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SELECTED ARTICLES FROM THE RECENT LITERATURE 2007
December 19, 2007
A Challenge to the Role of the Eosinophil in Asthma?
Summary
This investigation was a multicenter, randomized, double-blind, placebo-controlled evaluation of mepolizumab in two doses (250 or 750 mg) given at monthly intervals for three doses. The patient population consisted of 362 asthmatics experiencing persistent symptoms in spite of inhaled corticosteroid therapy (400-1000 mcg of beclomethasone or equivalent daily).
Multiple features were monitored. These included morning peak flow, FEV1, rescue beta-adrenergic use, symptom scores, quality of life measures, and exacerbation rates. In addition, induced sputum and blood eosinophil levels were monitored.
In spite of the fact that there were statistically significant decreases in blood and sputum eosinophils in both treatment groups, there were no statistically significant changes in any of the clinical end points assessed. There was a nonsignificant trend for a decrease in exacerbation rate in the higher dose (750 mg) group.
The authors concluded that mepolizumab did not appear to add clinically significant benefit to this patient group (persistent asthma in spite of inhaled corticosteroid therapy). They suggested, however, that further studies were needed to investigate the effect of mepolizumab on exacerbation rates, employing protocol specifically tailored to patients with asthma with persistent airway eosinophilia.
Editor's Comments
The article was accompanied by an excellent editorial from Paul O'Byrne entitled "The Demise of Anti-IL-5 for Asthma, or Not." In this editorial, Dr. O'Byrne mentioned several issues needed to be considered before mepolizumab therapy could definitively be abandoned. Perhaps the most important of these was in concert with the suggestion of the authors of the paper and related to a further study of exacerbation rates in an investigation powered to assess this variable.
Reference
Flood-Page P. A study to evaluate safety and efficacy of mepolizumab in patients with moderate persistent asthma. In: American Journal of Respiratory and Critical Care Medicine 2007; 176:1062-1071.
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