Obefazimod Demonstrates Durable Efficacy in Phase 3 ABTECT Maintenance Trial

Despite the growing number of advanced therapies for moderately to severely active ulcerative colitis (UC), many patients do not achieve durable remission, highlighting the need for treatments that provide sustained disease control, minimize treatment burden, and support long-term quality of life.

Obefazimod is an investigational oral, first-in-class enhancer of microRNA-124 (miR-124) designed to restore the mucosal immune balance in UC. The global ABTECT UC program is evaluating more than 1200 patients across 3 pivotal trials

ABTECT-1 and ABTECT-2 are 8-week induction trials evaluating obefazimod for the treatment of moderately to severely active UC. In both studies, obefazimod 50mg met the primary endpoint of clinical remission and achieved all key secondary efficacy endpoints, as presented at United European Gastroenterology Week in October 2025.

In the Phase 3 ABTECT maintenance trial, obefazimod met the primary endpoint and all key secondary endpoints as well, supporting its potential as a once-daily oral maintenance for adults with moderately to severely active UC.

The ABTECT maintenance trial was a global 44-week, multicenter, randomized, double-blind, placebo-controlled study where 580 clinical responders from the 8-week ABTECT-1 and ABTECT-2 induction trials were re-randomized to receive obefazimod 25 mg, obefazimod 50 mg, or placebo once daily. The primary endpoint was clinical remission, defined as a stool frequency subscore (SFS) of 0–1, rectal bleeding subscore (RBS) of 0–1, and Mayo Endoscopic Subscore (MES) of 0–1. Key secondary endpoints included endoscopic improvement, endoscopic remission, histologic-endoscopic mucosal improvement (HEMI), corticosteroid-free clinical remission, and sustained clinical remission.

At week 44 (week 52 overall), both obefazimod 25 mg and 50 mg met the primary endpoint and all key secondary endpoints in the Phase 3 ABTECT maintenance trial. Obefazimod 50 mg achieved clinical remission in more than 50% of patients, representing an approximately 40% placebo-adjusted treatment difference (p<0.0001), and endoscopic remission (MES=0) in 48% of patients, representing an approximately 38% placebo-adjusted treatment difference (p<0.0001).

Obefazimod was generally well tolerated over 44 weeks, with a favorable safety profile and no new safety signals reported. Treatment discontinuation due to treatment-emergent adverse events (TEAEs) occurred in 2.6% (5/193) and 4.6% (9/195) of patients in the obefazimod 25 mg and 50 mg groups, respectively, compared with 6.8% (13/192) in the placebo group. Serious TEAEs were observed in 2.6% (5/193) and 5.6% (11/195) of patients in the 25mg and 50 mg arms, respectively, compared with 4.2% (8/192) for placebo. Two serious/severe (grade ≥ 3) infections and opportunistic infections were reported in the 25 mg treatment arm and one in the 50 mg treatment arm, compared with two in the placebo group. No deaths were reported in the study.

Among patients treated with 50 mg obefazimod, one case of prostate cancer and one case of breast cancer were reported. Investigators deemed both events unrelated to obefazimod treatment, and no organ-specific clustering or shared patterns observed. The incidence of these cases was consistent with malignancy (excluding non-melanoma skin cancer) rates reported in other Phase 3 randomized, placebo-controlled maintenance trials of approved UC therapies.

Abivax remains on track to submit a New Drug Application to the FDA for obefazimod in UC treatment late in the fourth quarter of 2026.

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