Abstract
BACKGROUND: Vedolizumab (VDZ) is a humanized monoclonal IgG1 antibody which inhibits leukocyte vascular adhesion and migration into the gastrointestinal tract through α4β7 integrin blockade. This agent became available in Canada in mid-2015 for the treatment of moderate to severe ulcerative colitis (UC). AIMS: To investigate the real-world efficacy and safety of vedolizumab (VDZ) as induction therapy in UC patients at a tertiary IBD centre and to examine predictors of remission. METHODS: Demographic and clinical data for UC patients treated with 300mg VDZ infusions at weeks 0, 2, 6 and 14 was gathered retrospectively. Clinical remission (CR, partial Mayo score≤2) and steroid-free clinical remission (SFCR) after the first 3 infusions (induction phase) between weeks 8–12 were the primary endpoints. Secondary endpoints were CR and SFCR after 4 infusions (1(st) maintenance infusion) between weeks 16–20. Adverse events were also recorded. RESULTS: Data from 68 UC patients (63% male, median age 33 years, median disease duration 6 years, median pMayo 7) were analyzed. Anti-TNF naive were 31% and 69% had pancolitis. At the time of first infusion, 49% were on systemic steroids and 20% on an immunomodulator, while 44% patients were started on VDZ monotherapy. Median partial Mayo scores and median CRP levels improved significantly after 3 and 4 VDZ infusions compared to baseline (p<0.05). After 3 infusions (n=68), 37% and 31% of the patients achieved CR and SFCR respectively. After 4 infusions (n=53), 36% and 32% of the patients were in CR and SFCR respectively. Seventy percent of the non-responders after the 3(rd) infusion remained non-responders after the 4(th) infusion. Baseline characteristics including disease duration less than 5 years, no prior anti-TNF exposure, immunomodulator concurrent treatment, mild disease (p=0.025) and CRP less than 5mg/L (p=0.004) were associated with clinical remission after the first 3 infusions. Clinical remission after 3 VDZ infusions was significantly associated with sustained clinical remission after 4 infusions (p<0.001). Overall, 12% discontinued VDZ due to no response and 7% underwent elective proctocolectomy. There were no infusion reactions or serious side effects. The most common side effect was headache (7%). CONCLUSIONS: VDZ is an effective, safe and well tolerated treatment option in refractory UC patients. Clinical remission and steroid-free clinical remission can be achieved in 1/3 of the patients after the induction phase. This real life series in a tertiary care centre demonstrates similar efficacy results as the other real-world clinical studies. Assessment of VDZ response after the 3(rd) infusion could be critical to determine treatment benefits and decide further management. FUNDING AGENCIES: None