Efficacy and safety of praziquantel plus Artemisinin-based combinations in the treatment of Kenyan children withSchistosoma mansoniinfection: an open-label, randomized, head-to-head, non-inferiority (SCHISTOACT) trial

Abstract

Background: Praziquantel alone is insufficient for the control of schistosomiasis. Unlike praziquantel, artemisinin derivatives are effective for treating juvenile schistosome worms but not adult worms. Few studies have assessed the role of combination therapy, including praziquantel and artemisinin-based combinations, in treating schistosomiasis. Methods: A randomized, open-label, noninferiority trial was conducted in central Kenya to assess the efficacy and safety of praziquantel plus one of four artemisinin-based combination therapies in treating intestinal schistosomiasis. 540 children aged 9-15 years with Schistosoma mansoni infection were randomly assigned (1:1:1:1:1) to receive a single oral dose of praziquantel (40mg/kg/day) alone or in combination with a 3-day course of artesunate plus sulfalene/pyrimethamine or artesunate plus amodiaquine or artesunate plus mefloquine or dihydroartemisinin-piperaquine. The primary endpoint was the cure rate assessed at six weeks in a per-protocol population. The noninferiority margin was defined as the lower limit of 95%CI of the risk difference in cure rates less than -10%. Results: Cure rates were available for 523 children. Overall, 82.5%, 81.7%, 76.2%, 88.7% and 85.7% of patients on praziquantel, praziquantel plus artesunate-sulfalene/pyrimethamine, praziquantel plus artesunate-amodiaquine, praziquantel plus artesunate-mefloquine, and praziquantel plus dihydroartemisinin-piperaquine, respectively, were cured. Non-inferiority was declared for praziquantel plus artesunate-mefloquine (difference 6.2 [95%CI -3.3 to 15.6]) and praziquantel plus dihydroartemisinin-piperaquine (3.2 [-6.7 to 13.1]) but not for praziquantel plus artesunate-sulfalene/pyrimethamine (-0.8 [-11.2 to 9.6]) or praziquantel plus artesunate-amodiaquine (-6.3 [-17.3 to 4.6]). A significantly lower number of adverse events were reported in the praziquantel arm than in the combined treatment arm. No serious adverse events were observed. Conclusions: Combination therapy using praziquantel with artesunate plus mefloquine or praziquantel with dihydroartemisinin-piperaquine is a promising complementary transmission control strategy, but further research is needed to investigate strategies to improve the effectiveness and safety outcomes.