Abivax ABTECT Part 2 data back obefazimod NDA submission in UC
Abivax has reported topline results from ABTECT Maintenance Part 2, a supplemental arm of its Phase 3 programme for obefazimod in moderately to severely active ulcerative colitis (UC). The data, released on 29 June 2026, show that the oral miR-124 enhancer delivered clinically meaningful outcomes in two patient populations that had previously not responded to or had relapsed on treatment, bolstering the company's planned New Drug Application to the US Food and Drug Administration in the fourth quarter of 2026.
Obefazimod works by enhancing the expression of microRNA-124, a mechanism that modulates inflammatory signalling in the gut. Part 2 of the maintenance trial enrolled patients who either failed to achieve clinical response after eight weeks of induction or who experienced disease relapse during the re-randomised Part 1 maintenance study, making this a more refractory cohort than those assessed in the registrational readout.
Efficacy results
Among induction non-responders treated continuously with the 50 mg dose through to Week 44, clinical remission was achieved by 37.2% of patients, clinical response by 61.5%, endoscopic improvement by 48.0%, and endoscopic remission by 34.5%. These rates were consistently higher than those seen in the 25 mg arm, which reported clinical remission in 23.5% and endoscopic remission in 22.2% of the same population.
For patients who had relapsed during Part 1 and were escalated to open-label 50 mg obefazimod, outcomes were stronger still. Those switching from placebo achieved clinical remission in 45.0% of cases and clinical response in 69.7%; those escalating from 25 mg reached 45.5% and 66.7% respectively. Abivax described these findings as supporting a "flexible maintenance treatment strategy" in which dose escalation can recapture disease control after relapse.
Remo Pannacione, Professor of Medicine and Director of the IBD Clinic at the University of Calgary, said the expanding 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."
Safety and regulatory path
Across the integrated Phase 2 and Phase 3 programme, covering 1,704 patient-years of exposure, exposure-adjusted incidence rates for malignancies excluding non-melanoma skin cancer (NMSC) were 0.35 events per 100 patient-years in the all-active combined cohort and 0.64 in the 50 mg cohort, both within the published UC background range of 0.30 to 0.70. NMSC rates in the integrated programme were similarly within the UC background reference range. No new safety patterns emerged from the additional Part 2 exposure.
Abivax remains on track to submit its NDA to the FDA in Q4 2026. A Phase 2b induction trial in Crohn's disease, ENHANCE-CD, is also underway, with topline results anticipated around mid-2027.
Market context
UC is a crowded and competitive indication. Approved biologics and small molecules include vedolizumab, ustekinumab, the JAK inhibitors tofacitinib and upadacitinib, and the S1P modulator ozanimod, among others. The differentiation case for obefazimod rests on its oral route, its distinct miR-124 mechanism, and the argument that its malignancy signal sits within background epidemiological rates, a point that will receive close FDA scrutiny given the agency's heightened attention to malignancy risk with JAK inhibitors. The Part 2 dataset, by expanding cumulative patient-years, is designed partly to address that regulatory sensitivity ahead of the NDA review. Analysts will assess whether the remission rates in refractory patients are commercially compelling relative to established second- and third-line options, and whether the dose-escalation flexibility translates into a practical label claim.