Abivax SA announced positive topline results from the ABTECT Maintenance Part 2 trial for obefazimod, demonstrating meaningful clinical benefit in patients with refractory ulcerative colitis. The data supports a planned New Drug Application submission to the U.S. Food and Drug Administration in the fourth quarter of 2026. The supplemental Phase 3 maintenance trial evaluated obefazimod in adults with moderately to severely active ulcerative colitis who either did not respond to induction treatment or relapsed during the maintenance trial.

Efficacy in Induction Non-Responders

Among patients who failed to achieve clinical response after 8 weeks of induction, continued treatment with obefazimod resulted in clinically meaningful rates of clinical and endoscopic endpoints at Week 44. Patients treated continuously with 50 mg obefazimod demonstrated the strongest outcomes across all endpoints.

Dose Escalation Strategy

Dose escalation to obefazimod 50 mg recaptured clinical remission in 45.5% of patients who relapsed during ABTECT Maintenance Part 1. Patients who relapsed on placebo and moved to 50 mg achieved a 45.0% clinical remission rate, while those escalating from 25 mg to 50 mg achieved a 45.5% remission rate. This supports a practical dose-escalation strategy for regaining and sustaining disease control.

Safety Profile

The integrated Phase 2 and Phase 3 UC program, encompassing 1,704 patient-years of exposure, showed exposure-adjusted incidence rates (EAIRs) for malignancies excluding non-melanoma skin cancer (NMSC) were 0.35 and 0.64 events per 100 patient-years in the all-active combined and 50 mg cohorts, respectively. These rates are consistent with expected UC background rates. In Part 2 specifically, EAIRs for malignancies excluding NMSC were 0.48 and 0.69 events per 100 patient-years in the all-active combined and 50 mg cohorts.

Marc de Garidel, MBA, Chief Executive Officer of Abivax, stated that the results represent an important milestone, demonstrating meaningful clinical benefit while substantially expanding the long-term safety database. The company plans to submit its NDA in the fourth quarter of 2026.

The Schall Law Firm, a national shareholder rights litigation firm, announced it is investigating claims on behalf of investors of Abivax S.A. regarding potential violations of federal securities laws. The investigation centers on whether Abivax issued false or misleading statements or failed to disclose pertinent information to investors. This scrutiny follows the release of results from the company's Phase 3 ABTECT trial for obefazimod, which revealed rare malignancy cases. Consequently, shares of Abivax fell sharply on June 2, 2026.

The firm is examining whether the company's disclosures regarding the trial results were accurate and timely. The Phase 3 ABTECT trial data is a critical component of Abivax's development pipeline for obefazimod. The emergence of rare malignancy cases in the trial results has raised concerns about the drug's safety profile and the company's reporting practices.

Investors who suffered losses in Abivax S.A. are encouraged to contact the Schall Law Firm to discuss their rights. The firm specializes in securities class action lawsuits and represents investors globally. Brian Schall of the Schall Law Firm is available to provide free consultations regarding the investigation.

Key Details of the Investigation

The Schall Law Firm represents investors around the world and focuses on securities class action lawsuits and shareholder rights litigation. This press release may be considered Attorney Advertising in some jurisdictions under applicable law and rules of ethics.