Omalizumab: a review of its use in patients with severe persistent allergic asthma.

Omalizumab (Xolair(®)) is a subcutaneously administered monoclonal antibody that targets circulating free IgE and prevents its interaction with the high-affinity IgE receptor (FCεRI), thereby interrupting the allergic cascade. In the EU, the drug is approved as add-on therapy in adults, adolescents and children aged ≥6 years with severe persistent allergic asthma. In well designed clinical trials, add-on omalizumab significantly reduced the asthma exacerbation rate (primary endpoint) compared with placebo in adults, adolescents and children with severe persistent allergic asthma. Furthermore, add-on omalizumab reduced the need for inhaled corticosteroids in adults and adolescents, and improved asthma control and symptoms, and asthma-related quality of life in all age groups. The efficacy of omalizumab was also demonstrated in the real-world setting, with add-on therapy leading to reduced rates of hospitalizations, emergency room visits and unscheduled doctor's visits, as well as improvements in asthma symptom scores and the physician's overall assessment of treatment response. More data are needed to determine the optimum duration of treatment, and currently the duration is at the discretion of the treating physician. Omalizumab was generally well tolerated in clinical trials; the most common adverse event was transient injection-site reactions. In cost-utility analyses modelled over a life-time horizon, add-on omalizumab was cost effective compared with standard therapy, with incremental cost-effectiveness ratios falling within generally accepted willingness-to-pay thresholds. Thus, in difficult-to-treat patients with severe persistent allergic asthma, omalizumab provides a valuable treatment option.