Abstract
Background and aims: Azathioprine or 6-mercaptopurine is commonly used as a first-line maintenance treatment in the management of autoimmune hepatitis (AIH). When either intolerance or inadequate response to first-line therapy occurs, a secondline agent such as mycophenolate mofetil (MMF) is used. Tioguanine is commonly used in New Zealand to treat inflammatory bowel disease, and its use for autoimmune hepatitis has recently increased. This study aims to compare the effectiveness of tioguanine and MMF as second-line treatments for achieving biochemical remission in autoimmune hepatitis (AIH).
Method: Patients in Canterbury who fulfilled the Simplified AIH Diagnostic Criteria and were treated with tioguanine or MMF were identified. Cases were included if tioguanine or MMF were commenced as a second-line but excluded if commenced as a firstor third-line agent. Biochemical remission is defined as ALT<30 U/L. Flare is defined as elevation of ALT after achieving biochemical.remission. Statistical comparisons were conducted using Chi-square or Fisher’s exact test for sample sizes <5.
Results: A total of 356 AIH patients were identified. MMF and tioguanine were commenced as a second-line agent in 42 and 10 patients, respectively. Their first-line treatments ceased because of intolerance in 67% and inadequate response in 33%. Comparing tioguanine with MMF, biochemical remission was achieved in 40% versus 57% at 6 months and 78% versus 68% at 12 months. MMF had significantly more flares than the tioguanine group (38% vs 0%; p = 0.016). Subgroup analysis showed that in patients with inadequate response to first-line treatment, the tioguanine group had significantly higher biochemical remission in 12 months (100% vs 45.5%; p = 0.037). Adverse effects were rare for both groups, only resulting in one MMF patient withdrawing treatment.
Conclusion: This is the first study comparing tioguanine against MMF in AIH management. Both tioguanine and MMF had high and comparable efficacy in achieving biochemical remission in AIH patients as a second-line agent. Tioguanine was well tolerated even in patients intolerant to azathioprine and may perform better than MMF in patients with inadequate response to first-line treatment.
Poster presentation.