The anti-asthma drug Xolair (omalizumab) has been linked to a possible increased risk of many severe side effects, including heart attack, stroke, blood clots, and cancer.
What is Xolair?
Xolair is an injection medication for the treatment of severe allergic asthma or chronic hives. It is manufactured by Genentech and has been on the market since 2003.
Xolair is primarily used in people who have severe asthma attacks from inhaling allergens (e.g., pollen, mold, pet dander, etc.). It is only approved for people 12 years and older whose symptoms are not controlled by asthma inhalers that contain anti-inflammatory corticosteroid medications.
What is the problem?
In September 2014, the FDA warned that Xolair may increase the risk of deadly blood vessel problems in the heart and brain.
Life-threatening side effects may include:
- Transient ischemic attacks
- Heart attacks
- Sudden, unexpected chest pain
- High blood pressure in arteries of the lungs (pulmonary hypertension)
- Blood clots in the lungs (pulmonary embolism)
- Blood clots in veins (venous thrombosis)
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These conclusions were based on an evaluation of a 5-year safety study comparing Xolair to a placebo. The study suggested a serious safety signal, but due to weaknesses in how the study was designed and carried out, the FDA cannot definitively confirm the increased level of these risks.
The study, Evaluating the Clinical Effectiveness and Long-Term Safety in Patients with Moderate to Severe Asthma (EXCELS), involved 5,000 patients with asthma who were treated with Xolair, compared to 2,500 patients who did not take Xolair. Data linking Xolair and heart problems appeared early in the study.
In July 2009, the FDA began investigating studies linking Xolair with an increased number of cardiovascular and cerebrovascular adverse events.
Xolair and Cancer
Xolair prevents asthma attacks by blocking human immunoglobin E (IgE), which is an antibody that is commonly involved in allergic reactions. IgE may play an important role in the body’s recognition of cancer cells, which suggests that blocking IgE could be associated with cancer risks.
In clinical trials, cancer was reported in 0.5% of patients treated with Xolair compared to 0.2% of control patients. However, other studies have found no higher risk of cancer.
The FDA found no difference in the rate of cancer after reviewing the EXCELS safety study, but they cannot rule out a potential risk of cancer. The EXCELS study was only five years, and cancer often takes much longer to develop. The label on Xolair has been updated to include this risk information.