Abstract: Omalizumab is an mAb targeted against IgE. It reduces asthma exacerbations and symptoms and has low anaphylactic potential. In the placebo-controlled double-blind study, INNOVATE, omalizumab was used in the patient population with the greatest unmet clinical need, who being those meeting the Global Initiative for Asthma 2002 step 4 criteria for severe persistent asthma. When added to existing therapy, patients treated with omalizumab had a 26.2% lower rate of clinically significant asthma exacerbations, after an adjustment to take into account an observed pre-study imbalance in the exacerbation rate (P = 0.042). The Global Initiative for Asthma has recognized the role of anti-IgE therapy in treating patients with severe persistent asthma. Initiation of anti-IgE therapy is now recommended for these patients at step 4. Severe asthma has a major impact on health-care resource utilization. To date, treatment options have been limited in this target population. Omalizumab reduces symptoms, exacerbations and emergency visits in patients who are not adequately controlled on inhaled corticosteroids and long-acting beta agonists. It is a valuable therapeutic option, addressing an unmet need in the area of severe asthma.