Clinical Context

Multiple sclerosis (MS) is a chronic autoimmune disease characterized by inflammation and degeneration of the central nervous system, leading to various neurological symptoms and disability. Secondary progressive multiple sclerosis (SPMS) is a stage of MS where patients experience a gradual worsening of symptoms and disability after an initial relapsing phase. Currently, treatment options for SPMS are limited, and the management primarily focuses on symptom relief and slowing disease progression. There is a significant need for effective therapies that can address the underlying disease mechanisms in SPMS. The recent phase 3 trial of tolebrutinib evaluated its efficacy in reducing disability progression in patients with nonrelapsing SPMS, aiming to fill this treatment gap.