Patients with severe refractory ulcerative colitis (UC) or those who received placebo in study F506-CL-1107 will receive tacrolimus for a maximum of 12 weeks. Safety and efficacy will be evaluated.

Patients with severe refractory ulcerative colitis (UC) or those who received placebo in study F506-CL-1107 study can participate in this study. Patients will receive tacrolimus for a maximum of 12 weeks in an open-label study manner. Improvement of Disease Activity Index (DAI) score and other efficacy scores will be evaluated during the drug administration period.

Inclusion Criteria:

• Severe refractory UC patients who meets the following criteria

  • Disease activity: more than 6 times of stool a day, bloody stool, moderate to severe endoscopic finding
  • Steroid resistant or dependent

OR

• Moderate to severe refractory UC patients who participated and received placebo in F506-CL-1107 study

Exclusion Criteria:

• Mild or fulminant type
• Renal failure patients, hepatic failure patients
• Patients taking 6-mercaptopurine, cyclosporin or other immunosuppressants within 12 weeks prior to entry
• Patients who received LCAP or GCAP within 2 weeks prior to entry
• Patients who changed the dose of steroid or started steroid within 2 weeks prior to entry
• Patients who changed the dose of steroid or started steroid within 1 week prior to entry in case they received more than 40 mg/ day or 1mg/kg/day of steroid just before the study