High-efficacy options—natalizumab, ocrelizumab, ofatumumab, alemtuzumab, cladribine, and S1P modulators like fingolimod or ozanimod—achieve up to 70%–85% relapse reduction but carry higher risks, including opportunistic infections (e.g., PML with natalizumab), autoimmune complications (e.g., thyroiditis with alemtuzumab), or cardiovascular effects (e.g., bradyarrhythmia with fingolimod). Here, MBTPS1 is linked to progressive multifocal leukoencephalopathy.