Omalizumab added to standard therapy may help control severe allergic asthma

Omalizumab may help control severe allergic asthma when added to standard therapy, a new study suggests.

Researchers performed a randomized, double-blind, placebo-controlled trial at 193 sites in the U.S. and four in Canada to determine the efficacy and safety of omalizumab in patients with uncontrolled severe asthma who were receiving high doses of inhaled corticosteroids and long-acting β₂-agonists. Patients were randomly assigned to receive omalizumab (dosage was based on body weight and total serum IgE level at screening) or placebo in additional to their existing therapy for 48 weeks. The study's primary end point was the exacerbation rate over the study period. Secondary end points included the change from baseline to week 48 in mean daily puffs of albuterol, mean total asthma symptom score, mean overall score on the standardized Asthma Quality of Life Questionnaire (AQLQ[S]), and frequency and severity of treatment-emergent adverse events. The study, which was industry-funded, appeared in the May 3 Annals of Internal Medicine.

Included patients were 12 to 75 years of age and had at least a one-year history of severe allergic asthma. Asthma was considered to be poorly controlled if patients had persistent symptoms despite current therapy. Four hundred twenty-seven patients were assigned to the omalizumab group, and 423 patients were assigned to the placebo group. Over the 48 weeks of the study, patients who received omalizumab in addition to their existing therapy had statistically significantly fewer asthma exacerbations than those who received placebo (0.66 vs. 0.88 per patient; P=0.006), as well as better AQLQ(S) scores, fewer mean daily albuterol puffs, and lower mean asthma symptom scores. Both groups had similar rates of adverse events (80.4% vs. 79.5%) and serious adverse events (9.3% vs. 10.5%).

The authors acknowledged that almost 21% of patients discontinued therapy early and that their study was not designed to detect rare safety events, among other limitations. However, they concluded that omalizumab appeared to offer additional clinical benefit in patients with severe allergic asthma not controlled by high doses of inhaled corticosteroids and long-acting β₂-agonists.