Response to Omalizumab in Black and White Patients with Allergic Asthma

Background: Higher asthma burden is more likely to be experienced by Black than White patients. In clinical research, underrepresentation of minority populations is observed. Objective: To estimate response to omalizumab in Black and White patients in North America with moderate to severe asthma. Methods: Data from placebo-controlled (EXTRA) and single-armed (PROSPERO) omalizumab studies were used for this post hoc analysis. We used a Poisson regression model to examine exacerbation rates. An analysis of covariance model was used to estimate placebo-corrected change in FEV₁ and Asthma Quality of Life Questionnaire (AQLQ) by racial group. Results: This analysis included 631 White and 176 Black patients from EXTRA and 567 White and 130 Black patients from PROSPERO. In EXTRA, placebo-corrected exacerbation rate reductions (relative rate change [95% confidence interval], 22.6% [2.0-38.9%] vs 22.0% [−18.0% to 48.4%]) and FEV₁ improvements were similar for White and Black patients. There was a trend toward greater AQLQ improvements for Black versus White patients (least squares mean treatment differences: 0.0 vs 0.3, 0.6 vs 0.4, and 0.6 vs 0.2 at weeks 16, 32, and 48, respectively) throughout the study. In PROSPERO, on-study exacerbation rates (0.76 [0.65-0.88] vs 0.77 [0.56-1.10]) and AQLQ improvements (least squares mean change from baseline: 1.2 vs 1.2 and 1.3 vs 1.2 at month 6 and end of study, respectively) were similar for White versus Black patients. A trend toward greater FEV₁ improvement was observed in White versus Black patients throughout the study. Conclusions: This analysis of EXTRA and PROSPERO suggests that Black and White patients with moderate to severe asthma experience similar improvements in exacerbations, FEV₁, and AQLQ with omalizumab.