Image caption MS can cause problems with walking and balance

Existing drugs for motor neurone disease, asthma and heart disease are being tested as possible treatments for advanced multiple sclerosis (MS).

About 500 people with late-stage MS are to enrol in clinical trials in England and Scotland to see if three common drugs can slow disease progression.

Research suggests the medicines may protect the brain from further damage.

There is currently no treatment for secondary progressive MS, a form of the disease marked by increased disability.

About 100,000 people are living with MS in the UK. Symptoms include problems with walking, balance, speech, vision and extreme fatigue.

Multiple Sclerosis Multiple sclerosis (MS) is a disease affecting nerves in the brain and spinal cord, causing problems with muscle movement, balance and vision

Around 8 out of 10 people with MS have the relapsing remitting type of MS, where symptoms are mild or disappear altogether at times - for days, weeks or sometimes months

Remission is followed by a sudden outbreak of symptoms, known as a relapse, which can last for weeks or months

After about 10 years, around half of people with relapsing remitting MS go on to develop secondary progressive MS

In secondary progressive MS, symptoms gradually worsen and there are fewer or no periods of remission

The least common form of MS is primary progressive MS where symptoms gradually get worse over time and there are no periods of remission

Source: NHS Choices

Treatments are available to help with relapses and symptoms of MS during the early stages of the disease. However, despite clinical trials, scientists have so far failed to find a medicine that works in the late stages of MS.

Now, after reviewing published data on drug treatments that might help protect nerves in the brain, UK researchers are focusing on three drugs that are licensed for other conditions.

The three drugs are amiloride - currently licensed to treat heart disease and high blood pressure; ibudilast - an asthma drug used in Japan - ; and riluzole, the sole treatment for motor neurone disease.

All have shown some promise as a treatment for MS in small-scale trials.

Participants in the larger trials in London, Edinburgh and 13 other sites in the UK will be monitored for signs of progression of MS with scans and other clinical tests.

Dr Jeremy Chataway is consultant neurologist at University College London, which will carry out the London study.

He said the drugs selected are the most promising candidates for testing to see if they have an effect in slowing the progression of MS.

He told BBC News: "There is no treatment for secondary progressive MS. This is a really appropriate and scientific way of getting a pipeline of drugs so that we can one day get a treatment that works."

Case study Anthony Stone, aged 50, from London is living with MS. "Once you're secondary progressive there aren't any disease-modifying treatments, so anything that addresses that is something to welcome - it's very encouraging," he told BBC News. " In the past - in my case - it was about the management of decline and I think that the possibility of drug treatments for secondary progressive MS - halting the progress - is something to be welcomed. "For lots of people with secondary progressive [MS] there aren't the treatments out there - people may feel they're being ignored."

Patients entering the trial will be given brain scans at the beginning and end of the two-year study to see whether the drugs have an effect on slowing down brain tissue loss.

"We hope at least one of these drugs will show that it significantly reduces the rate of brain loss - we're hoping for 30% or 40% reduction," he added.

Step forward

The MS-SMART trial, as it is known, will test the three drugs against a dummy treatment (placebo) in 440 people with secondary progressive MS.

Dr Susan Kohlhaas, head of biomedical research at the MS society, said: "People with MS have lived for years in hope that one day we will find an effective treatment for secondary progressive MS; this trial, although still early stage, takes us one step closer to make that hope a reality."

Commenting on the approach to the research, Prof Jayne Lawrence, chief science adviser for the Royal Pharmaceutical Society, said finding new medical uses for existing drugs offered hope to patients.

Aspirin, for example, had found many therapeutic uses - as a painkiller and in preventing strokes and heart disease, she said.

"It's becoming much more popular now because it costs so much to develop a [new] drug. At least you've got an idea of what the toxicity is so you can reduce the time it takes to develop the drug."

The research is funded by the Medical Research Council and the Multiple Sclerosis Society.

More information on the study can be found at MS-SMART Trial - Home