Retrospective Study on the Association of Biomarkers With Real-world Outcomes of Omalizumab-treated Patients With Allergic Asthma
Clinical Therapeutics, 2019
Purpose
Biomarkers, including blood eosinophils (EoS) and fractional exhaled nitric oxide (FeNO), may affect omalizumab outcomes in allergic asthma, but evidence in the literature remains mixed. This study assessed omalizumab outcomes in real-world patients with allergic asthma stratified by pretreatment biomarker levels.
Methods
Patients with allergic asthma aged ≥12 years initiated on omalizumab with ≥12 months of data after index were identified in the Allergy Partners electronic medical records (2007-2018). Patients with ≥1 diagnosis of chronic obstructive pulmonary disease in combination with ≥10 pack-years of smoking, cystic fibrosis, Alpha-1 antitrypsin deficiency, bronchiectasis, interstitial lung disease, and sarcoidosis in the 12 months before or after index were excluded. Patients were stratified by pretreatment EoS (≥/<300 cells/μL) and FeNO (≥/<25 parts per billion). Outcomes, including Asthma Control Test (ACT) scores, forced expiratory volume in 1 second (FEV1), and FEV1 as a percentage of predicted value (FEV1% predicted), were compared using generalized estimating equations at 6 and 12 months after versus before index date in stratified patients with outcome measures available at both time periods.
Findings
A total of 77 and 86 patients were stratified into the high and low EoS strata, respectively, and 56 patients into each of the intermediate-high and low FeNO strata. Compared with 6 months before index, mean difference (MD) in ACT scores at 6 months after index reached the minimally important difference of ≥3 points in high (MD = 3.75; 95% CI, 2.05-5.45) and low (MD = 4.56; 95% CI, 2.86-6.26) EoS, as well in the intermediate-high (MD = 3.75; 95% CI, 1.95-5.55) and low (MD = 3.55; 95% CI, 1.53-5.57) FeNO strata. Statistically significant improvements in mean FEV1 were observed in the high EoS (MD = 0.22 L/s; 95% CI, 0.08-0.35 L/s) and intermediate-high FeNO (MD = 0.13 L/s; 95% CI, 0.03-0.24 L/s) strata but not in the lower strata. In terms of mean FEV1% predicted, a statistically significant improvement was observed in high EoS stratum (MD = 4.95%; 95% CI, 0.60%-9.30%). Results that compared 12 months after versus before index date were similar.
Implications
Omalizumab was associated with statistically significant improvements in ACT scores largely reaching or exceeding minimally important difference across biomarker levels and with a statistically significant improvement in lung function more evident in high biomarker strata. Although response varied by biomarkers for some outcomes, all strata indicated improvements on ≥1 measure. Real-world patients with allergic asthma could benefit from omalizumab regardless of pretreatment biomarker levels, suggesting that pretreatment biomarker levels might not inform response.
Authors
Kavati A, Zhdanava M, Ortiz B, Lecocq J, Schiffman B, Pilon D, Ho H, Lefebvre P, Stone B