omalizumab

Omalizumab is a recombinant humanized monoclonal antibody that specifically targets the Fc portion of free circulating IgE antibodies. By binding to IgE, it prevents IgE from attaching to high-affinity FcεRI receptors on mast cells and basophils, thereby blocking the allergic cascade. This mechanism reduces inflammatory mediator release (histamine, leukotrienes, cytokines) that occurs during allergic reactions. The drug is administered subcutaneously every 2-4 weeks, with dosing based on baseline IgE levels and body weight. Clinical benefits include reduced asthma exacerbations, improved symptom control, and decreased need for rescue medications. Omalizumab is indicated for moderate to severe persistent allergic asthma in patients ≥6 years old with positive skin test or in vitro reactivity to perennial aeroallergen, and for chronic idiopathic urticaria in patients ≥12 years old who remain symptomatic despite H1 antihistamine treatment. Notable adverse effects include injection site reactions and rare but serious anaphylaxis (0.1-0.2% of patients), requiring observation after administration and availability of emergency treatment.