Best Practices in Liver Biopsy Histologic Assessment for Nonalcoholic Steatohepatitis Clinical Trials: Expert Opinion

Background. In most clinical trials focusing on precirrhotic nonalcoholic steatohepatitis (NASH), a liver biopsy is required for confirmation of diagnosis, staging fibrosis, and grading steatohepatitis activity. Reliance on the biopsy, both as a requisite for study entry, as well as for a primary endpoint in clinical trials, poses several challenges that need to be overcome: patient reluctance to undergo the procedure; potential sampling error; concern regarding the handling, processing and shipping of the biopsy of the biopsy material to the central reader(s); and the degree of pathologists’ intra- and interobserver variability in biopsy interpretation. Aims. To provide recommendations for improving the liver biopsy process in order to maximize the accuracy of its histological interpretation in NASH clinical trials. Methods and Results. These recommendations were created by an expert panel of participants from the United States and European Union who met multiple times and reached alignment through review of available data and their individual clinical experiences. The recommendations include the methodology for biopsy procedure, central lab and pathology processing of the specimen, and recommendations to minimize the intra- and intersubject variability. Finally, we are discussing digital pathology technology and machine learning applications as important additions to enhance liver biopsy interpretation.Conclusions. Liver biopsy poses multiple challenges in clinical trials in NASH, and there is a need to standardize the processes to maximize accuracy and minimize variability. Many questions remained unanswered due to limited available data. New evolving modalities may help in the future, but generation of robust data is warranted.