Anti-IgE antibody treatments are a newer type of preventive drug therapy used to reduce asthma symptoms caused by allergies. Anti-IgE antibody treatments disrupt the sequence of events that causes an allergic reaction – known as the allergic cascade. The drugs are taken through an injection every two to four weeks and work by stopping the release of histamine, which causes allergy symptoms.

Anti-IgE antibody treatment is available by prescription only. There is currently only one type of anti-IgE antibody treatment available in the United States. Future treatments may someday be available for the treatment of allergy conditions unrelated to asthma, such as allergic rhinitis and food-induced anaphylaxis.

Because they represent a new form of treatment, many people are hopeful that anti-IgE antibody drugs will soon be able to completely prevent allergic reactions from taking place. Today’s anti-IgE antibody treatments are effective at reducing the number and severity of asthmatic reactions, but they do not cure the condition. Most physicians use the treatment in people with moderate to severe asthma, and only when corticosteroid treatments are not sufficient to control asthma symptoms.

Research into anti-IgE antibody treatments is ongoing and many of the long-term side effects of this type of therapy are still unknown. Patients should always discuss this type of treatment with their physicians before use.

Many people with asthma find their conditions are exacerbated by inhaling certain allergens (e.g., pollen, mold, dander, dust mites). In susceptible individuals, the allergic reaction results in swelling in the nasal passages and airways, making it hard to breathe and triggering an asthma attack. The inflammation that takes place during this process is caused by the release of IgE antibodies into the bloodstream.

When an allergen enters the body of an allergic individual – through the respiratory tract (nose, throat and lungs) in the case of allergic asthma – it stimulates the immune system to prepare to repel the invader. This is a process known as sensitization. T-cells recognize the allergen as a threat and send a signal to certain B-cells, which begin to produce IgE antibodies. The IgE antibodies that are produced are specific to that allergen, and will not react with other types of allergens. In this way the IgE antibodies allow the immune system to recognize a particular allergen if it is ever encountered again.

If a person does encounter an allergen after being sensitized to it, the immune system responds with a full-blown allergic reaction. The IgE antibodies, which have attached themselves to mast cells and basophils throughout the body, trigger these cells to release inflammatory chemicals such as histamine into the bloodstream. The resulting inflammation these chemicals create in the airways and nasal passages can trigger an asthma attack in susceptible individuals.

Anti-IgE antibody treatments work by interrupting the normal function of IgE in the allergic cascade. This treatment is the first biological therapy approved by the U.S. Food & Drug Administration (FDA) to treat moderate to severe allergy-related asthma. It is also called a monoclonal antibody because the drug introduces a specific type of antibody to the body.

The anti-IgE antibody treatment prevents the body's IgE antibodies from binding to the mast cells and basophils. The anti-IgE antibodies interfere with the receptors on the mast cells and basophils so that IgE antibodies cannot attach to these cells. This effectively blocks any interaction between IgE antibodies and mast cells or basophils, and prevents the subsequent release of inflammatory chemicals. The antibodies also combine with IgE in the blood, which may help the body get rid of them.

Anti-IgE antibody treatments are given through regular injections, usually one every two to four weeks. The injection is usually performed under a physician’s supervision, though some individuals who require more frequent injections may self-administer the treatment.

Dosage should be determined by a physician, who will take into account the patient’s size and natural level of IgE (as measured by a blood test). The size of the required dose will determine whether a patient will receive one, two or three injections per dose. Individuals who require multiple injections per dose will receive each shot in a separate place on the body. 

Asthma symptoms may not immediately improve after taking an anti-IgE antibody treatment, and it often takes several treatments for the therapy to take full effect.  Anti-IgE treatments may prove to be effective at reducing reactions to allergens, but they are not currently approved for use as an allergy treatment.

Anti-IgE treatments have been available in the United States for only a short period of time as the FDA only approved the first anti-IgE antibody treatment (omalizumab) in 2003. For this reason, it is unclear what the long-term effects of the treatment may be. At this point, many physicians use the therapy only for asthma that is not adequately controlled with corticosteroids. Any individuals interested in taking this treatment should discuss the pros and cons of its use with their physician.

Anti-IgE antibody therapies have the potential to be a revolutionary new type of treatment for allergies and allergic asthma. Because they can prevent allergies from ever taking place, future therapies could make the diagnosis of specific allergy conditions unnecessary. Many different clinical studies are currently taking place to evaluate the possible uses of these drugs.

It is important to note that anti-IgE antibody treatments are designed to be used in conjunction with inhaled corticosteroids. It is not a substitute for the other asthma medications a patient has been prescribed. Therefore, patients should not discontinue the use of, or change the dose of, their other asthma medication unless a physician advises them to do so.

There is currently only one type of anti-IgE antibody treatment available in the United States. The U.S. Food and Drug Administration (FDA) approved omalizumab for use in asthma treatment in 2003. However, other anti-IgE treatments are being developed by drug manufacturers. Omalizumab is also being studied as a possible treatment for various allergic conditions, including peanut allergies.

Less common side effects include:

• Hives, itching or skin rash.
  
  

  

• Swelling of the face, throat, tongue or lips (angioedema).
  
  

  

• Headache.
  
  
• Dizziness.
  
  
• Ear pain.
  
  
• Leg pain or arm pain.
  
  
• Joint pain.
  
  
• Fatigue.
  
  
• Malignancy (an abnormal growth that tends to invade and damage surrounding tissues). Several types of cancer were seen in patients receiving anti-IgE antibody treatment in clinical studies.  
  
  
• Anaphylaxis. A severe allergic reaction affecting two or more body systems. Without prompt emergency treatment, anaphylaxis can quickly progress to life-threatening anaphylactic shock, which is characterized by difficulty breathing due to constricted airways and a dangerous drop in blood pressure. Symptoms of anaphylaxis may include:
  
  
  • Hives
  • Severe shortness of breath
  • Tightening in the chest or throat
  • Swelling of the throat or tongue (angioedema)
  • Choking
  • Loss of consciousness

Anaphylactic reactions to omalizumab typically begin within two hours of receiving the drug. However, patients may experience a delayed reaction occurring anywhere from two hours to 24 hours or longer after receiving the drug.

Individuals who suspect that they are experiencing an anaphylactic reaction should seek emergency medical attention immediately. Those experiencing less serious side effects should consult their physician.

Research into anti-IgE antibody treatments is ongoing, and many of the long-term side effects of this type of therapy are still unknown.

Patients should consult their physicians before taking any additional prescriptions, over-the-counter medications, nutritional supplements or herbal medications. There are no known drug or food interactions with anti-IgE antibody treatments. However, individuals who discontinue corticosteroid treatment when starting an anti-IgE antibody treatment should not stop taking corticosteroids abruptly. Corticosteroid use should be discontinued gradually and under a physician’s supervision.

The only anti-IgE antibody medication currently on the market in the United States is omalizumab. This medication has been classified by the U.S. Food and Drug Administration (FDA) in pregnancy risk category B. This means clinical testing in animals did not demonstrate any toxic effects on the animal fetuses. Though there has not yet been testing in humans, the FDA believes this medication should not interfere with human pregnancy. Pregnant women should always discuss their condition with their physicians before taking any medication.

It is still unclear whether omalizumab can be passed on to nursing children during breastfeeding. Natural occurring IgE is secreted in human milk, and many physicians believe this means it is likely that omalizumab can also be present – though probably in a highly diluted state. Though there is no evidence that omalizumab is capable of harming a nursing child, breastfeeding mothers should use caution and speak with their physicians before taking this medication.

Preparing questions in advance can help patients to have more meaningful discussions with their physicians. Patients may wish to ask their doctors the following questions about anti-IgE antibodies:

1. Would anti-IgE antibodies be effective at treating my condition?
   
   
2. What side effects might I develop while receiving anti-IgE antibody treatment?
   
   
3. How often will I require an injection? How long will the treatment continue?
   
   
4. Will using anti-IgE antibodies allow me to come into contact with allergens I currently avoid?
   
   
5. Will you be giving me the injection or will I be injecting myself?
   
   
6. Will I experience pain during the injection? What about after?
   
   
7. When should I begin noticing an improvement?
   
   
8. Will the results I experience from this treatment be permanent?
   
   
9. Is it safe for me to stop taking my other asthma medication if I feel the anti-IgE antibodies are working and I have not experienced any asthma symptoms?
   
   
10. Can I take anti-IgE antibodies if I am pregnant or breastfeeding?