This study has the objective of providing compassionate use access to omalizumab (Xolair) and to evaluate the Safety of Xolair in subjects with severe allergic asthma who remain symptomatic despite optimal therapy according to GINA step 4 treatment guidelines.

Inclusion Criteria:

• male or female, ≥ 6years of age;
• who have a diagnosis of allergic asthma ≥ 1 year duration according to American Thoracic Society (ATS) criteria;
• severe persistent allergic asthma who remain symptomatic despite optimal therapy (as per Canadian Asthma Consensus Report (1999));
• Subjects having successfully completed one of the following protocols: CIGE025A011E3, CIGE025A2425, CIGE025AIA05;
• elevated immunoglobin E levels

Exclusion Criteria:

• significant systemic disease
• pregnancy or lactation
• an active lung disease other than allergic asthma (eg: cystic fibrosis, bronchiestasis);
• history of food or drug related severe anaphylactoid or anaphylactic reaction(s);
• current treatment with warfarin (Coumadin®), immunomodulatory therapy (e.g., methotrexate, gold, cyclosporine), or antiplatelet therapy.