Tolebrutinib for the treatment of primary progressive multiple sclerosis

Tolebrutinib is currently in clinical development for the treatment of primary progressive multiple sclerosis (MS). MS is a condition where the body’s immune system mistakenly attacks the nerves in the central nervous system (CNS) which consists of the brain and spinal cord. This damage prevents messages travelling from the CNS to other parts of the body. It causes a range of potential symptoms from pins and needles to difficulties with balance and walking. It can lead to increased mortality and is one of the most common causes of disability in younger adults. Progressive MS can occur in primary or secondary forms; primary progressive MS is a gradual worsening of symptoms from the initial primary symptoms. Current disease-modifying treatments are effective mainly in relapsing forms of MS; there is an unmet need for disease-modifying treatments for primary progressive MS.