Patients ( N = 17 ) aged 6 to 26 years ( mean age , 16.4 years ) with poorly controlled persistent allergic asthma , less than 50 % adherence to inhaled corticosteroid therapy , a forced expiratory volume in 1 second ( FEV1 ) of 60 % predicted or higher , and adenosine provocation concentration that caused a decrease in FEV1 of 20 % ( PC20 ) of 60 mg/mL or less were randomized to receive 4 months of omalizumab or placebo in a double-blind , crossover trial with a 3 - to 4-month washout between treatments .