Fampridine is a drug that has been shown to improve walking speed for some adults with multiple sclerosis.
It has been approved for use by NHS Wales and NHS Scotland for the improvement of walking in adults with MS who have an EDSS between 4 and 7. It is not currently available on the NHS in England or Northern Ireland.
In 2018, the patent on fampridine expired, and a cheaper version of the drug, called dalfampridine, was developed and licensed in the US.
Fampridine is taken orally as tablets. Most people are prescribed one tablet in the morning and one at night. Fampridine is formulated as a prolonged-release tablet which means that the drug is released slowly to give a more steady supply of fampridine in the body.
Urinary tract (bladder) infections are very common. Other common side effects include dizziness, headache, back pain, difficulty sleeping, feeling sick and stomach upsets. Dalfampridine may worsen trigeminal neuralgia.
Fampridine is only available on prescription under the supervision of a doctor with knowledge of MS. The doctor usually provides an initial prescription for two to four weeks and then the treatment is assessed to see if it is working, usually by timing how long it takes to walk a short distance (eg. 25 feet).
Up to a third of people find that fampridine improves their mobility, so only this group would be prescribed fampridine in the longer term. The initial two to four week trial is currently funded by the manufacturer.
In England, fampridine is currently not recommended for use within the NHS. The 2022 NICE Clinical Guideline acknowledged that fampridine is clinically effective for some people, but it is not considered to be cost-effective.
In Wales, fampridine was recommended for use within the NHS in December 2019.
In Scotland, fampridine was recommended for use within the NHS in April 2020.
Fampridine is a formulation of 4-aminopyridine, a potassium channel blocker. It works by stopping potassium leaving nerve cells which have been damaged by MS. This lets signals pass down the nerve more normally. Consequently, some people are able to walk better.
For reasons that are not understood, some people respond well to fampridine and experience improved mobility, but others do not.
There have been a number of clinical trials of fampridine. For example, a phase III study involving 301 people with relapsing or progressive MS who were treated for 14 weeks, showed a greater proportion of people taking fampridine had a consistent improvement in walking speed compared to people taking placebo (35% v 8%). This improvement was maintained for the duration of the study.
A review of a wide range of clinical trials by NICE, completed as part of the development of the 2014 MS Clinical Guideline, concluded that fampridine had a positive effect on walking speed compared with placebo. However, there was little good evidence for an appreciable effect on EDSS, a commonly used measure of disability.
In 2019, the ENHANCE trial of fampridine reported a clinically meaningful improvement in walking ability (not just speed) in patients who had taken fampridine, compared to placebo. This study included 636 adults with MS who had an EDSS between 4 and 7.