There are currently no approved therapies for nonalcoholic steatohepatitis (NASH). In a planned month-18 interim analysis of a multicentre, randomized, double-blind phase III study of the use of obeticholic acid, a farnesoid X receptor agonist, in the treatment of NASH, patients with NASH who had stage F2–F3 fibrosis received oral placebo (n = 311), obeticholic acid 10 mg (n = 312) or obeticholic acid 25 mg (n = 308). The fibrosis improvement primary endpoint (≥1 stage with no worsening of NASH) was met by 12% of patients in the placebo group, 18% of patients receiving obeticholic acid 10 mg (P = 0.045) and 23% of patients receiving obeticholic acid 25 mg (P = 0.0002). An alternative primary endpoint of NASH resolution with no worsening of fibrosis was not met. Serious adverse events were similar across the groups. Thus, obeticholic acid 25 mg significantly improved fibrosis in patients with NASH and the study is ongoing to assess clinical outcomes.