A boxed warning on the product label for omalizumab, marketed as Xolair, has been requested to Genentech, Inc. by the Food and Drug Administration (FDA).

The warning is related to a possibility of anaphylaxis after Xolair use. Anaphylaxis can include troubled breathing, chest tightness, dizziness, fainting, itching, and hives.

The FDA has also asked Genentech to offer a Medication Guide for patients with an aim to strengthen the existing warning for anaphylaxis.

From News-Medical.Net:

Xolair was approved in 2003 to treat adults and adolescents (12 years of age and above) with moderate to severe persistent asthma who have tested positive for a perennial aeroallergen (pollen, grass or dust) and whose symptoms are inadequately controlled with inhaled steroids. In clinical trials, Xolair decreased the rate of asthma exacerbations, which were defined as a worsening of asthma that required treatment with systemic corticosteroids or a doubling of baseline inhaled corticosteroid dose.

Anaphylaxis was reported following administration of Xolair in clinical trials and was therefore, discussed in the initial product labeling. The cases were reported at a frequency of approximately one in a thousand patients (0.1%). Due to the nature of continued reports in the post-marketing experience, including their life-threatening potential, frequency, and the possibility for the delayed onset of anaphylaxis, FDA has now requested that Genentech, Inc., add the boxed warning and strengthen the existing warning. As the agency gains experience and collects data about a marketed product the determination may be made to strengthen the product label to ensure that consumers are aware of newly identified significant risks.

The strengthened warning includes the possibility of anaphylaxis at any stage even if there was no reaction to the first dose.