In the last decade,
pharmaceutical companies, governments and global health organisations under the leadership of the World Health Organization (WHO) have pledged large-scale donations of
anthelmintic drugs, including
ivermectin (IVM),
praziquantel (PZQ),
albendazole (ALB) and
mebendazole (MEB). This worldwide scale-up in
drug donations calls for strong monitoring systems to detect any changes in
anthelmintic drug efficacy. This review reports on the outcome of the WHO Global Working Group on Monitoring of
Neglected Tropical Diseases Drug Efficacy, which consists of three subgroups: (i) soil-transmitted
helminthiases (ALB and MEB); (ii)
onchocerciasis and
lymphatic filariasis (IVM); and (iii)
schistosomiasis (PZQ). Progress of ongoing work, challenges and research needs for each of the four main drugs used in helminthic preventive
chemotherapy (PC) are reported, laying the ground for appropriate implementation of
drug efficacy monitoring programmes under the co-ordination and guidelines of the WHO. Best practices for monitoring
drug efficacy should be made available and capacity built as an integral part of
neglected tropical disease (NTD) programme monitoring. Development of a disease-specific model to predict the impact of PC programmes, to detect outliers and to solicit responses is essential. Research studies on genetic polymorphisms in relation to low-efficacy phenotypes should be carried out to identify markers of putative resistance against all NTD drugs and ultimately to develop diagnostic assays. Development of combination and co-administration of NTD drugs as well as of new
drug entities to boost the armamentarium of the few drugs available for NTD control and elimination should be pursued in parallel.