Chemotherapy refers to cell killing (cytotoxic) drugs. Although the word is better known as a description of treatments for cancer, several chemotherapy drugs have been used in multiple sclerosis as disease modifying drugs. Chemotherapy is also used in stem cell therapies for MS.
In MS the immune system attacks the myelin sheath around the nerves of the central nervous system. Chemotherapy drugs are used to kill white blood cells, which are part of this attack. This may slow down or stop disease activity in MS.
Lemtrada (alemtuzumab), which is used to treat relapsing remitting MS, is a chemotherapy drug. Other drugs that have been used to treat MS include azathioprine, cyclophosphamide, methotrexate and mitoxantrone. These are not usually used in the UK.