[Review] Bruton's tyrosine kinase inhibitors: a new class of multiple sclerosis therapeutics

Bruton's tyrosine kinase (BTK) is an intracellular enzyme involved in a wide range of cellular functions. BTK inhibitors (BTKIs) are of interest in the treatment of multiple sclerosis (MS). This is because they modulate various types of immune cells that play a key role in the pathophysiological processes of MS. These immune cells include B cells and microglia. Furthermore, BTKIs are small molecules. This allows them to potentially cross the blood-brain barrier. Consequently, they can modulate relevant cells directly within the central nervous system.