Long-Term Safety of Ontamalimab in Patients with Moderate to Severe Inflammatory Bowel Disease

Purpose

Although ontamalimab showed promise for treatment of patients with ulcerative colitis (UC) and Crohn's disease (CD), the Phase 3 clinical development program was terminated in 2020. Here we report the results of a long-term safety (LTS) extension study. Patients and methods: The study enrolled patients with UC or CD who previously participated in the randomized, placebo-controlled phase 3 induction and maintenance clinical trials that evaluated the efficacy and safety of ontamalimab. During the LTS study, patients received ontamalimab 25 mg or 75 mg once every 4 weeks or were switched from 25 mg to 75 mg. Long-term safety outcomes, including the frequency and severity of adverse events (AEs), were assessed in eligible patients for up to 6 years of treatment. Efficacy was not formally evaluated in this study.