Allergy & Asthma-Kent H. DeYarman, MD

Topics in Allergy

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Xolair (Omalizumab)-Anti IgE

Asthma is a lung disease that results from inflammation (injury) of the lining of the bronchial tubes. Several different factors can contribute to the inflammation including inborn (hereditary) factors, allergies, smoking, viral illnesses and others. Many, but not all, people with allergies have allergic inflammation contributing to the injury in the bronchial tube lining.

 

Allergic inflammation occurs when one makes IgE antibody. An antibody is a chemical that recognizes another foreign chemical-in this case, foreign materials such as dust mites, molds, animals, pollens, etc. IgE antibody has a Y shape. The single end of the Y attaches to the surface of mast cells in the respiratory tract. Each branch of the other end is made to recognize a foreign material (allergen). The IgE is made by cells called B-lymphocytes. It is released into the body and eventually becomes attached to the mast cell. When the foreign material (allergen) attaches to IgE that is already bound to the mast cell, it causes the mast cell to release many products that cause injury to the airway and cause inflammation cells to move into the airway to cause further injury.

 

Until now, the only way to reduce the injury from allergic inflammation has been to eliminate exposure to the allergen (often difficult) or to be treated with traditional allergy shots. Traditional allergy shots or immunotherapy is a treatment that involves injecting gradually increasing amounts of the material to which you are allergic. This eventually causes your body to produce less IgE and become less allergic. Traditional allergy shots can be very effective but carry some risk of anaphylaxis (severe allergic reaction to the allergy shot). This is a particular risk to those with severe forms of asthma.

 

Xolair is a new treatment to reduce the injury from allergic inflammation. It is currently approved only people 12 years of age and older to treat moderate to severe persistent asthma who have definite evidence of allergic sensitivity to perennial (year round) allergens and whose disease is inadequately controlled by inhaled cortisone medications. Eventually it may be approved for younger age groups and for treatment of other allergic problems (hay fever, some food allergies, etc).

 

Xolair is given in a shot (a very small injection similar to a traditional allergy shot) every 2-4 weeks. The dose is determined by your weight and by your total IgE level. Xolair works quite differently than traditional allergy shots. Xolair is an antibody made not against an outside allergen but against the end of the IgE molecule that attaches to the mast cell. Therefore, Xolair will "tie up" all IgE molecules, no matter what they are made against and prevent them from becoming attached to mast cells. If the IgE cannot become attached to mast cells, the allergic reaction (and consequent injury or inflammation from the allergy) cannot take place.

 

Xolair can be given in full dose without the buildup of traditional allergy shots from the beginning and the risk of anaphylactic reactions to the shots is almost eliminated because we are not injecting something to which you are already allergic.

 

Xolair reduced the number and severity of asthma flares and allowed some reduction in medications.

 

Xolair is generally well tolerated with few side effects. Rare anaphylactic reactions (severe allergic reactions) were noted. Some people had local swelling and redness at the injection site. Other side effects were infrequent.

 

Malignancies (cancer) was found in 0.5% (5 out of 1000) of patients treated with Xolair compared with 0.2% (2 out of 1000) in a similar group of patients not on Xolair. The significance of this finding is not clear as the patients were only observed for 1 year and the numbers of patients were small for studying this type of side effect.

 

Xolair is expensive and nearly always requires preauthorization by your insurance company.

 

To start Xolair we must:

 

a. Determine if you have asthma of the type and severity to qualify for treatment with Xolair. This requires allergy tests and a lung function test and treatment with asthma medications.

b. Determine your total IgE level (a blood test).

c. Obtain approval from your insurance company. This requires completing a STATEMENT OF MEDICAL NECESSITY FORM and a PATIENT AUTHORIZATION FORM. These will be sent to one of five national specialty pharmacies.

The national specialty pharmacy will then contact you and begin to work with you to get through the red tape to get your Xolair prescription approved. If it is approved, the pharmacy will then deliver your prescription. If your insurance company does not approve Xolair, the specialty pharmacy will help with your insurance company's appeals process. They can also help with coverage for people who do not have insurance company coverage for Xolair.