Introduction

Tumor necrosis factor–like cytokine 1A (TL1A) promotes inflammation and fibrosis. PRA023 is an anti-TL1A monoclonal antibody in development for multiple inflammatory/fibrotic diseases. ARTEMIS-UC was a phase 2 multicenter, double-blind, placebo-controlled trial of PRA023 in adults with moderately to severely active ulcerative colitis (UC). The primary endpoint of clinical remission was statistically significantly higher in the PRA023 arm compared with the placebo arm. Here, we report the impact of PRA023 on endoscopic and histologic outcomes.

Aims & Methods

Adults with a modified Mayo score of 4 to 9, centrally read endoscopy subscore of ≥2, rectal bleeding subscore of ≥1, and history of insufficient response, loss of response, and/or intolerance to conventional and/or advanced therapies (≤4 advanced agents from ≤3 classes allowed) were randomized 1:1 to receive placebo or intravenous PRA023 (1000 mg on day 1, and 500 mg at weeks 2, 6, and 10). Endoscopic improvement (defined as a Mayo endoscopic subscore ≤1 with no friability), endoscopic remission (defined as a Mayo endoscopic subscore of 0), histologic improvement (defined as Geboes score ≤3.1), and mucosal healing (defined as Geboes score ≤2B.1 and endoscopy subscore ≤1) were measured after 12 weeks of induction therapy. Improvements in other histologic parameters were assessed by changes in Geboes scores.

Results

Of 135 randomized patients, 60/67 (89.6%) in the placebo arm and 68/68 (100%) in the PRA023 arm completed the 12-week induction period. Baseline characteristics were similar between treatment groups. Among alpha-controlled secondary endpoints, endoscopic improvement was observed in 36.8% of PRA023-treated vs 6.0% of placebo-treated patients (Δ30.8%, p<0.0001) at week 12. Histologic improvement occurred in 46.2% of patients receiving PRA023 vs 17.5% receiving placebo (Δ28.6%, p=0.0009) and mucosal healing in 30.8% vs 3.5% (Δ27.3%, p<0.0001), respectively. The mean change (SD) from baseline in the Mayo endoscopic subscore was −0.8 (0.93) for PRA023 vs −0.2 (0.54) for placebo. Furthermore, in a post hoc analysis, a significantly greater proportion of patients who received PRA023 achieved endoscopic remission (11.8% PRA023 vs 0% placebo, Δ11.8%, p=0.004). Of the patients with eosinophils in the lamina propria (LP) at baseline, 21.8% receiving PRA023 and 5.8% receiving placebo experienced complete resolution. Similarly, the resolution rates in those with neutrophils in the LP at baseline were 41.2% and 15.4% in PRA023-treated and placebo-treated patients, respectively; and of those with neutrophils in the epithelium at baseline, values were 40.4% vs 11.3%, respectively.

Conclusion

In patients with moderately to severely active UC, PRA023 resulted in a significantly greater proportion of patients achieving endoscopic remission, endoscopic improvement, histologic improvement, and mucosal healing, endpoints associated with an improved prognosis. Resolution of eosinophil and neutrophil infiltration suggests a reduction in the inflammation associated with UC.

Disclosure

SD has received consultancy fees from AbbVie, Alimentiv, Allergan, Amgen, Applied Molecular Transport, AstraZeneca, Athos Therapeutics, Biogen, Boehringer Ingelheim, Bristol Myers Squibb, Celgene, Celltrion Healthcare, Dr. Falk Pharma, Eli Lilly and Company, Enthera, Ferring, Gilead, Hospira, Inotrem, Janssen, Johnson & Johnson, Morphic, MSD, Mundipharma, Mylan, Pfizer, Roche, Sandoz, Sublimity Therapeutics, Takeda, Teladoc Health, TiGenix, UCB Inc., Vial, and Vifor and lecture fees from AbbVie, Amgen, Ferring, Gilead, Janssen, Mylan, Pfizer, and Takeda.
BES has served as a consultant for or received speaker’s fees from AbbVie, Abivax, Adiso Therapeutics, Alimentiv, Amgen, Arena Pharmaceuticals, Artizan Biosciences, Artugen Therapeutics, AstraZeneca, Bacainn Therapeutics, Biora Therapeutics, Boehringer Ingelheim, Boston Pharmaceuticals, Bristol Myers Squibb, Calibr, Celltrion Healthcare, ClostraBio, Connect Biopharma, Cytoki Pharma, Eli Lilly and Company, Entera, Evommune, Ferring, Fresenius Kabi, Galapagos, Gilead, Genentech, GSK, Gossamer Bio, HMP Acquisition, Imhotex, Immunic, InDex Pharmaceuticals, Innovation Pharmaceuticals, Inotrem, Ironwood Pharmaceuticals, Janssen, Johnson & Johnson, Kaleido, Kallyope, Merck, MiroBio, Morphic Therapeutic, MRM Health, OSE Immunotherapeutics, Pfizer, Progenity, Prometheus Biosciences, Prometheus Laboratories, Protagonist Therapeutics, Q32 Bio, RedHill Biopharma, Sun Pharma Global, Surrozen, Synlogic, Takeda, Target RWE, Theravance Biopharma R&D, TLL Pharmaceutical, USWM Enterprises, Ventyx Biosciences, and Viela Bio and has received stock options from Ventyx Biosciences.
LPB has served as a consultant for or has received fees from AbbVie, Allergan, Alma, Amgen, Applied Molecular Transport, Arena, Biogen, Boehringer Ingelheim, Bristol Myers Squibb, Celgene, Celltrion Healthcare, Eli Lilly and Company, Enterome, Enthera, Ferring, Fresenius Kabi, Galapagos, Genentech, Gilead, Gossamer Bio, Hikma, Index Pharmaceuticals, Inotrem, Janssen, MSD, Mylan, Oppilan Pharma, OSE Immunotherapeutics, Nestlé, Norgine, Roche, Pandion Therapeutics, Pfizer, Pharmacosmos, Samsung Bioepis, Sandoz, sterna biologicals, Sublimity Therapeutics, Takeda, Theravance Biopharma, Tillotts Pharma, and Vifor; has received grants from AbbVie, Fresenius Kabi, MSD, and Takeda; and has stock options from CTMA.
DTR has served as a consultant for AbbVie, AltruBio, Aslan Pharmaceuticals, Athos Therapeutics, Bellatrix Pharmaceuticals, Boehringer Ingelheim, Bristol Myers Squibb, Celgene Chronicles, Corp/Syneos, ClostraBio, Connect Biopharma, Eco R1, Eli Lilly and Company, Genentech/Roche, Gilead Sciences, Iterative Health, Janssen Pharmaceuticals, Kaleido, Pfizer, Prometheus Biosciences, Reistone Biopharma, Seres Therapeutics, Takeda, Target RWE, and Trellus Health and has received grant support from Takeda, Helmsley Charitable Trust, and the Gastro-Intestinal Research Foundation.
DDN, QD, AM, JL and BD are employees and shareholders of Prometheus Biosciences.
RK has received grants from Janssen and Takeda.
TER has been a speaker for Takeda Pharmaceuticals, Janssen, Pfizer, Bristol Myers Squibb, and Abbvie; has served on advisory boards for AbbVie, Ardelyx, Arena, Boehringer Ingelheim, Bristol Myers Squibb/Celgene, Eli Lilly and Company, Ferring, Genentech/Roche, Gilead, Intercept, Iterative Scopes, Janssen, Pfizer, Prometheus Biosciences, Sanofi, and Takeda; and has been a shareholder for Iterative Scopes.
RP has been a consultant for Abbott, AbbVie, Abivax, Alimentiv (formerly Robarts), Amgen, Arena, AstraZeneca, Biogen, Boehringer Ingelheim, Bristol Myers Squibb, Celgene, Celltrion Healthcare, Cosmos Pharmaceuticals, Eisai, Elan, Eli Lilly and Company, Ferring, Galapagos, Fresenius Kabi, Genentech, Gilead Sciences, GSK, BIOJAMP, Janssen, Merck, Mylan, Novartis, Oppilan Pharma, Organon, Pandion, Pendopharm, Pfizer, Progenity, Prometheus Biosciences, Protagonist Therapeutics, Roche, Sandoz, Satisfai Health, Shire, Sublimity Therapeutics, Takeda, Theravance Biopharma, Trellus, Viatris, Ventyx, and UCB; has received speakers fees from AbbVie, Amgen, Arena, Bristol Myers Squibb, Celgene, Eli Lilly and Company, Ferring, Fresenius Kabi, Gilead Sciences, Janssen, Merck, Organon, Pfizer, Roche, Sandoz, Shire, and Takeda; and has served on advisory boards for AbbVie, Alimentiv (formerly Robarts), Amgen, Arena, AstraZeneca, Biogen, Boehringer Ingelheim, Bristol Myers Squibb, Celgene, Eli Lilly and Company, Ferring, Fresenius Kabi, Genentech, Gilead Sciences, GSK, BIOJAMP, Janssen, Merck, Mylan, Novartis, Oppilan Pharma, Organon, Pandion Pharma, Pfizer, Progenity, Protagonist Therapeutics, Roche, Sandoz, Shire, Sublimity Therapeutics, Takeda, and Ventyx.

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.