Resolution of glial activation in relapsing and primary progressive MS over 2 years with ocrelizumab: longitudinal MR spectroscopy study

Motivation: Need for treatment tracking biomarkers in multiple sclerosis (MS). Goal(s): To demonstrate increased sensitivity to metabolite changes in a more homogeneous MRS voxel in RMS and to investigate whether PMS exhibits a similar trend with treatment. Approach: Single voxel spectroscopy to examine metabolite changes in a large white matter region over time in ocrelizumab treated MS patients compared to single timepoint healthy controls. Results: Marker of glial cell density and activation decreased over 2 years of treatment in both relapsing (similar to previously study) and progressive MS. A weak correlation was observed between the glial marker and measure of disability at baseline. Impact: Magnetic resonance spectroscopy (MRS) offers biomarkers of glial density/activation that may solve a clinical unmet need to track the neuroinflammatory response to multiple sclerosis (MS) therapies. This study demonstrates how MRS biomarkers change with treatment in MS white matter.