EFFICACY OF A FIXED DOSE OF OMALIZUMAB DURING MULTI-ALLERGEN ORAL-IMMUNOTHERAPY

Introduction: Omalizumab has shown efficacy as an adjuvant to multi-food oral immunotherapy (mOIT). However, there is no evidence of the minimum dose necessary for optimal outcome. Methods: In a pilot study, multi-food allergic participants were enrolled and received three monthly doses of 150 mg of omalizumab prior to initiating mOIT for 18 weeks. There were two treatment arms with mOIT maintenance of 300 mg or 1200 mg and included 2-5 food allergens. Each participant’s omalizumab dose was calculated by dividing their 150 mg dose by their weight and total IgE and findings compared between participants receiving <0.016 mg/kg/(IU/mL) and > 0.016 mg/kg/(IU/mL) of omalizumab. Results: Sixty participants were randomized 1:1 to each mOIT treatment arm. Within each treatment arm, 9 subjects received <0.016 mg/kg/(IU/mL) and 21 received >0.016 mg/kg/(IU/mL) of omalizumab. Baseline characteristics and AE rates were comparable between the two omalizumab groups. When stratified by omalizumab dose group, significant differences in time to maintenance were found (p=0.018). Those receiving ≥0.016 mg/kg/(IU/mL) of omalizumab were 4.2 times more likely to reach maintenance by 18 weeks (hazard ratio: 4.2; 95% CI: 1.7, 10.7; p=0.0026). Omalizumab dosing of ≥0.016 mg/kg/(IU/mL) was associated with achieving the primary endpoint of at least a 25% increase in specific IgG4/IgE ratio from baseline for at least two allergens. Conclusion: In our pilot study, standard, weight-based dosing of omalizumab [≥0.016 mg/kg/(IU/mL)] is a significant factor when aiming for a higher maintenance OIT and inducing an increase in specific IgG4/IgE ratio by 25%.