Tolebrutinib for treating relapsing and progressive forms of multiple sclerosis

Tolebrutinib is currently in clinical development for the treatment of relapsing and progressive forms of multiple sclerosis (MS). MS is a chronic autoimmune condition that affects the brain and spinal cord. It can lead to increased mortality and is one of the most common causes of disability in younger adults. Relapsing remitting multiple sclerosis (RRMS) is the most common form and is characterised by episodes of acute worsening of function (relapsing) followed by partial or complete recovery (remitting). Progressive MS can occur in primary or secondary forms; primary progressive MS is a gradual worsening of symptoms from the initial primary symptoms. Secondary progressive MS is a stage which comes after RRMS and where symptoms, including new ones must have worsened for approximately six months. Common symptoms around the time of diagnosis are problems with eyesight, slowed thinking (cognitive symptoms), unusual feelings in the skin (such as pins and needles or numbness) and fatigue.