Background: This study aimed to evaluate the efficacy of oral tacrolimus in patients with inflammatory bowel disease (IBD) refractory to conventional therapy, including azathioprine, 6-mercaptopurine, and infliximab.
Methods: Retrospective review of all patients with IBD treated with oral tacrolimus was undertaken. Tacrolimus was administered t an initial dose of 0.05 mg/kg twice daily, aiming for serum trough levels of 5-10 ng/mL. We evaluated clinical response, a retrospective estimated Crohn's disease activity index (CDAI) for Crohn's disease (CD), modified Truelove-Witts index for ulcerative colitis (UC), and modified pouch disease activity index (mPDAI) for pouchitis. Patients had been monitored clinically for benefit and side effects and by whole blood tacrolimus level approximately every 4 weeks for the duration of treatment. Clinical remission was defined as an estimated CDAI <150 (CD), an inactive disease score on the Truelove-Witts index (UC), and mPDAI <5 (pouchitis).
Results: Twelve patients with CD, six with UC, and one with pouchitis, all resistant to previous therapies, were treated for a median of 5 months. After 4 weeks 10 CD (83%), four UC (67%) patients, and one pouchitis patient had a clinical response. There was a median reduction of the estimated CDAI of 108 points (range 35-203; P = 0.002) and stool frequency of three per day at week 4. Remission was achieved in 42% (5/12) of CD and 50% (3/6) of UC patients at the end of follow-up. Side effects included temporary elevated creatinine (n = 1), tremor (n = 3), arthralgia (n = 1), insomnia (n = 1), and malaise (n = 1). Four patients discontinued treatment due to side effects. CONCLUSION-: Oral tacrolimus is well tolerated and effective in patients with refractory IBD in the short- to medium-term. Further controlled, long-term evaluation is warranted.