The purpose of this study is to investigate the efficacy of 24 weeks intravenous treatment with QAX576 in patients with persistent asthma not adequately controlled with inhaled corticosteroids and long acting beta2-agonists.

Inclusion Criteria:

• Male and female patients
• Female patients must be surgically sterilized or postmenopausal
• Male patients must use two forms of contraception
• Body mass index must be between 18 and 39 kg/m2
• Diagnosis of asthma for at least one year, which is not adequately controlled by inhaled corticosteroids and long acting beta-2 agonists

Exclusion Criteria:

• Smoking history >10 pack-years
• Patients with a diagnosis of chronic obstructive pulmonary disease (COPD)
• Patients who have experienced a severe asthma attack/exacerbation requiring systemic corticosteroids or an increase in maintenance doses, within 6 weeks of screening
• Patients who have had a respiratory tract infection within 6 weeks prior to screening
• History of schistosomiasis, within 6 months of screening, or traveling to a country endemic with schistosomiasis within 6 months of completing the study