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Blood eosinophil count predicts ICS response on COPD exacerbations

Patients with COPD and high blood eosinophil count experienced a greater benefit from the use of inhaled corticosteroids to reduce exacerbation frequency compared with patients with low eosinophil count, according to study results.

“Our findings have immediate clinical implications as they show that blood eosinophil count, a readily available and easy to interpret measure, is potentially suitable for use as a biomarker to identify which patients are most likely to benefit from inhaled corticosteroids,” Steven Pascoe, MBBS, of GlaxoSmithKline, and colleagues wrote.

The researchers conducted a post-hoc analysis of data from two replicate, randomized, double blind 12-month trials held between September 2009 and October 2011. Once-daily 25 µg Breo Ellipta (vilanterol, GlaxoSmithKline) was compared with 25 µg vilanterol plus 50 µg, 100 µg or 200 µg fluticasone furoate in patients with moderate to severe COPD.

The researchers included 3,177 patients in the analysis. At the beginning of the study, 66% of patients had blood eosinophil counts of 2% or higher. When combining all the combination therapies and comparing them with vilanterol alone, patients with eosinophil counts of 2% or more saw a 29% decrease in COPD exacerbations.

COPD exacerbations decreased by 10% in patients who had eosinophil counts less than 2% and received the combination therapy vs. vilanterol alone.

“Patients with mild or no history of exacerbation in the previous year were not included in the study, therefore, we cannot comment on the usefulness of eosinophil count as a biomarker in these patients,” the researchers wrote. “Our analysis … supports the view that the use of blood eosinophil cell counts as a biomarker of inhaled corticosteroid response would result in an improved risk-benefit ratio for this treatment.”

Disclosure: Pascoe reports being employed by and holding stock in GlaxoSmithKline. Please see the full study for a list of all other authors’ relevant financial disclosures.