Treatable Traits Approach in Asthma Management

Asthma, a common inflammatory disease that globally affects over 300 million people, was once taken as a single disorder but now proves to be several complex but relevant conditions. And these conditions, mainly divided into Type 2 inflammation and non-type 2 inflammation, have different underlying triggers based on their biological mechanisms.

For instance, Type 2 inflammation includes allergic asthma and eosinophilic asthma, in which allergic asthma is an inflammatory result of allergens like cockroaches, pollen, dust mites, mold, and pet dander. The immune system responds to such stimuli by overproducing antibodies, or known as Immunoglobulin E (IgE). Extremely high levels of IgE can lead to inflammation of the lungs' airways and cause breathing problems, so allergen-specific IgE has been taken as the predominant inflammatory biomarker for allergic asthma. As for eosinophilic asthma, it's characterized by high levels of white blood cells known as eosinophils, with a symptom of swelling throughout the entire respiratory tract, from the nasal region to the tiniest airways in the lungs.

Though major improvements have been made in treating asthma in the early 21^st century with the introduction of inhaled corticosteroids to treat eosinophilic airway inflammation. However, these improved asthma outcomes are now gradually being weakened along with the stagnation of adopting new assessment techniques and asthma biomarkers in practice as well as sluggish development in new drug discovery.

Increasing deaths worldwide and ongoing acute attacks and symptoms are demanding new approaches and therapies in asthma and other airway disease management. Researchers propose to apply a precision medicine approach to asthma treatment, which has significantly improved the outcomes of many other respiratory diseases and cancer. One of the precision medicine approaches, treatable traits, has been advised to manage obstructive airway diseases, including asthma. In this strategy, asthma patients are individually assessed to identify a specified set of clinically important and treatable problems, which could be identified as therapeutic targets by phenotypes or endotypes through a validated biomarker, after which an individualized treatment program is developed and implemented based on this multidimensional assessment.

The treatable traits approach can improve clinical asthma outcomes for individuals and minimize unnecessary side effects. Similar to other disease areas, multidimensional assessment could be included in asthma treatments to identify disease complications, and just like the diagnostic development of cancer, biomarkers would be involved to guide  the diagnosis and treatment of asthma. Indeed, the treatable traits approach is applicable even when a diagnosis of asthma or chronic obstructive pulmonary disease (COPD) is confirmed. An advantage of the treatable traits method is a tolerance of diagnostic imprecision.

Compared with patients with usual care, the clinical trials result of both asthma and COPD based on the treatable traits approach has shown significant improvements in patients' health‐related quality of life and biological outcomes, as well as reductions in primary care visits. The treatable traits approach is now a well developed and described management approach and moves beyond diagnostic labels for asthma and other airway diseases, but the challenge is to apply it to clinical practice and how to communicate this approach to patients since patients with asthma and COPD would prefer to objective tests for the diagnosis and monitoring of their disease and direct feedback from their clinicians.