within the next decade or two by expansion of MDA with available drugs. This review considers the attributes of anthelmintics that favor or limit attainment of the scaled-up plans for elimination, and highlights situations for which new or reformulated drugs may be needed.

Many challenges face elimination campaigns. Anthelmintic needs include, first, a macrofilaricidal regimen that speeds up elimination, is safe to use in regions of Onchocerca volvulus and Loa loa coendemicity, and provides a rapid method to resolve infections introduced into previously controlled areas; second, a replacement of praziquantel for schistosomiasis should a resistance arise; third, formulations of praziquantel to enhance compliance, and pediatric formulations for preschool children; fourth, a regimen that provides high efficacy against Trichuris trichiura (new anthelmintic, prolonged dosing strategy or anthelmintic combinations); fifth, pediatric formulations of albendazole and mebendazole compatible with elimination operations; and sixth, an alternative to benzimidazoles in the anticipation of the development of drug resistance.

Expansion of MDA programs to attain elimination of human helminthiases is a noble and worthwhile endeavor. Increased drug pressure should be expected to select resistance alleles. Alternative anthelmintics and regimens should be developed for deployment to ensure that the ambitious goals for elimination are not endangered due to an inadequate pharmacopeia.