Irving, Peter Miles

Abstract Inflammatory bowel diseases (IBD), principally Crohn’s disease (CD) and ulcerative colitis (UC), are common chronic disorders involving inflammation and often progressive tissue damage. Genome-wide association studies have mapped many risk signals, but the causal variants, effector genes and relevant cellular contexts remain difficult to resolve, limiting mechanistic interpretation and therapeutic translation. Here we performed a multi-ancestry GWAS meta-analysis of 125,992 individuals with IBD and more than 1.2 million controls, identifying 619 independent association signals (374 novel) at 420 IBD regions that account for 77–80% of SNP-based heritability. Fine-mapping resolved 81 high-confidence variants, 41 not previously reported. Although most signals were shared between CD and UC, 39% showed IBD subtype specificity, with UC signals showing stronger enrichment in functional annotations from intestinal epithelial, secretory and enteroendocrine cells, and CD showing stronger genetic correlations with circulating inflammatory biomarkers, including C-reactive protein and glycoprotein acetylation. Latent causal modelling supported a causal effect of decreased high-density lipoprotein on CD risk. By integrating bulk and single-cell eQTL and pQTL resources using colocalisation and Mendelian randomisation, together with coding-variant evidence from exome sequencing, we prioritised 664 candidate effector genes across 341 signals, including 390 newly implicated IBD genes, revealing new biological mechanisms and candidate therapeutic targets supported by human genetics.

Abstract Inflammatory bowel disease (IBD) is a chronic immune-mediated disorder of the gastrointestinal tract whose genetic basis is only partly resolved because most risk variants identified by genome-wide association studies (GWAS) lie in non-coding regions, limiting direct gene assignment and biological interpretation 1,2 . Here we analysed whole-exome and whole-genome sequencing data from 86,213 IBD cases and 478,363 controls of European ancestry. We identified 68 IBD genes directly implicated by conditionally independent protein-coding associations across the allele frequency spectrum. Many newly implicated IBD genes are supported by orthogonal genomic or pleiotropic evidence, pointing to disease-related pathways and nominating targets with therapeutic relevance. We further identified allelic series and non-additive effects at key loci such as NOD2 and TYK2. These results show that large-scale sequencing can resolve disease genes and pathways that remain ambiguous from non-coding association alone, providing a more direct route from human genetics to biological insight and therapeutic hypotheses.

Abstract Background Etrasimod is an oral, once-daily (QD), selective sphingosine 1-phosphate (S1P)1,4,5 receptor modulator for the treatment of moderately to severely active ulcerative colitis (UC). Previous work has shown age can impact treatment safety and efficacy in patients with inflammatory bowel disease.1 This post hoc analysis investigated the impact of age on the safety and efficacy of etrasimod in patients with UC in the phase 3 ELEVATE UC clinical programme. Methods Data pooled from the ELEVATE UC 52 (NCT03945188) and ELEVATE UC 12 (NCT03996369) trials were analysed in patients receiving etrasimod 2 mg QD and placebo. ELEVATE UC 52 had a treat-through design comprising a 12-week induction period followed by a 40-week maintenance period. ELEVATE UC 12 was a 12-week induction trial. Proportions and incidence rates (IRs) per 100 patient-years from pooled data of treatment-emergent adverse events (TEAEs) and events of interest were stratified by age (<40 years, 40–59 years, ≥60 years) and analysed in patients who received ≥1 dose of etrasimod or placebo. Efficacy analyses were evaluated in patients with baseline Modified Mayo score (MMS) 5–9 for the primary efficacy endpoint (clinical remission) and select secondary endpoints at Week 12 (both trials) and Week 52 (ELEVATE UC 52) stratified by age. Results There were 787 patients enrolled in the ELEVATE UC programme, of whom 420 (53.4%) were aged <40 years, 276 (35.1%) were aged 40–59 years and 91 (11.6%) were aged ≥60 years. The proportions and IRs of TEAEs and events of interest were mostly similar between age groups and treatment arms (Table). IRs of arthralgia, fatigue, hypertension and pyrexia were higher in older age groups, regardless of treatment arm. Serious AEs and AEs leading to treatment discontinuation were low and consistent across all age subgroups. Serious infections and infection events of interest were balanced across age groups and treatment arms. Regardless of age subgroup, significantly more patients treated with etrasimod 2 mg QD vs placebo achieved the primary and select secondary efficacy endpoints at Week 12 and Week 52 (Figure). Conclusion The safety profile of etrasimod 2 mg QD in the UC population was consistent across age groups, and with no new risks other than the estimated risks associated with increasing age.2 Patients receiving etrasimod in the ELEVATE UC programme showed significant clinical benefit as assessed by clinical remission, symptomatic remission and endoscopic improvement compared with placebo, regardless of age. References 1. Lichtenstein GR et al. Inflamm Bowel Dis 2023; 29: 27–41. 2. Luo J et al. JMIR Med Inform 2016; 4: e30.

Abstract Background Perianal fistulas are common and cause significant quality of life impairment in patients (pts) with Crohn’s disease (CD). In previous phase 2/3 studies, ustekinumab (UST) showed some evidence of efficacy on fistula resolution, with no clear dose-response relationship. Additional studies are needed to evaluate the role of UST in perianal fistula treatment. Here, we report fistula data from two recent studies of UST in CD, SEAVUE and STARDUST. Methods In SEAVUE, biologic-naïve pts with moderate-to-severe CD were randomized to receive blinded UST (⁓6mg/kg IV at baseline then 90mg SC q8w) or adalimumab (ADA; 160/80mg SC at baseline/W2, then 40mg SC q2w). In STARDUST, biologic-naïve and biologic-failure pts with moderate-to-severe CD received open-label UST ⁓6mg/kg IV at baseline and UST 90mg SC at W8. At W16, pts were randomized to maintenance treatment under standard of care (90mg SC q12w or q8w) or treat-to-target (90mg SC q12w or q8w with potential adjustment to q4w) regimens. In both trials, the number of open and draining perianal fistulas was evaluated at baseline and the end of maintenance (SEAVUE W52, STARDUST W48). Fistula resolution was defined as closure of all fistulas. Pts with missing data at W52/W48 were considered to not have been in fistula resolution. In SEAVUE, pts who had a prohibited CD-related surgery, discontinued for lack of efficacy or an adverse event of worsening CD, or had prohibited concomitant medication changes before W52 were considered not to be in fistula resolution. Results In SEAVUE, 7 of 13 pts (53.8%) with active perianal fistulas at baseline in the UST group had complete fistula resolution at W52, and 6 of 16 patients (37.5%) in the ADA group had fistula resolution. In STARDUST, 9 of 19 pts (47.4%) with active perianal fistulas at baseline had complete fistula resolution at W48. Of the 9 pts in fistula resolution, 2 were receiving q12w at W48, 6 were receiving q8w, and 1 was receiving q4w. Of the 10 pts without fistula resolution, 2 were receiving q12w at W48, 3 were receiving q8w, 1 was receiving q4w and 4 discontinued before W48. In both studies, among pts with evaluable samples for pharmacokinetic analysis, fistula closure at W52/48 was not associated with higher serum drug concentrations at either the early time point of W16 or at the end of maintenance (Figure). This result was consistent for UST in both studies as well as ADA in SEAVUE. Conclusion Of pts with perianal fistulas at baseline in SEAVUE and STARDUST who received UST (32 pts in total), half were in fistula resolution after ~1 year of maintenance treatment. No relationship was observed between fistula resolution and serum drug concentrations, but no definite conclusions can be drawn given the relatively small sample size.

Abstract Background Entry criteria and outcome measures of Crohn’s disease (CD) clinical trials have evolved. Patients are now required to have active inflammation on screening endoscopy, with some studies requiring moderate-severe SES-CD scores. Recent trials have endoscopic response as a co-primary endpoint and endoscopic remission (ER) and deep remission (DR) as major secondary endpoints. Pivotal CD maintenance studies typically examine only responders to induction. The SEAVUE study required ≥1 ulceration of any size (SES-CD≥3) at baseline and had a treat-through design. To examine the results in the context of these trial design characteristics, we evaluated endoscopic outcomes at wk52 in the subgroup of pts with moderate-severe baseline SES-CD scores in SEAVUE, as well as those who were in clinical response after induction. Methods Biologic-naïve pts failing or intolerant to conventional therapy with CDAI≥220/≤450 and SES-CD≥3 were eligible. Pts were randomized, 1:1 to UST (~6mg/kg IV at wk0 then, 90mg SC q8w) or ADA (SC, 160mg at wk0, 80mg at wk2, then, 40mg q2w). Endoscopic outcomes were evaluated in all pts and the subgroup with moderate-severe endoscopic disease (baseline SES-CD≥6 for ileocolonic or colonic disease or SES-CD≥4 for isolated ileal disease). Endoscopic response was a ≥50% reduction from baseline in SES-CD, SES-CD≤3, or SES-CD=0 for pts with baseline SES-CD=3. ER was SES-CD≤3 or, 0 in pts with baseline SES-CD=3. DR was CDAI<150 and ER. Results Endoscopic outcomes for the subgroup with moderate-severe endoscopic disease were similar to those of the full cohort of pts. In UST-treated pts, endoscopic response was achieved at wk52 in, 41.9% in the full cohort and, 43.1% in the moderate-severe subgroup (Table, 1). In ADA-treated pts, endoscopic responses were, 36.9% and, 35.4%, respectively. For pts who were in clinical response after induction (Table, 1), endoscopic response rates were, 48.2% in the full cohort and, 49.5% in the moderate-severe subgroup for UST and, 44.8% and, 43.1%, respectively, for ADA. ER and DR rates were generally similar between the full cohort and the moderate-severe subgroup (Table, 2; eg, ERs were UST, 28.5% and ADA, 30.7% in full cohort; UST, 27.1% and, 27.8% ADA in subgroup). ER and DR rates were, 3%-7% higher in induction responders compared with the full cohort. Of note, even among wk16 nonresponders, some pts attained endoscopic outcomes at wk52 (eg, endoscopic responses in wk16 nonresponders were UST, 21.4% and ADA 13.3%). Conclusion In SEAVUE, both the UST and ADA treatment groups achieved high endoscopic response, ER, and DR rates at wk52. Results in pts with moderate-severe endoscopic disease were similar to those of the full cohort, but clinical responders after induction had higher rates than the full cohort.