Combination of omalizumab and specific immunotherapy is superior to immunotherapy in patients with seasonal allergic rhinoconjunctivitis and co-morbid seasonal allergic asthma

Summary Background The treatment of allergic asthma by specific immunotherapy (SIT) is hampered by potential side-effects. Objective The aim of this study was to study the effect of omalizumab, a monoclonal anti-IgE antibody, in combination with SIT in patients with seasonal allergic rhinoconjunctivitis (SAR) and co-morbid seasonal allergic asthma (SAA) incompletely controlled by conventional pharmacotherapy. Methods A randomized, double-blind, placebo-controlled, multi-centre trial was performed to assess the efficacy and safety of omalizumab (Xolair®) vs. placebo in combination with depigmented SIT (Depigoid®) during the grass pollen season. Omalizumab or placebo was started 2 weeks before SIT; the whole treatment lasted 18 weeks. Primary endpoint was daily ‘symptom load’, the sum of daily scores for symptom severity and rescue medication use. Results A total of 140 patients (age 11–46 years) were randomized; and a total of 130 finished the study. Combination therapy reduced the symptom load by 39% (P=0.0464, Wilcoxon test) over SIT monotherapy. This difference was mainly due to reduced symptom severity (P=0.0044), while rescue medication use did not change significantly. Combination therapy also improved asthma control (Asthma Control Questionnaire, P=0.0295) and quality of life in the case of asthma (Asthma Quality of Life Questionnaire, P=0.0293) and rhinoconjunctivitis (Rhinoconjunctivitis Quality of Life Questionnaire, P=0.0537). Numbers of patients with ‘excellent or good’ treatment efficacy according to ratings of investigators (75.0% vs. 36.9%) or patients (78.5% vs. 46.1%) were markedly higher in the combination group than under SIT alone. Conclusion Combination of omalizumab with SIT for treatment of patients with SAR and co-morbid SAA was safe and reduced the symptom load in a statistically significant and clinically meaningful manner.