This article is part of MPR‘s coverage of the American Thoracic Society International Conference, taking place in Dallas, Texas. Our staff will report on medical research related to asthma and other respiratory conditions, conducted by experts in the field. Check back regularly for more news from ATS 2019.

DALLAS — Compared with patients who took a placebo, patients with moderate to severe asthma treated with omalizumab demonstrated lung function improvements within the combination subgroups of high/low eosinophil levels and high/low forced expiratory volume in 1 second (FEV1) reversibility, according to research presented at the American Thoracic Society’s International Conference, held May 17 to 22, 2019, in Dallas, Texas.

Data from the 16-week inhaled corticosteroid dose-stable stage of two phase 3 omalizumab trials were used to evaluate the findings of recent pooled post hoc analyses that show lung function improvement after 16 weeks in patients with moderate to severe allergic asthma treated with omalizumab compared with placebo. Improvements shown in the post hoc analyses were more pronounced in the following subgroups: higher eosinophil levels, poorer baseline percent predicted FEV1, and higher FEV1 reversibility.

The current study sought to extend the findings within the combination subgroups of high (≥150/µL and ≥300/µL) and low (<150/µL and <300/µL) eosinophil levels and high (>20%) and low (≤20%) FEV1 reversibility. In both studies, eosinophil levels were measured at baseline, and reversibility was assessed at screening.

Of the total adults and adolescents age ≥12 years (N=1071), 542 were randomly assigned to receive omalizumab and 529 to receive a placebo. At week 16, participants with high FEV1 reversibility and eosinophils had the following least square mean (LSM) change in FEV1 from baseline for omalizumab vs placebo: 185.7 (95% CI, 104.6-266.8) vs 105.6 (95% CI, 25.4-185.8) mL. The LSM change from baseline in FEV1 for participants with low FEV1 reversibility and eosinophils for omalizumab vs placebo was 69.2 (95% CI, 15.6-122.8) vs -40.3 (-101.5 to 21.0) mL. Participants with high/low and low/high FEV1 reversibility/eosinophil levels (ie, >20%/<300/µL or ≤20%/≥300/µL) generally had LSM changes in FEV1 from baseline between those of the low reversibility/low eosinophil and high reversibility/high eosinophil subgroups. Less pronounced but similar LSM changes from baseline in FEV1 with omalizumab and placebo were seen for patients with FEV1 reversibility >20% vs ≤20% and eosinophil levels ≥150/µL vs <150/µL.

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Study investigators concluded, “Findings from this post hoc analysis support previous analyses by demonstrating improvements in lung function after 16 weeks in patients with moderate/severe allergic asthma treated with omalizumab compared with placebo within combination of subgroups with high/low reversibility and high/low eosinophil levels. The significant treatment-specific improvements in pulmonary function across these subgroups of patients highlight the therapeutic effect of omalizumab in patients who remain uncontrolled on current therapies.”

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Casale TB, Chipps BE, Haselkorn T, et al. Effect of reversibility and eosinophils on lung function improvement with omalizumab treatment: pooled analyses in patients with moderate or severe allergic asthma. Poster presented at: the American Thoracic Society’s International Conference; May 19, 2019; Dallas, TX. Abstract 1270/P658.

This article originally appeared on Pulmonology Advisor