Introduction

Inflammatory bowel diseases (IBD), including Crohn's disease and ulcerative colitis, are characterized by dysregulated T-cell responses, causing chronic intestinal inflammation.¹ While anti-TNF therapy is established in IBD, targeting additional pathways may improve outcomes for patients who do not respond adequately to current treatments.² OX40L, an immune co-stimulator, has been implicated in the pathogenesis of several inflammatory conditions.³ Our study provides a comprehensive analysis of the effects of combined TNF and OX40L blockade in a murine adoptive T cell transfer (ATC) model of colitis, examining body weight, detailed histopathological parameters, and a broad range of inflammatory cytokines in colon tissue.

Aims & Methods

Colitis was induced in severe combined immunodeficiency (SCID) mice by intraperitoneal transfer of CD4⁺CD45RB^high T cells isolated from healthy BALB/c donor mice. We established five treatment groups (n=8-10): 1) CD45RB^low transfer “healthy control”, 2) CD45RB^high transfer with isotype antibodies “disease control group”, 3) CD45RB^high transfer with anti-TNF antibody (XT3.11, 250 μg/mouse), 4) CD45RB^high transfer with anti-OX40L antibody (RM134L, 250 μg/mouse), and 5) CD45RB^high transfer with both antibodies at 250 µg/mouse, each. Body weight was monitored for 46 days as a measure of disease progression and normalized to baseline weight at day 1. At study termination, we collected colon tissue for analysis of inflammatory cytokines using multiplex immunoassays and conducted histopathological examination. Histopathological scoring was performed blinded using a validated scoring system for colonic inflammation.⁴

Results

Overall, combined anti-TNF/anti-OX40L therapy was most effective in preventing body weight loss compared to the isotype disease control group, followed by anti-TNF monotherapy and anti-OX40L monotherapy (p<0.0001, p=0.0009, and p=0.03, respectively). Mean normalized body weight (MNBW) of the CD45RB^low healthy control group at termination on day 46 was 115.2 %, while CD45RB^high cell transfer in the disease control group triggered disease induction and body weight loss, with a MNBW of 93.8 % at day 46. The CD45RB^high groups treated with anti-TNF or anti OX40L monotherapy reached a MNBW of 107.6 % and 102.9%, respectively. The CD45RB^high group treated with combination therapy reached 112.6%, closest to the CD45RB^low healthy control group. Notably, only combination therapy led to a significant improvement in histopathological scoring (p=0.0176) compared to the isotype disease control. Similarly, combination treatment consistently resulted in the strongest downregulation of several inflammatory cytokines including IFNg, IL-4, or TNFa, which are increased in colon tissue in the CD45RB^high disease group compared to the CD45RB^low healthy control group.

Conclusion

Combined blockade of TNF and OX40L demonstrated significantly greater efficacy in the ATC preclinical model of IBD in prevention of weight loss, downregulation of key inflammatory cytokines, and reduction of histological damage compared to either monotherapy. These data suggest potential additive efficacy for TNF and OX40L inhibition in controlling intestinal inflammation, and warrant further exploration of dual TNF/OX40L inhibition in clinical trials, particularly among those with inadequate response to anti-TNF monotherapy.

References

1. Kaser A, Zeissig S, Blumberg RS. Inflammatory bowel disease. Annu Rev Immunol. 2010;28:573-621.
2. Vermeire S. Combination biologic therapy for ulcerative colitis. Lancet Gastroenterol Hepatol. 2023;8:288-90.
3. Fu Y, Lin Q, Zhang Z, Zhang L. Therapeutic strategies for the costimulatory molecule OX40 in T-cell-mediated immunity. Acta Pharm Sin B. 2020;10:414-33.
4. Erben U, Loddenkemper C, Doerfel K, Spieckermann S, Haller D, Heimesaat MM, Zeitz M, Siegmund B, Kühl AA. A guide to histomorphological evaluation of intestinal inflammation in mouse models. Int J Clin Exp Pathol. 2014;7:4557-76.

Disclosure

Thomas Leeuw, Rolf Keiffer, Danping Ding-Pfennigdorff, Christian Asbrand, Raaj Mehta, Matthias Herrmann are employees of Sanofi and may hold stock or equity options in Sanofi

Introduction

Very early onset inflammatory bowel disease (VEO-IBD) is often associated with a severe disease course and unique characteristics including an underlying monogenic defect. In this study, we identified new pathogenic mutations in CGNL1 associated with VEO-IBD and other inflammatory GI disease. CGNL1 (Cingulin Like 1) encodes an epithelial junctional protein whose function was previously unknown in the gastrointestinal tract.

Aims & Methods

Whole exome sequencing (WES) was performed on the affected patient with VEO-IBD and all first-degree relatives with IBD and other inflammatory disease. Intestinal epithelial organoids (IEOs) were generated from the affected patient and were characterized by transepithelial electrical resistance (TEER), FITC-dextran permeability assay on epithelial cell monolayer, immunostaining, RNA sequencing, and transmission electron microscopy (TEM). In addition, we generated a new Cgnl1^-/- mouse model, which was characterized using FITC-dextran permeability assay, TEM, dextran-sodium sulfate (DSS)-induced colitis, and infections by Citrobacter rodentium and Clostridioides difficile. Single-cell datasets were analyzed to determine CGNL1 expression in IBD, primary sclerosing cholangitis (PSC), and autoimmune hepatitis (AIH).

Results

In the affected patient with VEO-IBD who required early total colectomy and pouch formation with coexistent PSC and celiac disease, WES identified two rare, new, pathogenic variants in the CGNL1 gene. Both pathogenic variants were also present in the patient’s younger sister, who has a similar history including early-onset, fulminant ulcerative colitis requiring total colectomy with ileostomy and PSC-AIH overlap syndrome. Furthermore, multiple relatives of the patient suffer from IBD and other inflammatory conditions including celiac disease, eosinophilic esophagitis, and type-1 diabetes. The RNA and protein levels of CGNL1 were significantly diminished in the patient’s intestinal epithelial cells compared to that of healthy individuals and other IBD patients by RNA-seq, immunoblotting, and immunostaining. The patient’s IEOs from pouch body and pre-pouch ileum formed smaller 3D spheroids with altered cell composition and significantly impaired barrier function compared to those from healthy controls and other IBD patients. Immunofluorescence and TEM demonstrated that CGNL1 is required for the assembly of junctional complexes in human IEOs and an epithelial cell line. Similarly to findings from the patient, impaired junctional complexes in intestinal epithelial cells and elevated intestinal permeability were present in Cgnl1^-/- mice at steady state. Cgnl1^-/- mice showed substantial vulnerability to DSS-induced colitis and bacterial infections that directly compromise the epithelial barrier. In addition, 6-month-old Cgnl1^-/- mice exhibited spontaneous inflammation in the colon and terminal ileum due to disrupted intestinal barrier, which was microbiome-dependent. Furthermore, single-cell analysis revealed diminished expression of CGNL1 in the intestinal and hepatic epithelial cells from patients with IBD or PSC/AIH, respectively.

Conclusion

The pathogenic CGNL1 variants contribute to VEO-IBD by disrupting gut barrier integrity, as demonstrated by patient’s cells and novel murine models. This study expands our understanding of epithelial barrier impairment in the pathogenesis of VEO-IBD, and highlights intestinal epithelium as a therapeutic target in some IBD patients.

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.

Introduction

Management of perianal fistulas in Crohn’s disease (CD) is challenging and requires a multidisciplinary approach, combining surgical drainage and biologic therapies, such as infliximab (IFX). Higher IFX trough concentrations have been associated with improved fistula healing rates. The subcutaneous (SC) formulation of IFX achieves 2–3 times higher and more stable trough levels compared to intravenous (IV) formulation. This study hypothesizes that SC IFX could enhance perianal fistula healing rates in CD patients.

Aims & Methods

REMSILAP study is part of the 3TLAP cohort, a French prospective multicenter observational study evaluating optimal therapeutic strategies for achieving clinical and radiological remission of perianal fistulas in CD at 12 months post-surgical drainage. The REMSILAP substudy focuses specifically on patients receiving SC IFX. Patients who received SC IFX after or within six months prior to surgical drainage were included. Baseline was defined as the day of surgical drainage. The primary outcome was the proportion of patients achieving complete clinical remission defined as Perianal Disease Activity Index (PDAI) fistula drainage subscore = 0 associated with PDAI activity restriction subscore <3 and absence of seton, and radiological remission at 12 months. Here, we present preliminary findings from REMSILAP.

Results

Among the 353 patients enrolled in the 3TLAP cohort, 54 were included in REMSILAP. The cohort consisted of 61.1% male patients, with a median age of 36 years and a median disease duration of 4.5 years. Penetrating disease (B3 phenotype) was present in 40.7%, and 33.3% had a history of surgical resection. At baseline, 40.7% of patients had quiescent disease regarding Harvey-Bradshaw index, while 5.6% had severe disease activity. Biologic exposure prior to inclusion was noted in 42.6%. Surgical drainage, with seton placement, was performed in 74.1% of patients. Forty-eight patients (88%) initiated SC IFX treatment after surgical drainage. Of the patients receiving SC IFX, 50% transitioned to SC IFX after less than three IV infusions. Among those on IV IFX at baseline, 20.4% were receiving a 10 mg/kg dose. Forty-three patients (79.6%) received SC IFX in combination with immunomodulators (azathioprine, methotrexate, or 6-mercaptopurine). The median duration of SC IFX treatment was 13.1 months, with treatment maintained for 67.5% of the follow-up period (mean: 19.3 ± 11.3 months). Forty-three patients (79.6%) were treated with a stable dose of 120 mg/14 days and 6 patients (11.1%) had an intensification of SC IFX dosage to 120mg / 7 days. At 12 months, 42 patients were evaluable for clinical outcomes. Complete clinical healing at 12 months was achieved in 11 patients (27.5%) and association of PDAI restriction subscore <3 and drainage subscore = 0 was found in 18 patients (42.9%). Thirteen patients (34.2%) from the 25 patients who had received at least 6 months of SC IFX treatment showed clinical healing at 6 months. Out of the 26 patients treated with at least 12 months of SC IFX treatment, clinical healing was achieved in 16 patients (61.5%) at 12 months. Among the 11 patients with clinical healing at 12 months, 8 (72.2%) were treated with SC IFX treatment following more than three IFX IV infusions. None of the 11 patients with available MRI date showed radiological healing at 12 months.

Conclusion

Subcutaneous infliximab following surgical drainage of Crohn’s disease perianal fistula demonstrates high treatment persistence and promising rates of fistula healing.

Disclosure

This study was funded by Celltrion Healthcare France