Document resource
Background and Importance Omalizumab is approved for chronic use; however, in patients with clinical remission, dose reduction may be feasible. Plasma omalizumab concentration and FcεRI receptor levels, related to free IgE, may help guide dosing optimisation.Aim and Objectives We aimed to assess the utility of plasma omalizumab and FcεRI levels as tools to optimise therapy in asthmatic patients in clinical remission.Material and Methods This study was a secondary analysis of the multicentre clinical trial OPT-OMA-ASTHMA (EuCT-number: 2025-520782-48-00). Patients with severe asthma on stable omalizumab therapy who had achieved clinical remission were included. Participants were assigned to two final dose reduction strategies: 25% (FDR-25%) or 50% (FDR-50%).Trough plasma concentrations (Cp) of omalizumab and FcεRI levels were measured at baseline and at 24, 48, and 96 weeks. Plasma concentrations were quantified using a commercial ELISA kit.Demographic variables, asthma duration, omalizumab treatment persistence, and mean dose per administration (Dm) were collected. Clinical (ACT score, exacerbations) and functional variables (FEV1% predicted) were also recorded.Statistical analysis: qualitative variables were expressed as counts and frequencies, and quantitative variables as mean (±standard deviation).Results A total of 25 patients were included: 12 in the FDR-25% group and 13 in the FDR-50% group.The mean age was 49 (±18) years; 10 patients (46%) were women, 20 (91%) were Caucasian, and the mean BMI was 27 (±5) kg/m2. The mean time since severe asthma diagnosis was 6 (±6) years, with a mean omalizumab treatment persistence of 5 (±4) years and a Dm of 477 (±115) mg. No significant differences were observed between groups.Abstract 4CPS-292 Table 1 Basal Week-24 Week-48 Week-48 Week-96 Week-96 FDR-25% FDR-50% FDR-25% FDR-50% Cp (µg/mL) 96(±69) 63(±37) 53(±29) 44(±16) 49(±24) 36(±18) FcRεI (Number of receptors/cell) 29986(±12703) 27463(±17763) 25315(±12371) 21906(±9140) 18736(±7558) 24728(±5827) Abstract 4CPS-292 Figure 1 ○× = Patients excludedNo asthma exacerbations were recorded, and clinical and functional stability was maintained throughout the study. Three patients discontinued treatment (one at week 20 and two at week 48) due to poor asthma control. The latter two presented low Cp.Conclusion and Relevance Plasma omalizumab concentration and FcεRI levels could be two complementary tools to monitor and adjust dosing in asthmatic patients in clinical remission.Conflict of Interest No conflict of interest