Clinical Validation of a Multi-protein, Serum-based Assay for Disease Activity Assessments in Multiple Sclerosis

Background and objectivesAn unmet need exists for validated quantitative tools to measure multiple sclerosis (MS) disease activity and progression. We developed a custom immunoassay-based MS disease activity (MSDA) Test incorporating 18 protein concentrations into an algorithm to calculate four Disease Pathway scores (Immunomodulation, Neuroinflammation, Myelin Biology, and Neuroaxonal Integrity) and an overall Disease Activity score. The objective was to clinically validate the MSDA Test based on associations between scores and clinical/radiographic assessments.MethodsSerum samples (N=614) from patients with MS at multiple sites were split into Train (n=426; algorithm development) and Test (n=188; evaluation) subsets. Subsets were stratified by demographics, sample counts per site, and gadolinium-positive (Gd+) lesion counts; age and sex were used to demographically adjust protein concentrations. MSDA Test results were evaluated for potential association with Gd+ lesion presence/absence, new and enlarging (N/E) T2 lesion presence, and active versus stable disease status (composite endpoint combining radiographic and clinical evidence of disease activity).ResultsA multi-protein model was developed (trained and cross-validated) using the Train subset. When applied to the Test subset, the model classified the Gd+ lesion presence/absence, N/E T2 lesion presence, and active versus stable disease status assessments with an area under the receiver operating characteristic (AUROC) of 0.781, 0.750, and 0.768, respectively. In each case, the multi-protein model had significantly (bootstrapped, one-sidedpDiscussionThe MSDA Test was clinically validated; the multi-protein model had greater performance compared with the top-performing single-protein model. The MSDA Test may serve as a quantitative and objective tool to enhance care for MS.