This open label study for patients with moderate to severe Crohn's disease will evaluate treatment options to improve capture of initial response and to regain loss of response to certolizumab pegol (Cimzia). It is a 26 week open label clinical trial that may be extended to 52 weeks in patients who respond to treatment during the initial 26 week study. The following dosing options will be tested: 1) Re-induction (one supplemental dose of 400mg) 2) Dose splitting (200mgQ2W) and 3) Dose Escalation (400mg Q2W. The highest dose in the study, 400mg Q2W, has been used in a large phase III trial (WELCOME) without any new safety signals. Efficacy and safety measures will be monitored.
