Cladribine Tablets: Collaborative Study to Evaluate Impact On Central Nervous System Biomarkers in Multiple Sclerosis

This is an open label, randomized, multicenter collaborative research Phase 4 biomarker study, designed to generate hypotheses to better understand the MoA of cladribine tablets in RMS (to include RRMS or active secondary progressive MS). The study is designed to generate hypotheses regarding the impact and relevance of cladribine tablet activity in the CNS by assessing the cerebrospinal (CSF) levels of lymphocyte subsets, other immune cells, neuronal injury markers and soluble immunological markers in study participants with RMS before and during treatment with cladribine tablets, and the association of these CSF markers with corresponding blood markers and with clinical outcomes.