P491 Comparison of the durability of response to subcutaneous anti-TNF therapy between ulcerative colitis and Crohn's disease

Abstract

Background: Subcutaneous anti-tumour necrosis factor alpha (TNF) therapies appear to have greater efficacy in Crohn's disease (CD) compared with ulcerative colitis (UC). We aimed to evaluate, in real world clinical practice, whether there was a difference in the outcome of subcutaneous anti-TNF therapy comparing UC and CD. We also assessed the association between blood inflammatory biomark-ers and therapy outcome. Methods: Consecutive patients commencing anti-TNF therapy for UC and CD between 2011 and 2016 were identified. Demographic and baseline biochemical data were collected. Date of initiation and discontinuation of anti-TNF therapy were determined. Time to dis-continuation of anti-TNF therapy was used as an index of therapy outcome. Primary analysis compared time to discontinuation of anti-TNF therapy between UC and CD cohorts. Secondary analyses eval-uated the associations between baseline CRP/Albumin ratio, CRP, Albumin and Week 8 CRP and time to discontinuation of subcutaneous anti-TNF therapy. P values less than 0.05 were considered statistically significant. Results: The study cohort comprised 157 IBD patients [n=76 CD/n=81 UC; Age (median, range) 42.6 years (17-81); 49% Male; 87% Adalimumab (ADA)/13% Golimumab (GLB). UC colitis extent: 0% proctitis, 48% left-sided & 52% extensive. Crohn's disease classification: L1 24%, L2 50%, L3 26% & L4 1%; B1 41%, B2 30% & B3 29%. Proportion receiving immunomodulators and systemic cor-ticosteroids, 45% and 44% respectively. Baseline CRP and Albumin (median [range]) were: 5 mg/L [1-88], and 42 [23-72] respectively. The median (95% CI) time to discontinuation of anti-TNF therapy comparing UC and CD cohorts was similar, 168.1 weeks (101.9-234.3) versus 96.2 weeks (51.0-141.5) respectively p=0.60. Neither baseline CRP, Albumin, CRP/Albumin ratio nor Week 8 CRP were associated with time to discontinuation of anti-TNF therapy p=0.98, p=0.15 and p=0.89 and p=0.76 respectively. There was a trend toward greater dose optimisation in UC compared with CD cohorts 37% versus 22%, p=0.07. Conclusions: In real world clinical practice the durability of response to subcutaneous anti-TNF therapy, measured by time to discontinuation of drug, is similar comparing UC and CD cohorts. This finding may reflect improved understanding of subcutaneous anti-TNF dosing requirements in UC along with proactive dose optimisation. Non-invasive biomarkers of inflammatory burden did not demonstrate a clear association with therapy outcome and may be more important in patient subgroups with severe disease.