Xolair for the Treatment of Chronic Hives

Omalizumab for the Treatment of Chronic Idiopathic Urticaria

Hives develop when histamine is released into the small blood vessels (capillaries). The capillaries dilate which causes a welt, and fluid oozes into the surrounding tissue, causing swelling. Histamine also causes intense itching. © ADAM

What is Chronic Urticaria?

Urticaria, the medical term for hives, is a condition that can affect up to one in five people at some point during their lifetime. The rash of urticaria is usually bumpy, red and itchy. The bumps can be the size of mosquito bites to coin-size or larger, and can group together into irregular shapes, which is called coalescing. The rash will tend to come and go within a few hours, moving from one place on the body to another.

The swelling that sometimes accompanies urticaria, called angioedema, can lead to swelling of the face, hands and feet. Angioedema is usually not red or itchy, but tends to sting and burn, and can be described as “numbness.” This swelling can be severe, and if it affects a person’s ability to breathe, can be life threatening.

Both urticaria and angioedema are a result of histamine and other chemicals released from mast cells in the skin and mucous membranes. This may occur through an allergic process or one in which mast cells release chemicals without IgE being involved.

Cases of urticaria and angioedema can be acute, lasting less than 6 weeks, or chronic, lasting more than 6 weeks. Unlike acute urticaria, only about 5 to 10 percent of chronic urticaria and angioedema are caused by allergies. The cause of chronic urticaria cannot always be identified, which is then referred to as chronic idiopathic urticaria (CIU).

CIU much more likely to be related to autoimmune causes than allergies. In the autoimmune form CIU, a person often makes antibodies against a component of their mast cells (either to the mast cell receptor for IgE antibodies, or to the actual IgE bound to the mast cell), triggering the release of histamine and causing symptoms.

The main treatment for CIU is with oral antihistamines. These are usually given in oral forms, and may need to be given in large or frequent doses to control the symptoms. However, more than 50% of people with CIU may not respond to treatment with usual dosing of oral antihistamines. Additional therapies for CIU are often required, but are unapproved by the U.S. Food and Drug Administration (FDA) for this purpose. Therefore, additional treatments for CIU, approved by the FDA, are needed for those people not responding to usual doses of oral antihistamines.

What is Xolair?

Xolair (omalizumab) is an injectable medication that is approved by the FDA to treat moderate to severe allergic asthma in people 12 years of age and older. Injections are given in the doctor’s office every 2 to 4 weeks, depending on a person’s weight and allergic antibody (IgE) level. Xolair is a monoclonal anti-IgE antibody, which binds to IgE in the bloodstream, allowing the body to remove them. This prevents IgE from attaching to mast cells (and therefore from binding to allergens) which ultimately results in the release of histamine and other chemicals.

It is these chemicals that cause worsening of asthma and other allergy symptoms, including urticaria and angioedema.

Can Xolair Be Used to Treat Chronic Urticaria?

Early studies are certainly promising. A number of different studies examined the benefit of Xolair for the treatment of CIU. The most recent study examined over 300 patients with CIU who still had symptoms despite taking usual doses of antihistamines. They were administered Xolair in various dosages every 4 weeks. Forty-four percent of people receiving high-dose Xolair, and 22% 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.

Other studies have found similar benefits, with rates of “remission” on Xolair in approximately 30% of people with CIU. The best data appears to be from a smaller study where the Xolair dose was similar to how it is given to a person with asthma. Patients in this study had evidence for autoimmune CIU based on the measurement of autoantibodies (antibodies against oneself) against thyroid hormones. Seventy-percent of people receiving Xolair had complete resolution of their CIU symptoms.

Therefore, studies show that Xolair is a safe and effective treatment for patients with CIU, and response to treatment seems to be less dependent on a person’s weight, serum IgE level, or autoimmune status. The benefits of Xolair probably only remain while the drug is being taken, meaning that there isn’t likely to be long-term remission induced by Xolair for people with CIU. Unfortunately, since Xolair is extremely expensive, and many people with CIU can be controlled with high doses of oral antihistamines, very few people are likely to receive Xolair for CIU. The U.S. Food and Drug Administration approved the use of Xolair for CIU in March 2014.

Sources:

Casale TB. Omalizumab for Chronic Urticaria. J Allergy Clin Immunol Pract. 2014;1:118-9.

Kahn DA. Alternative Agents in Refractory Chronic Urticaria: Evidence and Considerations on their Selection and Use. J Allergy Clin Immunol Pract. 2013;1:443-40.

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