P526 A prospective 52-week mucosal healing and deep remission assessment of small bowel and colonic Crohn's disease as detected by colon capsule endoscopy

Abstract

Background: Data on small bowel (SB) mucosal healing (MH) and deep remission (DR) in children with Crohn disease (CD) are rare. Recently, colon capsule endoscopy (CCE) has been proved effective as pan-endoscopy in pediatric CD. This is the first study to prospectively assess MH and DR on the entire GI tract by performing two subsequent CCE over 24 weeks in children with CD in comparison with biomarkers, magnetic resonance enterography (MRE) and SB contrast ultrasonography (SICUS). Methods: Children with known CD were prospectively recruited and underwent imaging studies followed by CCE, at baseline and after 24 weeks. The Lewis score (LS) and Simple endoscopic score for Crohn's disease (SES-CD) were calculated for SB and colon, respectively. C-reactive protein (CRP) and fecal calprotectin (FC) were also evaluated for their association with clinical activity, imaging and CCE findings. Clinical remission was defined as PCDAI<10. SB and colonic MH were defined as LS< 135 and SES-CD ≤ 1, respectively; moderate-to-severe inflammation was defined as LS >790 or SES-CD >7. Biomarker remission (BR) was defined as a combination of clinical remission (PCDAI<10) and normal biomarkers. Deep remission (DR) was defined as a combination of BR and MH. Therapy was calibrated according to CCE results. Results: Forty-eight patients (pts) were recruited, 22 with clinical and biomarker activity and 26 in remission. At baseline CCE confirmed significant inflammation (either in SB or colon) in 18 (82%) of 22 pts with clinical and/ or biomarker disease activity, while showed mild lesions and/or normal mucosa in 4 (18%). MRE and SICUS did not demonstrate active disease in 5/18 (23%) with lesions at CCE, but it found nonspecific findings in 2 of 4 with negative CCE. Biomarker levels were elevated with FC in 13 (59%); CRP levels in 10 (45%) and either biomarker in 15 (68%). In the 26 pts with remission, CCE showed SB lesions in 13 (50%) and colonic lesions in 6 (23%). Complete MH and DR were observed in 10 (39%). Imaging studies found lesions only in 7 (27%, p<0.05). At 24-week follow-up, CCE identified DR only in 8/20 (36%) of the active group; while in 12/20 (54%) showed a partial MH. In inactive pts, CCE revealed that only 7/10 pts maintained DR. Of 16 pts in remission and with lesions at baseline, CCE showed that 9 (56%) achieved DR and 5 (44%) a partial MH after a change of therapy. MRE and SICUS had a good concordance in evaluating DR (14/17, 82%) in both groups, but did not identify partial MH (only 8/17, 47%, p<0.05). FC and CRP were not able to accurately evaluate DR in either group. Conclusions: This study shows for the first time that CCE is effective for monitoring DR and MH of the entire GI tract and in directing therapy for pediatric patients with CD.