Mycophenolate Mofetil for Maintenance of Remission in Steroid-dependent Autoimmune Pancreatitis

Purpose: Systemic corticosteroids represent the standard treatment of autoimmune pancreatitis with IgG4-associated cholangitis. In patients who are steroiddependent, azathioprine has been reported for maintenance of remission. Mycophenolate mofetil and rituximab have been suggested as alternative therapies in patients who fail or who are intolerant of azathioprine. However, there are no reports to date in the English literature on the use of mycophenolate mofetil in adult patients with autoimmune pancreatitis. A patient with autoimmune pancreatitis refractory to steroids and intolerant of azathioprine was treated with mycophenolate mofetil, whose mechanism of action is inhibition of de novo guanine synthesis and blockade of both B and T lymphocyte production. Introduction of mycophenolate mofetil and uptitration to 1000 mg by mouth twice daily over a treatment period of four months was associated with improvement in the patient's energy level and blood glucose control and was not associated with any adverse events. The patient was managed without a biliary stent. However, there was a return of symptoms, jaundice, elevation in the transaminases, and hyperbilirubinemia when the prednisone dose was tapered to 11 mg per day. In the first case report of mycophenolate mofetil use in an adult patient with IgG4-associated autoimmune pancreatitis and cholangiopathy, the introduction of mycophenolate mofetil was safe and was well-tolerated without side effects or adverse events. The introduction appeared to result in initial clinical improvement (energy, control of hyperglycemia) but did not enable taper of steroid therapy below 11 mg per day. Mycophenolate mofetil and other immunomodulatory therapies should continue to be studied for maintenance of remission in the large subset of patients with refractory or recurrent autoimmune pancreatitis.