Fuente: PubMed "hive" J Allergy Clin Immunol Pract. 2025 Nov 28:S2213-2198(25)01134-1. doi: 10.1016/j.jaip.2025.11.029. Online ahead of print.ABSTRACTBACKGROUND: Proposed negative biopredictors of omalizumab response in chronic spontaneous urticaria (CSU) patients are low baseline IgE (< 40 IU/ml), positive CU index test (CUI), and basopenia defined by blood histamine content (BHC) (< 8 ng/ml).OBJECTIVE: We hypothesized that patients with these negative biopredictors will have a poorer response to omalizumab.METHODS: We performed a retrospective analysis of 3-Phase III studies of antihistamine-refractory CSU subjects who received omalizumab 300 mg q4 weeks for 12 weeks. The relationship between baseline biopredictors and subjects with excellent symptom control measured by Urticaria Activity Score (UAS7 <6) or poor symptom control (UAS7>6) after 12 weeks were examined. We performed chi square, logistic regression, and ROC analysis.RESULTS: In 363 subjects, data were available for IgE and CUI; 266 had BHC measures. Subjects with UAS7 > 6 at 12 weeks significantly more often expressed a baseline negative biopredictor: IgE < 40 IU/mL (n=109, 50%) vs IgE > 40 (n=239, 33%); CUI positive (n=98, 55%) vs. negative (n=263, 32%); BHC < 8 ng/ml (n=64, 55%) vs. BHC > 8 ng/ml (n=202, 33%). CUI positivity significantly predicted a UAS7>6 at 12 weeks (p=0.0002; OR :2.54; 95% CI: 1.55-4.15). According to ROC curve analysis, a BHC of 6.4 ng/ml was distinguishing non-responders from responders. Among subjects with low baseline IgE, the presence of low BHC was predictive for non-responsiveness to omalizumab (χ2 is 4.215. The p=.040).CONCLUSION: Subjects with positive CUI, low BHC, or both low IgE and BHC have an increased likelihood of poorer response to omalizumab at 12 weeks.PMID:41319902 | DOI:10.1016/j.jaip.2025.11.029