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Ulcerative ColitisNovember 2022Summary reviewed June 2026

What Researchers Found Testing Obefazimod for Ulcerative Colitis

Researchers tested a pill called obefazimod (ABX464) in people with moderate to severe ulcerative colitis who hadn't responded to other treatments. After 8 weeks, all three dose levels improved symptoms significantly more than placebo, with patients seeing their disease activity scores drop by about 3 points compared to about 2 points with placebo.

What the trial was testing

The trial enrolled 217 patients with ulcerative colitis. The study was sponsored by Abivax S.A. and tracked outcomes across the full group of patients who matched the trial's eligibility profile.

It was mid-stage testing (phase 2/3). Trials at this stage are designed to produce evidence regulators and physicians can act on — not just observations to follow up later.

What the results showed

All three doses of obefazimod significantly improved ulcerative colitis symptoms compared to placebo after 8 weeks.

The lancet. Gastroenterology & hepatology · 2022 · NCT04023396

These findings — that patients taking 50mg obefazimod saw their disease activity scores drop by 3.2 points versus 1.9 with placebo — were published in the The lancet. Gastroenterology & hepatology and represent the headline result of the study.

Researchers tracked outcomes across 217 patients enrolled in the trial. The result was consistent enough across the group that the team felt confident reporting it.

What this means for patients

For patients with ulcerative colitis, this result changes the calculus on what to ask their care team about. Whether it changes day-to-day care depends on factors like disease subtype, prior treatments, and where the patient is in their care journey.

What you can do now

This was a mid-stage study and obefazimod is not yet FDA-approved for ulcerative colitis. A larger study is ongoing to confirm these results. If you have ulcerative colitis that hasn't responded to standard treatments, ask your doctor about open clinical trials testing obefazimod or other approved biologic options.

Eligibility for the treatments mentioned above depends on specific test results and clinical history. Bring this summary, the trial name, and your most recent labs or pathology report to your next visit.