ABSTRACT: NGM282, an engineered fibroblast growth factor 19 analogue, rapidly and significantly reduced liver fat content in a multicenter, randomized, double-blind, placebo-controlled study in patients with biopsy-confirmed nonalcoholic steatohepatitis (NASH). However, it is unclear whether these changes would be accompanied by histological improvement. In this open-label study, we assessed the histological efficacy of NGM282 in patients with biopsy-confirmed nonalcoholic steatohepatitis. Paired liver biopsies from 43 patients who received subcutaneous NGM282 (1 mg, n = 24; 3 mg, n = 19) once daily for 12 weeks were evaluated blinded to time point, subject, and clinical information. At week 12, NGM282 significantly reduced nonalcoholic fatty liver disease activity score (NAS; -1.9; 95% confidence interval, -2.6 to -1.2; P < 0.001 in the 1 mg group; -2.2, -3.1 to -1.3; P < 0.001 in the 3 mg group) and fibrosis (-0.5; -0.9 to 0; P = 0.035 in the 3 mg group) scores. Overall, 50% and 63% of the patients receiving NGM282 1 mg or 3 mg, respectively, improved NAS by 2 or more points without fibrosis worsening. Of the patients receiving NGM282 1 mg or 3 mg, 25% and 42%, respectively, improved liver fibrosis by one stage or more without worsening of steatohepatitis. Treatment with NGM282 led to relative reductions in liver fat content (-58% and -67% in the 1 mg and 3 mg groups, respectively), corrected T1 (cT1; -8% and -9%), alanine aminotransferase (ALT) (-67% and -60%), aspartate aminotransferase (-57% and -52%), and fibrogenesis biomarkers neoepitope-specific N-terminal propeptide of type III collagen (Pro-C3; -22% and -33%) and enhanced liver fibrosis score (ELF; -3% and -6%) at week 12. Greater reductions in Pro-C3, ELF, and cT1, but not in liver fat content, 7alpha-hydroxy-4-cholesten-3-one, or ALT, were observed in histological responders than in nonresponders. Conclusion: In this open-label study, NGM282 improved the histological features of NASH in 12 weeks with significant reductions in NAS and fibrosis scores, accompanied by improvements in noninvasive imaging and serum markers.