b'to placebo, it is shown to considerably reduce the neurofilament light chain levels and decrease the number of gadolinium-enhancing lesions. These neurolament chains show a correlation with the development of gadolinium enhanced lesions and indicate if the DMT is effective. During relapses, levels of NfL are elevated as much as 10 times compared to NfL levels during remission. Elevated levels of the neurolament light chains have been correlated to poorer neurologic function including decreased cognitive performance, manual dexterity, and walking speed. This reduction in NfLs suggests that evobrutinib mayreducethepossibletissuedamage linked to MS. During the Phase II studies, the most common side-effects were the common cold and increased levels of liver enzymes. Additionally, as an oral, twice-daily tablet, the patient burden could be signicantly reduced compared to the side-effects of other DMTs.Another covalent, irreversible BTK inhibitor that is currently being tested in trials, tolebrutinib, has been shown to be effective in reducing new, active brain lesions. This medication is being studied in relapsing- remitting MS and in both primary and active secondary progressive MS. By blocking Brutons tyrosine kinase, B cell activation is decreased, thus interfering with macrophages, and preventing the loss of myelin sheaths within the brain. This oral, once-daily tablet isreportingminimalsideeffectswiththe main reports of headaches, chest infections, and increased risk of getting the common cold.Althoughearlydataappearpromising, further trials will be required to conrm the efficacy and safety of BTK inhibitor use for treatment of MS. 57 msfocusmagazine.org'