Safety and Efficacy Study of Eculizumab in Patients With Mild Allergic Asthma

Inclusion Criteria: * diagnosed with stable, mild, allergic asthma; * history of episodic wheeze and shortness of breath; * sexually active women of childbearing potential must use contraceptive during the entire duration of study; * willing and able to give informed consent; * positive methacholine challenge; * positive skin prick test to common aeroallergens; * positive allergen-induced early and late phase bronchoconstrictor response * FEV1 at least 70% of predicted value; * PC20 at baseline that is within 1 doubling dose of that measured during screening Exclusion: * active bacterial infection; * respiratory tract infection or worsening of asthma within 28 days * use of inhaled or topical steroids within 28 days or use of systemic corticosteroids within 90 days; * use of cromoglycate, nedocromil, leukotriene receptor antagonists and inhibitors of 5-lipoxygenase within 14 days; * use of antihistamines, immunosuppressives, or any medications that interact with eculizumab; * use of theophylline-containing agents (any type), long-acting beta 2-agonists (salmeterol, formoterol) or long-acting anticholinergics within 14 days; * use of NSAIDs prior to spirometry; * use of tobacco products currently or within the previous 12 months; or smoking history \> 10 pack-years; * lung disease other than mild allergic asthma; * patients with LAR who have not been vaccinated against Neisseria meningitidis; * hepatitis B or HIV infection; * parasitic infection; * participation in any other investigational drug trial; * pregnant or breast feeding women, or intending to conceive during the course of trial; * known hypersensitivity to the treatment drug or any of its excipients; * history of illicit drug use or alcohol abuse within previous year; * any clinically significant abnormality on screening lab test results; * abnormal chest X-ray; * chronic use of any other medication for treatment of allergic lung disease other than short-acting beta2-agonists or ipratropium bromide; * any medical condition that might interfere with the subject's participation in the study or confound the assessment of the subject; * unwilling or inability to comply with the study protocol for any reason.