Obefazimod Achieves Clinical Remission in Phase III Ulcerative Colitis Trials

Results from the Phase III ABTECT-1 (NCT05507203) and ABTECT-2 (NCT05507216) trials show that Abivax’s obefazimod, a first-in-class oral miR-124 enhancer indicated for adults with moderately to severely active ulcerative colitis (UC), demonstrated statistically significant clinical remission.¹

“Today marks a significant milestone for Abivax, and more importantly, for the ulcerative colitis community,” said Marc de Garidel, CEO, Abiva, in a press release. “The strength of these results reinforces our belief in obefazimod, our first-in-class miR-124 enhancer, and its potential to become a transformative new treatment modality for patients with UC. Pending successful results from the 44-week maintenance trial, we are preparing to submit a New Drug Application to the FDA in the second half of 2026. We would like to thank the patients who participated in the trials as well as the investigators and staff at over 600 sites in 36 countries who contributed to the landmark trials.”

ABTECT Trial Design and Endpoints

• ABTECT-1 and ABTECT-2 were randomized, double-blind, placebo-controlled, multicenter trials evaluating once-daily oral obefazimod in 1,275 adults with moderately to severely active UC.
• ABTECT-2 also included patients with an inadequate response, loss of response, or intolerance to conventional and/or advanced therapies.
• The primary endpoint for both trials was the proportion of patients achieving clinical remission at week eight, based on the Modified Mayo Score (MMS).
• Key secondary endpoints included the proportion of patients achieving endoscopic improvement, clinical response, and symptomatic remission at week eight.^2.3

Efficacy and Safety Results

• Results showed that at week eight, the 50 mg once-daily dose of obefazimod met the primary endpoint in both trials, with statistical significance of 19.3% (p<0.0001) in ABTECT-1 and 13.4% (p=0.0001) in ABTECT-2.
• The 25 mg dose met the primary endpoint in ABTECT-1 (23.8% vs. 2.5%, p<0.0001) but did not reach statistical significance in ABTECT-2, although it demonstrated a strong clinical response signal.
• Endoscopic improvement rates at week eight reached 33% to 36% with obefazimod 50 mg, compared to 6% to 10% for placebo.
• Histologic endoscopic mucosal improvement (HEMI) was achieved by approximately 23% to 24% of patients in the 50 mg arms, with p-values <0.0001 in both trials.
• Treatment-emergent adverse events (TEAEs) occurred in 47% to 61% of patients receiving obefazimod, compared to 48% to 53% in the placebo group.
• Serious adverse events and discontinuations due to TEAEs were infrequent across all arms.
• No new safety signals were observed.¹

Expert Perspective and Next Steps

“The results of the two induction studies for this first-in-class therapy for ulcerative colitis are both statistically significant and clinically meaningful,” said David Rubin, MD, chief, section of gastroenterology, hepatology, and nutrition, director, inflammatory bowel disease center, University of Chicago Medicine, in the press release. “Based on the impressive safety and tolerability profile demonstrated to date, and pending similar results in the maintenance study, obefazimod will offer a welcome new option for those who suffer from ulcerative colitis, both as an attractive early option as well as for those who have had inadequate response or loss of response to prior advanced therapies.”

Based on these results, 678 patients have progressed into the 44-week maintenance study, with topline results expected in Q2 2026. If successful, Abivax plans to submit regulatory applications in the United States and EU.¹

“The exemplary results from the ABTECT induction trials reflect our dedication to scientific rigor and disciplined execution,” said Fabio Cataldi, MD, chief medical officer, Abivax, in the press release. “We are thrilled to report outcomes that not only met but exceeded the bar set by our Phase IIb trial, a remarkable achievement that speaks volumes about the quality of our development program. We look forward to presenting more detailed analysis, including patients with inadequate response to prior JAK therapy at an upcoming medical conference.”

References

1. Abivax Announces Positive Phase 3 Results from Both ABTECT 8-Week Induction Trials Investigating Obefazimod, its First-in-Class Oral miR-124 Enhancer, in Moderate to Severely Active Ulcerative Colitis. Abivax. July 22, 2025. Accessed July 24, 2025. https://ir.abivax.com/news-releases/news-release-details/abivax-announces-positive-phase-3-results-both-abtect-8-week
2. ABTECT-1 – ABX464 Treatment Evaluation for Ulcerative Colitis Therapy -1. Clinicaltrials.gov. Accessed July 24, 2025. https://www.clinicaltrials.gov/study/NCT05507203?spons=COVERAGE%5BFullMatch%5DEXPANSION%5BNone%5D(%22Abivax%20S.A.%22)&viewType=Table&rank=4
3. ABTECT-2 – ABX464 Treatment Evaluation for Ulcerative Colitis Therapy -2. Clinicaltrials.gov. Accessed July 24, 2025. https://clinicaltrials.gov/study/NCT05507216