What Biologics Are Approved For Asthma?
So, at the present time, there are only five biologics approved for asthma. Here is a list of these biologics along with a brief description of how they work.
What are biologics?
To understand what they are, please read my article “What Are Biologics?” But, just briefly here, they are large particles extracted from living organisms. Their structures are large and not well understood. They need proteins from living cells to replicate. So, they are kept in environments that contain living tissues from animals, bacteria, or yeast. They are allowed to replicate until they exist in large quantities. They also must be stored in solutions in vials. So, they must be given by subcutaneous injections, or just under the surface of the skin. They are usually injected into the upper arm, thigh, or abdomen 1-2 times per month.
What do biologics do?
Asthma is an abnormal immune response. During this response, immune cells recognize harmless proteins you inhale as harmful. One example of a harmless protein is allergens, like dust mites.
Many asthma subgroups are regulated by a type of white blood cell (leucocyte) called T-helper 2 (Th2) cells. They are told to release chemicals (proteins) that encourage the production of antibodies. These antibodies are called dust mite IgE antibodies. This begins a series of chemical reactions that lead to the release of other chemicals (cytokines) such as IL13 and IL5.3
- IgE antibodies. They are specially trained to recognize allergens like dust mites. When you are exposed to dust mites, they bind to them. They then transport them to Th2 cells. In response, Th2 cells release many cytokines, two of which are IL13 and IL5.
- Interleukine 13 (IL13). They directly causes airway inflammation. This inflammation irritates airway cells in such a way that causes asthma symptoms.4 These symptoms almost immediately. But, they are generally easy to control by getting away from dust mites or by using your rescue medicine.3
- Interleukine 5 (IL5). They indirectly cause airway inflammation. They travel through your bloodstream to recruit eosinophils. They are also responsible for the maturation of eosinophils.3-6
- Eosinophils. They are another type of white blood cells. They usually arrive on the scene about 4-8 hours after you’re exposed to dust mites. They are responsible for more aggressive airway inflammation and more severe asthma symptoms. Eosinophilic inflammation is usually more severe and difficult to control.3 Normally, eosinophil levels rise during asthma attacks and decline after. But, in some with severe asthma, they may stay elevated. In this way, they may be responsible for severe asthma.
So, biologics block the effects of these chemicals. In turn, they suppress the abnormal immune response responsible for asthma. They “down-regulate” this immune response. So, in this way, biologics block the specific processes that cause asthma, as opposed to just treating symptoms. (1, Boehncke)
What biologics are approved for asthma?
The following are FDA approved for severe asthma.
- Omalizumab (Xolair). It’s an anti-IgE monoclonal antibody made by Novartis. It binds with IgE antibodies. When this happens, it prevents IgE from binding with allergens. It thereby prevents IgE from doing it’s job. It was approved by the FDA for severe allergic asthma in 2003. It’s administered as a subcutaneous injection every 2-4 weeks.7-9>
- Mepolizumab (Nucala). It’s an anti-IL5 monoclonal antibody made by GlaxoSmithKline. It binds with IL5. When this happens, it prevents IL5 from binding with other cells. It thereby prevents IL5 from causing the maturation of and recruitment of eosinophils. It prevents IL5 from doing it’s job. It was approved by the FDA for severe asthma with an eosinophilic phenotype in 2015. Examples of eosinophilic phenotypes include eosinophilic asthma and Churg Strauss Syndrome. It’s administered as a subcutaneous injection once a month in your upper arm, thigh, or abdomen.10
- Benralizumab (Fesenra). It’s an anti-IL5 monoclonal antibody made by AstraZeneca. It binds with the receptor sites IL5 is attracted to. These receptor sites are on cells like eosinophils. So, it doesn’t let IL5 bind with eosinophils. In this way, it prevents IL5 from causing the maturation of or recruitmenet of eosinophils. It thereby prevents IL5 from doing its job. It was approved by the FDA for severe asthma 2017. It’s geven by injection once a month for three doses, then every 8 weeks.11
- Reslizumab (Cinqair). It’s an anti-IL5 monoclonal antibody made by Teva. It binds with IL5. When this happens, it prevents IL5 from causing the maturation of or recruitment of eosinophils. It also prevents IL5 from doing its job. It was approved by the FDA for severe asthma with an eosinophilic phenotype in 2016. It’s given by intravenous infusion. This means you have to have an IV inserted into your arm. The medicine is then injected into your IV. It should be given over a period of 20-50 minutes. It’s given once a month.12
How are biologics used?
They are only recommended for severe asthma as adjunct medicines with traditional asthma medicines. They must be given by infusions. This means that they must be injected into a vein. This must be done by a medical professional such as a nurse. This must occur 2-3 times a month, depending on the biologic used. And, unfortunately, due to the complex nature of making them, biologics tend to be very expensive. Still, they are neat options when needed. They are another neat option in the ongoing quest to help every asthmatic obtain ideal asthma control.
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