Pegbelfermin selectively reduces secondary bile acid concentrations in patients with non-alcoholic steatohepatitis

•Bile acids are elevated in patients with non-alcoholic steatohepatitis.•Pegbelfermin, a PEGylated human FGF21 analogue, is in phase II trials for non-alcoholic steatohepatitis.•Pegbelfermin treatment was associated with secondary, but not primary, bile acid reductions.•Pegbelfermin reduced expression of a gene responsible for secondary bile acid synthesis.•Further study is needed to assess the clinical significance of these observations.