{Reference Type}: Journal Article
{Title}: Re-evaluating Methods for Assessing Differences in Response in Ileal vs. Colonic Crohn's Disease: A Post-hoc Analysis of the FITZROY Trial.
{Author}: Ma C;Feagan BG;Wang Z;Zou G;Smith MI;Shackelton LM;Sands BE;Panaccione R;D'Haens GR;Vermeire S;Jairath V;
{Journal}: J Crohns Colitis
{Volume}: 0
{Issue}: 0
{Year}: 2024 Jul 20
{Factor}: 10.02
{DOI}: 10.1093/ecco-jcc/jjae113
{Abstract}: <B>OBJECTIVE: </B>The ileum is the most commonly affected segment of the gastrointestinal tract in Crohn's disease (CD). We aimed to determine whether disease location affects response to filgotinib, a Janus kinase (JAK) inhibitor, in patients with moderate-to-severely active Crohn's disease (CD) and applying appropriate methods to account for differences in measuring disease activity in the ileum compared to the colon.<BR><B>METHODS: </B>This post-hoc analysis of data from the FITZROY phase 2 trial (NCT02048618) compared changes in the Crohn's Disease Activity Index (CDAI) and Simple Endoscopic Score for Crohn's Disease (SES-CD) amongst patients with ileal-dominant and isolated colonic CD treated with 10 weeks of filgotinib 200 mg daily or placebo. A mixed effects model for repeated measures was used to test whether ileal disease responded differently than colonic disease, by evaluating for effect modification using the interaction term of treatment assignment-by-disease location.<BR><B>RESULTS: </B>Numerically greater proportions of patients with isolated colonic disease compared to ileal-dominant CD achieved clinical remission (CDAI <150, 75.9% vs. 41.6%) and endoscopic response (SES-CD reduction by 50%, 52.5% vs. 15.5%) at Week 10. However, after adjusting for baseline disease activity by disease location and within-patient clustering effects, there was no significant difference in treatment response by disease location (mean difference in ΔCDAI between ileal-dominant vs. isolated colonic disease +9.24 [95% CI: -87.19, +105.67], p=0.85; mean difference in ΔSES-CD -1.93 [95% CI: -7.03, +3.44], p=0.48).<BR><B>CONCLUSIONS: </B>Filgotinib demonstrated similar efficacy in ileal-dominant and isolated colonic CD when controlling for baseline disease activity and clustering effects.