A team of GSK researchers recently presented at the European Respiratory Society (ERS) Congress data showing eosinophil levels in the blood may be predictors of exacerbation rates in patients with Chronic Obstructive Pulmonary Disease (COPD).

Several scientific studies previously linked eosinophils (a member of the white blood cells’ family, an important component of the immune system) with an increased risk of exacerbations (meaning an increase in disease severity) among patients with COPD. These results prompted GSK researchers to reason that measuring and arranging patients with COPD by eosinophil levels in the blood could benefit when choosing patients’ most beneficial type of treatment. The team set out an analysis (post-hoc) of approximately 8,000 patients to investigate the possible link between eosinophil levels and patients’ response to treatment.

The data used in the GSK analysis was part of two other studies designed to evaluate the performance of Relvar® Ellipta® and Anoro® Ellipta®.

Relvar® Ellipta® is a combination inhaler with 2 active ingredients, fluticasone furoate/ vilanterol (FF/VI), an inhaled corticosteroid (ICS) and a long-acting beta‑2 agonist (LABA), respectively; Anoro® Ellipta® is a combination of umeclidinium/vilanterol (UMEC/VI), an anticholinergic and a long-acting beta‑2 agonist (LABA).

The study findings are outlined in the following section:

1. In COPD patients’ blood eosinophil count as a predictor of ICS efficacy in reducing exacerbations

Two randomized, double-blind, placebo-controlled 1-year trials’ data were analyzed. The trials’ aim was to compare, in patients with moderate to severe COPD, the rates of exacerbations. The results showed:

– eosinophil level ≥2% had exacerbation rates dropping by 29% (in a regiment of FF/VI when compared to VI alone)

– eosinophil level of <2% had exacerbation rates dropping 10% (FF/VI against VI alone)

Thus, patients in a FF/VI treatment baseline eosinophil levels may be predictors of exacerbation rates’ improvement. The level of predicament is proportional to eosinophil levels.

2. In COPD patients, blood eosinophil count is not a predictor of response to bronchodilators

Data from four six-month studies of UMEC/VI and VI was analyzed to evaluate their role in bronchodilator response. The results showed:

– the response to UMEC, VI or UMEC/VI was similar in patients with eosinophil level ≥2% and <2%; the parameters measured were bronchodilator response, health-related quality of life or dyspnoea.

Thus, blood eosinophils’ levels are not predictive of a bronchodilator response.

As Neil Barnes, Global Franchise Medical Head, Respiratory, GSK noted, “COPD is a heterogeneous disease and enhancing our understanding of how individual patients respond to different treatments is critical to allow treatment to be tailored to their specific needs, with the ultimate aim of improving outcomes. “These data, and those from other studies, are very valuable and support our belief that these circulating white blood cells could play an important role in guiding effective COPD management. We believe it is important that further work, including prospective studies, is undertaken to generate more evidence about the promising role of blood eosinophil levels as an indicator of response to an ICS-containing regimen.”

These findings need additional support by new extensive analysis of existing data but also by designing new studies to understand the role of eosinophil in COPD. This will allow physicians to adapt their treatment decisions.

RELVAR®, ANORO®, INCRUSE® and ELLIPTA® are trademarks of the GlaxoSmithKline group of companies.