Personalized medicine for asthma: Are we there yet?

Asthma has generally been defined as a chronic disorder of the lung, with variable airway obstruction, wheeze/cough, and an underlying inflammatory process. However, considerable heterogeneity exists within the population of patients with asthma-like symptoms. Clinically, asthma is being categorized into eosinophilic, neutrophilic, atopic, non-atopic, early onset, and late onset; and aspirin- or exercise-induced in cases with known triggers. [1] The disease is currently recognized as a complex condition with variable severity, natural history, and response to treatment. Treating asthma based on phenotypes that group observable characteristics, with no direct relationship to the disease mechanisms is suboptimal, given the variability in treatment response. Endotyping, which refers to defining subpopulations of a disease based on molecular mechanisms or treatment response has shown some success in designing a more effective treatment scheme.