This study is designed to compare the safety, tolerability, and pharmacokinetics of QBX258 (sequential administration of a fixed dose of VAK694 and single ascending doses of QAX576) in patients with well-controlled mild to moderate asthma.

Inclusion Criteria:

• Male and female subjects age 18-60 years (inclusive)
• Well controlled mild to moderate atopic asthma
• Female subjects must be post-menopausal or surgically sterile
• Male subjects must be using two methods of contraception
• Subjects must have a positive skin prick test to one or more common airborne allergen

Exclusion Criteria:

• Participation in any clinical investigation or use of other investigational drugs at time of enrollment
• A history of clinically significant ECG abnormalities
• History of malignancy of any organ system
• Smokers (use of tobacco products in the previous 3 months)
• Use of prescription drugs other than those required for control and relief of asthma
• Use of oral steroids within 12 weeks prior to dosing
• FEVI < 80% predicted at screening or baseline
• Use of albuterol more than twice a week for relief of asthma
• Patients suffering from active hay fever at baseline or likely to require treatment during the study
• History of chronic respiratory disease other than asthma or chronic allergic rhinitis
• Emergency room visit within 6 weeks of screening due to asthma
• Hospitalization for asthma in the last year
• History of intubation/assisted ventilation for asthma in the last 5 years
• Administration of live vaccines within the preceding month

Other protocol-defined inclusion/exclusion criteria may apply.