High Quality Content by WIKIPEDIA articles! Omalizumab (trade name Xolair, Genentech / Novartis) is a humanized antibody drug approved for patients with moderate-to-severe or severe allergic asthma, which is caused by hypersensitivity reactions to certain harmless environmental substances. Omalizumab`s cost is high ($10,000 to $30,000 per year), as compared to other drugs used for asthma, and hence omalizumab is mainly prescribed for patients with severe, persistent asthma, which cannot be controlled even with high doses of corticosteroids. Like other protein and antibody drugs, omalizumab causes anaphylaxis (a life-threatening systemic allergic reaction) in 1 to 2 patients per 1,000.