Omalizumab response in patients with asthma by number and type of allergen.

BACKGROUND: The anti-immunoglobulin E therapy, omalizumab, improves asthma control and reduces exacerbations in patients with moderate-to-severe allergic asthma. However, it has been suggested that omalizumab should be reserved for highly allergic patients with multiple allergen sensitivities or perennial-only sensitivities.

OBJECTIVE: To examine impact of allergy burden, including number and type of allergen sensitivities, on omalizumab response in a real-world setting.

METHODS: This post hoc analysis evaluated a subset of omalizumab-treated patients from the Prospective Observational Study to Evaluate Predictors of Clinical Effectiveness in Response to Omalizumab (NCT01922037) who had completed 13 allergen assessments (N=478). Patients were classified by allergen burden (nonsensitized, 1, 2-4, or ≥5 allergen sensitivities) and type of allergen (nonsensitized, seasonal, perennial, or both). Outcome measures included exacerbation rate vs previous year and improvements in lung function and Asthma Quality of Life Questionnaire (AQLQ).

RESULTS: Comparable adjusted exacerbation rates were observed after omalizumab initiation, regardless of number or type of allergen sensitizations (0.56-0.85/y). Improvements in forced expiratory volume in 1 second from baseline at months 6 (0.03-0.09 L) and 12 (-0.08 to 0.08 L) were also similar across subgroups. Least squares mean change in AQLQ from baseline at months 6 (1.0-1.2) and 12 (1.1-1.4) was comparable across patient subgroups, and similar percentages of patients achieved AQLQ minimal clinically important difference of at least a 0.5-point improvement at month 6 (71%-75%), which was maintained or improved to month 12 (71%-89%). In all analyses, 95% confidence intervals overlapped.

CONCLUSION: Overall findings suggest that patients with allergic asthma achieved comparable improvements across distinct outcome measures after omalizumab therapy in a real-world setting, regardless of number and type of allergen sensitizations.

TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01922037.