Steroid Resistance and Severe Asthma
There are 26 million people in the United States living with asthma; of those, 5 to 10% have severe asthma. Asthma is classified as severe when it doesn’t respond to medications that work for the average asthma case. Although it’s just a small fraction, this subgroup is responsible for half of the $56 billion dollars spent in asthma-related healthcare costs each year. People with severe asthma have more frequent flare-ups, missed days from work, and hospitalizations, and it can be challenging to find a medication that works to control their condition, since even inhaled corticosteroids (ICS) may not be effective. So, when steroids don’t work for severe asthma, how can you treat it?
Asthma is considered an inflammatory condition that causes the airways to swell, constrict, and produce excess mucus. Steroids, due to their anti-inflammatory properties, can effectively treat this in the majority of asthma cases. Yet for a small group of people, steroids either work poorly, or a very high dose is needed to control symptoms. This is known as steroid resistance, and it’s quite common for people with severe asthma.
In recent years, researchers have looked into the biology of asthma, learning more about what’s happening at the cellular level. They’ve discovered not all asthma is the same. For those with severe asthma, they’ve found different things can occur within the body to cause it to become resistant to steroids, from genetics to the way the cells communicate. Thankfully, considerable progress has been made in treating severe asthma, especially when it comes to gearing the right treatment to the right patient.
One bright light has been the development of biologics, a class of drugs made from living organisms. These medications can target specific points in the body’s inflammatory response, lessening severe asthma symptoms. They include:
Anti-interleukin-5 (IL-5) injections: Reslizumab (Cinqair) and mepolizumab (Nucala) can be used to treat severe asthma caused by an excess of eosinophils, a type of white blood cell that leads to inflammation. These medicines reduce eosinophils and help prevent asthma exacerbations.
Immunoglobulin E (IgE) inhibitors: When an allergic reaction causes severe asthma symptoms, omalizumab (Xolair) can help. This injection blocks IgE, an antibody that’s produced when you’re exposed to allergens like pet dander and dust mites, reducing your risk of having an asthma attack.
Bronchial thermoplasty is a different type of treatment for severe asthma. Completed as a series of short outpatient procedures, it uses heat to decrease the amount of muscle in the airway, making it harder for the airway to contract. Patients undergoing bronchial thermoplasty report a decrease in the number of asthma attacks and a much lower incidence of emergency room visits.
Research continues to reveal other underlying mechanisms that contribute to steroid-resistant asthma. For example, an exciting discovery recently occurred at the University of Melbourne in Australia when an enzyme that plays a role in our bodies’ circadian rhythms was also noted to disrupt steroid sensitivity in the lungs. With this knowledge, researchers hope to develop a new inhaled asthma treatment that blocks this specific enzyme in the lungs, overcoming steroid resistance.
If you’re struggling with frequent asthma flares, even when you’re taking your medications correctly and avoiding known triggers, talk to your doctor. Many things need to be ruled out first, but if you’re diagnosed with severe asthma, be sure to explore all of your treatment options.