AIM:To study the efficacy, safety, and feasibility of a granulocyte adsorptive type apheresis system for the treatment of patients with chronically active ulcerative colitis despite standard therapy.METHODS: An open label multicenter study was carried out in 39 patients with active ulcerative colitis (CAI6-8) despite continuous use of steroids (a minimum total dose of 400 mg prednisone within the last 4 wk).Patients received a total of five aphereses using a granulocyte adsorptive technique (Adacolumn(R), Otsuka Pharmaceutical Europe, UK). Assessments at wk 6 and during follow-up until 4 mo comprised clinical (CAI) and endoscopic (EI) activity index, histology, quality of life(IBDQ), and laboratory tests.RESULTS: Thirty-five out of thirty-nine patients were qualified for intent-to-treat analysis. After the apheresis treatment at wk 6, 13/35 (37.1%) patients achieved clinical remission and 10/35 (28.6%) patients had endoscopic remission (CAI＜4, EI＜4). Quality of life (IBDQ) increased significantly (24 points, P＜0.01)at wk 6. Apheresis could be performed in all but one patient. Aphereses were well tolerated, only one patient experienced anemia.CONCLUSION: In patients with steroid refractory ulcerative colitis, five aphereses with a granulocyte/monocyte depleting filter show potential short-term efficacy. Tolerability and technical feasibility of the procedure are excellent.