A 26-week, Randomized, Double-blind, Placebo-controlled, Multicenter Study to Evaluate the Effect of Omalizumab on Asthma Control in Patients with Persistent Allergic Asthma

Objective: The 2007 National Heart, Lung, and Blood Institute (NHLBI) asthma guidelines shifted the focus of care from asthma severity to ongoing assessment of asthma control using the components of impairment and risk. We evaluated the effect of omalizumab on asthma control in patients with persistent allergic asthma inadequately controlled with NHLBI Step 4 or above asthma therapy.

Methods: In this double-blind, placebo-controlled study, patients ≥12 years (n = 271) received omalizumab (n = 136) or placebo (n = 135) every 2 or 4 weeks for 24 weeks. The primary efficacy variable, change from baseline in Asthma Control Test (ACT) total score, and Investigator's Global Evaluation of Treatment Effectiveness (IGETE, secondary efficacy variable) were evaluated at week 24.

Results: ACT score improved more with omalizumab compared with placebo (least squares means [LSMs]: 5.01, 4.36); however, the difference was not significant (p = .1779). Similarly, IGETE was not significantly different (p = .1177), but more patients treated with omalizumab (26/127, 20%) compared with placebo (19/131, 15%) had IGETE rated as "Excellent." Significant benefits were observed for omalizumab compared with placebo for change in ACT score (LSMs: 6.66, 5.27; p = .0334) and IGETE (p = .0321) at week 24 in a subgroup of patients with very poorly controlled asthma (ACT ≤ 15) at baseline. There were no significant differences for the subgroup of patients with forced expiratory volume in 1 second ≤ 80% predicted at baseline. Adverse events (AEs) were similar between groups with no drug-related serious AEs or deaths.

Conclusions: For allergic asthma patients with NHLBI Step 4 or above asthma therapy, omalizumab consistently improved asthma control; however, compared with placebo, differences were not significant. Placebo-treated patients had substantial improvement in their ACT score, which may have limited the ability to detect differences between treatment groups. Subgroup analyses showed significant improvements with omalizumab versus placebo in patients with very poorly controlled asthma.