Omalizumab for angioedema

Last updated April 25, 2024, by Marisa Wexler, MS
Fact-checked by Joana Carvalho, PhD

What is omalizumab for angioedema?

Omalizumab is an antibody-based therapy that’s used to manage some types of allergy-related conditions. It is not approved for the treatment of angioedema, but it may be used off-label in some patients, particularly those with idiopathic angioedema whose swelling attacks lack a clear cause.

Brand names and formulations

In the U.S., omalizumab is jointly marketed by Novartis and Genentech under the brand name Xolair. There, the therapy currently is approved to treat four allergy-related conditions:

• chronic rhinosinusitis (nose-and-sinus inflammation) with nasal polyps in adults who don’t respond to first-line treatment with nasal corticosteroids
• persistent asthma that doesn’t respond well to treatment with inhaled corticosteroids in certain patients ages 6 and older
• some types of food allergies in patients ages 1 and older
• chronic spontaneous urticaria (CSU), a condition characterized by recurring hives, in certain patients ages 12 and older.

Xolair, first approved in the U.S. in June 2003 for the treatment of moderate to severe asthma, is administered via a subcutaneous (under-the-skin) injection. The therapy is approved for similar indications in other countries and regions worldwide.

Therapy snapshot

How does omalizumab work in angioedema?

Omalizumab is a monoclonal antibody that’s designed to bind and neutralize the activity of a type of antibody called immunoglobulin E, or IgE. These antibodies are important for helping to defend the body against infections, but they are also known to play a key role in allergic reactions, where the body’s immune system overreacts to a harmless substance like pollen.

In idiopathic angioedema, by definition, the cause of recurrent swelling is not known with certainty. But it’s thought that, at least in some patients, swelling might be driven by an allergic reaction to an allergen that hasn’t been identified. As such, by neutralizing IgEs, omalizumab may help to ease swelling in these individuals.

How is omalizumab administered in angioedema?

Omalizumab is supplied as a solution in a prefilled single-dose syringe, or in a prefilled single-dose autoinjector, at three different strengths (75 mg/0.5 mL, 150 mg/mL, and 300 mg/2 mL). It is also available as a powder in single dose vials containing 150 mg of the therapy’s active ingredient that must be diluted in sterile water before being administered.

Omalizumab is given by subcutaneous injection, and it should be administered under the guidance of a healthcare professional. The therapy can be self-administered in some cases.

Since omalizumab is not formally approved for angioedema, there is no standardized dosing regimen for its use in people with the condition. However, in a Phase 4 clinical trial, patients with idiopathic angioedema were given omalizumab at a dose of 300 mg every four weeks, following the same dosing regimen that’s recommended for patients with CSU.

Omalizumab in angioedema clinical trials

Some clinical trials and case reports have described the use of omalizumab in patients with angioedema.

Data from Phase 3 trials in CSU patients, up to 53% of whom also had angioedema, indicated that omalizumab could help ease angioedema symptoms. Some case reports also describe positive effects of the therapy’s use, exclusively in patients with idiopathic angioedema.

The University of Wisconsin at Madison sponsored a small randomized, double-blind, and placebo-controlled Phase 4 trial clinical (NCT02966314) to evaluate omalizumab in people with idiopathic angioedema. The study enrolled 10 adults who had experienced at least two attacks of idiopathic angioedema in the past six months. Five were given monthly subcutaneous injections of omalizumab (300 mg), while the other five received placebo injections, all given on top of standard therapy, for about six months.

Trial results showed that, compared with patients on placebo, patients treated with omalizumab had significantly fewer and shorter swelling episodes. Specifically, while patients on placebo experienced a total of 56 angioedema episodes over the course of treatment, each lasting more than five hours, patients on omalizumab had seven episodes that lasted just over one hour.

Four of the five patients given omalizumab were deemed to be in remission following treatment. Omalizumab-treated patients also showed significant improvements on standardized measures of symptom severity and life quality.

The therapy’s safety profile in the Phase 4 trial was identical to that observed in previous studies involving patients with asthma and CSU. No serious side effects or deaths were reported.

Common side effects of omalizumab

The safety profile of omalizumab specifically in people with idiopathic angioedema is not fully known. In its approved indications, common side effects of omalizumab include:

• injection site reactions, such as pain, swelling, itching, or skin discoloration
• joint pain (arthralgia)
• fever
• cold or flu-like symptoms
• abdominal pain
• upper respiratory infection
• headache
• dizziness
• sore throat (pharyngitis)
• ear infection (otitis)
• sinus infection (sinusitis).

Anaphylaxis

Omalizumab’s prescribing information carries a boxed warning noting that it can cause severe, life-threatening allergic reactions (anaphylaxis). These typically develop within an hour or two of the therapy being administered. Symptoms of anaphylaxis can include difficulty breathing, low blood pressure, fainting, hives, and swelling in the throat and tongue.

Due to these risks, omalizumab should only be administered in a healthcare setting equipped to manage anaphylaxis, and patients receiving the medication should be monitored for an adequate period of time following dosing. If symptoms of anaphylaxis arise, patients should seek immediate medical care.

Risk of cancer and parasitic infections

Omalizumab’s use has been linked to a slight increase in the risk of some types of cancer in clinical studies, although other studies haven’t found consistent results.

Treatment with omalizumab also may increase the risk of certain parasitic infections, like roundworm and hookworm. Patients at risk of encountering these parasites should be carefully monitored while on omalizumab.

Inflammatory and systemic reactions

Rare cases have been reported of asthma patients on omalizumab developing an inflammatory condition called eosinophilia, which can cause nerve damage, heart damage, and rash. Omalizumab treatment should be stopped if patients show signs of eosinophilia.

There also have been reports of patients on omalizumab developing a combination of symptoms, including joint pain, rash, fever, and enlarged lymph nodes. Treatment should be stopped if patients display this constellation of symptoms.

Use in pregnancy and breastfeeding

A registry study did not find evidence of an increased risk of major birth defects or miscarriage when omalizumab was used during pregnancy. There was an association between omalizumab and lower birth weight, though it wasn’t clear if this association was due to the therapy itself, or because women treated with omalizumab tended to have more severe asthma than those not on the therapy. Animal reproduction studies also found no evidence indicating that omalizumab might be harmful to the developing fetus.

Solid data indicating omalizumab’s presence in breast milk are lacking. However, given the fact that omalizumab is a monoclonal antibody, it’s expected that small amounts of the therapy would be present in breast milk. Most infants in the pregnancy registry study were breastfed, and findings did not reveal any notable increase in the frequency of infections among infants breastfed by women on omalizumab compared with those not exposed to the medication or not breastfed.

A decision on whether to use omalizumab in these situations should always be made by carefully weighing the potential benefits and risks for the mother and the infant.

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