Brain Imaging and Immune Changes During Remibrutinib Treatment in Multiple Sclerosis.

Multiple sclerosis (MS) is associated with ongoing inflammation within the central nervous system that may contribute to disease progression even when relapses are controlled. Remibrutinib, a Bruton tyrosine kinase (BTK) inhibitor, may affect immune cells involved in this process, but its effects on inflammation within the brain and spinal cord are not fully understood. \[REDEFINE\_p...2026\_clean \| Word\] This study will evaluate changes in neuroinflammation and immune activity in participants with relapsing MS by combining advanced imaging and biomarker assessments. Measurements of microglial activity using positron emission tomography (PET), cerebrospinal fluid (CSF) analyses, blood-based biomarkers, and magnetic resonance imaging (MRI) will be used to assess changes associated with remibrutinib treatment. \[REDEFINE\_p...2026\_clean \| Word\] The study will examine whether changes in imaging and fluid biomarkers are associated with measures of disease severity and whether these biomarkers may help predict longer-term clinical outcomes. Results may improve understanding of the biological effects of BTK inhibition in MS and help identify biomarkers that can be used to monitor treatment response and disease progression.