As one of the country’s most common chronic diseases, chances are that most of us will know someone who lives with asthma.[ii]
Thanks to advances in treatments and care over the years, many are now able to live near-normal lives, but for some the ability to breathe normally remains a daily struggle.
In the words of one patient: “I have to schedule everything around my lungs.”
It is estimated 1 in 13 people in the U.S. have asthma, and of those, 5 to 10 percent have severe asthma, or asthma where a person is still struggling with symptoms and suffering asthma attacks despite taking medication as prescribed.
For many patients with uncontrolled or severe asthma, even simple tasks can become difficult. Many live in fear of their next attack, of not being able to breathe.
Not all asthma is the same
Asthma is a chronic lung disease characterized by inflammation and narrowing of the airways. This can lead to symptoms such as coughing, wheezing, breathlessness and chest tightness. When these symptoms become worse, it can lead to an asthma attack.
Developments in therapy mean that many patients are able to manage their disease with daily treatment. But for some this isn’t enough.
Research has shown that not all asthma is the same. Asthma can have a number of underlying causes and different types of inflammation. For some people, their inflammation may be triggered by environmental allergens, such as dust mites, pollen and molds.
When nature’s natural defenses work against us
All of us have eosinophils in our body. They are a type of white blood cell, produced in our bone marrow, and are an important part of our immune system. Found primarily in the gut, they fight parasites and, together with other cells, they form a complex network that helps protect us and keep us healthy.
But in some people, eosinophils can cause trouble. In around half of people with severe asthma, a raised level of eosinophils in their bloodstream can cause inflammation and swelling in the airways that deliver vital oxygen to the lungs, making it difficult to breathe and increasing the risk of an asthma attack.
Eosinophils are also a biomarker – this is a characteristic by which a particular disease can be recognized. By understanding how biomarkers work – and the part they play in the body – scientists can identify ways of developing treatment approaches that are tailored to the specific needs of individual patients.
This recognition has led scientists to develop biologics which are thought to treat severe asthma by normalizing levels of these white blood cells through targeting a particular protein. A simple blood test can help to identify patients who may be most likely to benefit from this precise approach.
As the understanding of asthma increases, scientists are looking at whether eosinophils can be used as a biomarker more broadly in asthma. They are also exploring if there are further biomarkers or identifiable characteristics known as ‘treatable traits’ that can help doctors adopt a more personalized approach to determining how best to help their patients.
Alongside eosinophil levels, there are many other features of asthma which seem to have an impact on how well a patient responds to different treatment approaches.
By looking at specific groups of asthma patients included in clinical trials, scientists are able to classify these ‘treatable traits’ giving them a better understanding of the disease features which may need to be addressed to improve outcomes for patients.
For example, some patients have limited airflow in their lungs meaning they may require medicines designed to open their airways, others have bacteria present and others cough. A patient’s weight may be a factor, as could be the level of resistance in their lungs.
All of these traits may be options for doctors to address to help minimize the impact of asthma on each individual patient. Instead of a ‘one-size fits all’ approach, it’s becoming more and more clear that different strategies are needed to establish good asthma control for as many patients as possible. And treatable traits may help doctors establish the most appropriate medicine for their patients, reducing the burden of their disease.
A precision-medicine future
For as long as patients are struggling with asthma, there is more for us to do.
Our understanding of this common but complex disease is evolving all the time. As we get better at unlocking its secrets, our hope is that treatable traits will help drive our medicines development, enabling a more personal approach and representing a big step forward for patients.#
[i] CDC. Asthma - Data and Surveillance - Asthma Surveillance Data. Available at: http://www.cdc.gov/asthma/asthmadata.htm. Last accessed July 2020
[ii] Asthma and Allergy Foundation of America. Asthma Facts and Figures. Available at: https://www.aafa.org/asthma-facts/. Last accessed July 2020