The effectiveness of ant-TNF 'biologic' therapy in is well supported in the management of moderate to severe Crohn's Disease (CD). Our first 'SAVANT' study was to our knowledge the first study report one- year outcomes in patients (n=60) who switched from previous anti-TNFa treatment to Cimzia/Certolizumab. This current study (SAVANT 2) follows up on longer term outcomes and provides additional clinical and biochemical data that may contribute to therapeutic responses. This IRB approved study was a retrospective analysis of the initial patients included in SAVANT 1. Patients who were switched to TNF antagonist Certolizumab as an alternative biologic were followed an additional year. Retrospective consideration of immunomodulator use, smoking status and clinical data were also evaluated. Of 60 patients with moderate-severe CD who participated in the SAVANT 1 study, 15 patients were excluded due to inadequate follow up. 45 patients were studied for a total of two years following substitution with Certolizumab from prior anti TNF agent therapy. Clinical remission at 1 year was 75% (45/60) and 55% (25/45) at the second year. At the second year, 5 more patients had discontinued Certolizumab due to worse disease or adverse events, indicating a cumulative two-year failure rate of 33% (20/60). Smoking and concomitant use of immunomodulators were similar between 'success' and 'failure' groups. SAVANT 2, the first study to report long term outcomes of switching from Infliximab or Adalimumab to Certolizumab showed that at 2 years, 25 patient's maintained clinical remission. The discontinuation rates were 25 and 11% at years 1 & 2 respectively. The 5 patients who lost responsiveness after the first year were women, the majority of smoked. Additional prospective studies to assess the appropriateness and feasibility of biologic substitution are still needed.