P634 Clinical and Endoscopic Remission with Vedolizumab Treatment in Ulcerative Colitis

Vedolizumab (VDZ) is a gut-specific α4β7 integrin antagonist that has demonstrated efficacy in moderate to severe ulcerative colitis (UC) randomised controlled trials. The aim of this study was to evaluate the symptomatic and endoscopic response and remission rates achieved with VDZ therapy in UC in the real-world setting. A retrospective cohort study was performed at the University of Calgary with adult (≥18 years) UC patients receiving VDZ induction between 2012 and 2017. All patients received standard induction therapy with VDZ 300 mg IV at Weeks 0, 2, and 6 and were advanced onto a scheduled maintenance IV regimen. The primary outcome was clinical or endoscopic response and remission at 3, 6, and 12 months after induction. Clinical remission was defined by a partial Mayo score <2. Clinical response was defined by a reduction in partial Mayo score of ≥2. Endoscopic remission was defined by achievement of endoscopic Mayo subscore of 0. Endoscopic response was defined by a reduction in endoscopic Mayo subscore ≥1. We identified 100 UC patients treated with VDZ. Mean follow-up was 51.3 weeks (SD ± 35.8 weeks). Almost half (47 of 100) of patients had previously failed anti-TNF therapy. Steroid-free clinical remission at 3, 6, and 12 months after induction was 51.0% (51 of 100), 61.8% (55 of 89), and 61.9% (39 of 63), respectively. Steroid-free endoscopic remission occurred in 27.5% (11 of 40), 41.0% (16 of 39), and 47.8% (22 of 46) of patients at 3, 6, and 12 months, respectively (Figure 1). Twenty-five patients required dose escalation to 300 mg IV q4 weeks (20 patients) or q6 weeks (5 patients). VDZ was discontinued in 24 patients (15 for primary non-response, 6 for secondary loss of response, and 3 for other indications). An adverse event (AE) was reported in 24 patients (24.0%). The most common AEs were joint symptoms (6.0%), Cytomegalovirus (CMV) colitis (4.0%), and upper respiratory tract infections (4.0%). One patient developed a rectal adenocarcinoma after 6 months of VDZ initiation and required colectomy. Two deaths occurred in the cohort: one patient developed a stage IV high-grade neuroendocrine rectal tumour and a second patient died from recurrence of oropharyngeal carcinoma which had been initially diagnosed prior to VDZ initiation. Symptomatic and endoscopic response and remission rates with vedolizumab. In this cohort of UC patients, VDZ was safe and effective for inducing steroid-free clinical and endoscopic remission. Over half of patients achieved clinical remission and nearly half achieved endoscopic mucosal healing.