Praziquantel plasma concentration and its metabolic ratio suboptimally predict schistosomiasis cure among infected children.

Mnkugwe, Rajabu Hussein

Background: In recent years, biomarkers or surrogate endpoints have been shown to be vital in predicting treatment response. In schistosomiasis treatment using praziquantel, it has been suggested that drug level quantified at 4 hours post drug intake is an optimal sampling time for monitoring of its systemic exposure. However, no studies have established whether it is the parent drug plasma concentration or its major metabolic ratio which better predict treatment outcome. In addition, the cutoff threshold values for these biomarkers in predicting cure have not been studied. Results: A total of 287 participants were enrolled and followed up for 21 days. The median age of the study population was 12 years (range 7–16 years). The cutoff point for praziquantel concentration in predicting schistosomiasis cure was ≥ 222 ng/dL (Youden's index = 0.341, AUC = 0.688), while for metabolic ratio was ≥ 0.038 ng/dL (Youden's index = 0.276, AUC = 0.661). Praziquantel plasma concentration had a sensitivity of 63% (95% CI 56.5–69.2%), specificity of 71.2% (95% CI 56.9–82.9%) and diagnostic accuracy of 64.5% (95% CI 58.6–70.0%). While the positive and negative predictive values (PPV and NPV) were 90.8% (95% CI 83.5–94.8%) and 29.8% (95% CI 22.0–38.7%), respectively. The AUC for praziquantel plasma concentration was found to be 68.8% (95% CI 61.0–76.6%) (p < 0.001). Metabolic ratio had a sensitivity of 46.8% (95% CI 40.3–53.4%), specificity of 80.8% (95% CI 67.5–90.4%) and diagnostic accuracy of 53% (95% CI 47.0–58.9%). While the PPV and NPV were 91.7% (95% CI 85.2–95.9%) and 25.2% (95% CI 18.8–32.4%), respectively. The AUC for metabolic ratio was found to be 66.1% (95% CI 58.4–73.8%) (p = 0.0003). There was no statistically significant difference in the discriminatory power of praziquantel plasma concentration (AUC = 68.8%) and metabolic ratio (AUC = 66.1%) in predicting schistosomiasis cure (p = 0.25). Conclusion: Despite praziquantel plasma concentration having significantly higher sensitivity and negative predictive value than the metabolic ratio, both biomarkers suboptimally predicted schistosomiasis cure at 21 days follow-up.

SCHISTOSOMIASIS; PRAZIQUANTEL; TREATMENT effectiveness; POPULATION aging; BIOMARKERS

Bulletin of the National Research Centre, 2025, Vol 49, Issue 1, p1

2522-8307

Academic Journal

10.1186/s42269-025-01305-7