Individually dosed omalizumab: an effective treatment for severe peanut allergy.

Background Treatment with omalizumab has shown a positive effect on food allergies, but no dosages are established. Basophil allergen threshold sensitivity (CD-sens) can be used to objectively measure omalizumab treatment efficacy and correlates with the outcome of double-blind placebo-controlled food challenge to peanut. Objective To evaluate whether individualized omalizumab treatment monitored by CD-sens could be an effective intervention for suppression of allergic reactions to peanut. Methods Severely peanut allergic adolescents (n = 23) were treated with omalizumab for 8 weeks, and CD-sens was analysed before and after. Based on whether CD-sens was suppressed after 8 weeks, the patients either were subject to a peanut challenge or received eight more weeks with increased dose of omalizumab, followed by peanut challenge or another 8-week cycle of omalizumab. IgE and IgE-antibodies to peanut and its components were analysed before treatment. Results After individualized omalizumab treatment (8-24 weeks), all patients continued with an open peanut challenge with no (n = 18) or mild (n = 5) objective allergic symptoms. Patients (n = 15) needing an elevated omalizumab dose (ED) to suppress CD-sens had significantly higher CD-sens values at baseline 1.49 (0.44-20.5) compared to those (n = 8) who managed with normal dose (ND) 0.32 (0.24-5.5) (P < 0.01). Median ratios for Ara h 2 IgE-ab/IgE were significantly higher in the ED group (17%) compared to the ND group (11%). Conclusions and Clinical Relevance Individually dosed omalizumab, monitored by CD-sens, is an effective and safe treatment for severe peanut allergy. The ratio of IgE-ab to storage protein Ara h 2/IgE as well as CD-sens to peanut may predict the need of a higher omalizumab dose.