Introduction

Barrier healing (BH) has emerged as a novel treatment target in Inflammatory Bowel disease (IBD). Persistence of barrier impairment despite endoscopic and histological remission has been associated with worse long-term outcomes. However, accurate real-time assessment of intestinal barriers remains challenging in clinical practice. This study explores the role of advanced endoscopy (ultra-high magnification endocytoscopy [ECS] and confocal laser endomicroscopy [CLE]) for real-time, in vivo, structural and functional assessment of epithelial and vascular intestinal barrier. Further, we aim to investigate their correlation with automated barrier protein expression and clinical outcomes in IBD.

Aims & Methods

IBD patients undergoing endoscopic evaluation and healthy controls (HC) were recruited from two tertiary university centres.
The intestinal mucosa was assessed with ECS or CLE by novel scoring systems including epithelial and vascular features. BH was defined as ECS score ≤1 or CLE score ≤4, with preserved villi/crypt architecture, normal vessels, and, for CLE, absence of fluorescein leakage.
Biopsies were collected from both inflamed and non-inflamed areas. Epithelial (ZO-1, Claudin-2, E-cadherin) and vascular (PV-1 and CD-31) barrier markers were analysed through confocal microscopy, and their mean expression was automatically quantified using QuPath (v0.5.1). A biopsy-wise analysis assessed the correlation between endoscopic and histopathological evaluation. Moreover, occurrence of clinical outcomes at 6-month follow-up according to imaging-detected barrier impairment was evaluated.

Results

A total of 74 IBD patients (39 Crohn’s disease [CD], 35 Ulcerative colitis [UC]) and 9 HC) were considered. 46% (34/74) and 42% (30/74) IBD patients were in endoscopic and histological remission, respectively, while advanced imaging-defined BH was present in 24.3% (18/74) patients (Table 1). Barrier impairment was significantly associated with clinical outcomes at 6-month follow-up (p<0.01).
Mean expression of Claudin-2 was significantly higher in UC with ECS-based barrier impairment (85.5 vs 175.1, p 0.02), while PV1 expression was elevated in CD with CLE-based barrier dysfunction (362.1 vs 442.2, p 0.1). Significant correlations were found between ECS/CLE scores and epithelial and vascular barrier proteins.
In UC, Claudin-2 showed a moderate correlation with altered crypt architecture, goblet cell depletion and ECS total score (r 0.5), while PV-1 was moderately associated with altered vascular pattern and ECS total score (r -0.4).
In CD, Claudin-2 demonstrated a moderate correlation with crypt distortion, goblet cell depletion and total CLE scores (r 0.5), while PV-1 moderately correlated with fluorescein leakage, altered vessel architecture and total CLE score (r 0.4).

Conclusion

pCLE and ECS enable real-time intestinal barrier assessment in IBD, showing good correlation with epithelial and vascular barrier proteins and predicting clinical outcomes. This approach shows promise for targeting BH, guiding early and long-term disease management, and enabling flare-up prediction.

Introduction

Despite recent advances in IBD therapy, there is a need for novel effective, safe oral drugs. Mufemilast has demonstrated sustained efficacy and safety in plaque psoriasis¹. Here we report the efficacy and safety of Mufemilast at 12 weeks from this phase 2 trial (NCT05486104).

Aims & Methods

Patients with moderate to severe UC were randomized (1:1:1) to placebo (n=31), mufemilast 45mg (n=31) or 60mg (n=30) twice daily (BD) for 12 weeks. Eligibility criteria required participants to have a modified Mayo score (mMS) of 4-9, including an endoscopy score of ≥ 2 , inadequate /loss of response to conventional therapy (5-ASA, Steroids, immunomodulators), or biologics (anti-TNF, anti-integrin, anti-interleukin 12/23). Stable co-treatment with oral 5'ASAs and corticosteroids was permitted if it was stable for at least ≥2 weeks before microscopy within the screening period and needed to remain stable for the duration of the study. Patients with positive Quantiferon tests were also eligible. Efficacy definitions were according to FDA guidance².

Results

Conclusion

Mufemilast efficacy and safety were consistent across subgroups regardless of previous biologic use, suggesting Mufemilast is a viable potential future treatment option in patients with moderate to severe UC that breaks through the current 20% ceiling for clinical remission. A phase 3 study will be conducted to confirm these results.

References

¹Jones, C.; Zhang, J.; Wang, L.; Dai, X.; Wang, H.; Bi, X.; Duan, X.; Meng, Z.; Tian, Z.; Xu, A.; et al. A Double-Blind, Placebo-Parallel Controlled Phase III Clinical Study of the Efficacy and Safety of Hemay005 Tablets in Patients with Moderate to Severe Chronic Plaque Psoriasis in China. Arthritis Rheumatol ACR Converg. 2023, 75.
² Food and Drug Administration. Ulcerative Colitis: Developing Drugs for Treatment. Guidance for Industry - Draft Guidance; 2022. Accessed May 11, 2025. https://www.fda.gov/media/158016/download

Introduction

Artificial Intelligence (AI)- enabled endoscopy and histology offer accurate, objective, and rapid assessment of disease activity in Ulcerative Colitis (UC). Emerging multi-source AI models integrating diverse datasets may enhance standardised disease evaluation and outcome prediction.

Aims & Methods

This study aimed to develop a novel AI model fusing endoscopic and histological findings to improve the assessment of disease remission and predict early response to therapy in UC clinical trials. A novel multimodal AI fusion algorithm was developed by integrating paired endoscopic videos and histological whole-slide images (WSIs) from the phase 2 clinical trial of Mirikizumab in UC (NCT02589665). The endoscopy branch of the model was trained with 291 white-light videos, using a convolutional neural network to select informative frames and the BioMedCLIP foundational model to extract features. The histology branch utilised the CONCH foundational model and was fine-tuned on 291 WSIs to obtain patch-level features. Features from both modalities were aggregated and fused using multi-head self-attention. The model’s ability to assess histological remission and response to therapy at weeks 12 and 52 was evaluated. Histological remission was defined as Geboes ≤2B.0, while a response to therapy at different time points was based on histological remission or improvement (Geboes <3.1).

Results

The fusion model outperformed single-modality assessments for histological remission, achieving a sensitivity of 89.72% (95% CI: 82.35–94.76), specificity of 89.67% (95% CI: 84.34–93.67), and accuracy of 89.69% (95% CI: 85.61–92.94). It demonstrated remarkable performance in assessing response to therapy at 12 and 52 weeks, with sensitivity of 97.96% (95% CI: 89.15–99.95), specificity of 86.84% (95% CI: 71.91–95.59) and accuracy of 93.10% (95% CI 85.59 – 97.43) for histological remission at week 52. Substantial agreement was observed between the AI fusion model and central readout.

Conclusion

This innovative multimodal fusion AI model enhances the assessment of histological remission and accurately predicts response to therapy. By potentially standardising central readouts and enabling automated disease assessment, this novel tool marks a significant advancement towards precision medicine in clinical trials.

Disclosure

Marietta Iacucci received research grants and consultant fees from Olympus, Pentax, Eli Lilly, and Janssen. All other authors declare no competing interests.

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

Treatment response in inflammatory bowel disease (IBD) is highly variable, with an urgent need for biomarkers to guide therapeutic decisions. Circulating monocytes, key players in intestinal immunity, act as precursors to tissue macrophages and contribute to inflammation and mucosal healing. The transcriptional programs that govern monocyte fate and their association with treatment outcomes remain poorly defined. Ikaros family proteins regulate gene expression through distinct mechanisms in lymphocytes, but little is known about their role in monocyte-macrophage function in IBD. We aimed to investigate the role of Ikaros family (Ikaros, Helios, Aiolos, Eos, Pegasus) in shaping monocyte function linked to advanced therapies response.

Aims & Methods

Peripheral blood samples were collected at baseline (W0) and after 8-12 weeks of induction therapy (W8/12) from IBD patients who initiated or switched advanced therapy [biologics, oral synthetics] and from healthy controls (HC) (n=8). We included patients achieving clinical remission after induction [Super-Responders] SR (n=18) and those showing no response [Non-Responders] NR (n=16). Immune phenotype and expression of Ikaros proteins were assessed via multiparametric flow cytometry (FACS) and correlated with clinical outcomes. To assess functional roles of Ikaros proteins, monocyte-derived macrophages were generated in vitro from buffy coat (n=6). Cells were polarised using cytokine cocktails to induce pro-inflammatory (LPS+IFNγ or TNF+PGE2+Pam3CSK4; TPP), alternative (IL1β+LPS), or regulatory (IL10) phenotypes. siRNA-loaded nanoparticles were used to silence Ikaros or Helios prior to polarisation. Phenotypic changes were analysed by FACS; cytokines secretion by ELISA; genes expression by qPCR; and phagocytosis by fluorescent beads uptake.

Results

At W0, IBD patients exhibited a significant increase in circulating monocyte counts (vs HC, p<0.001). At W8/12, monocyte levels significantly decreased in the SR group, while remaining elevated in the NR group. FACS analysis revealed an increased proportion of non-classical monocytes (CD14⁻CD16⁺) in the IBD group at W0 (vs HC; p< 0.05), persisting in NR at W8/12 (vs SR; p<0.05). IBD monocytes also showed higher expression of CCR2 and CX3CR1 compared to HC. Helios expression was absent in monocytes from IBD patients at W0, while the mean expression of Helios was 47.31% in monocytes from the HC group. At W8/12, Helios expression re-emerged in 34.14% of monocytes derived from the SR patients but remained undetectable in the NR. In vitro, macrophages treated with LPS+IFNγ or TPP upregulated Ikaros, STAT1, and CXCL10 gene expression (p< 0.01), while Helios, TGM2, and MCR1 were upregulated in response to IL10 (p< 0.05). Helios expression was absent in TNF-stimulated macrophages. Ikaros silencing reduced pro-inflammatory markers, IL6 and IL1β cytokines secretion, and inhibited phagocytosis in response to LPS, whereas Helios silencing increased macrophages activation, and pro-inflammatory markers in response to IL10.

Conclusion

Monocyte subsets distribution and Helios, Ikaros expression dynamics clearly distinguished SR from NR in IBD. Sustained absence of Helios and persistence of non-classical monocytes in NR suggest a failure to transition toward a regulatory phenotype. This may further contribute to altered migratory capacity and influence their functional fate within intestinal tissue. Functional assays confirm opposing roles of Ikaros and Helios in the macrophages activation, underscoring their unique potential as biomarkers or therapeutic targets to modulate inflammation in IBD.