Scientists have found that a drug commonly used to lower cholesterol may help treat the chronic stage of multiple sclerosis (MS), for which there is currently no treatment.

MS is a chronic disease of the central nervous system, which causes a gradual degeneration of the nerves. This results in a progressive deterioration in various functions controlled by the nervous system, such as vision, speech and movement.

It is Ireland's most common disabling neurological condition, affecting some 8,000 people here.

In its early stages, people with MS are affected by neurological symptoms which can come and go. However, within 10 to 15 years of disease onset, over half of patients develop what is known as secondary progressive MS. This sees symptoms worsen and leads to an increase in disability.

No drugs have so far shown to be effective in halting or reversing this stage.

However, an earlier clinical trial involving the statin, simvastatin, appeared to have some effect on people with early-stage MS. Statins are a class of drug which are often prescribed to people with high LDL cholesterol levels. LDL cholesterol is known as ‘bad' cholesterol and it can increase a person's risk of developing heart disease or suffering a heart attack or stroke. These drugs are used by millions of people worldwide.

Scientists from the UK decided to assess whether simvastatin had any effect on the later stages of MS.
Some 140 adults with secondary progressive MS were randomly assigned to receive the statin or a placebo every day over a two-year period.

The phase two study found that the drug slowed down brain atrophy (shrinkage) by 43% over the two years compared to the placebo. It was also well tolerated by the participants.

"In the progressive stage of MS the brain shrinks by about 0.6% a year. Our main measure of success was to reduce the rate of brain atrophy," noted the study's leader, Dr Jeremy Chataway, of University College London Hospitals.

The study also noted small but significant improvements in disability among the patients taking the statin.

"Our promising results warrant further investigation in larger phase three disability-driven trials. After nearly two decades of research, it is immensely gratifying to see this work progress into the clinic to deliver benefits to patients," the scientists said.

Details of these findings are published in the medical journal, The Lancet.