Introduction

A marked decrease of Faecalibacterium prausnitzii is a well-established hallmark of Crohn’s disease (CD)-associated dysbiosis and predicts disease relapse (1-2). Several strains of F. prausnitzii exhibit anti-inflammatory effects in vitro and in rodents colitis models, positioning this species as a promising therapeutic candidate (3-4). However, it has never been administered to humans. Here, we present the development and first-in-human evaluation of F. prausnitzii strain EXL01 for CD treatment.

Aims & Methods

F. prausnitzii EXL01, isolated from a healthy donor, was selected based on strict safety and preliminary in vitro efficacy criteria. Its anti-inflammatory effect was tested in trinitrobenzenesulfonic acid (TNBS)-induced colitis in rats and dextran sodium sulfate (DSS)-induced colitis in mice. After favorable toxicological studies, a first-in-human, open-label, single-arm study (Part A) was conducted in patients with mild to moderate ileal CD (CDAI 180–350), following clinical remission (CDAI <150) or response (CDAI decrease ≥70) after corticosteroids (CS). EXL01 (10¹⁰ total cell count/day) was administered orally for 24 weeks, with a 6-week CS taper. Colonoscopies were performed at baseline and week 24. The primary endpoint was safety; secondary endpoints included clinical efficacy, blood/fecal biomarkers, transcriptomic analysis, and gut microbiota profiling. Part B, initially planned as a placebo-controlled phase, was not pursued due to low recruitment.

Results

According to classical evaluation endpoints, EXL01 demonstrated dose-dependent anti-inflammatory effects in both TNBS and DSS models. Between March 2023 and October 2024, 8 patients were enrolled across Belgium and Poland. Baseline characteristics were consistent with the target CD population. After corticosteroid induction, the parameters were as follow: CDAI = 78.1 (42-105); SES-CD= 6.9 (2-17); CRP = 5.7mg/l (3-13). EXL01 was well tolerated; no treatment-related serious adverse events or safety signals were observed. Six participants (75%) completed the 24-week treatment; two discontinued due to disease flare. Compared to patients who remained in remission, those who flared during the study showed higher baseline systemic inflammation markers (CRP, neutrophils, platelets) and innate immunity gene expression, with limited corticosteroid response. While gut microbiota composition remained largely stable, transcriptomic analyses revealed distinct changes in ileal gene expression following EXL01 treatment, notably modulation of immune-related genes and upregulation of energy metabolism pathways, similar to what we saw previously in vitro (bioRxiv 2024.10.06.616495).

Conclusion

EXL01, administered during and after CS tapering, was safe and well tolerated for up to 24 weeks in patients with CD. Though limited by small sample size, the study supports the biological activity of EXL01, notably through its impact on ileal gene expression. A phase 2 randomized controlled trial is ongoing to further assess efficacy.

References

1. Rajca S, Grondin V, Louis E, et al. Alterations in the intestinal microbiome (dysbiosis) as a predictor of relapse after infliximab withdrawal in Crohn's disease. Inflamm Bowel Dis. 2014 Jun;20(6):978-86. doi: 10.1097/MIB.0000000000000036. PMID: 24788220.
2. Pascal V, Pozuelo M, Borruel N, et al. A microbial signature for Crohn's disease. Gut. 2017;66(5):813-22.
3. Sokol H, Pigneur B, Watterlot L, et al. Faecalibacterium prausnitzii is an anti-inflammatory commensal bacterium identified by gut microbiota analysis of Crohn disease patients. Proc Natl Acad Sci U S A. 2008;105(43):16731-6.
4. Martin R, Chain F, Miquel S, et al. The commensal bacterium Faecalibacterium prausnitzii is protective in DNBS-induced chronic moderate and severe colitis models. Inflamm Bowel Dis. 2014;20(3):417-30.

Disclosure

HS, PhL and BH are co-founder of Exeliom. PR, DS, BH are employees of Exeliom Biosciences

Introduction

Complex perianal fistulas represent one of the most challenging manifestations of Crohn’s disease. Combined surgical and medical therapy with biologic drugs represents today the first-line treatment option, but its efficacy does not exceed 60% in terms of healing. Recently, new therapeutic approaches, such as autologous microfragmented adipose tissue (M-Fat) injection, have shown promising results. Indeed, a recent non-profit prospective pilot study on 15 patients has demonstrated that the local injection of M-Fat is a safe and promising “rescue therapy” for patients with multiresistant complex fistulizing Crohn’s disease (PCD), with a 66.7% rate of combined remission in such difficult patients. It has to be highlighted that the M-Fat injection is minimally invasive, with less risk of sphincteric damage and can be carried out in day-surgery setting.

Aims & Methods

The primary aim of this multicentre double-blind randomized controlled trial (ATTIC) is to evaluate the efficacy of the infiltration of M-Fat in the healing of perianal complex fistulas not-responding to treatment with biologics. Consecutive patients referring to the 6 investigation Centers for surgical treatment of persistent complex fistulizing PCD refractory to biosurgical approach were assessed for eligibility. After baseline pelvic magnetic resonance imaging, those included were submitted to surgical drainage with “cone-like” fistulectomy, and then randomized to receive a 15 to 20 cc local injection, at the internal orifice level and along fistula tracts, of M-Fat obtained by a lipoaspiration and processed with an enzyme-free technology (treatment group), or a suture placement and injection of 15 cc of saline solution at the internal orifice (control group). Clinical follow-up were conducted at 2, 4, 8, 12, and 24 weeks; at 24 weeks after surgery, pelvic magnetic resonance was obtained. Success was defined as “combined remission”, combination of clinical (absence of drainage upon gentle finger compression) and radiological healing (absence of residual collections > 3 mm). Clinical remission was defined as clinical healing of all external openings not confirmed at radiological assessment.

Results

An overall 92 patients were screened, and 66 (33 per group) completed the 24-week follow-up. A statistically significant difference in favour of the treatment group in terms of combined remission emerged at the primary endpoint at 24-week follow-up (control group, 18.18%; treatment group: 57.58%; p = 0.0020). No significant differences in clinical outcome measures were encountered at any of the other follow-up points. No significant differences emerged between the groups in terms of recurrence rate, complication rate, and number of adverse events. Clinical remission was 63.64% in the treatment group compared to 51.52% in the control group with no statistically significant difference (p > 0.05).

Conclusion

This multicentre double-blind randomized controlled trial demonstrates that the intraoperative injection of M-Fat, associated with surgical complete drainage of perianal sepsis, is safe, effective, and reproducible in healing complex multirefractory perianal Crohn's disease, while improving the quality of life and significantly reducing the risk of definitive oostomy.

Introduction

​​​​​Guselkumab (GUS) is a selective dual-acting IL-23p19 subunit inhibitor that potently blocks interleukin 23 (IL-23) and binds to CD64, a receptor on cells that produce IL-23¹. In patients with moderately to severely active Crohn’s disease (CD), the GALAXI-2 and GALAXI-3 Phase 3 studies established short- and long-term efficacy of GUS compared to placebo, and statistical superiority to ustekinumab (UST) in prespecified analyses of pooled data at Week (WK)48². We subsequently developed an endoscopic clustering method using Simple Endoscopic Score for Crohn's Disease (SES-CD) segmental scores in patients from GALAXI 2/3 which revealed higher endoscopic remission rates with GUS compared with UST at WK12 and WK48 in pts characterized by ileal disease and strictured right colon³. Here we report molecular differentiation of GUS compared with UST in isolated ileal disease based on serum pharmacodynamic (PD) markers and tissue transcriptomics in CD using pooled samples from the GALAXI studies.

Aims & Methods

Patients (pts) in GALAXI-2 (n=508) and GALAXI-3 (n=513) were randomized 2:2:2:1 to receive GUS 200mg IV q4w x3 → GUS 200mg SC q4w, GUS 200mg IV q4w x3→ GUS 100mg SC q8w, UST ⁓6mg/kg IV x1 → UST 90mg SC q8w or placebo IV q4w x3 (PBO). Serum biomarkers were measured in a subset of (n=50) pts per group at WK0, WK4 and WK12 using a proinflammatory panel and a high sensitivity IL-22 assay. Matched ileal and rectal biopsies were evaluated at WK0, WK12 and WK48 in a subset of 344 pts representative of the full study population. Transcriptional profiling was performed with bulk RNA sequencing (RNAseq) using transcriptional modules. Analysis of treatment effects was performed using molecularly inflamed samples (biopsy molecular inflammation score [bMIS]⁴ >0) from segments with SES-CD >0 at baseline. Serum proteins and transcriptional modules were evaluated for differential expression stratified by isolated ileal, isolated colonic and ileocolonic disease defined during screening.

Results

In pts with isolated ileal disease, GUS decreased serum protein levels of IL-22, IL-17A and IFNγ at WK12 while UST only reduced IFNγ. In ileal tissue, GUS significantly altered inflammatory modules at WK12 and WK48 including reductions in neutrophil, inflamed epithelium, IL-23/Th17 and inflammatory fibroblast biology compared with minimal changes observed with UST, which only significantly reduced neutrophil, plasma cell and macrophage modules at WK48. In contrast, in pts with isolated colonic or ileocolonic disease, both GUS and UST decreased IL-23-dependent serum proteins towards normal levels compared with an independent cohort of healthy control sera. In rectal tissue, both GUS and UST significantly altered key inflammatory transcriptional modules in rectal biopsies at WK12 and WK48. Overall, greater effects of GUS vs UST were observed in ileal tissue at WK12 and at WK48 in transcriptional modules associated with decreasing disease-related features and restoring epithelial health than UST.

Conclusion

GUS decreased IL-23-dependent serum proteins and improved tissue transcriptional profiles in pts with isolated ileal disease while UST only reduced serum IFNγ and had a minimal impact on IL-23-dependent transcriptional modules. These data suggest potential differences in IL-23 and IL-12 pathway enrichment in isolated ileal disease where inhibition of IL-23p19 subunit with GUS achieved greater molecular treatment effects early which were maintained through WK48 and associated with differential clinical outcomes in patients with isolated ileal disease.

References

1. Sachen K, Hammaker D, Sarabia I, et al. Guselkumab binding to CD64+ IL-23–producing myeloid cells enhances potency for neutralizing IL-23 signaling. Frontiers in Immunology. 2025; doi:10.3389/fimmu.2025.1532852
2. Panaccione R, Danese S, Feagan BE, et al. Efficacy and safety of guselkumab therapy in patients with moderately to severely active Crohn’s disease: results of the GALAXI 2 & 3 phase 3 studies. Gastroenterology. 2024; 5 (Supplement): p1057b
3. Richards D, Seridi L, Sohn, K, et al. Guselkumab shows higher endoscopic remission rates than ustekinumab in patients characterized by isolated ileal and srtictured right colon Crohn’s disease: Post-hos analysis of GALAXI 2/3 Ph3 trials. DDW 2025 Abs #4253526; poster.
4. Argmann C, Hou R, Ungaro, R, et al. A biopsy and blood-based molecular biomarker of inflammation in inflammatory bowel disease. Gut. 2022; 0:1-17.

Disclosure

DR, KS, MZ, RP, BM, NAT, MV, DC and PB are current or former employees of Janssen and may hold stock in Johnson & Johnson.
WR has served as a speaker for AbbVie, Celltrion, Ferring, Janssen, Galapagos Medice, MSD, Roche, Pfizer, Sobi, Takeda, as a consultant for AbbVie, Amgen, AOP Orphan, Boehringer Ingelheim, Bristol Myers Squibb, Calyx, Celltrion, Eli Lilly, Galapagos, Gilead, Index Pharma, Janssen, Medahead, Microbiotica, Pfizer, Takeda; as an advisory board member for AbbVie, Amgen, Boehringer Ingelheim, Bristol Myers Squibb, Celltrion, Galapagos, Janssen, Pfizer, and has received research funding from AbbVie, Janssen, Sandoz, Sanofi, Takeda.