Characterisation of Mucosal Healing with Adalimumab Treatment in Patients with Moderately to Severely Active Crohn’s Disease: Results from the EXTEND Trial

Background and Aims Mucosal healing [MH] is an important goal for patients with Crohn's disease [CD], yet is incompletely characterised. We investigated whether MH differed by segments across the colon and ileum in patients who received adalimumab maintenance treatment in the EXTEND study. Methods In this double-blind study in adults with moderate to severe ileocolonic CD and mucosal ulceration, all patients received adalimumab induction [Week 0, 160 mg; Week 2, 80 mg]. At Week 4, patients were randomised to 40 mg adalimumab or placebo every other week until Week 52. In this post-hoc analysis, MH was assessed by CD Endoscopic Index of Severity [CDEIS], Simple Endoscopic Score for CD [SES-CD], and Colonic and Ileal Global Histologic Disease Activity Scores [CGHAS/IGHAS]. Results Baseline endoscopic severity was similar across segments. At Week 52, mean changes in CDEIS surface involved and ulcerated surface were -68.5% to -90.6% in the rectum, sigmoid/left colon, and transverse colon compared with -22.3% to -50.0% in the right colon and ileum. Favourable shifts by Week 52 in ulcer size and ulcerated surfaces per SES-CD were more pronounced in the rectum, sigmoid/left colon, and transverse colon vs the right colon and ileum. At Week 52, CGHAS and IGHAS healing was more common in the colon [28.3%] vs the ileum [21.2%]. Conclusions This analysis suggests differing propensities of the ileocolonic segments to heal endoscopically during adalimumab treatment. In the sigmoid/left and transverse colon, higher MH rates may be achieved, compared with the ileum, in patients with moderate to severe CD.