お知らせ • Jun 30
Abivax Reports Positive Abtect Maintenance Part 2 Results for Obefazimod in Refractory Ulcerative Colitis Patients
Abivax announced topline results from ABTECT Maintenance Part 2, the supplemental portion of its Phase 3 UC maintenance program evaluating obefazimod, its investigational oral miR-124 enhancer, in adults with moderately to severely active UC. Part 2 of the Phase 3 Maintenance trial enrolled patients who either did not achieve clinical response following induction treatment or who experienced disease relapse during the re-randomized maintenance trial (Part 1), expanding both the efficacy and safety results in a more refractory patient population than the registrational maintenance cohort. The additional safety results generated through Part 2 expand the Phase 3 maintenance database and provide important context for interpreting the safety findings reported following the Maintenance Part 1 readout. The integrated post-hoc analyses presented include the new Part 2 results, the combined Phase 3 maintenance program, and the broader Phase 2 and Phase 3 clinical development program. Obefazimod delivered meaningful clinical benefit in a highly refractory ulcerative colitis population, with 37.2% of induction non-responders achieving clinical remission and 34.5% achieving endoscopic remission at Week 44 following continued 50 mg treatment. Dose escalation to obefazimod 50 mg recaptured clinical remission in 45.5% of patients who relapsed during ABTECT Maintenance Part 1, supporting a practical dose-escalation strategy for regaining and sustaining disease control over time. Across the integrated Phase 2 and Phase 3 UC program (1,704 patient-years of exposure), exposure-adjusted incidence rates for malignancies excluding non-melanoma skin cancer were 0.35 and 0.64 events per 100 patient-years, and for non-melanoma skin cancer were 0.59 and 0.64 events per 100 patient-years in the all-active combined (50 mg + 25 mg) and 50 mg cohorts respectively, all consistent with expected UC background rates. In ABTECT Maintenance Part 2, exposure-adjusted incidence rates for malignancies excluding non-melanoma skin cancer were 0.48 and 0.69 events per 100 patient-years, and for non-melanoma skin cancer were 0.95 and 0.69 events per 100 patient-years, in the all-active combined and 50 mg cohorts respectively, all consistent with expected UC background rates. Among patients who failed to achieve clinical response after 8 weeks of induction, continued treatment with obefazimod resulted in clinically meaningful rates of clinical, endoscopic, and combined histologic-endoscopic endpoints at Week 44. Patients treated continuously with 50 mg obefazimod demonstrated the strongest outcomes across all endpoints, including clinical remission (37.2%), clinical response (61.5%), endoscopic improvement (48.0%), Histologic-Endoscopic Mucosal Improvement (44.6%), and endoscopic remission (34.5%). Among patients who relapsed during Maintenance Part 1, re-treatment with 50 mg obefazimod resulted in clinically meaningful rates of clinical remission, clinical response, endoscopic improvement, Histologic-Endoscopic Mucosal Improvement and endoscopic remission by Week 44. Patients who achieved clinical response with obefazimod during induction and relapsed after being re-randomized to placebo in Part 1 of the maintenance trial were treated with open-label 50 mg obefazimod and achieved clinical response and remission rates of 69.7% and 45.0%, respectively, while patients who relapsed on 25 mg and escalated to 50 mg achieved clinical response and remission rates of 66.7% and 45.5%, respectively. The post-hoc analyses below are presented progressively, from the combined Phase 2 and Phase 3 UC programs to the Phase 3 maintenance dataset (Part 1 + Part 2), and then to the Part 2 maintenance dataset, to illustrate how increasing cumulative patient-years strengthens the overall safety assessment. In Part 2, four total non-melanoma skin cancer events were reported, two in the 25 mg arm and two in the 50 mg arm, which all occurred in patients with established non-melanoma skin cancer risk factors including advanced age, thiopurine use, prior skin cancer history and failure of multiple prior advanced therapies. There were also two non-non-melanoma skin cancer malignancies reported in the 50 mg arm, both deemed unrelated to obefazimod by the study investigators. Because non-melanoma skin cancers and malignancies excluding non-melanoma skin cancers are uncommon events, incidence-rate estimates become more precise as cumulative exposure increases. The ABTECT Maintenance data should be interpreted using the totality of the exposure-adjusted evidence, together with patient characteristics and representative published UC epidemiologic reference ranges. The results in the tables below demonstrate that the exposure-adjusted incidence rate in the combined all active (25 mg + 50 mg) treatment arms for both non-melanoma skin cancers and malignancies excluding non-melanoma skin cancers are within the UC background reference range based on published UC studies. Malignancies (Excluding NMSC) – EAIR Analysis: Integrated UC Program (Phase 2 + Phase 3): Placebo IR/100 PY 0.00, 25 mg IR/100 PY 0.00, 50 mg IR/100 PY 0.64, All Active IR/100 PY 0.35, Expected UC Background 0.30 – 0.70. Phase 3 Maintenance (Part 1 + Part 2): Placebo IR/100 PY 0.00, 25 mg IR/100 PY 0.00, 50 mg IR/100 PY 0.91, All Active IR/100 PY 0.56, Expected UC Background 0.30 – 0.70. Part 2 Only: 25 mg IR/100 PY 0.00, 50 mg IR/100 PY 0.69, All Active IR/100 PY 0.48, Expected UC Background 0.30 – 0.70. NMSC – EAIR Analysis: Integrated UC Program (Phase 2 + Phase 3): Placebo IR/100 PY 0.46, 25 mg IR/100 PY 0.53, 50 mg IR/100 PY 0.64, All Active IR/100 PY 0.59, Expected UC Background 0.70 – 1.40. Phase 3 Maintenance (Part 1 + Part 2): Placebo IR/100 PY 0.68, 25 mg IR/100 PY 1.09, 50 mg IR/100 PY 1.37, All Active IR/100 PY 1.26, Expected UC Background 0.70 – 1.40. Part 2 Only: 25 mg IR/100 PY 1.52, 50 mg IR/100 PY 0.69, All Active IR/100 PY 0.95, Expected UC Background 0.70 – 1.40. The overall safety results observed in Part 2 were consistent with those previously observed in the broader obefazimod clinical development program. No new safety pattern emerged with the additional cumulative exposure provided by Part 2. Detailed exposure-adjusted analyses by trial, dose, cumulative patient-years, and patient characteristics will be presented during the investor webcast. The ABTECT Maintenance Part 2 results expand the integrated clinical dataset supporting the planned New Drug Application for obefazimod in UC. The Company remains on track to submit its New Drug Application to the U.S. Food and Drug Administration in the fourth quarter of 2026. Next anticipated key milestones: September 21, 2026 – Half-year 2026 financial results; Fourth Quarter 2026 – Planned New Drug Application submission for obefazimod in UC; Mid-2027 – Topline results from the Phase 2b ENHANCE-CD induction trial evaluating obefazimod in Crohn's disease.