Xolair (Omalizumab): Treatment for Allergic Asthma

Safety, side effects, and more

Xolair (omalizumab) is an injectable medication used to treat moderate to severe allergic asthma. It can be used in people 12 years and older who still have uncontrolled asthma despite typical asthma medications, such as inhaled steroids.

Injections are given in the healthcare provider’s office every two to four weeks depending on a person’s weight and allergic antibody (IgE) level. (Check to see if your asthma is controlled by taking the asthma control test.)

Woman with hand on her chest struggling to breathe

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What Exactly Is Xolair?

Xolair is a monoclonal anti-IgE antibody which binds to IgE in the bloodstream, allowing the body to remove them. The drug is produced in mice and therefore contains approximately five percent mouse protein (it does not appear that an allergy to mouse protein causes problems for people receiving Xolair).

This prevents IgE from attaching to mast cells and binding to allergens, which ultimately results in the release of histamine and other chemicals. It is these chemicals which cause worsening of asthma and other allergy symptoms.

The drug has been shown to decrease asthma attacks, improve the overall quality of life for people with asthma, and reduce corticosteroids needed. Generally, it can take a few months of injections for Xolair to begin to work. And the medication can be very expensive. Xolair is not a cure for asthma—symptoms would be expected to worsen a few months after Xolair therapy is stopped.


Xolair currently has a “black box” warning, which is a precautionary statement given to the medication by the U.S. Food and Drug Administration (FDA). This warning has come about as a result of reports of people experiencing anaphylaxis (allergic reaction) after receiving Xolair.

While there are no reports of fatal anaphylaxis as a result of Xolair, some cases have been serious and potentially life-threatening. For this reason, the FDA requires that people receiving Xolair be monitored in their healthcare provider’s office for a period of time after their injections. (The actual amount of time is determined by the healthcare provider.)

People who receive Xolair should watch out for the following symptoms of anaphylaxis, which could occur up to 24 hours (or longer) after the injection:

  • Wheezing, shortness of breath, coughing, chest tightness, or trouble breathing
  • Low blood pressure, dizziness, fainting, rapid or weak heartbeat
  • Flushing, itching, hives, or swelling
  • Nausea, vomiting, diarrhea, or abdominal pains
  • Swelling of the throat, tongue, lips, or eyes
  • Throat tightness, hoarse voice, trouble swallowing
  • Sudden severe sneezing, severe runny nose, or nasal congestion
  • Anxiety or feeling of panic

Should any of these symptoms occur, it is important to notify your healthcare provider immediately. Many healthcare providers prescribe patients with injectable epinephrine to use in the case of anaphylaxis 24 hours after their Xolair injection.

Increased Cancer Risk

During clinical development, rates of cancer were slightly higher in people receiving Xolair compared to people receiving placebo injections. The types of cancers seen in people receiving Xolair include breast cancer, skin cancer, and prostate cancer. It is not yet known what the potential long-term effects of Xolair use may have on people who are prone to getting cancer, such as the elderly.

While it would appear that Xolair has potentially severe side effects, it must be remembered that anaphylaxis and cancer formation occurred only in a very small number of patients. It is still not known why these side effects occur, although studies are ongoing to determine the reason.

It is also important to realize that uncontrolled asthma can lead to severe complications, including death. And medications used to treat asthma attacks, such as oral and injected corticosteroids, have a long list of side effects with long-term use. It is, therefore, important to discuss with your healthcare provider the risks and benefits of taking Xolair for asthma that is not controlled on typical asthma medications.

Xolair for Other Health Conditions

A number of different studies examined the benefit of Xolair for the treatment of chronic idiopathic urticaria (hives), or CIU. The most recent study examined over 300 patients with CIU who still had symptoms despite taking usual doses of antihistamines.

Subjects were administered Xolair in various dosages every four weeks. Forty-four percent of people receiving high-dose Xolair, and 22 percent of people receiving medium-dose Xolair, had complete resolution of hives within one to two weeks of treatment. Symptoms slowly worsened after Xolair was stopped, so there was no sign of long-term benefit. In March 2014, the FDA approved the use of Xolair for CIU.

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