In the randomized, double-blind, phase 3 GRAPHITE study (NCT03657160), anti-α4β7 integrin antibody vedolizumab showed greater efficacy than placebo for prevention of lower-gastrointestinal (GI) acute graft-versus-host disease (aGVHD) after unrelated allogenic hematopoietic stem cell transplantation (allo-HSCT). This post hoc analysis assessed the efficacy and safety of vedolizumab versus placebo for lower-GI aGVHD prevention in Japanese and non-Japanese patients, when added to standard GVHD prophylaxis (calcineurin inhibitor + methotrexate/mycophenolate mofetil + / − anti-thymocyte globulin [ATG]). The analysis included 35 (18 vedolizumab-treated, 17 placebo-treated) Japanese and 298 (150 vedolizumab-treated, 148 placebo-treated) non-Japanese patients. Lower-GI aGVHD-free survival by day + 180 after allo-HSCT (primary endpoint) was 94% in vedolizumab-treated versus 81% in placebo-treated Japanese patients (HR 0.36; 95% CI 0.03–4.01; P = 0.2) and 84% in vedolizumab-treated versus 70% in placebo-treated non-Japanese patients (HR 0.47; 95% CI 0.28–0.78; P = 0.002). The number of events for the 5 key secondary endpoints (lower-GI aGVHD-free and relapse-free survival, Grade C–D aGVHD-free survival, non-relapse mortality, overall survival, and Grade B–D aGVHD-free survival) by day + 180 was lower in vedolizumab- versus placebo-treated Japanese patients. No safety concerns were identified for vedolizumab use as lower-GI aGVHD prophylaxis in Japanese patients.
