S2324 Mycophenolate Mofetil vs Azathioprine for Maintenance Therapy in Autoimmune Hepatitis: A Retrospective Matched Cohort Study

Introduction: Autoimmune hepatitis (AIH) is a chronic immune-mediated liver disorder that requires long-term immunosuppressive therapy to prevent disease progression and relapse. While azathioprine (AZA) remains the standard maintenance treatment following corticosteroid induction, mycophenolate mofetil (MMF) is increasingly used in patients who are intolerant or unresponsive to AZA. This study aims to compare the clinical and biochemical outcomes of MMF versus AZA in the maintenance treatment of AIH. Methods: A retrospective cohort analysis was conducted on adult patients with AIH who achieved disease remission following corticosteroid induction and were subsequently treated with either MMF or AZA. Patients were matched for baseline characteristics, including liver enzyme levels and immunoglobulin G (IgG) values. Biochemical response was assessed through changes in serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels. Tolerability and adverse events were also recorded. Results: A total of 52 patients were included, with matched cohorts for MMF and AZA. After induction, patients treated with MMF experienced a greater reduction in alanine aminotransferase (−27.1 U/L vs −20.3 U/L) and AST (−31.4 U/L vs −23.6 U/L) compared to those on AZA. The rate of biochemical normalization was higher in the MMF group, and MMF was generally well tolerated with no significant increase in adverse events. No patients required escalation to second-line therapy during the follow-up period. Conclusion: In this matched analysis of AIH patients, MMF was associated with greater improvements in liver enzyme levels compared to AZA, suggesting superior biochemical response. MMF may be a more effective and well-tolerated maintenance option in selected AIH patients, particularly those unable to tolerate or respond adequately to AZA. Further prospective studies are warranted to validate these findings.