Guselkumab in East Asians With Moderate‐to‐Severe Ulcerative Colitis: Subgroup Analysis of the QUASAR Induction and Maintenance Studies

BACKGROUND AND AIM: The global QUASAR (NCT04033445) clinical program demonstrated the efficacy and safety of guselkumab, a dual-acting interleukin-23 p19 subunit inhibitor, as induction and maintenance therapy in participants with moderate to severely active ulcerative colitis (UC). We report a subgroup analysis in East Asian participants. METHODS: The QUASAR program included two randomized, placebo-controlled, 12-week induction studies of guselkumab 200 mg (and 400 mg, Phase 2b) IV every 4 weeks (q4w) in adults with baseline modified Mayo scores of 5-9 and inadequate response/intolerance to conventional and/or advanced UC therapy. Clinical responders to guselkumab induction were re-randomized (1:1:1) at maintenance study baseline to SC guselkumab 200 mg q4w, 100 mg q8w, or placebo. Primary endpoints were clinical response (Phase 2b) or clinical remission (Phase 3) at induction Week 12 (I-12) and clinical remission at maintenance Week 44 (M-44). Subgroup analyses included participants from sites in China, Japan, Korea, and Taiwan region. RESULTS: Data were from 71 (Phase 2b) and 135 (Phase 3) East Asians in the induction studies and 106 in the maintenance study. At Week I-12, 45.5%-58.8% of guselkumab versus 25.5%-29.2% of placebo participants achieved clinical response and 16.0%-23.8% versus 4.2%-5.5%, respectively, achieved clinical remission. At Week M-44, 37.1%-46.3% of guselkumab versus 13.3% of placebo participants achieved clinical remission. The adverse event profile was generally consistent with the global QUASAR population. CONCLUSIONS: Results support the efficacy and safety of guselkumab induction and maintenance in East Asians with moderately to severely active UC, consistent with findings from the global QUASAR studies. TRIAL REGISTRATION: ClinicalTrials.gov, NCT04033445; EudraCT, 2018-004002-25.