Assessment of the implementation of risk minimization measures for bosentan: a retrospective study.

Background: Bosentan is associated with adverse hepatic effects. To minimize such risk, regulators implemented risk minimization measures (RMMs), including testing for liver injury biomarkers (alanine and aspartate transaminase and bilirubin) prior to therapy initiation and monthly throughout therapy. This study aimed to examine the adherence to hepatic monitoring requirements.

Research design and methods: This retrospective cohort study collected data about bosentan new-users from the Real-world Evidence Research Network from 2016 to 2022. We ascertained hepatic tests from laboratory files. Adherence to RMM definition was performing the required tests within 90 days before initiation and categorized adherence to monthly testing requirement based on the expected number of tests throughout therapy as low (<50%), moderate (50-74%), and high (≥75%).

Results: One hundred patients entered the study cohort and 71% were females, with a median age of 25 years. Adherence to testing prior to bosentan initiation was 60%. Adherence to monthly testing was low in the majority of patients (58.2%).

Conclusions: Adherence to bosentan RMMs relevant to minimizing risk of hepatotoxicity either before starting or throughout therapy was low. Our findings could be used as a baseline for monitoring trends in implementation of RMMs over time or to compare performance of various minimization strategies.