Biologics for the Management of Severe Asthma

For many patients with asthma, their asthma is controlled by identifying and avoiding triggers, taking a daily inhaled or oral controller medication, and using a quick-relief inhaler when symptoms develop. For some patients though, these medications are not enough to control their asthma. Recently, several new medications, known collectively as “biologics,” have been approved for the treatment of moderate-to-severe asthma. Biologics are unique in that they target a specific antibody, molecule, or cell involved in asthma. Because of this, they are known as “precision” or “personalized” therapy.

What is a biologic?
A biologic is a medication made from the cells of a living organism, such as bacteria or mice, that is then modified to target specific molecules in humans. For asthma, the targets are antibodies, inflammatory molecules, or cell receptors. By targeting these molecules, biologics work to disrupt the pathways that lead to inflammation that causes asthma symptoms.  

When would you need a biologic?
A biologic is used for patients who continue to have symptoms despite use of standard daily controller medications. Symptoms of poorly controlled asthma include frequent coughing, wheezing, or shortness of breath; waking up at night with difficulty breathing; requiring a fast-acting reliever medication, such as albuterol, several times a day or week; and recurrent hospital admissions, emergency room visits, or need for oral steroids for exacerbations. Before prescribing a biologic, your doctor should make sure you are taking your other controller medications as instructed, avoiding any potential triggers for your asthma, and treat any other associated medical conditions that could be making your asthma worse.  

What are the benefits of a biologic?
The primary benefit of biologics has been a decrease in the frequency of asthma exacerbations, including emergency room visits, hospitalizations, and need for oral steroids. Other benefits include reduced asthma symptoms, reduced dosage of other controller medication, and less missed school and work days. Biologics have been shown to improve quality of life for patients with asthma. Some biologics have been found to improve lung function in patients with severe asthma.  

What biologics are available for asthma?
Currently there are six approved biologics for asthma – omalizumab, mepolizumab, reslizumab, benralizumab, dupilumab, and tezepelumab – with several others currently in development. Omalizumab targets allergy antibodies known as IgE. Mepolizumab, reslizumab, and benralizumab all target pathways that affect eosinophils, a cell involved in allergic inflammation. Dupilumab targets a receptor for two molecules that drive allergic inflammation.  Tezepelumab blocks a chemical thought to be important in the initiation and persistence of airway inflammation. Your doctor will obtain screening tests, such as blood work or environmental allergen skin prick testing, to help decide which biologic would be best to treat your asthma. Omalizumab is approved for patients as young as 6 years old, while all the other biologics except for reslizumab are approved for patients as young as 12 years old. Reslizumab is approved for adults 18 and over.

How are biologics administered?
Unlike other medications for asthma, most biologics are currently administered in a doctor’s office either as a subcutaneous injection or as an intravenous infusion when beginning treatment. With some biologics, your doctor may want to observe you in the office between 30 minutes and two hours after administration. Many biologics may eventually be administered at home. The frequency of administration of each of these biologics are different, ranging from every two weeks to every eight weeks.

What are the side effects of biologics?
Overall, studies have shown biologics to be very safe. For one of these medications, omalizumab, there has been a small risk of anaphylaxis. In this case, your doctor will likely prescribe an epinephrine autoinjector to have in case of a severe reaction. With mepolizumab, your doctor may ask if you are at risk for certain types of parasitic infections or ask about your varicella vaccination status prior to administering. Other common side effects include soreness at the injection site, headache, sore throat, and fatigue.

How long do I need to be on a biologic?
There are currently no set recommendations on how long a patient should be on a biologic.  Guidelines recommend trialing the medication for at least four months to see if it is helping improve your asthma. Your doctor will work with you to decide how long to keep you on a biologic if your asthma is under good control.

How much do biologics cost?
Compared to other controller medications for asthma, biologics are more expensive, costing upwards of thousands of dollars per year or more. Given the cost, you and your doctor should work together to see if they are the best medications for you. You should also check with your insurance company to make sure they are covered prior to starting.