Ulcerative colitis disease severity affects the speed of symptom relief under filgotinib treatment: a post hoc analysis of the phase 2b/3 SELECTION study.

Background/aims: Filgotinib is an oral, once-daily, Janus kinase 1 preferential inhibitor approved for the treatment of ulcerative colitis (UC). This study aimed to assess symptomatic response with filgotinib 200 mg (FIL200) according to disease severity using baseline partial Mayo Clinic Score (pMCS).

Methods: In the phase 2b/3 SELECTION study (NCT02914522), adults with moderate-to-severe UC were randomized to receive FIL200, filgotinib 100 mg, or placebo for 11 weeks in induction studies A (biologic-naive) and B (biologic-experienced). In this post hoc analysis, symptomatic remission (Mayo rectal bleeding subscore of 0 and stool frequency subscore ≤ 1) rates were assessed daily from baseline to day 15 and fortnightly from week 2 to week 10 by baseline pMCS (pMCS ≥ 7, pMCS < 7) in patients who received induction FIL200.

Results: Of those who received FIL200 in induction studies A and B, 90 and 148 patients had a pMCS ≥ 7, and 155 and 114 had a pMCS < 7, respectively. Symptomatic remission rates were generally significantly higher in the pMCS < 7 than ≥ 7 group from day 2-15 (day 2: 8.4% vs. 1.1%, P= 0.009 [induction study A]; 8.8% vs. 0.7%, P= 0.004 [induction study B]). However, by week 10, there was no longer a significant difference in the rates between the pMCS ≥ 7 and < 7 groups (43.3% vs. 54.8%, P= 0.124 [induction study A]; 26.4% vs. 39.5%, P= 0.099 [induction study B]).

Conclusions: Symptomatic response to FIL200 occurred more rapidly in the less severe disease groups than in the more severe disease groups; however, regardless of disease severity, both groups benefited from continued FIL200 treatment.