Efficacy and safety of a recombinant anti‐immunoglobulin E antibody (omalizumab) in severe allergic asthma

Background Patients with severe asthma are often inadequately controlled on existing anti‐asthma therapy, constituting an unmet clinical need.

Objective This randomized, double‐blind, placebo‐controlled trial evaluated the ability of omalizumab, a humanized monoclonal anti‐IgE antibody, to improve disease control sufficiently to enable inhaled corticosteroid reduction in patients with severe allergic asthma.

Methods After a run‐in period when an optimized fluticasone dose (1000 μg/day) was received for 4 weeks, patients were randomized to receive subcutaneous omalizumab [minimum 0.016 mg/kg/IgE (IU/mL) per 4 weeks; n=126] or matching placebo (n=120) at intervals of 2 or 4 weeks. The study comprised a 16‐week add‐on phase of treatment followed by a 16‐week fluticasone‐reduction phase. Short‐/long‐acting β₂‐agonists were allowed as needed.

Results Median reductions in fluticasone dose were significantly greater with omalizumab than placebo: 60% vs. 50% (P=0.003). Some 73.8% and 50.8% of patients, respectively, achieved a 50% dose reduction (P=0.001). Fluticasone dose reduction to 500 μg/day occurred in 60.3% of omalizumab recipients vs. 45.8% of placebo‐treated patients (P=0.026). Through both phases, omalizumab reduced rescue medication requirements, improved asthma symptoms and asthma‐related quality of life compared to placebo.

Conclusion Omalizumab treatment improves asthma control in severely allergic asthmatics, reducing inhaled corticosteroid requirements without worsening of symptom control or increase in rescue medication use.