Obefazimod Delivers Week 44 Remission in Refractory UC Patients

Continued obefazimod treatment led to Week 44 clinical and endoscopic responses in a substantial proportion of induction non-responders with moderately to severely active ulcerative colitis, including 37.2% achieving clinical remission and 34.5% achieving endoscopic remission on the 50 mg dose.

ABTECT Maintenance Part 2 is the supplemental portion of the Phase 3 maintenance program evaluating obefazimod, an investigational oral miR-124 enhancer, in adults with moderately to severely active ulcerative colitis. The analysis included patients who did not achieve clinical response after an 8-week induction period and were subsequently maintained on continued therapy through Week 44.

“The robust efficacy results observed in both induction responders (Part 1) and induction non-responders (Part 2) demonstrate a consistent treatment effect across clinically important patient populations,” Remo Pannacione, MD, Professor of Medicine and Director of the IBD Clinic at the University of Calgary said in a press release.

Among induction non-responders who continued treatment, obefazimod was associated with consistent improvements across multiple endpoints at Week 44, including clinical response (61.5%), endoscopic improvement (48.0%), and histologic-endoscopic mucosal improvement (44.6%), in addition to clinical remission (37.2%) and endoscopic remission (34.5%).

These findings suggest that lack of early response does not preclude later clinical or endoscopic benefit, reinforcing the potential for delayed treatment response with continued exposure to obefazimod.

Dose escalation associated with response recapture after relapse

In a separate exploratory analysis, dose escalation to 50 mg obefazimod was associated with recapture of clinical and endoscopic outcomes in patients who relapsed during Maintenance Part 1.

Patients who initially responded during induction but relapsed after switching to placebo achieved clinical response and remission rates of 69.7% and 45.0%, respectively, following re-treatment with 50 mg. Those who relapsed on 25 mg and escalated to 50 mg achieved clinical response and remission rates of 66.7% and 45.5%, respectively, suggesting potential for re-establishing disease control following loss of response during maintenance therapy.

Safety consistent with prior experience across integrated program

Across the integrated Phase 2 and Phase 3 ulcerative colitis program, which includes 1,704 patient-years of exposure, exposure-adjusted incidence rates for malignancies excluding non-melanoma skin cancer remained consistent with expected background rates in ulcerative colitis populations. Rates of non-melanoma skin cancer were also generally consistent with published epidemiologic benchmarks, with no new safety signals identified.

Findings from ABTECT Maintenance Part 2 were consistent with the broader program, including the Phase 3 maintenance dataset, and did not reveal any new safety concerns with increased cumulative exposure.

Clinical perspective: delayed response and flexible maintenance exposure

Taken together, the ABTECT Maintenance Part 2 results suggest that early non-response to obefazimod does not necessarily predict lack of later benefit, with clinically meaningful responses observed through Week 44 in a substantial proportion of patients. The data also indicate that disease control may be re-established following relapse with dose escalation, supporting a flexible maintenance approach in a heterogeneous ulcerative colitis population.

Conclusion

Overall, the findings expand the evidence base for obefazimod in ulcerative colitis by demonstrating late and recaptured responses in patients with refractory disease, while maintaining a safety profile consistent with expected background rates. These results support continued evaluation of obefazimod as a potential long-term therapeutic option across a broad spectrum of patients with ulcerative colitis.

References

1. Abivax Reports Positive ABTECT Maintenance Part 2 Results for Obefazimod, Demonstrating Meaningful Clinical Benefit in Refractory Ulcerative Colitis Patients and Strengthening the Phase 3 Maintenance Safety Database. Abivax. Published June 30, 2026. Accessed June 30, 2026. https://ir.abivax.com/news-releases/news-release-details/abivax-reports-positive-abtect-maintenance-part-2-results

2. ABTECT-1 - ABX464 Treatment Evaluation for Ulcerative Colitis Therapy -1. Clinical Trials. Published 2025. Accessed June 30, 2026. https://clinicaltrials.gov/study/NCT05507203