The Prednisone-sparing Effect of Anti-IL-5 Antibody (SB-240563)

Eosinophilic bronchitis, which is identified by quantitative sputum cell counts (eosinophils greater than 2%) is responsive to corticosteroid treatment. It occurs alone or in association with asthma or in some patients with chronic obstructive pulmonary disease (COPD). In most patients the eosinophilic bronchitis responds to treatment with inhaled steroids but in some it requires a minimum dose of prednisone to keep it controlled. At present, there is no outstanding drug which can have a prednisone-sparing effect. Interleukin (IL)-5 is a cytokine specifically focused on the development, differentiation, recruitment, activation and survival of the eosinophil. The specificity of IL-5 has raised the possibility that blocking it's activity, using humanized monoclonal antibodies, may be useful therapy for eosinophilic bronchitis. Such an antibody (SB-240563) has been introduced for clinical trial. The investigators will compare its effect versus placebo in patients with prednisone-dependant symptomatic eosinophilic bronchitis (with or without asthma) before and after a reduction in prednisone dose to identify if it has a prednisone-sparing effect. The study is divided into 3 sequential study periods. Period 1: symptomatic eosinophilic bronchitis (with or without asthma) on the same dose of prednisone for 6-weeks or more. Period 2: standardized prednisone reduction (and inhaled steroid if prednisone is discontinued during the study treatment) at intervals of 4-weeks until there is a clinical and eosinophilic exacerbation or bothersome steroid withdrawl effects. Period 3: washout. The patients will be seen every 2 weeks. Intravenous injections of SB-240563 750mg or placebo will be given at weeks 2,6,10,14 and 18. Doses of prednisone will be reduced in a standard way.