Omalizumab safety concerns

IgE and mast cells play key roles in the pathophysiology of allergic diseases. In 2003, omalizumab was the first anti-IgE mAb licensed in the United States when initially US Food and Drug Administration-approved for the treatment of allergic asthma. Since that time, the number of US Food and Drug Administration-approved indications for treatment with omalizumab has grown to include chronic spontaneous urticaria, chronic rhinosinusitis with nasal polyps, and food allergy. Although omalizumab is generally considered relatively safe and well tolerated, a number of safety concerns have been raised since its initial approval. These concerns focus on specific adverse events of interest, including anaphylaxis, pregnancy, malignancy, cardiovascular events, and infections. For each of these issues, data from clinical trials and postmarketing surveillance have been evaluated extensively. In this review, we examine these safety data, provide context for safety and risk assessments, and summarize a safety profile for each of the adverse events of interest. In doing so, we aim to provide a resource for shared decision making when treatment with omalizumab is being considered. (J Allergy Clin Immunol 2025;155:31-5.)