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Although you may not have heard of it, schistosomiasis is one of the world’s most prevalent parasitic diseases. According to the World Health Organization, of the estimated 236 million people who required treatment for schistosomiasis in 2019, 90 % lived in Africa.
The tropical disease, which is caused by parasitic worms that live within freshwater snails and infect humans by penetrating the skin, is particularly dangerous to young children. “Not only can infection cause chronic inflammation of the organs, which itself can be fatal, it can also lead to anaemia, stunted growth, and impaired cognitive development,” says Remco de Vrueh, global health portfolio co-lead at Lygature, a foundation providing management for large, multistakeholder partnerships in the life sciences.
Because there is no child-friendly method for treating the disease, nearly 50 million preschool-aged children have gone untreated. But this could soon change. Through the EU-funded Pediatric Praziquantel Consortium, an international public-private partnership led by Merck, work has been ongoing to develop, register and provide equitable access to an effective and safe paediatric treatment for schistosomiasis.
A kid-approved tablet
The partnership has developed a potential treatment option, which comes in the form of an orodispersible, or orally disintegrating, tablet that is suitable for children aged 3 months to 6 years. Unlike the large, 500-600 mg praziquantel tablets currently available as the standard-of-care treatment for schistosomiasis, the new “arpraziquantel” tablet developed by the consortium is small – just 150 mg – making it suitable for preschool-aged children.
“We designed this tablet to dissolve in the mouth, making it easy and safe for a young child to take orally without the risk of choking,” explains de Vrueh.
De Vrueh says that the tablet can be taken with or without water and is able to withstand the hot and humid tropical environment of Africa. Furthermore, to ensure a ‘kid-approved’ flavour, researchers conducted a taste study in Tanzania with children between 6 and 11 years of age. The ultimate outcome is that the arpraziquantel tablets have a taste acceptable for young children.
Confirmed efficacy and safety
In November 2021, the project successfully completed the full clinical development programme with the positive data announced from the pivotal phase III clinical trial. During the trial, infected children in Côte d’Ivoire and Kenya were given a single dose of the medication. With clinical cure defined as no parasite eggs in the stool (for one parasite species: Schistosoma mansoni) 17 to 21 days after treatment or urine (for another parasite species: Schistosoma haematobium) 17 to 21 days and additionally 35 to 40 days after treatment, the trial showed a cure rate of close to or above 90 %.
“This trial clearly confirmed a favourable efficacy and safety profile of arpraziquantel,” adds de Vrueh.
Based on this success, the project has now entered the regulatory filing stage. With plans to submit the Marketing Authorisation Application to the European Medicines Agency by the end of 2022, on behalf of the consortium, Merck aims to have the product available in the first endemic African country by 2024.
Affordable and equitable access
However, having a new medication in hand and getting it to the people who need it most are two different things. “Together with relevant stakeholders, we’ve put significant effort into exploring a sustainable mechanism for providing access in an affordable and equitable manner,” notes de Vrueh. “Once approved, the medicine will be made available on a not-for-profit basis through local manufacturers.”
As de Vrueh explains, the consortium has and continues to work closely with national ministries of health, local access programmes, and such global organisations as the World Health Organization and UNICEF.
“Working with a range of stakeholders, and especially with those in Africa who have first-hand knowledge of the situation and challenges in a specific country, facilitates ensuring that our work will have a strong impact where it is needed most,” concludes de Vrueh.