Licensed disease modifying drugs
These drugs are injected. Clinical trials have shown the drugs reduce the number of relapses by around a third over two years.
Tysabri is given as a monthly infusion into a vein for people with more 'aggressive' MS, or people who have had an increase in the number or severity of relapses while taking one of the other disease modifying drugs.
Gilenya is an oral tablet. It was licensed in the UK for the treatment of rapidly evolving relapsing remitting MS in April 2011.