Beneficial response to mycophenolate mofetil by patients with autoimmune hepatitis who have failed standard therapy, is predicted by older age and lower immunoglobulin G and INR levels

BackgroundMycophenolate mofetil is a commonly used salvage therapy for patients with autoimmune hepatitis (AIH). AimTo evaluate the predictors of response to mycophenolate rescue therapy to facilitate clinical decision making. MethodsWe performed a retrospective observational cohort study of AIH patients managed in 17 major Australian liver centres who received mycophenolate after an inadequate response or intolerance to corticosteroids with/without thiopurine(s). Baseline demographic, clinical and laboratory variables were compared between responders and nonresponders. A multivariable logistic regression model was developed using forward selection to identify independent predictors of treatment response. ResultsA total of 105 patients received mycophenolate rescue therapy of whom 63 (60%) achieved biochemical remission. On univariable analysis, older age (P=0.003), INR<1.1 (P=0.02), and lower immunoglobulin gamma (IgG; P<0.002) levels were associated with treatment response, while no association was found with cirrhosis status (P=0.07) or treatment indication (P=0.63). On multivariable analysis, lower pre-treatment serum IgG level (P=0.01), higher age at commencing mycophenolate (P=0.01) and higher INR (P=0.03) were the only significant independent predictors. An IgG level <17g/L had a positive and negative predictive value for response of 71% and 60% respectively, while age 54years when commencing mycophenolate had a positive and negative predictive value for response of 80% and 59% respectively. ConclusionMycophenolate remains an excellent treatment option for patients with AIH refractory to or intolerant of standard therapy with those most likely to benefit being older and/or having lower pre-treatment IgG levels.