Mode of Action
Omalizumab is a humanized murine anti-human IgE monoclonal antibody directed against an IgE fragment (Cε3) epitope that binds to the high affinity IgE receptor (FcεRI). Omalizumab interferes with IgE binding to that receptor, thus attenuating IgE-mediated release of inflammatory mediators from mast cells, basophils and possibly other inflammatory cells.
Omalizumab reduces airway inflammation but does not attenuate bronchial hyper responsiveness (5).
Administration is based on 2 or 4 weekly regimes.
Most common side effects are lower respiratory tract infections and nasopharyngitis. In controlled studies, however, the incidence of adverse events was comparable to placebo effects.
Severe hypersensitivity reactions occur in <0.1% of patients.
Omalizumab reduces the frequency of asthma exacerbations regardless of the underlying allergen-specific IgE sensitization and improves symptom scores and asthma quality of life.
Omalizumab can be used for its steroid sparing effect, and it reduces rescue medication usage. Improvement in upper airway symptoms in patients with allergic rhinitis has also been demonstrated.
The US Food and Drug Administration (FDA) has approved Omalizumab in adults with moderate-severe persistent allergic asthma not controlled by ICS.
Treatment is limited to individuals weighing < 150kg and exhibiting elevated IgE between 30-700 IU and allergy to common perennial allergens, as evidenced by skin tests or a radioallergosorbent test (RAST).