Anti IgE antibodies for the treatment of difficult asthma

INTRODUCTION: Immunoglobulin E (IgE) is a key factor of allergic reaction and is known to be involved in the immunopathology of asthma. In this review, we discuss the results of trials of a monoclonal antibody (omalizumab) against IgE in patients with allergic asthma. STATE OF THE ART: Omalizumab is a humanised murine IgG1 kappa monoclonal antibody which is administered subcutaneously every 2 to 4weeks at a dose calculated according to the patient's body weight and total plasma IgE concentrations. It binds free circulating IgE thus preventing it from binding to high affinity receptors. Omalizumab therapy significantly reduces asthma exacerbations, improves quality of life and has a steroid-sparing effect. It has a good safety profile. This treatment appears to be more effective in the patients with the most severe disease and the worst lung function. CONCLUSION AND PERSPECTIVES: Omalizumab therapy is an important novel treatment for difficult-to-control allergic asthma. Because of its systemic mechanism of action, it may be of particular use in patients displaying multiple allergic pathologies. It remains unknown whether the beneficial effects of omalizumab could be extended to patients with severe non allergic (so-called "intrinsic") asthma, a variant of the disease which is often difficult to control.