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The following is a summary of “A Streamlined Strategy for Basophil Activation Testing in a Multicenter Phase III Clinical Trial,” published in the September 2024 issue of Allergy and Immunology by Suárez-Fariñas et al.

Due to technical complexities, the basophil activation test (BAT) has traditionally been constrained to research environments. However, recent innovations, including developing dry, ready-to-use reagents and simplified protocols, have opened up opportunities for broader clinical application. This study aimed to evaluate the feasibility of implementing a streamlined BAT (sBAT) within the multicenter framework of the EPITOPE trial, which investigates EPicutaneous ImmunoTherapy (EPIT™) for peanut allergy, and to assess its predictive value for outcomes in peanut double-blind placebo-controlled food challenges (DBPCFC). Whole blood samples from 241 children aged 1-3 years, who were undergoing baseline DBPCFC as part of the EPITOPE study across 15 North American clinical sites, were prepared using sBAT reagents and analyzed within five days of collection at a central laboratory. 

The eliciting dose (ED) for DBPCFC was determined following PRACTALL criteria. Employing a machine learning (ML) approach that integrated BAT-derived features, clinical characteristics, and peanut-specific IgE levels, the study aimed to predict DBPCFC outcomes, including ED (<300 mg or >300 mg) and epinephrine usage, using randomly partitioned training (n=182) and validation (n=59) subsets. Results indicated that the expression of basophil activation markers CD203c and CD63 was significantly correlated with ED and severity outcomes. The most relevant peanut extract concentrations for these associations in the sBAT assay were 1 and 10 ng/ml. Notably, ML models based solely on BAT-derived features achieved high sensitivities of 0.86 and 0.85 for predicting ED and epinephrine use, respectively, though specificities were more variable, ranging from 0.60 to 0.80. 

Incorporating specific IgE and skin prick test (SPT) data did not enhance the prediction of severe reactions but improved the identification of patients with an ED exceeding 300 mg. In conclusion, sBAT supports its potential integration into multicenter trials and confirms its utility in characterizing allergic patients and predicting outcomes of oral food challenges.

Source: sciencedirect.com/science/article/abs/pii/S2213219824009310