BackgroundPatients with inflammatory bowel disease (IBD) are at risk of developing dysplasia and, subsequently, colorectal cancer (CRC) owing to chronic inflammation. Patients may also experience other severe disease complications, such as hospitalization and surgery. Several biologics are available for the treatment of patients with IBD and some patients require multiple lines of treatment owing to loss of response or tolerability to their prescribed biologic. Previous studies suggest that the choice of initial biologic treatment may impact the outcomes of later treatment lines. In this study, we assessed adverse clinical outcomes in patients with Crohn’s disease (CD) or ulcerative colitis (UC) who received different biologic treatment sequences.MethodsROTARY part B was a retrospective cohort study using the Optum® Clinical Database that evaluated the incidences of IBD-related hospitalization, IBD-related surgery, dysplasia, CRC, and infections in patients with CD or UC who received two biologics successively. First-line biologics included adalimumab, infliximab, ustekinumab (CD only), and vedolizumab; second-line biologics included infliximab and adalimumab.ResultsIn patients with CD, the treatment sequence of ustekinumab to infliximab was associated with the highest overall incidences of hospitalization (51.9%), surgery (40.7%), CRC (3.7%), and infection (37.0%). Vedolizumab followed by an anti-tumor necrosis factor alpha (anti-TNFα) treatment was associated with a significantly lower risk of experiencing an adverse medical event (hospitalization, surgery, or infection) than two successive anti-TNFα treatments (odds ratio, 1.526; 95% confidence interval, 1.004–2.320; P < 0.05). In patients with UC, the treatment sequence of vedolizumab to adalimumab resulted in the lowest overall incidence of adverse outcomes (20.3%, 6.3%, 0.0%, 6.3%, and 4.7% for hospitalization, surgery, CRC, dysplasia, and infection, respectively).ConclusionsWe describe differences in adverse clinical outcomes associated with sequencing of biologics in patients with CD or UC and demonstrate favorable results in patients who received vedolizumab as a first-line biologic. These results provide potential guidance to clinicians choosing sequences of biologic treatments in patients with IBD.