Durability of the First Biologic in Patients with Crohn's Disease: A Nationwide Study from the epi-IIRN.

Background: In this nationwide study we aimed to compare the durability of the first initiated biologic in Crohn's disease [CD], stratified by monotherapy and combotherapy.

Methods: We used data from the epi-IIRN cohort, which includes 98% of the Israeli inflammatory bowel disease population [2005-2020]. Durability was defined as consistent treatment without surgery or added medications [except for combination therapy with thiopurines or methotrexate]. All comparisons were based on stringent propensity-score matching and paired time-to-event analyses.

Results: A total of 19 264 patients with CD were included, of whom 7452 [39%] received biologics with a median follow-up of 6.8 years (interquartile range [IQR] 3.6-10.7). Time to biologics decreased gradually from 6.7 years [IQR 2.7-10.4] in 2005 to 0.2 years [0.07-0.23] in 2020. The durability of the first biologic after 1 and 3 years was higher with adalimumab monotherapy [88%/61%] than vedolizumab monotherapy [81%/59%; n = 394 matched patients, p = 0.04] and similar between infliximab monotherapy and vedolizumab monotherapy [65%/43%; n = 182 matched patients, p = 0.1]. Durability was higher in adalimumab monotherapy vs infliximab monotherapy [83%/62% vs 71%/48% at 1/3 years; p <0.001] and it was similar in adalimumab monotherapy vs infliximab combotherapy [87%/63% vs 80%/58%, respectively; p = 0.1]. Durability was higher in combotherapy compared with monotherapy for both infliximab [85%/64% vs 67%/43%, respectively; n = 496 matched pairs, p <0.001], and adalimumab [93%/76% vs 82%/62%, respectively; n = 540 matched pairs, p <0.001].

Conclusion: Durability of the first biologic in CD was highest for adalimumab monotherapy. Combotherapy further increased the durability of adalimumab and infliximab. Unless otherwise indicated, our data may support using anti-tumour necrosis factors [TNFs] as first-line biologics in CD, particularly adalimumab if monotherapy is advised.