By definition,
chronic obstructive pulmonary disease (
COPD) is associated with an abnormal inflammatory response of affected lungs. Therefore, the search for an effective anti-inflammatory
therapy for this debilitating disease is intense. However, to date, there is no such anti-inflammatory treatment for
COPD. While there are some modest effects of inhaled
corticosteroids on selected clinical endpoints in
COPD, it remains to be proven that the observed effects are due to changes in the underlying
inflammation, in particular since relevant clinical endpoints of
COPD can be significantly improved by treatments not targeting
inflammation. Therefore, it appears justified to reconsider the present knowledge about any linkage of local and systemic
inflammation and clinical features of
COPD, including lung function, exacerbations,
disease progression, and mortality. Any such link needs to be carefully established before future anti-inflammatory
therapies for
COPD are developed and investigated in clinical trials, in particular since proof-of-concept trials aiming merely at inflammatory markers in
COPD may not be predictive of clinical success or failure. The present review summarizes current knowledge about the role of
inflammation in
COPD, and critically analyzes results from clinical trials with inhaled
corticosteroids and
phosphodiesterase-4 inhibitors in
COPD, the two classes of putative
antiinflammatory agents with the richest body of evidence from controlled studies.