Vedolizumab more likely to be discontinued than ustekinumab in anti-TNF-experienced patients with fistulizing Crohn's disease.

Background: Data on the performance of newer biologics in patients with fistulizing Crohn's disease (CD) are limited.

Objective: Our study's objective was to evaluate the response to ustekinumab (UST) and vedolizumab (VDZ) in patients with fistulizing CD.

Design: Retrospective cohort.

Methods: We used natural language processing of electronic medical record data to identify a retrospective cohort of individuals with fistulizing CD at a single academic tertiary-care referral center and then performed a chart review. Individuals were eligible for inclusion if a fistula was present at the time of UST or VDZ initiation. Outcomes included medication discontinuation, surgical intervention, development of a new fistula, and fistula closure. Groups were compared with unadjusted analyses and competing risk analyses using multi-state survival models.

Results: In all, 68 patients were included (48 UST and 20 VDZ). Most patients had one fistula (79%) and had prior anti-tumor necrosis factor-α treatment (98% in UST group, 80% in VDZ group, p = 0.01). VDZ was significantly more likely to be discontinued than UST (p < 0.0001), most frequently due to inadequate clinical response. Those on UST had a longer median time to surgery for CD than those on VDZ (p = 0.008). In those without surgical fistula repair, 79% on UST and 100% on VDZ still had an active fistula at 1 year (p = 0.30).

Conclusion: In individuals with fistulizing CD, our data suggest that UST has better clinical utility than VDZ based on lower rates of discontinuation, though the sample size is small. These findings highlight the importance of further research on the treatment of perianal fistulizing Crohn's disease.