WHO releases priorities for research and development of age-appropriate medicines for treatment of neglected tropical diseases

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21 November 2023

The World Health Organization (WHO) has today released the first ever list of priority paediatric formulations for five neglected tropical diseases (NTDs) to target research and development in addressing the specific needs of infants and children. The diseases are human African trypanosomiasis, onchocerciasis, scabies, schistosomiasis and visceral leishmaniasis.

The list results from a “ Paediatric Drug Optimization” (PADO) exercise carried out by WHO, the purpose of which is to identify priority medicines and formulations to be investigated and developed to address the needs of children aged 3–5 years (PADO priority list) or with a time horizon of 5–10 years (PADO watch list). Prioritization is a necessary first step to enable a targeted approach to research and development, which needs to be undertaken in conjunction with developing and updating normative guidance on the use of medicine for treating and preventing communicable and noncommunicable diseases. As such, WHO leads and convenes this work and develops it in collaboration with appropriate stakeholders in each disease area.

NTDs are a diverse group of infectious diseases that differ in epidemiology, local prevalence, control and elimination strategies, and challenges regarding the availability of treatments designed for children. There is a severe lack of pharmacokinetic data for NTD medicines, which are required to optimize doses for children. Only 11% of pharmacokinetic studies for NTD medicines included children and, for most medicines, these data are not available. Generally, limited financial incentives have resulted in fewer new medicines being developed for NTDs. Paediatric formulations have faced added challenges because of the limited participation of children in clinical trials and the absence of dosing and treatments tailored to their age. Research conducted in 2022 showed that, overall, less than half of WHO-recommended medicines for NTDs are approved for children, highlighting the urgent need to increase research activity for NTDs in this area.

“I welcome the extension of the PADO concept to NTDs. Increasing access to paediatric formulations is key as NTDs affect large numbers of children and because only by targeting all age groups, including children, we will be able to interrupt NTD transmission and achieve elimination,” said Dr Ibrahima Socé Fall, Director, WHO Global NTD Programme. “I invite more investments to complete the development of these formulations, support their production and facilitate their access to the most vulnerable.”

The PADO priority list for NTDs released today includes six medicines across five disease areas: acoziborole for human African trypanosomiasis; ivermectin and moxidectin for scabies and onchocerciasis; miltefosine and amphotericin B for visceral leishmaniasis; and L-praziquantel (150 mg or 300 mg) for schistosomiasis.

The PADO watch list includes three promising compounds: emodepside and oxfendazole for scabies and onchocerciasis, and LXE408 for visceral leishmaniasis.

Across disease areas, the development of medicines for children lags unacceptably behind than for adults by nearly a decade due to limited investments and lack of market incentives, among other reasons. Following the adoption of resolution WHA69.20 by the World Health Assembly (Promoting innovation and access to quality, safe, efficacious and affordable medicines for children), WHO and partners in the Global Accelerator for Paediatric Formulations Network (GAP-f) have scaled up activities to deliver on this global commitment.

WHO’s PADO work to identify key priority products and their preferred product characteristics for research and development has been successfully undertaken for HIV, hepatitis C, tuberculosis and antibiotics, demonstrating their potential and impact to accelerate access to optimal formulations in the context of fragmented, small markets for medicines for children.

Continued and concerted investment in research and development of better paediatric formulations of priority NTD medicines is needed to accelerate actions towards more equitable access to appropriate treatment for infections globally.