Introduction

Inflammatory bowel disease (IBD), comprising Crohn’s disease (CD) and ulcerative colitis (UC), is part of a broader spectrum of immune-mediated inflammatory diseases (IMIDs). Clinical and epidemiological studies indicate a higher prevalence of IMIDs among patients with IBD and their first-degree relatives, with a significant proportion of patients with IBD also diagnosed with conditions such as asthma, psoriasis, and rheumatoid arthritis^1,2. These patterns suggest shared genetic and/or environmental risk factors. The clinical intersections call for a multidisciplinary management strategy in which decisions account for the broader immune landscape rather than focusing on each diagnosis in isolation^1,3.

Aims & Methods

This study aimed to characterize the relationship between IBD and other IMIDs and disentangle genetic and environmental contributions. This was done by analyzing the tetrachoric correlation⁴ between disease codes registered for 107,651 full sibling pairs born between 1910 and 2010 in the Danish nationwide health registries. We then estimated SNP-based correlations based on summary statistics from genome-wide association studies of each disease using LDSC⁵. Lastly, we downloaded and reanalyzed all V3-V4 16S rDNA fecal microbiota samples available from NCBI⁶ in a unified bioinformatical pipeline. We used this data to generate microbiota disease profiles and estimate their correlations across IBD and IMIDs.

Results

We show that CD and UC have distinct patterns of correlations with other IMIDs. Asthma and celiac disease were correlated with CD (asthma: ρ=0.12, 95% CI=0.10-0.13, celiac disease: ρ=0.12, 95% CI=0.08-0.17), but not UC within full siblings. Oppositely, sarcoidosis (ρ=0.16, 95% CI=0.13-0.19), multiple sclerosis (ρ=0.09, 95% CI=0.06-0.12), systemic lupus erythematosus (SLE) (ρ=0.19, 95% CI=0.13-0.25), and Sjögren’s syndrome (ρ=0.15, 95% CI=0.10-0.20) correlated with UC but not CD. The IMIDs Graves’ disease, type 1 diabetes, iridocyclitis, psoriasis, psoriatic arthritis, rheumatoid arthritis, and ankylosing spondylitis correlated with both CD and UC. Evaluating genetic and gut microbial correlations highlighted that UC exhibits microbiota-linked correlations with multiple sclerosis (ρ=0.11, 95% CI=0.01-0.21) and SLE (ρ=0.15, 95% CI=0.05-0.24) despite an estimated negative genetic overlap (multiple sclerosis: ρ=-0.18, 95% CI=-0.32--0.04, SLE: ρ=-0.21, 95% CI=-0.32--0.09), suggesting a key role for environmental factors, including microbial. In contrast, for both IBD subtypes rheumatoid arthritis showed consistent genetic (CD: ρ=0.12, 95% CI=0.02-0.21, UC: ρ=0.17, 95% CI=0.08-0.27) as well as microbial convergence (CD: ρ=0.30, 95% CI=0.20-0.38, UC: ρ=0.12, 95% CI=0.02-0.22), whereas the correlation with psoriasis appeared to be mainly genetically driven (CD SNP correlation: ρ=0.23, 95% CI=0.14-0.33, CD microbiota correlation: ρ=-0.13, 95% CI=-0.23--0.03, UC SNP correlation: ρ=0.25, 95% CI=0.15-0.35, UC microbiota correlation: ρ=0.06, 95% CI=-0.04-0.16).

Conclusion

These findings uncover heterogeneity in shared etiological pathways across immune diseases, underscoring the need for stratified approaches to diagnosis and therapeutic intervention in IBD. Importantly, our findings demonstrate that CD and UC—though often co-studied—harbor distinct immunogenetic and microbial associations, reinforcing the need for subtype-specific approaches in clinical management and research design. Further, the correlation between IBD and other IMIDs appears to be driven by different genetic and environmental mechanisms, which must be further explored.

References

1. Bezzio C, Corte C Della, Vernero M, et al. Inflammatory bowel disease and immune-mediated inflammatory diseases: looking at the less frequent associations. Therap Adv Gastroenterol 2022;15. Available at: https://journals.sagepub.com/doi/full/10.1177/17562848221115312 [Accessed March 14, 2025].
2. García MJ, Pascual M, Pozo C Del, et al. Impact of immune-mediated diseases in inflammatory bowel disease and implications in therapeutic approach. Sci Rep 2020;10:10731. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC7330038/ [Accessed March 14, 2025].
3. Park SW, Kim TJ, Lee JY, et al. Comorbid immune-mediated diseases in inflammatory bowel disease: a nation-wide population-based study. Aliment Pharmacol Ther 2019;49:165–172. Available at: https://pubmed.ncbi.nlm.nih.gov/30506945/ [Accessed March 14, 2025].
4. Falconer DS, Mackay TFC. Introduction to Quantitative Genetics. Third Ddit. Longman Scientific & Technical; 1989.
5. Bulik-Sullivan B, Finucane HK, Anttila V, et al. An atlas of genetic correlations across human diseases and traits. Nature Genetics 2015 47:11 2015;47:1236–1241. Available at: https://www.nature.com/articles/ng.3406 [Accessed March 14, 2025].
6. Sayers EW, Bolton EE, Brister JR, et al. Database resources of the national center for biotechnology information. Nucleic Acids Res 2022;50:D20–D26. Available at: https://pubmed.ncbi.nlm.nih.gov/34850941/ [Accessed March 14, 2025].

Disclosure

TJ reports consultancy for Ferring and Pfizer. The remaining authors have no disclosures.

Introduction

Cholestatic pruritus is common, debilitating and undertreated in patients with primary biliary cholangitis (PBC). Here, we describe the results of GLISTEN (NCT04950127), a Phase 3 study investigating the efficacy and safety of the ileal bile acid transporter inhibitor linerixibat for pruritus in PBC.

Aims & Methods

In this double-blind, randomised, placebo-controlled study, patients with PBC and moderate-to-severe pruritus received oral linerixibat 40 mg or placebo twice daily. Pruritus severity and pruritus-related sleep interference were assessed using a 0–10 numerical rating scale. The primary endpoint was change from baseline in worst itch over 24 weeks. Secondary endpoints included: at Week 2, change in worst itch; over 24 weeks, change in sleep interference; at Week 24, proportion of responders (≥ 2-, ≥ 3-, ≥ 4-point reduction in worst itch) and analysis of responses to 2 patient global impression items (itch severity and change). Safety endpoints included adverse event (AE) reporting.

Results

238 patients were randomised; 95% were female, itch severity was mean (standard deviation [SD]) 7.34 (1.54), 52% had alkaline phosphatase < 1.67 times upper limit of normal, and 47% were receiving stable therapy for pruritus. Pruritus improvement over 24 weeks was significantly greater with linerixibat than placebo: least-squares (LS) mean change -2.86 versus -2.15, adjusted mean difference -0.72; p = 0.001. At Week 24, the observed mean (SD) difference from baseline in pruritus was -3.66 (2.50) with linerixibat and -2.82 (2.32) with placebo. The effect of linerixibat was rapid and superior to placebo at Week 2: LS mean change -1.78 versus -1.07, adjusted mean difference -0.71; p < 0.001. Linerixibat also significantly improved pruritus-related sleep interference over 24 weeks versus placebo: LS mean change ‑2.77 versus -2.24, adjusted mean difference -0.53; p = 0.024. At Week 24, more patients on linerixibat than placebo achieved a ≥ 2-point (68% vs 64%), ≥ 3-point (56% vs 43%) or ≥ 4-point (41% vs 29%) reduction in pruritus and a higher proportion of linerixibat than placebo-treated patients reported their pruritus was very much improved (55% vs 37%) or absent (21% vs 9%). AEs reported more frequently with linerixibat than placebo were predominantly gastrointestinal (GI), including diarrhoea (61% vs 18% of patients) and abdominal pain (18% vs 3% of patients); 4% of patients in the linerixibat group discontinued treatment due to diarrhoea.

Conclusion

In patients with PBC and moderate-to-severe pruritus, linerixibat rapidly and significantly improved pruritus and pruritus-related sleep interference versus placebo. While GI AEs were more common with linerixibat than placebo, they rarely led to treatment discontinuation.

Disclosure

Funded by GSK. Various authors declare conflicts of interest as consultants, employee, recipients of grants and stockholders. These will be reported in full during the presentation.