Abstract: Four studies (606 patients) were included. All of the studies were rated as having a low risk of bias. Pooled analyses revealed that vedolizumab was significantly superior to placebo for induction of remission, clinical response, and endoscopic remission and prevention of relapse. After 4 to 6 weeks of therapy 77% (293/382) of vedolizumab patients failed to enter clinical remission compared to 92% (205/224) of placebo patients (RR 0.86, 95% CI 0.80 to 0.91; 4 studies 606 patients). After 6 weeks of therapy 48% of vedolizumab patients failed to have a clinical response compared to 72% of placebo patients (RR 0.68, 95% CI 0.59 to 0.78; 3 studies 601 patients). After 4 to 6 weeks of therapy 68% of vedolizumab patients failed to enter endoscopic remission compared to 81% of placebo patients (RR 0.82, 95% CI 0.75 to 0.91; 3 studies, b583 patients). After 52 weeks of therapy, 54% of vedolizumab patients had a clinical relapse compared to 84% of placebo patients (RR 0.67, 95% CI 0.59 to 0.77; 1 study, 373 patients). One small study (28 patients) found no statistically significant difference in endoscopic response (RR 1.00, 95% CI 0.62 to 1.61). GRADE analyses indicated that the overall quality of the evidence for the primary outcomes was high for induction of remission and moderate for relapse (due to sparse data 246 events). There was no statistically significant difference between vedolizumab and placebo in terms of the risk of any adverse event (RR 0.99, 95% CI 0.93 to 1.07), or serious adverse events (RR 1.01, 95% CI 0.72 to 1.42). There was a statistically significant difference in withdrawals due to adverse events. Six per cent of vedolizumab patients withdrew due to an adverse event compared to 11% of placebo patients (RR 0.55, 95% CI 0.35 to 0.87; 2 studies, 941 patients). Adverse events commonly reported across the studies included: worsening ulcerative colitis, headache, nasopharyngitis, upper respiratory tract infection, nausea, and abdominal pain. Moderate to high quality data from four studies shows that vedolizumab is superior to placebo for induction of clinical remission and response and endoscopic remission in patients with moderate to severely active ulcerative colitis and prevention of relapse in patients with quiescent ulcerative colitis. Moderate quality data from one study suggests that vedolizumab is superior to placebo for prevention of relapse in patients with quiescent ulcerative colitis. Adverse events appear to be similar to placebo. Future trials are needed to define the optimal dose, frequency of administration and long-term efficacy and safety of vedolizumab used for induction and maintenance therapy of ulcerative colitis. Vedolizumab should be compared to other currently approved therapies for ulcerative colitis in these trials.

Plain-language summary: Four studies including 606 patients were included in this review. Pooled analysis of these trials revealed vedolizumab is significantly more effective than placebo (sham infusion) for inducing clinical remission and response (improvement of symptoms), as well as endoscopic remission (healing of inflamed mucosa in the colon) in patients with moderate to severely active ulcerative colitis. Evidence from one study suggests that vedolizumab is superior to placebo for preventing relapse (recurrence of active disease) in patients with ulcerative colitis in remission. Patients receiving vedolizumab were no more likely than placebo patients to experience side effects or serious side effects. Commonly reported side effects included: worsening ulcerative colitis, headache, nasopharyngitis (inflammation of nose and throat), upper respiratory tract infection, nausea, and abdominal pain. Further research is needed in order to define the optimal dose, frequency of drug administration and the long-term effectiveness and safety of vedolizumab used for induction and maintenance of remission in ulcerative colitis. Vedolizumab should be compared to other currently approved therapies of ulcerative colitis in these studies.