Efficacy of 6-Mercaptopurine as Second-Line Treatment for Patients With Autoimmune Hepatitis and Azathioprine Intolerance

BACKGROUND & AIMS: Autoimmune hepatitis (AIH) is a chronic inflammatory liver disease that requires long-term immunosuppressive therapy. Although most patients have an excellent response to standard therapy (azathioprine in combination with corticosteroids), approximately 10%-15% have intolerance or an insufficient response to azathioprine treatment. We investigated whether 6-mercaptopurine (6-MP) is an effective second-line therapy for patients with AIH.

METHODS: We performed a retrospective study of 22 patients with AIH who were switched to 6-MP therapy after treatment with the combination of azathioprine and prednisolone at 2 tertiary care institutions in Europe (Germany and the United Kingdom) before November 15, 2014. We performed statistical analyses of data on clinical and biochemical responses collected 4 weeks after 6-MP treatment and then at regular physician visits.

RESULTS: A total of 15 of 20 patients with prior azathioprine intolerance (75%) responded to 6-MP treatment; 8 of these patients had a complete response and 7 had partial remission, based on biochemical features. In these 15 patients, 6-MP was well tolerated, whereas the 5 remaining patients had to be switched to different immunosuppressive regimes because of 6-MP intolerance. The 2 patients with insufficient response to azathioprine treatment also showed no response to 6-MP.

CONCLUSIONS: In patients with AIH and azathioprine intolerance, 6-MP seems to be an effective and well-tolerated second-line treatment. 6-MP might be ineffective in patients with insufficient response to azathioprine.