Asthma Health Center

Omalizumab (Xolair) is a medicine approved by the U.S. Food and Drug Administration (FDA) for use in people age 12 and older with moderate or severe persistent asthma. It should be used only after first-line treatments (such as corticosteroids and long-acting beta2-agonists) have failed. Omalizumab is much more expensive than any of the conventional treatments for asthma, and its role in asthma treatment is not clear.

Omalizumab works by blocking immunoglobulin E (IgE) from attaching to allergens. When IgE attaches to an allergen, it sets off a process that eventually leads to the symptoms of an allergic reaction.

Initial studies show that omalizumab reduces asthma episodes, improves peak expiratory flow (PEF), reduces the need for other medications, and reduces emergency room visits and hospitalization.¹ But it has been studied only in people with positive skin tests to indoor allergens such as dust mites, animal dander, cockroaches, and molds.

Omalizumab is injected, and the dose is determined by a person's body weight and IgE level.

Omalizumab appears to be effective in people who:¹

• Are age 12 and older.
• Have moderate or severe persistent asthma.
• Have asthma that can be improved.
• Have had a positive skin or blood test for a specific allergen.
• Have blood levels of immunoglobulin E between 30 and 700 IU per milliliter.

Omalizumab can be considered in people who meet the above criteria and whose asthma is not well controlled after using inhaled corticosteroids and long-acting beta2-agonists or leukotriene pathway modifiers for 3 months. People who use oral or injected (systemic) corticosteroids or who require high doses of inhaled corticosteroids for daily control can also consider using omalizumab.

Severe allergic reactions, including anaphylaxis, are possible when taking omalizumab, although this is rare. So people who get omalizumab are watched for 2 hours after they receive their first 2 doses. They should also carry epinephrine (EpiPen) in case they have an allergic reaction after omalizumab treatment.