Study of Asthma Phenotypes and Pharmacogenomic Interactions by Race-Ethnicity (SAPPHIRE)

Inhaled corticosteroids (ICS) are considered first-line therapy for the management and control of patients with persistent asthma. Use of inhaled steroids has been associated with improved lung function, diminished symptoms, and fewer exacerbations. However studies show considerable inter-subject variability in ICS response. It has also been estimated that corticosteroid resistance accounts for half of all asthma-related health care costs. Therefore, identifying factors associated with ICS response is both clinical and economically important. African-American patients have been understudied with respect to genetic predictors of asthma controller medication response, and to date there have been no sufficiently powered genome-wide association studies of ICS treatment response among African American individuals with asthma. This issue is of particular importance, since African-American individuals are disproportionately affected by asthma-related complications. In this proposal, we seek to identify novel genetic loci associated with ICS treatment responsiveness (defined by the change in Asthma Control Test score) among African American individuals treated with beclomethasone dipropionate (BD) for 6 weeks. We will attempt to validate loci identified in the discovery set by 1) reassessing these variants for their interaction with ICS treatment on asthma exacerbations in a separate group of African American individuals with asthma, and 2) by reexamining the genetic association with change in asthma control among similarly treated (i.e., treatment with 6 weeks of BD) European Americans with asthma.