Abivax has reported positive topline results from Part 2 of its Phase 3 Abtect maintenance trial, showing that obefazimod delivered meaningful clinical benefit in patients with refractory ulcerative colitis while further strengthening the long-term safety profile of the investigational therapy.

The additional data come from patients who either failed to respond during the induction phase of treatment or experienced disease relapse during the first part of the maintenance study. The findings expand the efficacy and safety dataset supporting Abivax’s planned New Drug Application (NDA) submission to the FDA later this year.

Among patients who did not achieve a clinical response after induction treatment, continued treatment with 50 mg obefazimod resulted in clinical remission in 37.2% of patients by Week 44. Clinical response was achieved in 61.5% of patients, while endoscopic improvement and endoscopic remission were reported in 48.0% and 34.5% of patients respectively.

The study also demonstrated that increasing the dose to 50 mg helped recapture disease control in patients who relapsed during maintenance treatment. Among patients whose dose was escalated from 25 mg to 50 mg, 45.5% achieved clinical remission and 66.7% achieved clinical response by Week 44, supporting dose escalation as a potential strategy for maintaining long-term disease control.

Marc de Garidel, chief executive officer of Abivax, said: “The results from Abtect Maintenance Part 2 represent an important milestone in the clinical development of obefazimod, demonstrating meaningful clinical benefit in patients with highly refractory ulcerative colitis while substantially expanding our long-term safety database.”

The latest findings also extend the safety database for obefazimod across both the Phase 2 and Phase 3 clinical development programme. Abivax reported that exposure-adjusted incidence rates for malignancies, including non-melanoma skin cancer, remained consistent with expected background rates for patients with ulcerative colitis. The company said no new safety pattern emerged with the additional patient exposure included in Part 2.

The integrated ulcerative colitis programme now represents 1,704 patient-years of treatment exposure, providing additional evidence to support the therapy’s long-term benefit-risk profile ahead of regulatory submission.

Remo Panaccione, professor of medicine and director of the IBD Clinic at the University of Calgary, said: “The Abtect Maintenance Trial delivered compelling evidence supporting the clinical potential of obefazimod in ulcerative colitis. 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, while the expanding long-term safety dataset continues to provide reassurance, with observed rates of malignancies and non-melanoma skin cancers remaining consistent with expected background rates in ulcerative colitis.”

Obefazimod is an investigational oral miR-124 enhancer being developed for adults with moderately to severely active ulcerative colitis. The latest results are intended to support Abivax’s planned NDA submission to the FDA in the fourth quarter of 2026. The company is also continuing development of the therapy in Crohn’s disease, with topline Phase 2b induction data from the Enhance-CD trial expected in mid-2027.