Phenotyping and Endotyping in COPD: The Search for Targeted Therapies. Written by Dr Emma McNally, Respiratory SpR and Professor Eddie Moloney, Respiratory Consultant,
Tallaght University Hospital

Chronic obstructive pulmonary disease (COPD) is a heterogeneous condition. Patients display various pathophysiological and clinical features. These include chronic predominantly neutrophilic inflammation of the airways and irreversible airflow obstruction. This leads to emphysematous destruction of lung tissue and deterioration of pulmonary function. The most common cause is cigarette smoking. Genetics, childhood lung development and environmental exposures also play a role. The clinical presentation ranges from exertional dyspnea and respiratory tract infections, to progressive severe exacerbations of the disease. However, they may require hospitalisation, reduced exercise tolerance, respiratory failure, and associated co morbidity including pulmonary hypertension, sleep disordered breathing, depression and an increased risk of lung cancer. But it remains the third leading cause of death worldwide.1

To date, treatment has focused predominantly on guideline directed therapy primarily concentrated on symptom management and treatment of exacerbations with inhaled bronchodilator and corticosteroid therapy, an often chronic reliance on oral corticosteroids and frequent antibiotics. Adjunctive, non-pharmacological therapies including oxygen prescription, non-invasive ventilation, and pulmonary rehabilitation are also implemented. Although the identification of COPD endotypes, may allow for targeted treatment strategies directed towards specific biological pathways.

Conclusion

COPD is phenotypically heterogeneous. Therefore an improved understanding of the underlying biological mechanisms which drive the chronic inflammation associated with the disease is required to aid the identification of endotypes. In recent years, progress has been made with the recognition of eosinophilic COPD as an endotype and its inclusion in treatment guidelines. Although, currently there are number of promising areas of research into the identification of additional endotypes and potential biomarkers which will need refinement and longitudinal assessment of their viability and stability over time as therapeutic targets.

References on request

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