Obefazimod Meets Primary Endpoint in Phase 3 ABECT Program for Ulcerative Colitis

Abivax SA has announced positive topline results from its phase 3 ABTECT-1 (Study 105) and ABTECT-2 (Study 106) 8-week induction trials evaluating obefazimod (ABX464) in adult patients with moderately to severely active ulcerative colitis (UC).1

According to a July 22, 2025, press release from Abivax, results from the ABTECT-1 and ABTECT-2 trials showed obefazimod met its FDA primary endpoint of clinical remission at week 8 in the 50 mg once-daily dose regimens for both trials.1

“The results of the two induction studies for this first-in-class therapy for ulcerative colitis are both statistically significant and clinically meaningful,” David Rubin, MD, Chief, Section of Gastroenterology, Hepatology and Nutrition, and Director of the Inflammatory Bowel Disease Center at the University of Chicago Medicine, said in a statement.1 “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.”

An orally administered small molecule that has previously demonstrated the potential to enhance the expression of a single microRNA, miR-124, obefazimod is being explored for the treatment of both UC and Crohn’s disease (CD). In addition to the ABECT Program in UC, a phase 2b clinical trial in CD is ongoing, with the first patient enrolled in October 2024.2

ABTECT-1 and ABTECT-2 are global, multicenter, randomized, double-blind, placebo-controlled trials assessing once-daily oral administration of obefazimod at 25 mg or 50 mg doses in adult patients with moderately to severely active UC. Eligible participants had inadequate response, loss of response, or intolerance to conventional and/or advanced therapies.1

The trials were conducted simultaneously and have enrolled 1275 patients from > 600 participating clinical trial sites in 36 countries with the intent to satisfy regulatory requirements globally. According to Abivax, the ABTECT Program is one of the largest phase 3 UC trials ever conducted and includes the largest population of patients with inadequate response to JAK inhibitor therapy.1

Results from ABTECT-1 and ABTECT-2 showed obefazimod met its FDA primary endpoint of clinical remission at week 8 in the 50 mg once-daily dose regimens for both trials. Specifically, it led to a pooled 16.4% (P <.0001) placebo-adjusted clinical remission rate at week 8 in both ABTECT-1 and ABTECT-2. Individually, the 50 mg dose demonstrated a placebo-adjusted remission rate of 19.3% (P <.0001) in ABTECT-1 and a placebo-adjusted remission rate of 13.4% (P = .0001) in ABTECT-2.1

While the 25 mg once-daily dose of obefazimod achieved the FDA primary endpoint of clinical remission at week 8 in ABTECT-1 with a placebo-adjusted remission rate of 21.4%, the 25 mg dose did not achieve statistical significance for this endpoint in ABTECT-2. However, it achieved a pooled placebo-adjusted clinical response rate of 28.6%, indicating a strong signal for these patients to achieve clinical remission with extended treatment in the ongoing ABTECT Maintenance Trial (ABX464-107).1

Of note, the safety profile of obefazimod remained consistent with prior clinical experience. No new safety signals were observed in either trial and the treatment was generally well tolerated across both dose groups.1

Abivax noted topline results from the maintenance trial are expected in Q2 2026 and are intended to support regulatory filings globally. Contingent on positive 44-week maintenance results, the Company described plans to submit a New Drug Application to the FDA in the second half of 2026.1

“We are thrilled to report outcomes that not only met but exceeded the bar set by our Phase 2b trial, a remarkable achievement that speaks volumes about the quality of our development program,” said Fabio Cataldi, M.D. Chief Medical Officer of Abivax.1 “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. 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. July 22, 2025. Accessed July 23, 2025. https://ir.abivax.com/news-releases/news-release-details/abivax-announces-positive-phase-3-results-both-abtect-8-week/

2. Abivax. Abivax Announces First Patient Enrolled in ENHANCE-CD, the Phase 2b Trial of Obefazimod in Crohn’s Disease. October 3, 2024. Accessed July 23, 2025. https://ir.abivax.com/news-releases/news-release-details/abivax-announces-first-patient-enrolled-enhance-cd-phase-2b