HEALTH FACT ARCHIVE
The product, omalizumab, is a monoclonal antibody. It has been shown to be safe and effective to treat people 12 years of age and older with moderate to severe allergy-related asthma inadequately controlled with inhaled steroid treatments. In these patients, omalizumab, marketed as Xolair, has been shown to decrease the number of asthma exacerbations or episodes of airway narrowing that result in wheezing, breathlessness, and cough. The product is given as an injection under the skin. Asthma is an airway disease affecting approximately 17 million Americans. It is estimated that a relatively small percentage of these people would be appropriate candidates for this new drug. It is a second-line treatment, recommended only after first-line treatments have failed. However, it is not approved for children under the age of 12. Moreover, it is known to work and is approved only for patients with moderate to severe, allergy-related asthma.
While the cause for most forms of asthma is unclear, asthma caused by allergies is better understood. It results from the immune system's over-reaction to inhaled allergens such as dust mites or animal dander. The body forms antibodies in response to the allergen. Then, this immune system reaction prompts inflammation causing airway narrowing and other symptoms. Xolair is a genetically engineered protein that blocks this immune response.
Only patients who have asthma caused by allergies can benefit from this new treatment. Therefore, the product's labeling states that this type of asthma should be established by skin or blood test to diagnose the allergy before treatment.
The effectiveness of Xolair was mainly assessed in two placebo-controlled studies lasting six months that included over 1,000 adolescents and adults. These patients all had persistent symptoms despite the use of inhaled corticosteroids. About 80-85% of patients treated with Xolair had no exacerbations of their asthma symptoms compared to about 70-75% of placebo treated patients. During the clinical trials, more patients treated with Xolair developed a new or recurrent cancer (0.5%) compared to control patients (0.2%). The sponsor is planning long-term studies in an attempt to determine whether there is a relationship between Xolair treatment and cancer.
The other major safety concern with Xolair identified in the clinical trials was severe allergic reactions or anaphylaxis. Anaphylaxis occurred in three patients; all responded to and recovered following medical treatment.
Xolair is manufactured by Genentech, San Francisco, Calif. Genentech will
jointly market the product in conjunction with Novartis Pharmaceutical Corp.,
East Hanover, NJ.
For more, please visit the Asthma Center.
Source: FDA Talkpaper #T03-49, June 20, 2003
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