An insight into pharmacological and clinical basis of anti-IgE for add-on therapy of severe asthma

IgE antibodies are crucially involved in mediating, maintaining and amplifying the allergic cascade. The humanized monoclonal anti-IgE antibody omalizumab is currently the only biologic drug approved for asthma treatment. Anti-IgE inhibits allergic responses by binding to serum IgE, thus preventing their interactions with cellular IgE receptors. Omalizumab is also capable of down-regulating the expression of high affinity IgE receptors on inflammatory cells, as well as the numbers of eosinophils in both peripheral blood and induced sputum. Randomized clinical trials showed relevant clinical effects of omalizumab including improvements of respiratory symptoms and quality of life. Moreover, a marked reduction of asthma exacerbations, emergency room visits, and use of systemic corticosteroids and rescue bronchodilators was also observed. Omalizumab is relatively well tolerated, and only rarely induces anaphylactic reactions. Therefore, this drug represents a valid option as add-on therapy for most severe patients with persistent allergic asthma, inadequately controlled by high doses of standard treatments.