An anti-IgE biologic
Omalizumab
An injected biologic that targets the allergy antibody IgE, used for severe allergic asthma and chronic urticaria (hives).
What is Omalizumab?
Omalizumab is a biologic medicine that targets immunoglobulin E (IgE), the antibody that drives allergic reactions. It is used for severe allergic asthma that is not controlled by usual treatment and for chronic spontaneous urticaria (long-lasting hives). It is given by injection under the skin, usually in a clinic, with doses spaced weeks apart. The most important caution is a small risk of a severe allergic reaction (anaphylaxis), so the early doses are given where help is available. It is not broadly immunosuppressive, but as with other biologics live vaccines are generally planned around treatment.
Education and reference only. This is a plain-language guide to Omalizumab — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Omalizumab is a biologic medicine, made from living cells, that targets immunoglobulin E (IgE), the antibody at the centre of allergic reactions. It is used for severe allergic asthma that remains poorly controlled despite usual inhaled treatment, and for chronic spontaneous urticaria, a condition of long-lasting itchy hives that has not responded to antihistamines. It is given by injection under the skin, usually at a clinic or hospital, especially in the early stages of treatment.
How it works
In allergic asthma and chronic hives, the antibody IgE triggers immune cells to release the chemicals that cause airway tightening or itchy, raised skin. Omalizumab attaches to IgE and reduces the amount free to set off these reactions, so over time it can lessen asthma attacks or settle persistent hives. It does not suppress the immune system broadly. Because the medicine itself acts on the allergy system, it carries a small risk of triggering a severe allergic reaction, which is why early doses are given where help is on hand.
Company & origin
Originated / developed by: Novartis and Genentech.
A biologic medicine developed to treat severe allergic asthma and chronic spontaneous urticaria by targeting the allergy antibody IgE.
What it treats
Conditions Omalizumab is used for
Practical use
How to take Omalizumab
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- It is given by injection under the skin, usually at a clinic or hospital, especially for the early doses.
- Be prepared to wait for a short time after early injections, as there is a small risk of a severe allergic reaction.
- Seek urgent help if you get swelling of the face or throat, difficulty breathing, a rash or faintness after an injection.
- Keep using your other asthma treatments, such as inhalers, unless your team tells you otherwise.
- Give it time, as it can take a couple of months to see the full benefit; keep your scheduled injection appointments.
Weighing it up
Advantages & disadvantages of Omalizumab
Advantages
- Can substantially reduce attacks in severe allergic asthma and settle long-lasting hives that have not responded to antihistamines.
- Targets the allergy antibody IgE specifically and is not broadly immunosuppressive.
- Given only every few weeks once established, fitting around other asthma or allergy treatments.
Disadvantages
- Carries a small risk of a severe allergic reaction (anaphylaxis), so early doses are given where help is available.
- Usually given at a clinic, at least to begin with, rather than freely at home.
- Can take a couple of months to show its full benefit.
Practical use
Good to know
The most important thing to know is that omalizumab carries a small risk of a severe allergic reaction (anaphylaxis), which can occasionally happen even after several doses; for this reason the early injections are given in a clinic or hospital where help is available, and you may be asked to wait for a short time afterwards. It is not broadly immunosuppressive, so it does not carry the same infection risk as many other biologics, but live vaccines are still usually planned around treatment. It is given by injection under the skin with doses spaced weeks apart, and it can take a couple of months to see the full benefit, so it is worth persevering. Tell your team straight away about any swelling of the face or throat, difficulty breathing, or faintness after an injection.
Who should not take it / use with caution
- People who have had a severe allergic reaction to omalizumab itself should not have it again.
- It is not suitable for treating a sudden asthma attack; it is a preventive treatment, not a reliever.
- It is used with care in those with a history of severe allergic reactions, with close observation around doses.
Monitoring
- Observation after early injections because of the small risk of a severe allergic reaction.
- Reviewing how well the asthma or hives respond, as it can take a couple of months to judge the benefit.
- Checking other treatments can be adjusted as control improves, and planning any vaccinations.
Side effects
- Redness, swelling or soreness where the injection is given is common and usually mild.
- Headache and, in some people, joint aches or feeling generally unwell.
- Rarely, a severe allergic reaction (anaphylaxis) with facial or throat swelling, breathing difficulty or faintness, needing urgent help.
Key interactions
- It is not broadly immunosuppressive, but live vaccines are usually planned around treatment.
- It is used alongside your existing asthma or allergy treatments rather than replacing them.
- Tell your team about all your medicines and any history of severe allergic reactions before starting.
Available as: Injection under the skin, usually given at a clinic or hospital, especially for the early doses.
Answers
Omalizumab: frequently asked questions
What does omalizumab target?
It targets immunoglobulin E (IgE), the antibody that drives allergic reactions, reducing the amount free to trigger asthma symptoms or hives.
Why are the first injections given at a clinic?
There is a small risk of a severe allergic reaction (anaphylaxis), so early doses are given where help is available and you may be asked to wait a short time afterwards.
Does it weaken the immune system?
It is not broadly immunosuppressive, so it does not carry the same infection risk as many other biologics, though live vaccines are usually planned around treatment.
How quickly will it work?
It can take a couple of months to see the full benefit for asthma or hives, so it is worth persevering and keeping your appointments.
What should I watch for after an injection?
Seek urgent help if you get swelling of the face or throat, difficulty breathing, a rash or faintness, as these can be signs of a severe allergic reaction.
Authoritative sources
- BNF
- NICE CKS
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