Motor neurone disease breakthrough: ‘milestone’ drug shows signs of slowing progressive muscle weakness

In a landmark global trial, patients reported better mobility and lung function a year after taking the drug tofersen

A “promising” new drug has been shown to slow down progression of motor neurone disease (MND) and could be a turning point for patient care, scientists claim.

Some patients with a faulty SOD1 gene, who took part in the global phase III trial, reported better mobility and lung function a year after taking the drug tofersen. It is an investigational drug, which means researchers have been examining its safety and efficacy closely during the clinical trials.

Scientists involved in the clinical trials said the findings, published in the New England Journal of Medicine, are “remarkable” for a disease characterised by “relentless decline”.

A patient who took part in the trial in 2016 said he “could actually walk in the house without sticks” a year after taking the drug.

MND, also known as amyotrophic lateral sclerosis (ALS), is a condition that affects the brain and nerves. The progressive disease affects a patient’s ability to walk, talk, use their arms and hands, eat and breathe.

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Around 5,000 people in the UK have MND, with 2% developing the condition due to a faulty SOD1 gene.

How was the trial carried out?

The phase III trial, funded by biotechnology company Biogen, involved 108 patients from 32 sites in 10 countries.

All patients had the defective SOD1 gene, where a “misfolded” version of the protein is created, giving rise to the condition.

In the trial, two-thirds (72) of the participants were randomly assigned to receive eight doses of tofersen over a 24-week period, while the remaining 36 people received eight doses of a placebo.

All participants were assessed at 28 weeks to measure motor function across four areas: swallowing and speaking, breathing, fine motor skills, and gross motor skills. They also gave samples of spinal fluid so the researchers could measure levels of proteins associated with MND.

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What were the results?

Results showed that the drug did not improve motor control and muscle strength after six months, but patients reported better mobility and lung function after 12 months. Improvements were also seen in the MND biomarkers in patients’ cerebrospinal fluid at six months.

However, some side effects from the tofersen drug did arise including temporary mild headaches, and some discomfort from having a lumbar puncture – a procedure where a needle is inserted in the lower part of the spinal cord to administer a drug.

Les Wood, 68, from Thorne inSouth Yorkshire, was diagnosed with MND 10 years ago and first took part in the Phase 3 trial in 2016.

He said: “After 12 months of taking the drug I could actually walk in the house without sticks, I was able to come off some of my painkillers and I felt a lot better in myself. MND is a progressive disease so although my symptoms have continued to worsen, I would not be without the drug and the difference I know it has made to my quality of life.

“It not only gives us hope, it gives you hope for the future for lots of people, my own family as well, because motor neurone disease is familial in my case, I think well, maybe my own family will benefit from this in time to come.”

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What have scientists said about the findings?

Dame Pamela Shaw, professor of neurology and director of Sheffield Institute for Translational Neuroscience (SITraN) at the University of Sheffield, said this is “an important treatment milestone.”

She said: “I have conducted more than 25 MND clinical trials and the tofersen trial is the first trial in which patients have reported an improvement in their motor function.

“Never before have I heard patients say, ‘I am doing things today that I couldn’t do a few months ago – walking in the house without my sticks, walking up the garden steps, writing Christmas cards’.”

While MND patients with SOD1 mutations are relatively rare, the researchers said their work will “change the future of MND trials for patients”.

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Chris McDermott, professor of translational neurology at SITraN and co-author of the study, said: “Although tofersen is a treatment for only 2% of those living with MND, we have learned much in doing this clinical trial that will help us do smarter and faster clinical trials in the future.”

Merit Cudkowicz, director of the Sean M Healey & AMG Center for ALS at Massachusetts General Hospital in the US, and one of the co-investigators in the trial, described the findings as a “promising development”. He said the drug has “the potential to improve the quality of life” of people living with MND.

Meanwhile, Dr Brian Dickie, director of research at the MND Association, said the results show “mounting confidence that tofersen is having both a biological and a beneficial clinical effect in people living with SOD1 MND.”

He added: “They also provide important ‘proof of concept’ that similar gene therapy-based approaches may be helpful for other forms of the disease.

“We are closely following the recent news that tofersen will be reviewed by the US drug regulatory authorities and are in contact with Biogen to discuss what the regulatory approval process will look like elsewhere.”