Real‐World Comparison of Vedolizumab and Ustekinumab in TNF Inhibitor–Experienced Ulcerative Colitis Patients Followed by Therapeutic Drug Monitoring

ABSTRACT Background and Aims Vedolizumab and ustekinumab are alternative therapies in patients with ulcerative colitis (UC) previously exposed to TNF inhibitors (TNFi). In Norway, treatment follows a national tender, and vedolizumab was first choice after TNFi discontinuation from 2016 to 2019 and ustekinumab from 2020 to 2022. We aimed to compare one‐year real‐world effectiveness of vedolizumab or ustekinumab in TNFi‐experienced UC patients followed by therapeutic drug monitoring. Methods This single‐center study included adult TNFi‐exposed UC patients treated with vedolizumab (2016–2019) or ustekinumab (2020–2022). Clinical remission was defined as 6‐point Mayo score ≤ 1, steroid‐free clinical remission as clinical remission, no steroid use 2 weeks prior to date of hospital visit, and biochemical remission as C‐reactive protein < 5 mg/L and fecal calprotectin < 250 μg/g. Targeted serum values were > 5 mg/L (ustekinumab) and > 20 mg/L (vedolizumab). Between‐cohort baseline differences were adjusted for in the analyses. Results Of 109 patients (52 vedolizumab and 57 ustekinumab), vedolizumab patients were less likely to achieve steroid‐free clinical and biochemical remission at 6 months (adjusted OR (aOR) = 0.3, 95% CI [0.1–0.9] and aOR = 0.2, [0.1–0.7], respectively). No difference in remission rates was found at 12 months. A higher proportion of ustekinumab patients received intensified dosing at 12 months (87% vs. 57%, aOR = 0.2, [0.06–0.6]). Conclusions Twelve‐month effectiveness was similar for the two drugs. Ustekinumab patients were more likely to achieve steroid‐free clinical and biochemical remission at 6 months, with a greater proportion requiring dose intensification to reach target drug levels.