Multiple sclerosis (MS) affects approximately 1 million Americans and is the most common cause of non-traumatic neurological disability in young adults, with onset typically between ages 20 and 40 and affecting women more than men (3:1 ratio). The autoimmune attack on the myelin sheath of CNS neurons causes plaques of demyelination and axonal injury, interrupting nerve conduction. Highly effective disease-modifying therapies (DMTs) — including natalizumab, ocrelizumab, alemtuzumab, and cladribine — reduce relapse rates by 50–70% and substantially slow disability accumulation compared with earlier-generation therapies. The principle of early, high-efficacy treatment is supported by mounting evidence that delaying neurological damage accumulation has lifelong benefits.
