Observational study on the effectiveness and safety of multiple regimens of triclabendazole in human fascioliasis after failure to standard-of-care regimens

Objectives: Triclabendazole (TCBZ) is the recommended anthelmintic against Fasciola hepatica at a dose of 10 mg/kg body weight administered as a single or double dose. However, treatment failures to TCBZ standard-of-care (SOC) doses have been reported in humans. The aim of this study was to describe the effectiveness and tolerability of alternative TCBZ regimens in those patients who failed the SOC regimen for fascioliasis in Peru. Methods: A retrospective study was conducted at a major referral centre for fascioliasis in Peru between 2002 and 2018. Inclusion criteria were cases with chronic F. hepatica infection who failed the SOC regimen for human fascioliasis with TCBZ at 10 mg/kg orally as single dose with food. Results: A total of 27 cases (59% female; mean age 39.4 years, range 6–71 years) with chronic fascioliasis failed at least once the current SOC regimen of TCBZ. Of 27 cases, 21 failed a second treatment regimen. Multiple regimens of TCBZ were given to these patients until three consecutive stool examinations were negative for Fasciola eggs. The overall cure rate was 74%. TCBZ was well tolerated with minimal side effects. Conclusion: According to the results of this study, patients labelled as having ‘TCBZ resistance’ may respond to multiple regimens of TCBZ with a cure rate of 74%. Thus, the term ‘TCBZ resistance’ should be re-evaluated using biomarkers.