Differential effect of omalizumab on pulmonary function in patients with allergic asthma with and without chronic rhinosinusitis

Background: Omalizumab, an anti-immunoglobulin E monoclonal antibody, is approved by the U.S. Food and Drug Administration for the management of patients with allergic asthma and with refractory disease, and has also proven beneficial in the management of selected patients with chronic rhinosinusitis (CRS). The common airway model indicates that patients with both allergic asthma and CRS may be more challenging to manage clinically. This is the first study to evaluate the response of omalizumab in patients with asthma and CRS versus those with asthma alone. Objective: To compare pulmonary function test (PFT) responses in omalizumab-treated patients with asthma with CRS with omalizumab-treated patients with asthma without CRS. Methods: This was a retrospective case-control study at a tertiary university clinic. Between 2007 and 2014, a total of 259 patients with allergic asthma had been prescribed omalizumab for asthma. Outcome measures were absolute, and the percentage changes in PFT results were compared with the baseline. Results: Overall, 81 patients had serial PFT results available for evaluation, among whom 59 (73%) had CRS. Average treatment duration was 27.2, 27.7, and 25.8 months for the entire sample, for patients with asthma and CRS, and for patients with asthma and without CRS, respectively. Overall, PFT metrics improved across all parameters (forced expiratory volume in 1 second, forced vital capacity, forced expiratory volume in 1 second to forced vital capacity ratio, and forced expiratory flow 25-75%). Significant improvement (p < 0.05, paired t-test) was observed for three of four metrics in patients with comorbid CRS but in none of these parameters in patients without CRS. Conclusion: Patients with allergic asthma who were treated with omalizumab manifested some improvement in PFT scores. CRS may add to the overall symptom burden experienced by patients with asthma, especially in those with increasing severity, but comorbid CRS did not adversely impact the therapeutic potential of omalizumab. In fact, the benefit of omalizumab was more likely to be observed in patients with asthma and with CRS than in patients with asthma and without CRS.