Markers of environmental enteric dysfunction are associated with changes in pharmacokinetics of praziquantel in preschool age children with Schistosoma mansoni infection in Albertine region of Uganda

Introduction Praziquantel (PZQ) is the only widely available chemotherapy that is effective against all species of schistosomes. Environmental enteric dysfunction (EED) is an acquired intestinal disorder of altered gut function whose effect on drug pharmacokinetics has not been directly explored. Methods Preschool-age children infected with S. mansoni were randomized to receive 40mg/kg or 80mg/kg of crushed PZQ tablets. Plasma PZQ concentrations were quantified using ultra-high performance liquid chromatography mass spectrometry. Maximum concentration (Cmax), time to Cmax (Tmax) and area under the curve (AUC) of PZQ were calculated. Biomarkers of intestinal inflammation (stool calprotectin), epithelial damage (plasma Intestinal Fatty Acid Binding Protein (IFABP)), permeability (urine lactulose:mannitol (LM) ratio and alpha-1 antitrypsin (AAT)), microbial translocation (plasma Endotoxin core antibodies (EndoCAb), systemic inflammation (plasma C-reactive protein (CRP)), and presence of faecal occult blood (FOB) were measured. Using linear regression, we assessed association of AUC, Cmax, Tmax and R- to S-PZQ exposure with each biomarker, adjusting for dose, age, and sex. Results Of the 184 participants included in the final analysis, 91 received 40mg/kg and 93 received 80mg/kg of PZQ. The Tmax was associated with LM ratio ({beta}=0.06, 95% CI 0.02 - 0.11, p=0.003) and calprotectin ({beta}=0.001, 0.0002 - 0.002, p=0.013). CRP was associated with AUC ({beta}=0.13, 95% CI 0.06 - 0.21, p=0.001) and Cmax ({beta}=0.12, 95% CI 0.05 - 0.21, p=0.002). Calprotectin ({beta}=0.12, 95% CI 0.04 - 0.20, p=0.003) and AAT ({beta}=0.09, 95% CI 0.02 - 0.15, p=0.008) were associated with a higher R-PZQ/S-PZQ AUC ratio, while CRP was not (p=0.38). Conclusion Elevated intestinal inflammatory markers were associated with increased Tmax, indicating reduced rate of absorption and relative increase in exposure to the active R-enantiomer. Systemic inflammation was associated with higher Cmax and AUC, implying increased exposure to PZQ. This is the first report linking alterations in praziquantel pharmacokinetics to EED markers and systemic inflammation.