Methods: Efficacy outcomes of interest were clinical response, clinical remission and mucosal healing at week 6 (induction phase); and clinical remission, durable clinical response, durable clinical remission, mucosal healing and glucocorticoid-free remission at week 52 (maintenance phase). Differences in outcome rates between vedolizumab and placebo in Asian countries (Hong Kong, India, Malaysia, Singapore, South Korea, and Taiwan) were assessed using descriptive analyses, and efficacy and safety compared between Asian and non-Asian countries.

Results: During induction, in Asian countries (n = 58), clinical response rates at week 6 with vedolizumab and placebo were 55.2% and 24.1%, respectively (difference 31.0%; 95% confidence interval: 7.2%-54.9%). In non-Asian countries (n = 316), response rates at week 6 with vedolizumab and placebo were 45.9% and 25.8%, respectively. During maintenance, in Asian countries, clinical remission rates at 52 weeks with vedolizumab administered every 8 weeks, vedolizumab administered every 4 weeks and placebo were 9.1%, 36.8%, and 31.6%, respectively; corresponding rates for mucosal healing were 45.5%, 47.4%, and 47.4%, respectively. Vedolizumab was well-tolerated; adverse event frequency was comparable in Asian and non-Asian countries.