Mode of Action Study of Omalizumab in Patients With Chronic Idiopathic Urticaria (CIU) Who Fail to Respond to Antihistamine Treatment

A Phase II, Multi-centre, Randomized, Double Blind, Placebo-controlled Study to Determine the Mode of Action of Omalizumab in Patients With Chronic Idiopathic Urticaria (CIU) Who Remain Symptomatic With Antihistamine Treatment (H1)

The study is designed to explore the mode of action for omalizumab therapy in patients with chronic idiopathic urticaria.

Inclusion Criteria:

• Diagnosis of chronic spontaneous urticaria refractory to H1 antihistamines at Baseline

Exclusion Criteria:

• Clearly defined underlying etiology for chronic urticarias other than CIU (main manifestation being physical urticaria). This includes the following urticarias: Acute, solar, cholinergic, heat, cold, aquagenic, delayed pressure or contact, as well as the following diseases as these diseases may have symptoms of urticaria or angioedema: Urticarial vasculitis, urticaria pigmentosa, erythema multiforme, mastocytosis, hereditary or acquired angioedema, lymphoma, leukemia, or generalized cancer.
• Previous treatment with omalizumab.
• A history or presence of atopic dermatitis, bullous pemphigoid, dermatitis herpetiformis, senile pruritus or other skin disease associated with itch.

Other protocol-defined inclusion/exclusion criteria may apply.