Study for the Treatment of Crohn's Disease With Adacolumn

Key Inclusion Criteria: Moderate to severe Crohn's disease Adequate peripheral venous access Agree to participate in the required follow-up visits Able to complete a diary Signed written informed consent document and authorization for use of protected health information Key Exclusion Criteria: Extremely severe Crohn's disease Known obstructive symptoms within the past 3 months Presence of toxic megacolon Major surgery within the past 6 weeks or anticipated need for surgery within 12 weeks Total colectomy, ileostomy, stoma or 100 cm of resected small bowel Requiring in-patient hospitalization A history of allergic reaction to heparin or heparin-induced thrombocytopenia A history of hypersensitivity reaction associated with an apheresis procedure or intolerance of apheresis procedures A history of severe cardiovascular or peripheral arterial diseases A history of cerebral vascular diseases Liver diseases Renal insufficiency Known bleeding disorder or use of concomitant anticoagulant therapy for purposes other than apheresis treatment Any hypercoagulable disorder Known infection with Hepatitis B or C, or HIV Severe anemia Leukopenia or granulocytopenia Evidence of current systemic infection Malignancy Pregnant, lactating or planning to become pregnant during the course of the investigational study Used within the last 30 days, an investigational drug, biologic or device or 5 half-lives, if known, for any investigational drug or biologic