This article is part of Pulmonology Advisor‘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 — Low-dose beclomethasone/formoterol maintenance and reliever therapy (MART) has demonstrated better efficacy than beclomethasone/formoterol plus salbutamol in reducing the exacerbation rate in patients with moderate to acute asthma, with the amount of eosinophilic airway inflammation significantly correlating with efficacy. This research was recently presented at the American Thoracic Society International Conference, held May 17-22, in Dallas, Texas.
This post hoc subgroup analysis included 852 participants who received MART and 849 participants who received salbutamol reliever therapy. Both groups had the same inhaled corticosteroid (ICS)/long-acting β2-agonist (LABA) maintenance regimen. The percentage of eosinophil in blood at baseline or absolute blood eosinophil count (BEC) in cells/μL was used to assess risk for exacerbation. Fixed BEC cutoff values were used to stratify analyses and consisted of <150, 150-300, and >300 eosinophils/μL or percentage subgroups of the median value cutoff or quartiles.
Individuals with higher baseline BEC had lower exacerbation rates. Compared with the ICS/LABA maintenance group plus salbutamol reliever, MART was strongly associated with 30% fewer exacerbations in patients with BEC of 150-300 cells/μL (risk ratio [RR], 0.705 [95% CI, 0.506-0.983]; P =.039) and 46% fewer exacerbations in patients with >300 cells/μL (RR 0.541 [95% CI, 0.397-0.738]; P <.001). In participants who received MART with BEC <150 cells/μL, exacerbations were 15% lower (RR 0.859 [95% CI, 0.602-1.227]). Quartile analysis showed Q1: 0%-2.1%; Q2: 2.2%-3.6%; Q3: 3.7%-5.9%; Q4: 6.0%-25% BEC. A 48% decreased risk for exacerbation was found in patients who received MART in Q3 (RR, 0.525 [95% CI, 0.363-0.759]; P <.001) and Q4 (RR, 0.522 [95% CI, 0.352-0.774]; P =.001). Analyzing with a 3.6% median blood eosinophil cutoff showed an association between MART and a 45% decrease in exacerbation (RR 0.547 [95% CI, 0.418-0.715]; P <.001) in participants with eosinophil percentages above the median.
The study researchers concluded, “In patients with moderate-to-severe asthma, low-dose beclomethasone/formoterol MART, as compared with beclomethasone/formoterol plus salbutamol as needed, consistently reduced exacerbation rate in all the subgroups of patients with a significant association with the degree of eosinophilic airway inflammation as evidenced by the blood eosinophil count at baseline.”
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Brusselle GG, Papi A, Nicolini G, Santoro L, Guastalla D. Exacerbation rate reduction according to baseline blood eosinophilic count in patients with asthma treated with ICS/LABA maintenance and reliever therapy. Poster presentation at: the American Thoracic Society International Conference; May 19, 2019; Dallas, TX. Abstract A1294/P682.