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

Inclusion Criteria: 1. Adult patients, aged 18-70 years, who have been followed as an outpatient and who have been found to require a minimum dose of prednisone treatment (in addition to high-dose inhaled steroid treatment) to prevent frequent exacerbations associated with induced sputum eosinophilia. 2. Patients will be enrolled if, at screening and baseline visits, they demonstrate sputum eosinophilia and symptoms. The symptoms may effect activity and sleep but should not, in the opinion of the treating physician, be severe enough to be of concern. 3. While FEV1 after withholding bronchodilators appropriately, before and after inhaled salbutamol (200 mg), and methacholine PC20 will be measured, these need not be abnormal since the prednisone is required for the control of eosinophilic bronchitis and any clinical consequences of this, and because the bronchitis can occur without these features of asthma. 4. On the same doses of corticosteroids for a least one-month. Exclusion Criteria: 1. Pregnancy, breast-feeding or lack of effective contraception in females of childbearing potential or females who are postmenopausal \<1 year. 2. Baseline FEV1 before bronchodilator of 40% or less of predicted. This lower FEV1 is acceptable since chronic airflow limitation secondary to the eosinophilic bronchitis or asthma is not an exclusion criteria. Neither is current or ex-cigarette smoking providing that the best FEV1 in these patients has been \>60% predicted normal or the best FEV1/VC ratio has been \>60% in the past two years. 3. Exposure to a relevant seasonal environmental allergen, known to worsen asthma control, during the study period. 4. Respiratory tract infection in the 4-weeks before the baseline visit. 5. Clinical exacerbation requiring extra prednisone treatment in the 4-weeks before V1. 6. Other cardiac, pulmonary, renal or systemic diseases that in the investigator's opinion may interfere with the study results or compromise subject's safety. 7. Previous participation in any study using anti-monoclonal drug.