Background Schistosomiasis, highly prevalent in tropical regions, affects over 240 million people. Praziquantel (PZQ) is considered the standard-of-care treatment. However, around 50 million preschool-aged children (PSAC) remain untreated in public health programs, mainly due to the lack of a child-friendly formulation. In 2012, the Pediatric Praziquantel Consortium was established to provide a treatment tailored for PSAC.

This work has resulted in the development of arpraziquantel: a novel (oro)dispersible tablet containing L-PZQ, the biologically active PZQ enantiomer. The 150 mg tablets are small, allow precise dosing and have improved taste properties.

Methods The new formulation was developed by Astellas (Japan) and Merck KGaA, Darmstadt, Germany. Farmanguinhos (Brazil) has established drug product production while Universal (Kenya) is preparing for local manufacturing. Phase I, II and III clinical trials have been completed. The latter was conducted in Côte d’Ivoire and Kenya in PSAC (3 months to 6 years) infected with Schistosoma mansoni or Schistosoma haematobium. 288 PSAC were treated with a single dose of arpraziquantel or PZQ. The primary endpoint was clinical cure at week 3.

Results High cure rates close to or above 90% were achieved in Schistosoma mansoni-infected children at a dose of 50 mg/kg, and in Schistosoma haematobium-infected children at 60 mg/kg. Egg reduction rates were very high (~99%) across all groups. The safety profiles of arpraziquantel and PZQ were similar, and no new safety issues were identified.

Conclusion Phase III results indicate that arpraziquantel is efficacious, well-tolerated, and shows improved palatability among PSAC. Through Merck KGaA, the Consortium has applied for a scientific opinion from the European Medicines Agency under the EU-M4all procedure for high-priority medicines intended for markets outside the European Union. A positive opinion would facilitate the inclusion of arpraziquantel in the WHO list of prequalified medicinal products as well as regulatory approvals in endemic countries.