Abivax Announces Acceptance of 22 Abstracts Evaluating Obefazimod in Inflammatory Bowel Disease at ECCO 2026, Featuring an Oral Presentation on Preclinical Anti-Fibrotic Findings

Breadth of Scientific Evidence: The acceptance of 1 oral presentation, 5 digital oral presentations and 16 posters reflect an expanding dataset for obefazimod, including additional efficacy, safety, and cytokine data from the Phase 3 ABTECT Induction Trials in moderate-to-severely active ulcerative colitis (UC)
Novel Anti-Fibrotic Preclinical Findings: Oral presentation on Saturday, February 21, 2026, "Obefazimod shows first evidence of anti-fibrotic activity in preclinical models of inflammatory bowel disease," will disclose new preclinical data addressing a critical complication in Crohn's disease (CD)

PARIS, France – December 17, 2025 – 10:05 pm CET – Abivax SA (PARIS:FR, NASDAQ:ABVX) ("Abivax" or the "Company"), a clinical-stage biotechnology company focused on developing therapeutics that harness the body's natural regulatory mechanisms to stabilize the immune response in patients with chronic inflammatory diseases, today announced that 22 scientific abstracts detailing advancements in the understanding of obefazimod for the treatment of inflammatory bowel disease (IBD) will be presented at The European Crohn's and Colitis Organization's (ECCO) 21st Annual Congress taking place February 18-21, 2026 in Stockholm, Sweden.

Subgroup Analyses from Phase 3 ABTECT Induction Trials

The accepted abstracts, based on subgroup analyses from ABTECT Induction Trials, illustrate obefazimod's clinical activity across a wide range of patient subpopulations, demonstrate downregulation of pro-inflammatory cytokines (IL-17A, IL-6), and highlight early symptomatic improvement along with other clinically meaningful benefits. The data also reinforces obefazimod's favorable tolerability profile.

Obefazimod Shows First Evidence of Activity in Preclinical Fibrotic Models

The upcoming oral presentation on anti-fibrotic activity addresses a significant unmet medical need in IBD. Fibrosis, or the excessive formation of scar tissue, is a serious complication, particularly in patients with CD. This scarring can lead to strictures (narrowing of the intestine) that often necessitate surgery. To date, no efficacious anti-fibrotic treatment is available for IBD patients.

The objective of the preclinical study was to assess the anti-fibrotic effects of obefazimod in an in vitro fibrosis model using human small-intestinal fibroblasts and in an in vivo TNBS-colitis mouse model. The data from this study, titled "Obefazimod shows first evidence of anti-fibrotic activity in preclinical models of inflammatory bowel disease," will be presented during the oral presentation session on Saturday, February 21, 2026.

Marc de Garidel, Chief Executive Officer of Abivax, said "We are highly enthusiastic about the strong presence of obefazimod data at the 21st ECCO Congress, highlighting the impactful and robust data we have generated in inflammatory bowel disease. Presenting a total of 22 abstracts highlights the increasing depth of clinical understanding we have gained from the ABTECT Induction Trials in ulcerative colitis. This important data, along with the oral presentation highlighting the first evidence of anti-fibrotic activity in a preclinical model, demonstrates the potential for obefazimod to address a critical unmet need in IBD beyond inflammation."

Fabio Cataldi, MD, Chief Medical Officer of Abivax, added, "Intestinal fibrosis is a major complication of Crohn's disease that is not fully addressed by current therapies. This often leads to debilitating symptoms and the need for resection surgery. We look forward to sharing these new insights on obefazimod's anti-fibrotic properties, alongside the expansive clinical data to demonstrate obefazimod's potential efficacy and favorable safety profile in ulcerative colitis, with the IBD scientific community in Stockholm."

Obefazimod Data to be Presented:

Date & Time	Session	Room	Abstract #	Title	Presenter
Oral Presentation
Sat, Feb 21 08:40–08:50	Holistic IBD Care - Session 10: Holistic Approach - Multidisciplinary Team	Plenary Hall	OP30	Obefazimod shows first evidence of anti-fibrotic activity in preclinical models of inflammatory bowel disease	Prof. Silvio Danese, MD, PhD Director of Gastroenterology and Gastrointestinal Endoscopy Unit at IRCCS San. Raffaele Hospital
Digital Oral Presentations (DOP)
Fri, Feb 20 08:42–08:48	DOP Session 7: Clinical Trials II	A5	DOP057	Obefazimod induction therapy for moderately to severely active ulcerative colitis: pooled analysis of inflammatory biomarkers from the two ABTECT Phase 3 double-blind, placebo-controlled induction trials	Prof. Britta Siegmund, MD Medical Director of the Medical Department, Division of Gastroenterology, Infectiology and Rheumatology, Charite Universitätsmedizin Berlin
Fri, Feb 20 09:00–09:06	DOP Session 7: Clinical Trials II	A5	DOP060	Impact of baseline disease extent on efficacy of obefazimod in patients with moderately to severely active ulcerative colitis: pooled results from ABTECT-1 and ABTECT-2 Phase 3 trials	Sonja Heeren, MD Gastroenterologist at LKH - Universitätsklinikum der PMU Salzburg, Austria
Fri, Feb 20 09:06–09:12	DOP Session 7: Clinical Trials II	A5	DOP061	Improvements in patient-reported, disease-specific and overall quality-of-life among patients with moderately to severely active UC treated with obefazimod induction therapy: pooled results from the 8-week ABTECT-1 and ABTECT-2 Phase 3 trials	Filip Baert, MD, PhD Head of the Department of Gastroenterology at AZ Delta Hospital
Fri, Feb 20 17:51–17:57	DOP Session 12: Clinical Trials III	A5	DOP101	Impact of baseline disease duration on the efficacy of once-daily oral obefazimod in moderately to severely active ulcerative colitis: week 8 results from the ABTECT-1 and ABTECT-2 Phase 3 trials	Prof. Geert D'Haens, MD, PhD Professor of Gastroenterology at Amsterdam University Medical Centers
Fri, Feb 20 17:57–18:03	DOP Session 12: Clinical Trials III	A5	DOP102	Improvements in patient-reported fatigue among patients with moderately to severely active UC treated with obefazimod induction therapy: pooled results from the 8-week ABTECT-1 and ABTECT-2 Phase 3 trials	Prof. Marla Dubinsky, MD Professor of Pediatrics and Medicine, Chief, Division of Pediatric Gastroenterology and Nutrition, Co-Director, Susan and Leonard Feinstein IBD Clinical Center, Mount Sinai Kravis Children's Hospital, Icahn School of Medicine Mount Sinai New York
Posters
Fri, Feb 20 12:40-13:40	Guided Poster Session	Poster Exhibition Hall A	P0690	Impact of concomitant corticosteroid use on efficacy and safety of obefazimod at week 8 in moderately to severely active UC	Prof. Xavier Treton, MD, PhD Professor of Gastroenterology (MD, PhD), Paris Inflammatory Bowel Disease (IBD) Center, Centre Ambroise Pare-Hartmann, Neuilly, France
Fri, Feb 20 12:40-13:40	Guided Poster Session	Poster Exhibition Hall A	P0694	Pooled analysis of efficacy and safety of once-daily oral obefazimod in North American patients from the ABTECT Phase 3 induction trials	Prof. Bruce E Sands, MD, MS Professor of Medicine, Icahn School of Medicine at Mount Sinai
Fri, Feb 20 12:40-13:40	Guided Poster Session	Poster Exhibition Hall A	P0712	Integrated summary of safety of obefazimod in Phase 3 ABTECT induction trials	Prof. Ursula Seidler, MD Professor of Internal Medicine and Gastroenterology, Hepatology, and Endocrinology; Senior Attending Physician at Medizinische Hochschule Hannover
Fri, Feb 20 12:40-13:40	Guided Poster Session	Poster Exhibition Hall A	P0713	Improvements in patient-reported bowel urgency and nocturnal bowel movements among patients with moderately to severely active UC treated with obefazimod induction therapy	Prof. Marla Dubinsky, MD Professor of Pediatrics and Medicine, Chief, Division of Pediatric Gastroenterology and Nutrition, Co-Director, Susan and Leonard Feinstein IBD Clinical Center, Mount Sinai Kravis Children's Hospital, Icahn School of Medicine Mount Sinai New York
Fri, Feb 20 12:40-13:40	Guided Poster Session	Poster Exhibition Hall A	P0804	Impact of prior inadequate response to advanced therapies on early symptomatic improvement with obefazimod induction in moderately to severely active UC	Prof. Raja Atreya, MD Professor of Translational Immunology in IBD Head of IBD Unit, Outpatient Clinic, Study Centre, University Hospital Erlangen
Fri, Feb 20 12:40-13:40	Guided Poster Session	Poster Exhibition Hall A	P0862	Continued efficacy improvement beyond induction with once-daily obefazimod: week 8–48 outcomes from the Phase 2b open-label maintenance study, stratified by prior advanced-therapy exposure	Alessandro Armuzzi ECCO President-Elect; Professor of Gastroenterology; Director/Leader of the IBD Unit and Co-Lead of the IBD Center, IRCCS Humanitas Research Hospital and Humanitas University, Milan, Italy
Fri, Feb 20 12:40-13:40	Guided Poster Session	Poster Exhibition Hall A	P0868	Obefazimod enhances miR-124 expression in blood and colon tissue and reduces IL-17A and IL-6 in serum of patients with moderate-to-severely active UC	Prof. Britta Siegmund, MD Medical Director of the Medical Department, Division of Gastroenterology, Infectiology and Rheumatology, Charite Universitätsmedizin Berlin
Fri, Feb 20 12:40-13:40	Guided Poster Session	Poster Exhibition Hall A	P0892	Impact of prior inadequate response to advanced therapy (ATIR) on the efficacy of obefazimod in patients with moderately to severely active UC	Filip Baert, MD, PhD Head of the Department of Gastroenterology at AZ Delta Hospital
Fri, Feb 20 12:40-13:40	Guided Poster Session	Poster Exhibition Hall A	P0894	Impact of prior advanced therapy inadequate response by drug class on symptomatic improvement with obefazimod in patients with moderately to severely active UC	Prof. Silvio Danese, MD, PhD Director of Gastroenterology and Gastrointestinal Endoscopy Unit at IRCCS San. Raffaele Hospital
Fri, Feb 20 12:40-13:40	Guided Poster Session	Poster Exhibition Hall A	P0922	Impact of obefazimod treatment on histologic and combined histologic-endoscopic outcomes in patients with moderately to severely active UC	Prof. Fernando Magro, MD, PhD ECCO President, Consultant in Gastroenterology and Director of the Clinical Pharmacology Unit, at the São João University Hospital in Porto, Portugal
Fri, Feb 20 12:40-13:40	Guided Poster Session	Poster Exhibition Hall A	P0923	Early symptomatic improvement with obefazimod in patients with moderately to severely active UC	Prof. Alessandro Armuzzi, MD, PhD ECCO President-Elect; Professor of Gastroenterology; Director/Leader of the IBD Unit and Co-Lead of the IBD Center, IRCCS Humanitas Research Hospital and Humanitas University, Milan, Italy
Fri, Feb 20 12:40-13:40	Guided Poster Session	Poster Exhibition Hall A	P0928	Improvements in patient-reported work productivity and activity impairment among patients with moderately to severely active UC treated with obefazimod induction therapy	Prof. Britta Siegmund, MD Medical Director of the Medical Department, Division of Gastroenterology, Infectiology and Rheumatology, Charite Universitätsmedizin Berlin
Fri, Feb 20 12:40-13:40	Guided Poster Session	Poster Exhibition Hall A	P0952	Impact of baseline Mayo endoscopic subscore on the efficacy of once-daily oral obefazimod in moderately to severely active UC	Prof. Laurent Peyrin-Biroulet, MD, PhD Professor of Gastroenterology, specialist in inflammatory bowel disease at Nancy University Hospital, France
Fri, Feb 20 12:40-13:40	Guided Poster Session	Poster Exhibition Hall A	P1048	Impact of age on the efficacy and safety of once-daily oral obefazimod in moderately to severely active UC	Prof. Fernando Magro, MD, PhD ECCO President, Consultant in Gastroenterology and Director of the Clinical Pharmacology Unit, at the São João University Hospital in Porto, Portugal
Fri, Feb 20 12:40-13:40	Guided Poster Session	Poster Exhibition Hall A	P1077	Impact of baseline body mass index (BMI) on efficacy of obefazimod in patients with moderately to severely active UC	David T Rubin, MD Professor of Medicine and Chief, Gastroenterology, Hepatology and Nutrition at The University of Chicago
Fri, Feb 20 12:40-13:40	Guided Poster Session	Poster Exhibition Hall A	P1159	Pooled analysis of efficacy and safety of once-daily oral obefazimod in European patients from the ABTECT Phase 3 induction trials	Prof. Franco Scaldaferri, MD, PhD Gastroenterologist, endoscopist Director of the Chronic Inflammatory Bowel Diseases Unit, IBD UNIT At the CEMAD UOC (Center for Digestive System Diseases) Gemelli Polyclinic Foundation IRCSS - Catholic University Of The Sacred Heart Dipartimento Di Medicina E Chirurgia Traslazionale, Università Cattolica Del Sacro Cuore, Roma

About Abivax

Abivax is a clinical-stage biotechnology company focused on developing therapeutics that harness the body's natural regulatory mechanisms to stabilize the immune response in patients with chronic inflammatory diseases. Based in France and the United States, Abivax's lead drug candidate, obefazimod (ABX464), is in Phase 3 clinical trials for the treatment of moderately to severely active ulcerative colitis.

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