PrecISE—a biomarker-stratified adaptive trial of 5 interventions in severe asthma: Final protocol and the baseline cohort

Background: The National Institutes of Health initiated the Precision Medicine in Severe and/or Exacerbation Prone Asthma (PrecISE) program with the objective of implementing adaptive design strategies to test multiple new treatments in biomarker-identified patient subsets. Objective: The PrecISE study sought to recruit a cohort of patients with severe asthma for a biomarker-stratified adaptive trial of 5 different interventions. Methods: Patients aged 12 years and older with a clinical diagnosis of asthma who were adhering to a stable medical regimen consisting of at least medium-dose inhaled corticosteroids and a second controller were enrolled if their diagnosis could be confirmed by bronchodilator responsiveness on spirometry or airway hyperreactivity to methacholine. Protocol adaptations over the course of the study to biomarker sampling and enrichment, interventions studied, the statistical analysis plan, and sample size are described. The baseline characteristics of the cohort were analyzed. Results: A total of 358 participants were randomized. The 4 predictive biomarkers used for intervention randomization assignments were blood eosinophil count (median = 180; interquartile range (IQR) = 100-290 cells/mL), fractional exhaled nitric oxide measurement (median = 18; IQR = 11-27 ppb); plasma IL-6 level (median = 2.5; IQR = 1.6-3.6 pg/mL), and ADH5 risk genotype (present in 253 participants [71%]). Blood eosinophil counts weakly correlated with fractional exhaled nitric oxide measures (Rs = 0.13; P = .02) and IL-6 levels (Rs = 0.17; P = .002); otherwise, these biomarkers were independent from each other. Specific intervention results will be reported separately. Conclusion: The PrecISE adaptive study design with multiperiod crossovers is an efficient and novel way to study multiple interventions simultaneously in a heterogeneous disease such as asthma.