Efficacy and safety of filgotinib as induction and maintenance therapy for Crohn's disease (DIVERSITY): a phase 3, double-blind, randomised, placebo-controlled trial

Background There is a need for efficacious therapies for patients with Crohn's disease that are better tolerated and more durable than available treatments. We aimed to evaluate the efficacy and safety of filgotinib, an oral Janus kinase 1 preferential inhibitor, for treating Crohn's disease. Methods This phase 3, double-blind, randomised, placebo-controlled trial was conducted in 371 centres in 39 countries. Eligible patients were aged 18-75 years with moderately to severely active Crohn's disease for at least 3 months before enrolment. Patients were enrolled into one of two induction studies on the basis of their experience with biological agents (induction study A included biologic-naive and later biologic-experienced patients and induction study B included biologic-experienced patients). In both induction studies, patients were randomly assigned (1:1:1), using an interactive web response system, to receive oral filgotinib 200 mg, filgotinib 100 mg, or placebo once daily for 11 weeks. Patients who received filgotinib and had two-item patient-reported outcome (PRO2) clinical remission or an endoscopic response at week 10 were re-randomised (2:1) to receive their induction dose or placebo orally, once daily to the end of week 58 in the maintenance study. Co-primary endpoints were PRO2 clinical remission and an endoscopic response at week 10 (induction studies) and week 58 (maintenance study). PRO2 clinical remission was defined as an abdominal pain subscore of not more than 1 and a liquid or very soft stool frequency subscore of not more than 3 (from eDiary data) and endoscopic response was defined as a reduction of at least 50% in Simple Endoscopic Score for Crohn's disease from induction baseline (from central reading of endoscopy). For the induction studies, efficacy was assessed in all randomly assigned patients who received at least one dose of study drug. For the maintenance study, efficacy was assessed in all patients from either filgotinib treatment group in the induction studies who reached PRO2 clinical remission or an endoscopic response at week 10, and who were re-randomised and received at least one dose of study drug in the maintenance study. Patients who received placebo throughout the induction and maintenance studies were not included in the full analysis set for the maintenance study. Safety was assessed in all patients who received at least one dose of study drug. This trial is complete and is registered with ClinicalTrials.gov, NCT02914561. Findings Between Oct 31, 2016, and Nov 11, 2022, 2634 patients were screened, of whom 1372 were enrolled (induction study A: n=707, induction study B: n=665, and maintenance study: n=481). There were 346(49%) women and 358 (51%) men in induction study A, 356 (54%) women and 303 (46%) men in induction study B, and 242 women (51%) and 236 men (49%) in the maintenance study. Significantly more patients had PRO2 clinical remission at week 10 with filgotinib 200 mg than with placebo in induction study B (29<middle dot>7% vs 17<middle dot>9%, difference 11<middle dot>9%; 95% CI 3<middle dot>7 to 20<middle dot>2, p=0<middle dot>0039) but not induction study A (32<middle dot>9% vs 25<middle dot>7%, 6<middle dot>9%; -1<middle dot>4 to 15<middle dot>2, p=0<middle dot>0963); there was no significant difference for endoscopic response (induction study A: 23<middle dot>9% vs 18<middle dot>1%, difference 5<middle dot>5%; 95% CI -2<middle dot>0 to 12<middle dot>9, p=0<middle dot>1365; induction study B: 11<middle dot>9% vs 11<middle dot>4%, 0<middle dot>1%; -6<middle dot>5 to 6<middle dot>6, p=0<middle dot>9797). At week 58, both co- primary endpoints were reported in greater proportions of patients who received filgotinib 200 mg than in those who received placebo (PRO2 clinical remission: 43<middle dot>8% vs 26<middle dot>4%, difference 16<middle dot>8%; 95% CI 2<middle dot>0 to 31<middle dot>6, p=0<middle dot>0382; endoscopic response: 30<middle dot>4% vs 9<middle dot>4%, difference 20<middle dot>6%; 95% CI 8<middle dot>2 to 33<middle dot>1, p=0<middle dot>0038). Co-primary endpoints were not met for filgotinib 100 mg in any study. In the induction studies, the most frequently reported treatment-emergent adverse events (TEAEs; >= 5% of patients in any group) were abdominal pain; arthralgia; an exacerbation, flare, or worsening of Crohn's disease; headache; nasopharyngitis; nausea; and pyrexia. In the maintenance study, the most frequently reported TEAEs (>= 5% of patients in any filgotinib or associated placebo group) were those reported in the induction studies (except for headache) and abdominal distension, upper abdominal pain, anaemia, and flatulence. Serious TEAEs were reported in 49 patients in induction study A (18 [8%]) of 222 patients in the filgotinib 200 mg group, 16 [7%] of 245 patients in the filgotinib 100 mg group, and 15 [6%] of 237 patients in the placebo group), 81 patients in induction study B (19 [9%] of 202 patients in the filgotinib 200 mg group, 36 [16%] of 228 patients in the filgotinib 100 mg group, and 26 [11%] of 229 patients in the placebo group), and 49 patients in the maintenance study (13 [11%] of 118 patients in the filgotinib 200 mg-filgotinib 200 mg group, five [9%] of 56 patients in the filgotinib 200 mg-placebo group, 14 [13%] of 104 patients in the filgotinib 100 mg-filgotinib 100 mg group, three [5%] of 55 patients in the filgotinib 100 mg-placebo group, and 14 [10%] of 145 patients in the placebo-placebo group). No deaths were reported during the induction and maintenance studies. Interpretation Filgotinib 200 mg did not meet the co-primary endpoints of clinical remission and an endoscopic response at week 10, but did meet the co-primary endpoints at week 58. Filgotinib treatment was well tolerated, and no new safety signals were reported. Funding Galapagos. Copyright (c) 2024 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license.