Understanding disease phenotype is crucial in the fight against asthma

As Asthma and Allergy Awareness Month draws to a close, it’s a good time to take stock of some sobering statistics regarding this chronic condition. 

• More than 25 million Americans have asthma. This equates to about 1 in 13 people, including 8% of adults and 7% of children.¹
• Asthma accounts for 9.8 million doctor’s office visits, 178,530 hospital discharges, and 1.6 million emergency room visits annually.²
• Asthma costs the U.S. economy more than $80 billion annually in medical expenses, deaths, and days missed from work and school.³
• Instances of asthma have trended upwards since the 1980s, making it one of the country’s most common and costly diseases.

There is no cure for asthma, making prevention and treatment of asthma attacks the primary means for battling the disease. Asthma is also a very multifaceted condition, with different characteristics causing the disease or triggering acute attacks in different patients. One important step to reduce complications arising from asthma is to match the most effective treatment with the disease phenotype present in a patient. 

Lab data reveals asthma phenotype insights

The following lab tests can indicate the type of asthma with which a patient is afflicted:

Eosinophil Count: Eosinophils are one of the five types of white blood cells (leukocytes). These disease-fighting cells are involved in the body’s immune response against multicellular organisms and other infections. Typically, eosinophils represent a small percentage of a person’s overall white blood cell count (~2%). However, during an infection, eosinophils (and their percentage in the leukocyte mix) increase. Asthmatic patients that have a consistent, abnormally high eosinophil count (>= 300 cells/uL), are considered to have an eosinophilic phenotype of the condition. High levels of eosinophils cause inflammation and can exacerbate a patient’s asthma, causing dangerous complications. 

Immunoglobulin E (IgE): A person with an allergy has an immune system that overreacts to a certain allergen by producing antibodies called Immunoglobulin E (IgE). These antibodies travel to cells that release chemicals, causing an allergic reaction. Total IgE testing indicates an overactive immune system, while substance-specific IgE testing determines the specific allergens causing the immune response. Patients with high IgE levels (>= 30 IU/mL) and asthma can have their symptoms exacerbated by the same allergens that produce an allergic response. 

Neutrophil Count: Neutrophils are the most plentiful of the five types of white blood cells (leukocytes), ranging from ~50-75% of the total leukocyte count. As with eosinophil cells, neutrophil counts can rise when the body is exposed to an antigen. Neutrophils provide the first line of defense in the immune system to bacterial or fungal infections, but are also involved in the body’s response to allergies and asthma. High neutrophil levels could indicate a neutrophilic asthma phenotype. 

Not all asthma is the same

The importance of understanding asthma phenotype is relatively straightforward for life science companies. Physicians use lab testing to match the best therapy to appropriate patients. Pharmaceutical brand teams can study which physicians diagnose and treat asthma patients and then compare how often those physicians test asthma patients to determine if they can support providers with education on testing’s importance. Or, they can use the above-mentioned lab tests, combined with prescription information for de-identified patients, to identify physicians who are about to make treatment decisions for patients who could possibly benefit from treatment alternatives. For example, if a patient’s existing small molecule treatment regimen is proving ineffective and they have consistently elevated eosinophil counts, then a biologic therapy could help improve symptoms. Similarly, when bringing a new asthma drug to market, identifying patients by their asthma phenotype can help you target your therapy and help the patients that need it most.  

The lab tests referenced in this blog can all be selected using the Cohort Designer for Prognos Factor. See how this and other criteria can help you build a custom patient data population to achieve your pharmaceutical product goals. Get a free demo today. 

1. Centers for Disease Control and Prevention. (2020). 2019 National Health Interview Survey data. U.S. Department of Health & Human Services
2. National Center for Health Statistics. (2017). National Ambulatory Medical Care Survey (2010-2017). U.S. Department of Health and Human Services, Centers for Disease Control and Prevention
3. Nurmagambetov, T., Kuwahara, R., & Garbe, P. (2018). The Economic Burden of Asthma in the United States, 2008–2013. Annals of the American Thoracic Society, 15(3), 348–356