18 September 2019

Pediatric Praziquantel Formulation: an urgent need for very young children and their families

With the implementation of the Phase III clinical trial, the Pediatric Praziquantel (PZQ) Consortium Formulation program is approaching its final objective of providing access to the new drug for patients.

We asked Russell Stothard, Professor at the Liverpool School of Tropical Medicine, how the new formulation might impact treatment of schistosomiasis in very young children, how severe the consequences of morbidities can be, and about his work and aspirations for the near future.

Prof. Stothard has recently been awarded the C.A. Wright Memorial Medal by the British Society for Parasitology (BSP) and works with a.o. the Global Schistosomiasis Alliance and CouNTDown. His collaboration and expert advice have been instrumental at the start of and throughout the Consortium’s program.

What is the impact of schistosomiasis in preschool-age children?

The impact of schistosomiasis depends on which species of Schistosoma we are referring to: urogenital or intestinal schistosomiasis.

The urogenital form of the disease, for example, may be recognized in adult women as a particularly important condition known as Female Genital Schistosomiasis (FGS)1.  It is likely that FGS disease starts much earlier in life than when we are first able to detect it. I am sure that it starts in childhood even at preschool-age, meaning that children under the age of 5 who were infected with S. haematobium could have life-long damage if their infection is not controlled and treated timely.

The intestinal form caused by infection with S. mansoni is quite common in preschool-age children; our original work in Uganda several years ago showed that over 50% of children under the age of 3 could have intestinal schistosomiasis with a sizeable portion exhibiting liver fibrosis as readily viewed by ultrasound examinations. This shows the importance of the Pediatric Praziquantel Consortium program, which aims to develop and provide access to a new pediatric drug for the children under the age of 6 for the treatment of both the species of Schistosoma. In my opinion, it can’t come soon enough as the burden of disease is now very clear.

How important is the issue and how severe can the consequences of morbidities caused by schistosomiasis be in very young children?

Consequences of morbidities in very young children are often very insidious and chronic. The chronic effects of stopping cognitive development or growing for example, are quite significant with long-life damages. No one would wish a child to be compromised simply by lack of access to medication.

Other aspects are not so clear, such as the relationship between schistosomiasis and cancer. So far, evidence of the link between urogenital schistosomiasis and bladder cancer has been proven in Egypt and Ghana, although ongoing surveillance remains insufficient. Moreover, the link to colorectal cancer starts now to be considered more formally and I imagine its connection will be soon to be confirmed with more detailed epidemiological studies. It is an unfortunate fact that many infected people in rural and remote areas, where schistosomiasis is common, do not have access to quality medical services.

And how important would it be for those families to be able to properly treat the youngest?

I think it is very important even critical. There is a chronic disease situation in young children with a clear need of treatment to be addressed as soon as possible. Therefore, all members of the consortium should continue working hard to address it and in so doing be proud of the efforts they are making in this cause. From my most recent trips to Uganda, there is advanced schistosomiasis in many young children and their families benefit grateful for prompt access to this pediatric medication.

What is your aspiration for the near future?

Well, I hope to remain active in the research and control of schistosomiasis and place more emphasis on the description of late-stage morbidities, especially in children, to spark the need for better diagnostic tools and prompter access to treatment. Schistosomes and snails continue to fascinate me. In Malawi we have found unexpected evidence for hybrid schistosomes now found in people that originated from schistosomes found in livestock, so I am looking to better understand this new aspect of schistosome biology and its challenges within the context of control.