Objective We performed a review of studies of
fluticasone propionate (FP)/salmeterol (SAL) (combination
inhaled corticosteroid (ICS)/long-acting β2-agonist
(LABA)) in patients with COPD, which measured baseline
(pretreatment) blood eosinophil levels, to test whether
blood eosinophil levels ≥2% were associated with a
greater reduction in exacerbation rates with ICS therapy.
Methods Three studies of ≥1-year duration met the
inclusion criteria. Moderate and severe exacerbation rates
were analysed according to baseline blood eosinophil
levels (<2% vs ≥2%). At baseline, 57–75% of patients
had ≥2% blood eosinophils. Changes in FEV1 and St
George’s Respiratory Questionnaire (SGRQ) scores were
compared by eosinophil level.
Results For patients with ≥2% eosinophils, FP/SAL
was associated with significant reductions in
exacerbation rates versus tiotropium (INSPIRE: n=719,
rate ratio (RR)=0.75, 95% CI 0.60 to 0.92, p=0.006)
and versus placebo (TRISTAN: n=1049, RR=0.63, 95%
CI 0.50 to 0.79, p<0.001). No significant difference was
seen in the <2% eosinophil subgroup in either study
(INSPIRE: n=550, RR=1.18, 95% CI 0.92 to 1.51,
p=0.186; TRISTAN: n=354, RR=0.99, 95% CI 0.67 to
1.47, p=0.957, respectively). In SCO30002 (n=373), no
significant effects were observed (FP or FP/SAL vs
placebo). No relationship was observed in any study
between eosinophil subgroup and treatment effect on
FEV1 and SGRQ.
Discussion Baseline blood eosinophil levels may
represent an informative marker for exacerbation
reduction with ICS/LABA in patients with COPD and a
history of moderate/severe exacerbations.