Transient impact of omalizumab in pollen allergic patients undergoing specific immunotherapy

Abstract

Recently, we showed that combination of omalizumab with specific immunotherapy (SIT) for treatment of patients with seasonal allergic rhinitis (SAR) and comorbid seasonal allergic asthma (SAA) is safe and reduced the symptom load in a statistically significant and clinically meaningful manner during the first pollen season. The aim of this study was to investigate long-lasting effects of an initial combination treatment with SIT+omalizumab, a monoclonal anti-IgE antibody, in a follow-up period with SIT treatment only in patients with SAR and comorbid SAA incompletely controlled by conventional pharmacotherapy. A randomized, double-blind, placebo-controlled, multicenter trial was performed to assess the efficacy and safety of omalizumab (Xolair(®)) vs. placebo in combination with SIT (depigmented allergoid vaccine, Depigoid(®)) during the first grass pollen season. Omalizumab or placebo therapy was started 2 wk before SIT; the whole treatment lasted 18 wk. After the first pollen season, SIT was given for two subsequent years without omalizumab. Primary end-point was daily 'symptom load', the sum of daily scores for symptom severity and rescue medication use in the second and third year. A total of 140 patients (age 11-46 yr) were randomized; 130, 128, and 114 patients finished the study after 1, 2, and 3 yr, respectively. The main efficacy variable was the mean daily symptom load as assessed in the patients' diary. No systematic differences between both analysis groups were detected in the findings from symptom load, symptom severity score, or rescue medication score. Further subjective data did not show differences between both groups in the quality-of-life data as assessed with the ACQ, AQLQ, and the RQLQ. Investigators' assessment of treatment effectiveness in the first and second year of study extension showed more patients with favorable long-term treatment outcome ('excellent' and 'good') in the SIT plus omalizumab group than in the SIT plus placebo group. In line with these findings, FEV1 improved at the end of both years in the group which was treated with the combination therapy in the double-blind study compared with the Depigoid plus placebo group. Eighteen weeks' treatment of omalizumab in combination with SIT in patients with SAR and comorbid SAA reduced the symptom load during the treatment period but showed no prolonged effect during treatment with SIT only. A slight increase in lung function (FEV1) in patients formerly treated with the omalizumab/SIT combination therapy should encourage further evaluation of long-term effects of omalizumab.