Used in the treatment of moderate to severe persistent allergic asthma, particularly in patients whose symptoms are not controlled by inhaled corticosteroids. It targets and binds to free immunoglobulin E (IgE), preventing it from triggering allergic reactions. Also applied in managing chronic spontaneous urticaria (previously called chronic idiopathic urticaria) in patients unresponsive to antihistamines. By reducing IgE-mediated inflammation, it helps decrease asthma exacerbations, improve symptom control, and reduce the need for high-dose corticosteroids. Employed as a reference standard in bioanalytical assays during development and testing of biosimilars and other anti-IgE therapeutics.